Tuning out understeer, 00 Camaro SS.

Rotary Junkie

Rotary Junkie

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Canton, MI
RJs_RX-7
K, so I'm tuning one for a race series somewhat like the WRS, just not quite the same; We've got two tracks and the strip to run on.

I've got a 401hp Camaro with a 1-way LSD, stage 1 weight reduc, R2 tires, FC suspension, race brakes, sports flywheel/clutch, semi-racing exhaust, stage 1 NA tuning, and a race chip. Problem is: IT WON'T STOP UNDERSTEERING! I've done well so far with setups, but this car HATES me. I've pulled a 1:40.1XX lap at NY Reverse, but I haven't been able to get back up to that. Any ideas? In the morning I'll post the current setup. BTW, the understeer is there in steady-state cornering as well. And NO, I am not allowed to change ANY parts.
 
your LSD is the culprit most likely. buy FC LSD and set it something like this:

I:25-30
A:10-15
D:7-10

let me know if it helps. also, post your suspension setup, so we could check the possible problems there.
 
Two secs and I'll have it up.

EDIT: Here it is!

Spring rate:--12.0/8.5
Ride Height:--140/144
Bound:-------3/3
Rebound:-----5/2
camber:------2.0/1.0
Toe----------0/0
'Bars:---------3/2

I've toyed with a lot of it, the wierd rear shocks seem to help, but I need the nose to stick more.
 
Hmmm...
Drop the front springrate to 10, drop the rideheight to 95/105, increase the rear rebound to 4 and put a -2 front and 1 rear toe on and try again.
Thing is, the softer you go, the more grip you will get, until a certain limit is breached. Too soft and the grip will be hampered. Lowering the car will make the fairly soft springs and dampers work better, and you also increase the cars aerodynamic capabilities. Plus, a lower car has a lower centre of gravity, and will thus corner better. Beware of a too soft suspension in a low car, as the bumpstops may come into play, or even bottoming out.
The rear rebound is what kind of keeps the rear wheels on the ground when driving over uneven surfaces, and should be kept stronger than the bounce, so that the wheel can simply rebound back as smooth as possible on the other side of a bump. Too strong is not advisable though, since it may bounce back too hard, and the ride will jitter over bumps instead of riding over them smoothly.
The toe should prevent some understeer aswell as stabilizing the car under braking and acceleration.
 
Good advice from 666 there. To elaborate a little, if you're after getting the understeer to go away I'd stiffen the dampers quite a bit. The Camaro is a heavy car and the soft Front Bound is not doing you any favours.

Try something like 5/5 or 5/6 Bound and 6/9 Rebound for a relatively smooth track. I know the high rebound conflicts with previous advice a touch but give it a try; you can always abandon it if it doesn't work after all.

Likewise, stiffen the rear Stabaliser. 3/2 is a stability-into-corners ratio. Give 3/5 a try. If that doesn't help then 4/4 is an excellent all-round setting for a big car.

Of course, this is all dependant on what kind of understeer you're getting. Corner entry understeer can often be the result of too much rear end grip rather than too little front (the back end just pushes the front off-line). The damper change I mentioned above may help with that. By the sound of things, the culprit for the mid-corner understeer is the LSD and the stabaliser ratio - or it just maybe that you're getting on the power too early (some cars in the game do not like that at all)?

As always, good advice is to read the great tuning-compilation posts that Scaff made - they'll cover all the ground we have here and more.
 
I read Scaff's guide, and it gave a lot of explanation, but I wasn't quite getting this car right.

Another thing: Doesn't stiffening the rebound make it SLOWER to react?

Also: Tracks are Mazda Raceway (Laguna Seca) and New York reverse. I'll try your recommendations later on, (read: After I get some sleep)
 
Alright, I tested the advice, and I love it. For Laguna Seca.

I need a way to improve corner entry responsiveness, and or off throttle. It understeers just a little bit still around ONE corner, and that is definitely hurting me. I feel that with that fixed, I will be able to break my near-identical-spec Cobra R's time. I had added ballast to it to equalize weight, (1372 KG) and it had 409HP to the 'Maros 401, and it had the same exact mods otherwise. It ran a 1:39.608 at NYC Reverse. Against my best of 1:40.156 in the 'Maro.
 
