Help with FR setup

[oatmeal so good]

I was recently driving my Z06 on deep forest. It has racing softs and 611 hp and fully adjustable suspension. I've noticed that under throttle, the car would understeer. Applying throttle would cause the load to move to the rear and the front simply loses grip and refuses to turn in. This is most likely a damper/spring rate issue. Where should I start to eradicate this understeer when accelerating? Suspension/physics gurus please help
edit:
setup:

LSD is at 9/54/5, toe is -.12 front/rear. 9.0 front/13 rear spring rate. 3/6 front and rear rebound 3/6 front and rear compression. 2/6 anti-roll

 

[Adrenaline]

Where should I start

Stickies, search, whichever you prefer.

 

[KingSakery]

Is it RM´d or stock ?? Do you have a Spoiler applied which adds rear Downforce (DF) ??

If you have any Rear DF both Premium Vettes will produce immense Understeer. Well this would be the first "control".

Well I did following things to my Vette:
Camber: 2.5 front and 2.0 rear
Toe: -0.20f -0.15r
Roll-Bares: 3f 3r
Springs: 12.8f 13.5r
Damper compression: 4f 4r
" extension: 9f 9r
Height: you can´t lower it but I think I raised the rear a bit

For me it still Understeers but not that much as before. Try it maybe it works for you too

PS: I don´t consider me as a "Suspension-Guru" but I hope I can help xD

 

[XDesperado67]

I was recently driving my Z06 on deep forest. It has racing softs and 611 hp and fully adjustable suspension. I've noticed that under throttle, the car would understeer. Applying throttle would cause the load to move to the rear and the front simply loses grip and refuses to turn in. This is most likely a damper/spring rate issue. Where should I start to eradicate this understeer when accelerating? Suspension/physics gurus please help

Not a guru here but would suggest stiffening rear spring rates. Also depending on what their currently set at slightly higher dampers could improve matters. Finally, and a number of people here won't agree on this, increasing rear ride height can help reduce understeer.
Since you indicate this is primarily an issue under heavy acceleration I'd start with the stiffer springs.

 

[oatmeal so good]

Stickies, search, whichever you prefer.

Trust me, I did. Came across lots of helpful threads, but there have been too many mixed responses for what to do. Gonna try my luck here, hopefully with some results 👍

 

[oatmeal so good]

Is it RM´d or stock ?? Do you have a Spoiler applied which adds rear Downforce (DF) ??

If you have any Rear DF both Premium Vettes will produce immense Understeer. Well this would be the first "control".

Well I did following things to my Vette:
Camber: 2.5 front and 2.0 rear
Toe: -0.20f -0.15r
Roll-Bares: 3f 3r
Springs: 12.8f 13.5r
Damper compression: 4f 4r
" extension: 9f 9r
Height: you can´t lower it but I think I raised the rear a bit

For me it still Understeers but not that much as before. Try it maybe it works for you too

PS: I don´t consider me as a "Suspension-Guru" but I hope I can help xD

Not a guru here but would suggest stiffening rear spring rates. Also depending on what their currently set at slightly higher dampers could improve matters. Finally, and a number of people here won't agree on this, increasing rear ride height can help reduce understeer.
Since you indicate this is primarily an issue under heavy acceleration I'd start with the stiffer springs.

Thanks guys, will test this out

 

[Adrenaline]

Trust me, I did. Came across lots of helpful threads, but there have been too many mixed responses for what to do. Gonna try my luck here, hopefully with some results 👍

So... your logic... is that threads like these, have mixed responses and your resolution, was to create another thread, asking another general question, with no hint as to what your current settings are and ask people to blindly fix it for you, and hope that some how, some way, you don't get mixed responses?

I disagree with both of the above posters, downforce is great to have, and rear ride height can't be blindly 'raised or lowered' without knowing the relation yo your current balance front to back, shock set up or spring rates...

I'm willing to bet, a huge chunk of your issue is the LSD, the second part is your toe.

 

[KingSakery]

Oh I totally forgot my LSD-Settings:
Initial Torque: 18
Acc: 28
Brake: 10

 

[oatmeal so good]

So... your logic... is that threads like these, have mixed responses and your resolution, was to create another thread, asking another general question, with no hint as to what your current settings are and ask people to blindly fix it for you, and hope that some how, some way, you don't get mixed responses?

I disagree with both of the above posters, downforce is great to have, and rear ride height can't be blindly 'raised or lowered' without knowing the relation yo your current balance front to back, shock set up or spring rates...

I'm willing to bet, a huge chunk of your issue is the LSD, the second part is your toe.

