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Tuning FAQ by NightmareHunter

Version: 1.42 | Updated: 02/21/07

Gran Turismo 4
Tuning Guide
Version 1.41
By NightmareHunter

After a long wait GT has returned to the PS2 with arguably the best instalment 
of the series. With over 700 cars and 50 tracks, it has an unbelievable amount 
of content to offer, but it really surprised me how much a particular aspect of
this game gets overlooked. Tuning. Now I will admit that when I first started 
playing GT I didn't use tuning myself, I was too afraid that I'd do something 
terrible to my cars that I wouldn't be able to fix. It took me quite a while to
build up the confidence to have a go. But I was immensely glad that I did. 
Tuning is not only a great way to get even more performance out of your already
insane cars, but it will also make winning races a whole lot easier. So this is
what this FAQ is for. To give all those me's out there some insight into the 
world of tuning in Gran Turismo. 
Tuning in GT4 is very similar to the tuning in GT3, so if you knew what to do 
in GT3, there probably won't be that much in this FAQ that you didn't already 
know. In that case hopefully this FAQ will serve as a refresher to tuning, as 
well as providing an insight into GT4.
And remember, there's no such thing as getting too much performance, a car that
can only do 380kmph just isn't fast enough.


Recently I've received a lot of information about different aspects of tuning 
from quite a few different people, some of it quite contradictory to each
other. Rather than pull previous contributions, I've decided to keep discussion
open and include them all as well as add my own thoughts in the hope that it 
will provide several different points of view and give readers all the 
information available.
However, if you find some of the contradicting information too confusing, let
me know and I'll re-evaluate it and cut out the parts I feel are the least 

Also, please note that it has been a while since I've played this game, and
as such I'm no longer responding to emails regarding it. Feedback is always
lovely, but I just don't have the time to do so anymore.


Version 0.90

14/03/05, 17/03/05, 18/03/05, 21/03/05
Completed Introduction, Contents, Parts, Tuning; Brakes, Suspension, 
Transmission, Driving Aids, Downforce, LSD, Weight Distribution, Tyres, N2O.
Completed E-mail Policy, Thanks And Copyright Information.

Version 0.95

23/03/05, 24/03/05
Added VCD Tuning Info, Fixed a few mistakes, added reader contributions: Engine 
Balance and Turbo Alternate Explanations. Added Tuning Setting, Damper.

Version 1.00

Added AYC Tuning Info, Transmission individual settings.

Version 1.10

Added reader contributions for Exhaust, Flywheels, and Downforce.
Added Original Turbine Kit.

Version 1.20

Added Original Suspension, Note on Prices.

Version 1.25

Added reader contributions: Alternate Explanation for AYC, fixed a few

Version 1.30

Added reader contributions: Extra Info for Spring Rates and Stabilisers.
Added FAQ Section.

Version 1.40

Added reader contributions: Extra Info for Exhausts, Turbo-lag, Flywheels, 
Downforce and Grip (see Section 5.4 - Suspension), Toe, and LSD.
Added Part Info for N2O, Variable LSD and Body Rigidity Refresher. Updated 
Camber Angle, Stabiliser, LSD Acceleration and LSD Deceleration, and

Version 1.41

Removed reader contributions at the request of the contributor.


[Important Note: This FAQ has been designed for convenience of the reader. If 
you're looking for a particular section simply highlight the relevant entry in 
the contents list, eg. [SECTION 4.1 - PARTS - EXHAUST], press ctrl+c to copy 
the text, then press ctrl+f to open the find window, press ctrl+v to paste and 
then hit enter to be taken to the section you want.]



In order to alter the settings in your cars, you must first purchase and 
install the parts capable of making the changes. This section contains all of 
the purchasable parts in the game, how much they cost, and what they do, and is
ordered in the same way the parts appear in the game.

A Brief Note on Prices

The prices listed here are far from definitive, different cars can mean 
different costs. The listed cost is fairly accurate though, while you may have 
to pay a bit more or less than the listed price, it is unlikely that you will 
have to pay more than 1,000cr.


Part: Sports Exhaust/Air Filter
Cost: 1,600cr.
Comments: The BHP increase that this yields is almost laughable. I always buy 
the Racing Exhaust/Air Filter; it's not much more expensive and gives you more 

Part: Semi-Racing Exhaust/Air Filter
Cost: 2,900cr.
Comments: Once again, go with the Racing Exhaust/Air Filter.

Part: Racing Exhaust/Air Filter
Cost: 4,800cr.
Comments: This exhaust provides you with the biggest BHP increase and is still 
reasonably cheap. I always buy it.

Thanks to Zimian for this information about Exhaust Systems

The reality is that backpressure is the enemy.  You want to keep it as low as
possible.  What you do want is to keep velocity up.  However, doing the
things that keep velocity high involves slightly more backpressure under
some conditions.  You want to keep the gasses moving as quickly as possible
to make both good torque and top end power.  The perfect exhaust system
would keep the gasses moving as fast as they did coming out of the cylinder
and have zero backpressure.  However, this is impossible to achieve in the
real world.  The best one can hope for on a turbo car is to keep velocity as
high as possible before the turbo by making all exhaust passages and piping
before and inside the turbo the smallest possible without creating excessive
backpressure and making the exhaust after the turbo the least restrictive

Regarding turbo lag, that is also a myth.  It is true that if you install a
turbo with certain characteristics and you try to drive the car as though
the turbo had different characteristics, the turbo will appear to be
performing poorly.  For example, if you install a turbo that starts to spool
up at 4500 rpm and provides maximum power at 7000 rpm and then you step on
the gas with a gear engaged at 2000 rpm, for certain you will experience
"lag."  If you want the turbo to respond at low rpm, you install a turbo
with appropriate characteristics to meet those needs, but you will be giving
up high-end power.  I see this all the time where someone puts a turbo
designed for high rpm on their street car because ABC Tuning said they use
it on their racing car, and then they wonder why they have no power at 2000
rpm.  This happens in GT as well.  If you install a high-rpm turbo, like
stage 3 or 4, and then don't increase the engine speed accordingly by
holding brake and throttle at the same time, you won't go anywhere very
quickly. Also, if the turbo did in fact have a longer spool-down time, that
would mean it would keep its speed up and would have LESS lag when you get
back on the gas.

I'll give you a real-world example.  My wife's car is an Audi A4 with a
stock K03 turbo, a tiny turbo if there ever was one.  The Audi 1.8T engine
is designed for maximum low-end torque including choice of pistons,
compression ratio, combustion chamber design, valve design, computer tuning
(fuel and boost control), turbo design, etc.  It hits peak torque around
1800 rpm and keeps it there until about 4500 rpm.  Past there, the torque
drops noticeably although power does continue to increase to the 6500 rpm
redline.  The pistons are high-compression which means more power when not
under boost at the expense of losing it at the high end.  Everything about
the engine is designed for the average everyday driver and works well in
that capacity.  One of my former cars was an A4, and I replaced the stock
turbo with a larger Garrett unit.  It didn't spool up until about 3200 rpm,
hitting peak torque at about 4300 and continuing to push to redline.
Because I didn't replace the pistons with lower-compression ones I couldn't
tune it more effectively for high-end power so it was still quite driveable.
When I sold it, the person who bought it had problems driving it, especially
launching from a stop, due to so-called "lag."  After a bit of instruction
and practise, he was able to drive it properly and did not experience any
problems.  Of course, the A4's gearbox and clutch aren't designed for an
engine with over double the power of the stock unit, which creates
additional complications.  It's just not designed as a performance car for
many reasons.