Hi RJ

Dampers are a complicated subject and it's something of an art rather than a science getting them dialed in. It varies from car to car and driver to driver as to exactly what rates will work satisfactorily. If you have a search on my username (restricted to the Settings fora for GT3 and GT4 you should find a number of posts on the subject that may (or may not :D) help).

In basic terms tho', the higher the number, the more resistance to movement in the damper. This is not necessarily the same as 'slower reacting' as a very stiff damper passes energy to the spring rather than absorbing it in the fluid. That is why you can work on a car gradually increasing a damper setting and then suddenly start to get an opposite effect to what you expected.

Also, the damper Bound and Rebound settings work in opposite pairs - the Front Bound with the Rear Rebound and vice versa but, generally, in GT4 at any rate, the stiffer end will lose traction first. That's why the general cure for an understeer problem is to run softer settings at the front.

It is also important to understand that tuning is always a compromise - it's a question of getting the best compromise you can where the negatives (from your point of view) are most minimised. Thus, it is unlikely that you can get a car to handle brilliantly for every corner on a track but if you can get it acceptable most places and great for the corners that really matter then you're on to a winner.

The following is a precis of the core damper 'rules' - it's provenance is unknown (I don't recall writing it myself so I must've nicked it :embarrassed:) but it is a condensation of an excellent series of tuning articles that I've used as a basis for GT spannering for years.

Code: 
ENTRY type 1 : Increasing braking + increasing steering
This phase is the first part of a fast decreasing radius turn. This phase will not occur at all if you get all your braking done *before* you turn-in. Since weight is being transferred both forward and outboard, the outside front damper moves in bump and the inside rear damper moves in rebound. these are the dominant two dampers in this phase of turn-in. The other two have minimal effects during this phase. 

ENTRY type 2 : Decreasing braking + increasing steering
This is the turn-in phase of a slow corner. This phase may or may not occur depending on the type of turn or driving technique. Weight is being transferred outboard and to the rear, so the outboard rear damper moves in bump and the inside front damper moves in rebound. The other two dampers are considered stationary. 

ENTRY type 3 : Increasing steering at constant throttle
This phase can be a chicane turn-in (GP2 has a lot of these!) or a turn entry taken at *full* throttle. Weight is being transferred outboard only, so *both* outside dampers are moving in bump and *both* inside dampers are moving in rebound. 

MID-CORNER TRANSITION : Decreasing steering back to zero at constant throttle
This is really the opposite of a type 3 entry. It's what happens in the middle of a chicane, as you flick the steering back away from the current cornering direction. As soon as the lateral acceleration passes back through zero, the turn reverts to a type 3 entry again. 

EXIT : Decreasing steering + increasing throttle (or decreasing braking)
This is the apex_to_exit phase. Weight is being transferred inboard and to the rear. The outside front damper moves in rebound and the inside rear moves in bump. The others are considered stationary. 
Here's a chart to help understand low speed damper adjustments: 

 CORNERING PHASE        MORE UNDERSTEER         MORE OVERSTEER

  Entry Type1            F bump +                 F bump -
                         R rebound -              R rebound +
 
  Entry Type2            F rebound +              F rebound -
                         R bump -                 R bump +
 
  Entry Type3            F bump +                 F bump -
                         F rebound +              F rebound -
                            or                       or
                         R bump -                 R bump +
                         R rebound -              R rebound +
 
  Mid-corner             F bump -                 F bump +
  Transition             F rebound -              F bump +
                            or                       or
                         R bump +                 R bump -
                         R rebound +              R rebound -
 
  Exit                   F rebound -              F rebound +
                         R bump +                 R bump -
 
                          + = increase adj.
                          - = decrease adj.
                          F = front
                          R = rear

Ack! That CODE tag didn't help with formatting at all. Here's a link to the original articles:

http://www.ozebiz.com.au/racetech/theory/shocktune1.html
 
RJ, change your camber values to something like 0.8/2.0. This should help the front turn in better. I use something similar mostly on my cars, often combined with a little higher rear than front suspension rate. It helps me going faster through turns. The car also becomes more difficult to drive and a mistake gets punished more severe, but that mostly goes hand in hand with a responsive front end.

For the drag strip this adjustments will mostly have a negative effect. Soft springs and low camber on the driven wheels will be the way to go there.

Disclaimer: For this advice I assumed you disabled all aids (since you didn't mention anything about them)
 
I'm interested in hearing how that works, Hugo. How is the rest of the suspension set-up?