No, I just wanted to know what to generally do. I can tell that the problem are my springs/dampers/maybe lsd because tampering with the other settings produce minimal results. Was hoping to get input, such as yours, and the others above, for this specific vehicle. Didn't know we were getting into semantics... Anyhow, I would greatly appreciate assistance. LSD is at 9/54/5, toe is -.12 front/rear. 9.0 front/13 rear spring rate. 3/6 front and rear rebound 3/6 front and rear compression. 2/6 anti-roll

 

[Adrenaline]

The Ultimate GT5 Link Collection for Tuning
Generally...

 

[oatmeal so good]

The Ultimate GT5 Link Collection for Tuning
Generally...

I have that thing bookmarked, good call on that. Also, can you please elaborate on the LSD/toe setting discrepancy? Those could indeed be two of the many the culprits

 

[Lost-on-drugz]

put a wing on the back of it and decrease the rear aero.

 

[oatmeal so good]

put a wing on the back of it and decrease the rear aero.

I am only reluctant to do this because the wing/decklid spoiler keeps the car that much more stable. I didn't even dial in the downforce that high. It is set at 9

 

[Adrenaline]

You say the car understeers on throttle. Is this on exit, in the center? Full throttle, partial throttle. Deep Forest, online or offline? How tight of a corner? Medium, low or high speed corner? You still didn't answer if it was RM'd or not. You didn't list if you have a spoiler, downforce settings, ride heights, brake balance, camber. Way too many variables, which is why 'general' questions are answered with 'general' answers'. If you want specifics, you've gotta give them.

Test 1: Is it really worth it, to do it yourself, when many extremely skilled tuners already went through the trouble?
Test 2: Put LSD to 5/5/5 - If the car gets better, your LSD was screwed up.
Test 3: Reset to default - Have you made the car worse than what it started with?
Test 4: Reverse your spring rates - Does the car get better or worse?
Test 5: Reverse your sway Bars - Same question

Based on looks alone, I'd say your front toe is backwards, your LSD Accel is too high, your spring rates are backwards and so are your ARB's. I'm going to bed, so get the specifics we need, and by the time I wake up, nicer people will have given you better advice.

 

[oatmeal so good]

You say the car understeers on throttle. Is this on exit, in the center? Full throttle, partial throttle. Deep Forest, online or offline? How tight of a corner? Medium, low or high speed corner? You still didn't answer if it was RM'd or not. You didn't list if you have a spoiler, downforce settings, ride heights, brake balance, camber. Way too many variables, which is why 'general' questions are answered with 'general' answers'. If you want specifics, you've gotta give them.

Test 1: Is it really worth it, to do it yourself, when many extremely skilled tuners already went through the trouble?
Test 2: Put LSD to 5/5/5 - If the car gets better, your LSD was screwed up.
Test 3: Reset to default - Have you made the car worse than what it started with?
Test 4: Reverse your spring rates - Does the car get better or worse?
Test 5: Reverse your sway Bars - Same question

Based on looks alone, I'd say your front toe is backwards, your LSD Accel is too high, your spring rates are backwards and so are your ARB's. I'm going to bed, so get the specifics we need, and by the time I wake up, nicer people will have given you better advice.

No it isn't an RM car. Yes it has a rear spoiler, downforce set at 9. Ride height is 0/0. Camber is 2.0 front and 1.5 back. Brake balance seems irrelevant, but it is 6/8. The problem appears online and offline during corner exits. Mostly med-high speed corners. And I think it is worth it to do the setup myself. I like to learn from my mistakes and it ends up being a rewarding experience. Anyhow, thanks for the tips guys. Adrenaline, no one said you weren't nice, that was actually quite insightful.

 

[nomis3613]

Try in this order (some are similar to Adrenoline's suggestions), the "cures" get more and more drastic so stop when you've fixed your problem:
1) front downforce if possible
2) LSD 5/10/whatever (you will lose some traction, but it might be worth it)
3) even up spring, damper and anti-roll (ie front = rear, not too stiff either)
4) front toe = 0
5) camber 2.5/1.0
6) 50kg front ballast
7) racing medium tyres all round
8) racing soft front / racing medium rear

 

[zodicus]

What i would do is try to keep weight on the front of the car while acclerating. Normally id start with what feels wrong first. Dose the car yank the nose up when you hit the gas? If so try more front ext, or more rear compression, possably both.
With it being on med to high speed corners it could be a load issue, try more front spring and or less front roll bar. if the rear downforce is not all the way down you could try lowering that.
Also less neg toe in the rear or slightly positive toe in the rear.
I would not recomend putting different tires on the front verse the rear, thats just a bandaid and not fixing the problem.
Watch you're replays, see if the car is leaning to much, or not enuf. Is it bottoming out, or overly bouncy?

 

[oatmeal so good]

Thank you all so much. It has now been fixed. It was indeed a bad combo of soft spring rates and a soft rebound at the front. The difference is night and day.