If Polyphony would build in a clutch control feature, that would really help
when driving a car with a large turbo because one could rev the engine and
control the clutch on launch or at low speed.  Unfortunately, the realism of
engaging the clutch when bouncing off the rev limiter is not very good.  All
versions of GT have had this problem.  The clutch is engaged and the rpm
drops to what it would be at the car's current speed with very little
slippage.  It's as if the tires and clutch suddenly have tons of grip,
drawing the rpm down.  Oh well.


Part: Racing Brakes Kit
Cost: 4,700cr.
Comments: Durable racing brakes designed to increase braking capacity. Grab a 
set of these when you can, they'll shorten your braking distance, which is 
always a good thing.

Part: Brake Balance Controller
Cost: 10,600cr.
Comments: Necessary to alter the brake balance on any car, so you'll need one 
to tune the brakes.


Part: Stage 1 NA Tuning
Cost: 4,900cr.
Comments: The smallest BHP increase for Naturally Aspirated cars, as well as a 
few that pack turbos. If you've got the cash buying a higher level, and if not,
save until you do, this really isn't worth it.

Part: Stage 2 NA Tuning
Cost: 12,500cr.
Comments: Good for the driver on a budget or in the early days, its not 
prohibitively expensive and still provides a good increase in BHP.

Part: Stage 3 NA Tuning
Cost: 75,000cr.
Comments: If you've got the cash, this is great for putting high power into 
your cars, just make sure you can control your extra 200-300 horses.

Part: Port Polish
Cost: 5,500cr.
Comments: A small BHP increase for a small price. If you've got the cash to 
spare, use it.

Part: Engine Balancing
Cost: 12,000cr.
Comments: I usually don't waste my money on this. The increase usually equates 
to less than 1 BHP per 1,000 credits.

Alternate Explanation - By Ryu Komiyama
Looking back at the FAQ, my eyes caught the Engine Balance
part, where you said that it was completely useless. I will disagree
with this, since getting this upgrade will reduce the friction of the
pistons and balance the weight of the pistons out, that will result in
having a higher RPM, gives you the opportunity to change rev-limiter
settings. For some cars, it is a lot more than 1 HP, FYI.

Part: Displacement
Cost: 8,500cr.
Comments: Not available to many cars, the BHP increase can justify the cost.

Part: Racing Chip
Cost: 1,500cr.
Comments: About 8 times cheaper than the Engine Balancing, the Racing Chip will
almost always give you more power. It still isn't much extra BHP, but for the 
price, it's well worth it.

Part: N2O (Nitrous)
Cost: 5,000cr.
Comments: I don't use N2O at all (just doesn't feel right in GT). But if you 
need a speed boost to help you win a race, then you're in the right place.


Part: Close Gearing
Cost: 5,700cr.
Comments: For less than double the price you can get a Fully Customisable 
Transmission, and if you can't afford that, a Super Close Gearing is the same 
price as this, so you should never buy Close Gearing.

Part: Super Close Gearing 
Cost: 5,700cr.
Comments: As above, you should buy a Fully Customisable Transmission, or wait 
until you've got the credits to get one, but for the same price as a Close 
Gearing, the Super Close Gearing will give you more options.

Part: Fully Customisable Transmission
Cost: 10,400cr.
Comments: This is what you really want. It'll allow you free reign over your 
gear ratios, which is very important when it comes to tuning your car. A must 
for anyone looking for maximum performance.

Part: Large Single Clutch
Cost: 1,700cr.
Comments: Clutches, especially when used in appropriate situations with 
lightweight flywheels, can greatly increase the acceleration of your car, 
however the Single, for 1,700cr. isn't really worth it when you can have the 
much better Twin or Triple for 2,700cr. or 4,700cr. respectively.

Part: Twin Clutch
Cost: 2,700cr.
Comments: Better than the Single, but not as effective as the Triple, so you 
should only buy this if you can't afford a Triple.

Part: Triple Clutch
Cost: 4,700cr.
Comments: The Triple Clutch is the most effective of the three available at 
increase a car's acceleration, especially when used with the Racing Flywheel. 
Highly Recommended.

Part: Sports Flywheel
Cost: 450cr.
Comments: The cheapest part you can buy, it may seem like a bargain, but the 
Semi-Racing and Racing are only 600cr. and 1,050cr. respectively, and provide 
much greater benefits in the right situations.

Part: Semi-Racing Flywheel
Cost: 600cr.
Comments: The Racing Flywheel is only 450cr. more than the Semi-Racing, if you 
can't afford that then there's something wrong.

Part: Racing Flywheel
Cost: 1,050cr.
Comments: A lightweight flywheel designed specifically for racing. A very 
useful part to have.

Thanks to Zimian for this information about Flywheels

  If you have an engine with any reasonable amount of power and keep it at
high rpm where it belongs anyway, you won't notice a problem with using a 
lightweight flywheel.  I live in a mountainous area and drive in the
mountains frequently.  Several of my past cars as well as my current car
have relatively light flywheels and I have noticed no performance problems
or "loss in speed," but then I drive the cars appropriately for their 
configurations and the conditions (or as closely as
I can, anyway!).

Part: 1 Way LSD (Limited Slip Differential)
Cost: 4,500cr.
Comments: The 1 Way LSD has its uses, but a higher level will allow much 
greater and more effective customisation. You should at least buy a 2 Way LSD, 
as it's the same price as the 1 and 1.5 Ways.

Part: 1.5 Way LSD
Cost: 4,500cr.
Comments: More useful than the 1 Way, but you should get a Variable LSD, or at 
least a 2 Way LSD, it's the same price as the 1.5 Way.

Part: Variable LSD
Cost: 6,600cr.
Comments: This can be used to great effect to alter the handling properties of 
a car, and as such is very useful to have. Get one if you can, the settings it 
allows you to alter can be the difference between winning and losing.

Cost: 6,600cr.
Comments: I haven't tested this yet. It looks, though, like an LSD to put on a 
4WD and this would allow torque to both the front and rear wheels to be 

Part: Carbon Driveshaft
Cost: 3,000cr.
Comments: You can only fit this to an FR (Front engine, rear wheel drive) car, 
but it's a good way to improve acceleration for a small cost.