Ordinarily, increasing front camber decreases understeer whilst increasing rear camber increases it, so to hear that decreasing front camber and increasing rear reduces understeer is a bit of a surprise.

Regardless, in GT, as long as the front is greater than the rear, camber changes have small effect in the main (unless you luck out on the 'perfect' combination), other than making your braking less effective :D.
 
Hugo Boss
For the drag strip this adjustments will mostly have a negative effect. Soft springs and low camber on the driven wheels will be the way to go there.

Disclaimer: For this advice I assumed you disabled all aids (since you didn't mention anything about them)
Click to expand...

Yes I disabled all aids.

And the strip? Meh. I PWN there. Got a Cougar that pulls the fronts. Check "Fastest Muscle Cars" for the pic. 505 HP is all I needed for that.

Oh, and Sukerkin: Thanks. I STILL think the car hates me... It just ain't working.
 
If you like, I'll have a go at dialling her in to suit me and see what times she runs. I'll pass the settings on and you can see if they suit you or not. It's unlikely but they might give you an idea of what would help.

What tracks (New York Reverese and Laguna Seca?) and what target times are we looking at?
 
We're shooting for sub-1:40s at NY Reverse, and sub-1:31s at Mazda (Laguna Seca). My current best at NY was with a now-lost setup, and it was a 1:40.147.

Current best for Mazda is 1:31.830 with 666's modifications.

Ya, see what you can do. Spec sheet is available at THIS SITE
 
sukerkin
I'm interested in hearing how that works, Hugo. How is the rest of the suspension set-up?

Ordinarily, increasing front camber decreases understeer whilst increasing rear camber increases it, so to hear that decreasing front camber and increasing rear reduces understeer is a bit of a surprise.

Regardless, in GT, as long as the front is greater than the rear, camber changes have small effect in the main (unless you luck out on the 'perfect' combination), other than making your braking less effective :D.
Click to expand...

How it works? Well, no idea, Sukerkin... GT isn't right on all aspects of the setup. My experience with GT4 is that 0.6-1.4 front camber (depending on the car) is enough on street cars to be able to point the car in the direction you want to have it. I'm a late breaker (no kamikazi into the corner, I do keep it tidy) and steer the car on the throttle. Low front and a little higher rear camber seem to suit me most. High front camber increases my braking distance and low rear cambers give me understeer when exiting corners.

Just noticed they fitted R2's on the Camaro. I hate them, but I'll try the Camaro too to see if my experiences work on those tyres as well.
 
I look forward to sharing our experimental outcomes, Hugo and I shall certainly give your 'reversed' camber idea a trial.

These days, I generally don't bother touching camber anymore in the game as it only ever seems to make things worse rather than better, if you can detect any change at all :lol:. So if there's a change that can be made that actually makes a noticeable contribution be sure I'll use it, even if it's counter-real-world (no sense being a prima donna when lap times are involved :D).
 
Okay, I just did a 5 lap initial run at the Laguna Seca raceway with the ASM/TCS off but nothing else changed.

On stock settings I got a 1'31.010 and I have to say that the car handles fine as it is :eek:. A bit weak on the braking because of not having a Balancer to tweak but by no means bad.

I'll throw a base-line set-up on it now and see what I get (results'll be edited into this post).

Changed the Ride Height to 99 fore and aft. Put the Dampers to 5/5 Bound and 8/9 Rebound. Five lap testing stint yielded 1'29.975. I find the braking performance is slightly worse and the back end to be a little too slidey (I can hear/feel the back tyres losing grip a bit too much).

Upped the Rear Bound to 6 which makes the grip release more predictable, altho' exit understeer appears a little worse in medium speed corners, low speed corners allow more vigorous throttle application which makes up for it {I do love being able to come out of a corner hard on the throttle :lol:}. Five laps done - BL 1'29.558.

Played around with the stabalisers and decided that I like them at the default 4/4 best i.e. no lap time improvement.

Having become familiar with the car and the track, I tried the Camber Inversion and I'm afraid to say that I don't suit it at all. Lap times were way down and I had a few 'offs' here and there due to lack of front-end grip. For reference, I used 0.8 Front and 1.4 Rear. I did note the counter-intuitive willingness of the nose to turn in to corners, which was a surprise but the exit understeer was very bad when on the loud pedal. It could be that I'd have to rethink the rest of the suspension to compensate and I may experiment with it more at a later date to see if I can adapt to it but, for now, I'll stay with my traditional 2.0 Front and 1.0 Rear :).

I hope that the above has helped a little RT.

Sorry I don't have time for the New York track today - it's stopped raining and the garden tasks are calling to me :lol:.
 
Yeah, that's fine. I somewhat LIKE a loose car, but that's just me. loose=fast, tight=safe. What I mean by that is a car that can set awesome lap times might not be one you'd want to drive in an endurance race/tight competition, as it's prolly a little unstable. But a setup that's a little bit tight in the corners might work out best in traffic/endurance races.

Thanks for the help, and I'll play around with the settings a bit more, see what I can do.

Apparently I suck as a driver. Well, I KNEW that after my 900hp Lotus got upstaged on lap times at Sarthe II. By ten seconds. By 500hp cars that barely broke 200. I did 250 EVERY lap down Mulsanne.:grumpy:

Thanks man. (for the tuning help, that is.)
 
Rotary Junkie
Apparently I suck as a driver. Well, I KNEW that after my 900hp Lotus got upstaged on lap times at Sarthe II. By ten seconds. By 500hp cars that barely broke 200. I did 250 EVERY lap down Mulsanne.
Click to expand...

Why do you expect to be good in a 900hp car? Can you imagine how difficult a "real" version of that car would be to drive? That is F1-level power, poured into a vehicle never designed to handle it.

Some quick tips would be:

1) Most (or all) cars can have some extra power added and still be great cars, but few cars are still great cars when pushed to the absolute max. Test that same Lotus at lower power levels on a circuit like Trial Mountain and find the point at which the car *consistently* gives you the fastest lap. Often that isn't with the max power upgrades.

2) It takes a long time for professional race-car drivers to conquer vehicles like that. They start out with slower, lower-power vehicles. Do the same thing and you'll be a better driver.
 
The car's GREAT. Corners well, and is killer down the straights. The only thing preventing me from posting a (much) better lap was the car abso-bloody-lutely LOVED to swing out the arse at the end of Mulsanne, heading into Mulsanne corner. Hit the brakes: OUT. So I had to brake well before the slight kink to get 'er down to 130ish just so it didn't come out from under me.

At least that RUF didn't beat me there, but it beat me at the strip. However, I now know he was using sauce.
 
Rotary Junkie
Apparently I suck as a driver.
Click to expand...

It's all in the practice my friend. You would not believe how bad I was when I started all this with GT1. Also, the sagest advice anyone can give you is that there is always someone better than you. My best placing in the world OLR stage was about sixth I think (multi-board challenge type thing). Like anyone I like to win ... but I like driving more :D.


Rotary Junkie
Thanks man. (for the tuning help, that is.)
Click to expand...

You're more than welcome. It was a nice change to not be able to tune some things that I would do as a matter of course (Brake Balance, Gearbox, Weight Distribution, LSD ratio's).

I hope that it served as a small flickering light as to what can be done simply by getting the car to act predictably for your style.
 
Due to illness I haven't been able to give it a go earlier, but here I am now.
I first drove with RJ's initial setup and noticed some unpredictable steering. I believe I drove a 1'40.1 after a few laps.

Then I changed to some (personal) basic settings:

Springs 9.6 / 10.8
Height 98 / 98
Damper B 2 / 7
Damper RB 7 / 7
Camber 0.8 / 2.4
Toe 0 / 0
Stabs 3 / 3

After about another 3 laps I was on a 1'38.9. This setup ain't a second faster ofcourse, but it did make it easier for me to go faster.

I also did 5 laps with the 'normal' camber setup from Sukerkin and was about 3 tenths slower with it. The change of direction after you stop braking is more direct, but I also noticed a longer braking distance and more understeer under throttle. So no big differences timewise, but a better feel for me with the reversed camber 👍

I also tried Laguna Seca. Not much difference there either. Better turn-in for the normal camber, but also more understeer. After 5 laps each, starting with my reversed camber, I managed a 1'28.5 and a 1'28.6 with the normal camber.

Conclusion: It's all personal preference after all :dopey:
 
Sorry to hear you've been ill, Hugo :(.

Thanks for taking the time to come back in and put an alternate view across; nice times too 👍.

I have to concur that I think your last line conclusion is an accurate one - preference and driving style makes all the difference in the world.
 

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