Part: Stage 1 Turbine Kit
Cost: 4,800cr.
Comments: High level Turbine Kits can get pretty expensive pretty quick, if you
don't have the cash for that kind of investment, a Stage 1 or 2 Kit can be 
quite helpful, and provide a reasonable BHP increase, especially in the early 
days, when you're least likely to have the cash for an 80,000cr. Turbine Kit.

Part: Stage 2 Turbine Kit
Cost: 13,500cr.
Comments: Beyond a Stage 2 the price really starts to jump, and the Stage 2 can
prove very useful, especially in the early days, so don't be afraid to spend.

Part: Stage 3 Turbine Kit
Cost: 42,500cr.
Comments: This is getting to the top of the Turbine range, both in price and 
BHP increase. A considerable price but a great boost, this is a Turbine Kit 
that should see regular use in your cars.

Part: Stage 4 Turbine Kit
Cost: 80,000cr.
Comments: Extreme power, and with a price tag to match. I wouldn't actually 
recommend you use it that much, for a couple of reasons. Firstly, 80,000cr. for
a single part is bloody expensive, and secondly, a lot of cars don't have the 
turning and braking response, or stability necessary to properly control a 
turbo of this size (what I meant to say is not that the car can't handle it,
but that often you can't control the car. I realise this didn't come out very 
well.) Ryu's explanation below explains this much better.

Alternate Explanation - By Ryu Komiyama 
If any of them can equip a Stage 4 turbo on it, then it CAN
handle it, however it depends on WHERE you use it. Stage 4 turbos are
great for drag racing and taking LONG or MANY straights, but it's
horrible on curvy courses such as Deep Forest. Why you may ask? It's
not ONLY the massive horsepower that the car can't handle, but since
you have a big-ass turbo in your car, you have a big-ass turbo-lag to
come with it. (I hope you know what a turbo-lag is) So it's hard to
accelerate out of a corner really fast with something so big. And the
superchargers, unlike the turbochargers, have absolutely no lag at
all. It has faster acceleration than turbos, but like you said they're
somewhat weaker than turbos.

A Note on 'turbo-lag'
For those of you who don't know, turbo-lag is the amount of time it takes for 
the turbine to spin up, ie. the time it takes to produce boost. The reason this
is greater in large turbos is because the turbine is bigger, therefore the 
exhaust gasses, which are used to power the turbine, must be moving much 
quicker to spool the turbine and thus produce boost. This also means large 
turbines can be less useful at low RPM.

Thanks to Zimian for this information about Turbo-lag
(In response to Ryu Komiyama's contribution and my own explanation above)

Comment: Here we go again with turbo lag.  I notice that no one mentioned
changing gearing or driving the car properly to deal with the so-called lag.
It is not hard to have the car in the correct gear and at the correct rpm
when accelerating out of a corner.  This is a skill common to NA and forced
induction cars alike.  I notice also that no one mentioned keeping on the
throttle while braking ("left-foot braking"), another technique common to
both NA and forced induction cars but essential on turbo cars with large
turbos while going through tight twisty corners.  One thing Polyphony needs
to do is
to offer an anti-lag system similar to what is used on WRC cars.  With those
systems, whenever the throttle is not on the ignition timing is retarded to
the point where the air/fuel charge in the cylinder is ignited when the
exhaust valves are open, which causes the power from the resulting explosion
to push exhaust gas out of the exhaust valve towards the turbo, keeping it
running as fast as possible.  This is the "popping" sound you hear when a
WRC car decelerates.

Another note is that power comes more from the volume of gas flowing from a
small container, the cylinder, to a larger container, the exhaust system and
outside world.  The velocity from the gas being forced out of the cylinder
by the rising piston contributes less to the spinning of the turbo.  A
larger turbo requires a larger volume of gas to push the turbine.  Turbo
power is about 60-65% from exhaust gas expansion and 35-40% from actual
velocity.  Heat is a factor too, so if the exhaust cools down too much
between the cylinder and the turbine then the molecules in the gas are
packed closer together, taking up less space and requiring more exhaust gas
to push the turbine than if the turbine were kept hotter.  This is why
sometimes you see large turbos with heat wraps or other heat-saving devices

The bottom line is that BOTH turbos and superchargers do not have lag as
long as you design the turbo properly (or choose the right turbo), have
correct gearing, and use correct driving techniques.

In GT1 the lag effect of a large turbo on a small engine was way overdone,
but Polyphony did a better job starting in GT2.

Part: Original Turbine Kit
Cost: 72,000cr.
Comments: This can only be purchased at the general tuning shop, not 
manufacturer's shops, and is the most effective turbo to get for most cars. 
It'll give you the biggest BHP increase and also allow your greater boost at
low RPM. If you've got the credits, buy this baby, you won't regret it.

Thanks to all those people who e-mailed about this, it was a great help.

Part: Sports Intercooler
Cost: 1,800cr.
Comments: A Racing Intercooler is only 1,200cr. more, and provides a better BHP
increase, so don't bother with this.

Part: Large Racing Intercooler
Cost: 3,000cr.
Comments: A good BHP increase for a good price.

Part: Supercharger
Cost: 1,500cr.
Comments: You can't put this on many cars, but on those you can don't hesitate,
it can provide a BHP increase of a few hundred in some cars. If there are other
forms of BHP increasing parts in the car (namely NA Tuning and Turbine Kits), 
then a Supercharger will probably take your BHP down, as the other parts will 
be removed (you can't have a Supercharger in your cars with other NA Tuning or 
Turbine Kits), so be aware of what you're putting in your car before you spend 
the credits.


Part: Sports Suspension Kit
Cost: 3,200cr.
Comments: The options this Kit gives you are limited, and you'll need the 
options of a Fully Customisable Suspension Kit later on in the game, so save 
your credits.

Part: Semi-Racing Suspension Kit
Cost: 7,400
Comments: This will provide you with more options than Sports Suspension, but 
you'll want to be saving your credits for Fully Customisable Suspension, as it 
provides you with many more options.

Part: Fully Customisable Suspension
Cost: 17,000cr.
Comments: Top of the line suspension, this'll allow you maximum control over 
the stability and handling of your cars, and its well worth the cost. Highly 

Thanks to all those who e-mailed me about the Original Suspension
Part: Original Suspension
Cost: 16,200cr.
Comments: This is the ultimate racing suspension. It allows all the same 
settings as Fully Customisable Suspension except the ranges are altered to
allow the suspension to be made stiffer, allowing for maximum racing 


Part: Standard/Economy Tyres
Cost: -
Comments: Standard Tyres can be put on very few cars, and really aren't worth 
the effort. You can pick up Sports Tyres reasonably cheap and they'll perform a
lot better than Standard Tyres. The Economy Tyres are designed for long life 
with less grip, but you'd be better off buying Sports/Hard Tyres, or Racing 

Part: Standard/Comfort Tyres
Cost: -
Comments: Once again, don't bother with these. They're designed for stability 
at the cost of grip, but you'd be much better off picking up a set of 
Sports/Medium Tyres, or Racing Tyres.

Part: Standard/Road Tyres 
Cost: -
Comments: Standard/Road tyres are designed for greater grip at the cost of 
endurance. You're better off getting Sorts/Soft Tyres, or Racing Tyres.

Part: Sports/Hard Tyres 
Cost: 5,100cr.
Comments: Sports Tyres are the tyres you're most likely to be using throughout 
the early stages of the game. They provide a reasonable degree of grip or 
endurance, depending on which types you buy. Sports/Hard Tyres are the most 
durable of the three varieties, providing a good lifespan at the cost of grip. 

Part: Sports/Medium Tyres 
Cost: 6,000cr.
Comments: Sports/Medium Tyres provide a greater grip than Sports/Hard Tyres, 
however they have a shorter life, and so equipping these tyres will mean you 
will have to pit more frequently.

Part: Sports/Soft Tyres 
Cost: 6,800cr.
Comments: The softest compound Sports Tyre. These provide the most grip but 
also have the shortest lifespan. Generally these should not be put on your cars
for races of more than a couple of laps, or for qualifying.

Part: Racing/Super Hard Tyres 
Cost: 8,400cr.
Comments: Racing Tyres are the highest quality tyres in GT4. They have better 
grip and endurance than other tyre types, but as a consequence are more 
expensive. Racing/Super Hard Tyres are the most durable Racing Tyres available;
therefore they also have the least grip.

Part: Racing/Hard Tyres 
Cost: 10,500cr.
Comments: Working on a sliding scale, these tyres have slightly more grip, at 
the cost of some lifespan.

Part: Racing/Medium Tyres 
Cost: 22,500cr.
Comments: The average Racing Tyres. They have a medium amount of grip and 

Part: Racing/Soft Tyres 
Cost: 35,000cr.
Comments: These tyres have a lot of grip, but a reasonably short life. In any 
race that's more than a few laps long, you shouldn't be using these tyres.

Part: Racing/Qualifying Tyres
Cost: 47,500cr.
Comments: These tyres have a lifespan of only a couple of laps, and, as the 
name suggests they should only be used for qualifying. Do not use these tyres 
in a race, ever, in fact, on some of the longer tracks don't even use them for 
qualifying, use Racing/Soft Tyres instead.

Part: Dirt Tyres
Cost: 22,500cr.
Comments: These tyres can only be put on a 4WD, and allow a car to drive off-
Thanks to Astralwolf (Astralwolf@hotmail.com) for pointing out that some FF and
FR cars can actually take dirt tyres.

Part: Snow Tyres
Cost: 22,500cr.
Comments: These tyres can only be put on a 4WD, and allow a car to drive on 
Thanks to Astralwolf (Astralwolf@hotmail.com) for pointing out that some FF and
FR cars can actually take dirt tyres.


Part: VCD (Variable Centre Differential)
Cost: 10,500cr.
Comments: This can only be put on 4WD and allows you to adjust the amount of 
power that goes to the front or rear wheels. Useful for changing the handling 
of a car.

Part: Weight Reduction Stage 1
Cost: 1,200cr.
Comments: This does pretty much what the name says, it reduces the weight of 
the car. This has numerous effects; the acceleration, braking and handling of 
the car are all improved.

Part: Weight Reduction Stage 2
Cost: 5,500cr.
Comments: The second stage of weight reduction further improves the car's 
capabilities, and cannot be bought until after Stage 1. 

Part: Weight Reduction Stage 3
Cost: 22,000cr.
Comments: The final stage of weight reduction, Stage 3 cannot be bought until 
after Stage 2.

Part: Increase Rigidity
Cost: 30,000cr.
Comments: This helps prevent the body of the car from warping out of shape due 
to long term use, as well as increasing the stability of the car.

Part: Body Rigidity Refresher
Cost: 50,000cr.
Comments: This is an interesting upgrade, which doesn't seem overly necessary
at first. However, as the car is driven further the body of the car will warp
(even with increased rigidity) and cause the car to handle very poorly and 
suffer large amounts of oversteer, and, if you let it go on, the car will
become fundamentally undrivable. This upgrade works like tyres, you only have
to buy it once and then it is reapplied to your car between every race, so you
never have to worry about body warp again (Unless of course you intend to
A-spec a 24 hour race, body warp will occur and the rigidity won't be refreshed
until after the race; I recently A-spec'd Le Mans II, and by the eight hour
mark the car becomes very difficult to control if you want to drive at maximum
pace, it continues to deteriorate until about the 11 or 12 hour mark, at which
point you have to drive at a reduced pace just to maintain control of the car.
Even going down the Mulsanne straight is a pain, because its so uneven).


Tuning is divided up into several sections, one for each type of part you can 
tune in the game. These are ordered the same way they appear in the settings 
menu in the game.

NOTE: All tuneable parts and settings are listed here, and you will need the 
highest level parts to be able to access all the settings, if you have medium 
or low level parts you will not have access to all tuning options. Also, some 
settings are only available to certain types of cars, therefore even with the 
highest level parts you will probably still not be able to tune absolutely 
everything on the one car.


While you can't actually tune tyres, I thought it would be a good idea to 
outline briefly how different tyres can be equipped and how they wear, to give 
an idea of what kind of tyres are effective in different situations.
There are two main considerations when equipping tyres; grip and endurance. 
Generally speaking you want a tyre that's going to last as long as possible, 
but which provides you with good grip. You're not going to get really high 
levels of both, and in most situations its best to sacrifice a bit of grip for 
The other thing to consider is putting different compound tyres on the front 
and rear wheels. Generally speaking, tyre temperature increases more quickly on 
the wheels on the axle that drives the car (ie. the axle that is connected to 
the diff.), so, for example, on an FR car you may want to put harder tyres on 
the rear than the front.
Grip, for cornering ability, is more important on the front wheels than the 
rear, and so you may consider putting a softer compound tyre on the front 
wheels, assuming it's not an FF car.
You can only put the same type of tyres on the car, by this I mean that if you
have racing tyres on the front wheels you must have racing tyres on the rear 
wheels, they can be a different compound but they have to be the same type.


N2O (Duration - Power)

N2O is your temporary speed boost. When BHP alone doesn't cut it, use N2O for 
that extra speed. This option allows you to change the density of the N2O in 
the tank, and therefore how it is used. It is measured on a scale of somewhere 
between 1 to 100, 1 being maximum duration, 100 being maximum power.
By setting it for duration, the boost you get will be less, but the N2O will 
last much longer. On the other hand though, set it to power and the boost will 
be much more considerable, but it won't last as long. Setting it in the middle 
will give you an average boost for an average amount of time. 
The trick to setting it correctly is to take into account both the layout of 
the track and the number of laps. On a track with a lot of straights and a lot 
of laps, setting the N2O for duration is the way to go, whereas on a tight 
technical track with a lot of turns and only a few laps, setting it for a more 
powerful boost will be most beneficial.
The other thing to take into account is what you want to use the N2O for. If 
you want something to have as a backup in case you end up side by side with the
car in second as you pull onto the final straight, setting it for maximum power
is the way to go, but if you want to use it gradually over the race to help 
increase or gain the lead, then a longer duration is better.
You only get one tank of N2O per race, pitting won't bring it back and once 
it's gone it's gone, so use it sparingly.


Brake Balance

The brake balance controls how quickly the brakes kick in when they are 
applied, and therefore controls the braking capacity of the car. How this is 
measured in the game is on a sliding scale of 0 to 30, which the brake balance 
controller allows you to alter. Increasing the number evenly for both front and
rear wheels will increase the braking capacity of the car; decreasing it will 
decrease braking capacity. The default setting for most cars is 3, but you 
should increase this for shorter stopping distances. Generally speaking I 
usually set the balance evenly at somewhere between 8 and 12, depending on the 
car and the course.
You can also alter the handling of a car using the brake balance, by setting 
either the front or rear brakes higher than the other. To create understeer in 
the car, increase the front and decrease or leave the rear. This is usually 
most helpful in cars that have a reasonable tendency to oversteer, and this can
help to correct that. Doing the opposite; increasing the rear and decreasing or
leaving the front, will create oversteer. While useful in cars that have a 
tendency to understeer, you have to be careful about just how high you set the 
rear brakes because the oversteer can become quite powerful and cause you to 
spin out.


Spring Rate

The Spring Rate relates to the stiffness and coil speed of the springs in your 
suspension, which can be altered to change the handling and stability of the 
car. It is measured on a scale of 10.0 to 20.0, 10.0 being the lowest, or 
softest setting, 20.0 being the highest, or hardest setting. 
By setting the spring rate low (less than 13), the springs will be able to 
compress and decompress quickly, giving you better stability over uneven 
Doing the opposite, and increasing the spring rate (anything over 15) will make
the suspension much more rigid, as the springs will compress and decompress 
slowly, and therefore will allow you greater cornering ability, as the 
suspension will push the tyres onto the road and allow greater traction. The 
downside to this is that over uneven ground the car will tend to bounce and 
skip across the road, and in extreme cases you can even get all four wheels off
the ground. This can be countered slightly by changing the settings of the 
dampers, see below. 
Therefore, one of the most important factors in effectively setting the spring 
rate is the track you will be racing on.  If the track has constant or numerous
changes in elevation, especially during bends and corners, then a lower spring 
rate is useful, as this will give the car stability. On a relatively flat track
on good road surface, a high spring rate will give you maximum cornering 
ability, but you will still need to be wary of some of the grip strips (red and 
white strips lining the sides of some corners and straights), because some of 
them are raised more than others, so if you've got hard suspension don't ride 
up onto all of them, or you'll find a couple of your wheels leaving the ground.
There is also a consideration about ride height that needs to be made when 
setting the spring rate. Every car's suspension has a range through which it 
can move, from the lowest point (compressed) to the highest point (extended), 
which is known as the stroke. If the ride height is set too low, it will breach
the stroke and when the suspension compresses cause either the wheel housing to
come into contact with the wheels, or the under-body to come into contact with 
the road. Needless to say this is not a good thing. Stiffening the spring rate 
can help to counteract this, and allow the lowest ride height possible.

Extra Information on Spring Rates and Stabilisers By Rock Hole

Both generally do change the ride characteristics of the car in much
the same way. While making sure that the car is more stable over bumps
is an issue on the *street*, it is not quite as applicable to the many
tracks of GT-4 as a majority of them are free of the bumps that will
cause you to screw up your ride. Particular care should probably be
taken on the Nurburgring, but I have had no trouble with any of the
other tracks.

Instead, spring/roll bar rates can better be changed in order to
control over/under steer and make your car more stable through mid
turn, and overall make the car adapt better to your driving style.

A simple overview of this is as follows:

Front spring/roll bar rates: A stiffer rate up front will cause the
car to under steer more, or reduce the over steer (good for rear drive
sports cars such as the RX-7) depending on how the car handles before
hand. The opposite effect comes from reducing the stiffness in the

Rear spring/roll bar rates: A stiffer rate in the back, however, will
cause the car to under steer less/over steer more. With the opposite
effect for reducing the stiffness.

Probably the better part to tune would be the anti-roll bars, as this
can cause less side effects than the spring rates. However, stiffening
the ride in both areas using the spring rates results in a much more
responsive car.

The reason this is so, is that with a harder spring and/or roll bar
rate, the car can transfer motion far quicker. Say you have an
incredibly stiff rear compared to the front, the rear of the car will
seemingly rotate around the front of the car causing for a very
"drifty" ride. Not the fastest, but surely the funnest.

Use these settings to make your car handle how you want it. Want a
drift monster, go for a super soft front and hard rear, do the
opposite for both ends and you can have a very stable straight line
car. Or just tinker around for a setting that will allow the car to be
very neutral, that tears through the corners as if it were equipped
with much more expensive/probably illegal on the road/two lap tread
life tyres.

In closing, this is definitely one of the most powerful tuning tools
available for your car, and should NEVER be overlooked when tinkering
around with your settings.

Ride Height

The ride height is how high the body of the car is from the road surface. This 
has an effect on the aerodynamic properties of the car. The game measures ride 
height on a scale which varies depending on the car, the default setting for 
most non-racing cars is somewhere in the middle of the range. Generally 
speaking, the lower the ride height the better. The reasons for this are that 
firstly, it lowers the centre of gravity of the car, providing greater 
stability and cornering capabilities, and secondly it reduces the amount of air
flowing under the car. This is a good thing as large amount of air flowing 
under the car can negatively affect suspension, by lifting the car up slightly,
so the wheels are not held firmly on the road. Admittedly this second reason 
relates more to downforce than ride height, but it does have a small effect.
When setting the ride height it is important to remember not to exceed the 
stroke of the suspension (see above: Spring Rate), or you'll find the body of 
your car coming into contact with the wheels or the road.

Alternate Explanation By - Ben Lau 
I just want to point out that the more you reduce your ride height, the air 
that flows underneath the car moves faster than the air above it, which means 
lower air pressure.  This causes car to "suck" into the ground more, not lift 
up. This relates to "mechanical" downforce  or ground effect (instead of 
aerodynamic downforce).  In scientific terms, this relates to bernouilli effect
Of course, having venturi tunnels and a flat surface under the car (such as in 
race cars or top end sports cars) further enhance and take advantage of this 
effect, but  basically the point here is that you get a small, intrinsic effect
of the car  being "sucked down" into the road instead of lifting up, as stated 
in your faq. Anyway, this was just a side note.

Thanks to Zimian for this information about Downforce and Grip
(In response to Ben Lau's contribution above)

Comment:  There is no such thing as "mechanical downforce."  There is
downforce, which is purely aerodynamic, and there is mechanical GRIP which
is how well the car grips without any aerodynamic effects, like at low
speed.  Setting a low ride height increases aerodynamic efficiency.  I
suppose "mechanical downforce" would apply to someone or some device pushing
the car into the road, like you would do if pushing around a toy car.  :)

Cheers to Philippe Maynard for letting me know you actually need Semi-Racing 
Suspension to tune the damper. (It's a combined setting of Bounce and Rebound, 
so you can't set them individually).

The dampers work to counteract the force of suspension, without them the 
suspension would continually bounce because there would be nothing to stop the 
movement of the springs. The strength of the damper is measured on a scale of 1
to 10, 1 being the weakest, 10 being the strongest.
In simple racing terms the damper's main effect is to help balance the springs,
and give the car stability. So the setting on the damper should be relative to 
the setting of the spring rate. If you have soft springs, where they will move 
a lot, especially over uneven ground, then the dampers should be fairly stiff
to stop the suspension once it's stabilised the car. If the springs are hard, 
then the dampers need not be as hard, but I wouldn't set them soft either. 
Remember that with the damper setting, you are setting both the bounce and the 
rebound, so setting it to one extreme isn't necessarily a good thing.
Damper (Bounce)

The bounce side of the damper is the strength at which the damper compresses. 
The bounce is measured on a scale of 1 to 10, 1 being the weakest setting and 
10 being the strongest. This works a bit like the spring rate, only it has more
of an effect on stability.  The stronger the bounce, the more stiff the car
will be. If the spring rate is also very stiff, the car will tend to become 
airborne off the slightest inconsistency in road surface.
In most cases you're better off softening the bounce the strengthening it, 
especially if you've hardened the spring rate because it will help give your 
car back some extra stability.

Damper (Rebound)

The rebound side of the damper is the strength at which the damper is allowed 
to decompress. Like bounce, it is measured on the same 1 to 10 scale. Since it 
is the bounce side which, if set hard, causes problems for the car on uneven 
ground, the rebound side can be set higher, as it is the decompression side, 
and returns stability to the car. The game recommends 2 to 4 times higher in 
fact, but I generally find that increasing it only a couple of places higher 
than the bounce is sufficient. If the bounce is set very low you may want to 
increase it to the level that the game says, but that is not always suitable.

Camber Angle

The camber angle is the angle at which the wheels sit on the roll plane. 
A camber angle of 0 degrees means the wheels are straight up and down, an 
angle greater than 0 degrees means that the wheels will be leaning inwards.
The camber angle is measured on a scale of 0.0 to 10.0 degrees, allowing you 
to exactly specify what you want the angle to be.
The camber angle increases cornering ability, but, if increased too much, 
will start to negatively affect braking, as the more you increase the angle,
the less surface area of the tyres are in contact with the road.
The game suggests that an angle of between 3 and 4 degrees will increase 
cornering ability with no negative affects, and I would agree with it. 
Generally speaking I keep the camber angle of most of my cars at about 3.5 
degrees, and never go over 4, but don't be afraid to increase it to 3 or 3.5.
The camber angle for front and rear wheels can be altered separately, I would 
increase the front up to 3.5, which will account for most of the cornering 
ability increase, but, depending on the track having the rear set that high may 
not be a good idea. While the camber angle puts maximum tyre surface on the
road in corners, it can greatly reduce tyre surface contact on straights,
which can negatively affect straight line acceleration (you'll still maintain 
good acceleration out of most corners). Therefore, on a track with many 
straights, it can be a good idea to set the camber angle to 2.0 or even 1.0 
degrees for greater straight line speed. On a tight track with a lot of turns
a higher angle on the rear wheels is much more feasible, and can assist in 
cornering ability.

Toe Angle

The toe angle is the angle at which the wheels sit on the yaw plane (not to 
be confused with camber angle). There are two types of toe. A negative number 
is called toe out, where the front of the wheels point out to the sides 
slightly, whereas a positive number is called toe in, where the wheels point 
inwards slightly. Toe is measured on a scale of -6 to 6. 
The affects of setting different degrees of toe to the front and rear wheels 
are as follows; Toe out on the front wheels gives you a greater cornering 
ability but at the cost of oversteer.
Toe in on the front wheels gives you more stability, especially during 
cornering, but limits you cornering ability.
Toe in on the rear wheels provides you with stability at a cost of cornering.
Toe out on the rear wheels gives greater cornering ability but also increases 
I would advise you most of the time to stay away for the toe angle completely 
though, because in addition to all the effects listed above, toe of any sort 
also increases tyre wear.

Thanks to Zimian for this extra information about Toe

Comment: Front toe-IN creates high-speed stability, not toe-out. (This
mistake has been fixed in the above section) Front toe should be set to 0.
There is little difference in responsiveness to be gained by setting front
toe-out, and usually upsets the handling more than it improves it.

Instead of causing oversteer, rear toe-out unsettles the rear end making it
more responsive.  This allows you to turn in later since the rear will come
around more easily, but it does make the rear end more sensitive and
increases the chance of a spin if you mishandle the car.  If you need
high-speed stability, set the rear toe at 0 or slightly in.


The stabilisers, also known as anti-roll bars, act to suppress roll in the body
of the car during cornering. The setting is measured on a scale of 1 to 7 and 
represents how stiff the stabilisers are, the higher the number the stiffer the
stabilisers. Stiff stabilisers allow weight transfer during corners to occur 
much more quickly, whereas soft stabilisers produce the opposite effect.
Stiff stabilisers can supplement a stiff Spring Rate, however, on some tracks, 
it can cause some cars to become quite erratic during corners.
The Stabilisers act in tandem with the spring rate and so how you set the 
them depends on the springs as well. Stiff springs and stiff stabilisers
will cause the car to be very unstable over uneven ground, and so if your 
springs are stiff you should either leave the stabilisers where they are (what 
I usually do) or lessen the stiffness.
One thing to keep in mind about stabilisers is that they aren't actually the 
primary of method of stabilisation in the car. They are always secondary to
your suspension settings, so make sure you tune the appropriately. 


Individual Settings

I've received a few e-mails about this and so I've decided to put it in the FAQ 
for those who want to tune the gear ratios individually.
The individual settings for the transmission allow you to alter each gear 
ratio. This allows you to achieve any of the results outlined below, as well as
making a few interesting changes. The most notable of these is tuning your car 
for acceleration without the loss of speed. This can be done by setting the 
lower gears; 1st, 2nd, and sometimes 3rd, close together, meaning the numbers 
for each gears setting should not be too far apart, then setting the higher 
gears slightly further apart, and then setting the final gear much higher than 
the others. This will allow you a high top speed without the loss of 
Other combinations are possible using the individual settings, be careful 
though, not all cars react the way you'd like when you alter the gear ratios. 
But if things get out of hand you can always use the default button to return 
the car to the default settings.

Auto Settings

The auto settings of the transmission allow you to alter the gear ratios 
without having to fiddle around with each individual gear setting. The auto 
setting is on a scale from 1 to 25, the higher the setting the further apart 
the gears are. 
Changing the gear ratios is useful for altering the acceleration and speed of a
car. Basically, the closer together the gears are, the greater the acceleration
of the car, at the cost of a high top speed. The higher the number the further 
apart, or wider the gear ratios, the greater the top speed of the car, at the 
cost of acceleration.
Alteration of the gear ratios should be dependent on the track which is being 
raced. If it is a tight technical track will a lot of corners and few 
straights, a close auto setting to provide maximum acceleration can be 
extremely helpful, while on a track with fewer turns and many straights use the
auto settings to widen the gear ratios and gain the advantage of speed.
NOTE: You can alter each gear individually to achieve the same affect, however 
this is very difficult to do well and the auto settings provide a much simpler 
method which achieve exactly the same results. When altering the gear ratios, I
only ever use the auto setting, and I would recommend that you do too.


ASM System (Oversteer)

This changes the power of braking, ie. the strength at which the brakes kick 
in, in order to maintain stability and prevent the car from suffering oversteer
and therefore spinning out, and is measured on a scale of 0 to 20. Increasing 
the number will increase braking power, and decreasing the number will decrease
The more you increase the number then, the more powerful your brakes will be, 
slowing you down quicker, and therefore increasing your stability through 
corners, although this does come at the cost of cornering, as a high setting 
can cause understeer. Decreasing the number does the opposite, it provides 
greater cornering ability at the cost of stability, and can, if set too low, 
cause significant oversteer which can cause you to spin out very often.
The best thing to do in not set the ASM too far one way or the other. You 
should try to find the balance that complements your driving style. Aggressive 
drivers will find that a slightly lower ASM will benefit them, whereas an 
increased ASM would be helpful to more conservative drivers.

ASM System (Understeer)

This changes the power of braking, ie. the strength at which the brakes kick 
in, in order to maintain stability and prevent the car from suffering 
understeer, and is measured on a scale of 0 to 20. This works exactly like ASM 
System (Oversteer), only it works to prevent understeer. This means that a high
setting will increase the cars ability to corner but if pushed too high can 
actually create a small amount of oversteer.
Lowering the number will cause the car to be more prone to understeer.
I would recommend the default setting for most cars, if you find that your cars
become prone to understeering then a small increase is probably best, simply 
maxing it out won't help you very much.

TCS (Traction Control System)

The TCS detects and arrests wheel-spin be limiting the RPM. This allows for 
greater traction, especially in the lower gears and while accelerating out of 
corners, when the wheels are most likely to spin. The downside to this is that
because the RPM is limited, so is the capability for acceleration. The TCS is 
measured on a scale from 0 to 10, the higher the number the more powerful the 
Increasing the number will limit wheel-spin to the point where it is 
nonexistent, however the acceleration of the car will be greatly reduced. On 
the other hand, decreasing the number will reduce the capacity of the TCS to 
eliminate wheel-spin to the point where the increased RPM and acceleration will
be negated by the lack of traction, and acceleration will therefore be slowed 
So, like with the ASM, the best thing to do is find the balance which suits 
your driving style. Generally speaking I never really change the TCS much, 
small increases are made for uneven tracks where traction may be a problem, but
that's about it.


NOTE: To alter downforce on a production line car you must first buy a wing 
from GT Auto (the place where you wash your cars and get oil changes). Any wing
will do, they all have the same affect, the only consideration in choice is 
what looks good.


Downforce is what keeps your car on the road. Have you ever seen footage of an
F1 car where the rear wing suddenly breaks off, and then a couple of seconds 
later the car points its N2Oe straight up and flips about thirty feet into the
air. In real life, that's what happens when you lose downforce. Luckily the 
game's response to lack of downforce is a little less fatal. Downforce is 
generated by two things, the first is called the airdam, the second the rear 
wing. The airdam, which plays the lesser role of the two, is mounted on or 
under the front bumper of the car, and limits the air that flows under the car.
The rear wing, (also commonly known as a spoiler) channels the air that passes 
over the car. When the air passing over the car comes into contact with the 
wing, it pushes the air up, over the back of the car, this action causes the 
car to be pushed down onto the road.
Downforce only works at high speeds; at low speeds the air moving past the car 
is not moving fast enough to push the car down. However at low speeds downforce
is not necessary for maximum stability.
Generally speaking, you should always maximise downforce on both the front and 
the rear, maximum stability and corner speed is always a good thing.


Initial Torque

The initial torque is the response of the LSD when the car is not cornering. 
What this refers to is the strength of the response of the LSD, and it can have
some affect on the car. The LSD, usually most effective during cornering, does 
have a small effect when the car is driving straight, and this allows you to 
alter that effect. It is measured on a scale of 0 to 20, 0 being the weakest 
response, 20 being the strongest response.
Increasing the number, or strength of the response, will actually cause the car
to be difficult to turn, but can increase traction. The trick is to find the 
right balance for each car, some cars benefit from a strong response and others
do not. You should start with a response somewhere in the middle, and alter 
accordingly depending on the performance of the car.

LSD Acceleration

This allows you to alter the amount of torque going to the wheels during 
acceleration, in order to provide better traction and reduce wheel-spin. The 
game measures this on a scale of 5 to 60, the highest being the strongest LSD 
response, the lowest being the weakest.
The stronger the LSD response, the greater the traction while accelerating, 
especially out of corners, which means less wheel-spin during corners.
In contrast to this, decreasing the response will increase the chance of wheel-
spin during corners, especially on the inside tyres, and result in poorer 
acceleration out of corners.
Setting the LSD Acceleration correctly can be the difference between winning
and losing, IMO it is the setting that will have the most altering affect on 
your car (Don't believe me. Jump in any medium to high powered car and drive a 
lap of Tokyo R246 with the LSD Acceleration at default setting. Then drive 
another lap with it at maximum. Notice the 4-5 seconds you knocked off the lap 
time. Okay it's not that effective on every track, but it has a positive affect 
on almost every track.) and in a highly contested race it may be this setting
alone that wins you the race (In the Formula GT Championship it will make you 
all but unbeatable). I would recommend a high setting for almost all tracks
(at least 45-50 if not higher), the exceptions being extremely tight tracks
like Cote D Azur.
There is downside, though, and it is that the stronger you make the response,
the stiffer the car seems to handle, therefore limiting cornering ability, 
however the extra exit speed you have will more than make up for it.

LSD Deceleration

This allows you to alter the amount of torque going to the wheels during 
deceleration, in order to provide better traction and reduce wheel-spin. The
game measures this on a scale of 5 to 60, the highest being the strongest LSD
response, the lowest being the weakest.
The stronger the LSD response, the greater the traction while braking into a 
corner, meaning shorter stopping distances and less wheel-spin. Increasing this
is very handy for anyone whose driving style incorporates late (for me 
sometimes very late) braking into turns, however it does come at a cost. If the
deceleration response is too strong, the car becomes very difficult to turn, so
I would recommend you don't set it too strong, no matter how late you brake.
Weakening the response can make the car easier turn, but will also result in 
less traction and the possibility of oversteer.

Thanks to Zimian for this extra information about the LSD

Comment: To me, in GT3 at least, this is the biggest difference in the whole
tuning game.  The description given by the game is actually incorrect, or at
least misleading.  A lower number means that less power will be transmitted
to the wheels, INCREASING traction, and a high number means that more power
will be transmitted, DECREASING traction.  

What this translates to, in GT3 anyway, is that for a RWD car you set the
acceleration effect to 5 and the deceleration effect to 60.  This means you
have maximum traction when powering out of a corner and the rear end comes
around when decelerating or braking, allowing you to turn very quickly.  Do
this on a Formula car and you will blow away all the other
Formula cars in the GT3 Formula GT series, with the possible exception of
the test course where it's all about aerodynamics, gearing, and drafting.

For a FWD car, set both accel and decel to 5 to keep maximum traction on the
front end when acceleration and braking, again allowing the rear end to
respond with maximum effect when turning.

For a 4WD car, set the front end like a FWD car and the rear end like a RWD
car, with the possible exception of slightly increasing the accel effect on
the rear diff, depending on the car and the conditions.

In GT4 the effect appears to be opposite that in GT3, i.e. it does what the
game says it should do.  However, the effect isn't as dramatic as in GT3,
and I am still experimenting with the settings to find what works well.  So
far, I've found that reversing the above advice seems to have a good effect,
which is why in GT4 I continue to make the fully customisable LSD one of my
first upgrades.


After a lot of painful searching I've finally figured out what the AYC does. 
Firstly I'd like to thank all the people who e-mailed me about this, it was 
really helpful.
AYC stands for Active Yaw Control, and allows you to alter the torque between 
the left and right wheels. It can only be put on Mitsubishi Lancers (type GSR's
to be exact), because it was actually developed by and is a trademark of 
It is measured on a scale of 30 to 130, and can be used to increase the 
cornering ability of the car. What it does is detect over or understeer while 
cornering and apply necessary torque to either the inside or outside wheels to 
counter it.
In the game this only applies under acceleration, so you must accelerate during
the corner to allow it to work.
Changing the number of the setting changes the strength of the response, a low 
number means the AYC will have little effect, a high number means it will have
a big effect. Increasing the number is generally alright, as it gives a 
reasonable cornering increase during acceleration, with no negative 

Alternate Explanation By - Veen

AYC (Active Yaw Control)  is actually an ingenious little device that
was cooked up by Mitsubishi, and used solely on Mitsubishi's cars,
namely the LanEvoIV and up.  Basically, the torque to the rear wheels
is entirely computer controlled, and as such, when you install the AYC
system, you'll only be able to adjust the front differential.

How the system works, is it gives more torque and power to one wheel,
while taking torque and power from the other.  For example, if you go
into a right turn, the power to the rear left wheel will be increased,
while the power to the right rear wheel will be decreased.  This
creates a "pulling" type action with the rear wheel, and allows the
"yaw" or rotation of the car to be adjusted.

In Gran Turismo 4, the more you slide the bar to the right in the
car's settings, the more radical the power change in the back.  Some
say it comes in really helpful in rally settings, where you can't get
much traction anyway, though some prefer the more predictable feeling
of a regular mechanical rear differential.  It does help if you're
trying to build a drift spec Evolution, though.


Variable Centre Differential

The VCD allows you to alter the amount of torque going to the front and rear 
wheels in a 4WD. This can be used to change the driving style of the car. It is
measured on a 10 to 50 scale, the default being 30. This means that, because 
the setting is in the middle, that the ratio of torque to the wheels is 50/50. 
Decreasing the number gives more torque to the rear wheels and less to the 
front, and increasing it does the opposite. Setting it at the minimum of 10 
will give all torque to the rear wheels, making the car handle like an FR car, 
which makes the car easier to turn, both on tarmac and dirt, although the car 
will lose speed more quickly off road. Setting all the torque to the front will
make the car handle like an FF car, off-road you'll keep a bit more speed, and 
turning response will be similar to FR qualities, but it will become easier to 
spin out.
Leaving the torque ratio somewhere in the middle will give the car maximum 
stability, but make it quite difficult to turn. This can be useful in some 
rallies, but on tarmac, it needs to be changed to give maximum cornering 
I usually prefer to use a setting which gives the car FR abilities, regardless 
of the surface I'm racing on, but you should try to find the setting which 
works best with your driving style.



Ballast is the weight which can be put into your car. You can put anywhere 
between 0 and 200kgs of weight into the car, providing greater stability and a
greater ability to even the weight balance in the car, but it has a negative 
affect on acceleration, braking and cornering. The more weight you put into the
car, the more it affects the other aspects of driving, so leave ballast alone 
if you can, and if you need to use it, put in the smallest amount that you can.

Front/Rear Balance

This is the position of the ballast. If there's no ballast in the car, then 
there's no need to worry about this. You can use this to balance the weight of 
cars which are front or rear heavy, as well as change the handling of the car 
by making the weight balance purposely uneven.
To even out the balance of a car, simply distribute the weight at the light end
of the car.
If you want to change the handling of the car, putting more or all ballast in
the front, thus making it front heavy, means the car will tend to oversteer,
whereas putting the ballast in the rear, thus making the car rear heavy, will
cause understeer.


Q. How do I get to the settings menu?
A. At the 'My Home' screen (with the Garage, Status, Options icons, etc.)
press the start button, or, at the pre-race screen (where you pick A-spec,
B-spec etc), select the red toolbox called settings.

Q. Can I buy different tyres for the Formula GT?
A. No, they give you Racing/Medium tyres and that's all you get.

Q. Where do I buy rear wings for my cars?
A. GT Auto, on the world map it's to the left of 'My Home'.


Questions, comments, critiques? E-mail me at devilmaycryfreak@hotmail.com, and
let me know what you think. And make sure you put the words GT4 and Tuning in
the subject or your e-mail will probably get deleted. What and what not to e-
mail me with are as follows:

What to E-mail me with:

1. - Constructive criticism about my FAQ.
2. - Helpful tips about tuning in GT4.
3. - Mistakes I've made in the FAQ.
4. - If you need help with tuning in GT4.

What not to E-mail me about:

1. - Anything that has nothing to do with tuning in GT4.
2. - Anything that has already been discussed in this FAQ.


Thanks go to the following people:

You - for reading my FAQ.
Polyphony - for making this awesome game.
CJayC - for running the best video game site for all these years.
Ben Lau, Ryu Komiyama, Astralwolf, Veen, Rock Hole and Zimian for 
their contributions.

And anyone else I forgot to thank.

Websites with permission to post this FAQ:


This FAQ may be not be reproduced, in part, or full, under any circumstances 
except for personal, private use. It may not be placed on any web site or 
otherwise distributed publicly without advance written permission. Use of this 
guide on any other web site or as a part of any public display is strictly 
prohibited, and is a violation of copyright.

This FAQ Copyright(c)2005 Michael Green aka NightmareHunter.

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