ways to defeat our understeer?

[Targa Tim]

Went out to a PCA event this am, sunny day, dry road, cool temp around 40-45 F. I was following a 997GT3RS on the highway with some minor curves. I found that I could not keep up not mainly due to hp, but to understeer. I basically need to slow down about 10 to 20mph (from him) in order to regain my steering. I'm running bone stock C2S, X51, PS2 tires, 19" techart wheels, and stock suspension and alignment. He has 19" stock wheels and MPSC. Not sure about his alignment. I know there are too many variables here, but what is some good and inexpensive way to defeat our understeer? Please fire away.

This ad is not displayed to registered and logged-in members. Register your free account today and become a member on 6SpeedOnline!

[keninirvine]

I'm sure Ed will chime in, since he races with these guys all the time.

[buckwheat986]

I like to hear opinions also....and I think we need to define inexpensive

[GT3 Chuck]

here is a chart that shows all the simple things like tire pressures, alignment, sway bars...I don't know if you have adj sway bars but you can swap for a stiffer rear or softer front...good luck...at speed an RS with cup tires will have a lot more grip due to aero, suspension, alignment and tires...you might be aiming too high

[Targa Tim]

Thanks Chuck. Your attached info is excellent. I'm sure my Techart wheels being heavy is one major factor.

I don't have any sway bar, car is bone stock.

Ed didn't attend this am.

[utkinpol]

Essentially all you can do on bone stock car is to get R compound tires (what will push you into group where you will not be competitive) or change alignment. Or install coilovers.

Mdrums gave me several advices on alignment numbers - check how your car is tuned. Below is what he suggested to me:
--------------------------

non-pasm street safe stock:

FRONT
-1 camber
.02 toe

Rear
-1.5 camber
.14 toe

stock sport pasm:

FRONT
-1.3 degrees camber per side
.02 degrees toe per side

REAR
-1.6 degrees camber per side
.14 degrees toe per side

Since I added front lower GT3 Cup control arms I am now aligned at:

-2.1 degrees camber per side
.02 degrees toe per side

REAR
-1.9 degrees camber per side
.14 degrees toe per side

Keep front toe at 0 to no more than .02 and keep rear toe at .11 to no more than .14 degrees.

[buckwheat986]

thanks chuck for the concise attachment...good info

[GT3 Chuck]

great..glad it helped...btw...check it again...for some reason the 2nd page didn't show the first time...

[JEllis]

You can also put wider wheels/tires on the front.

I run 9" wide on the front. The staggered setup is designed to keep the rear end in check but getting as close as possible to a square (without actually going square) setup will really help.

GMG's WC GT3's run a 10.5" wheel in the front!!

Jason

[stevepow]

Originally Posted by VSE Chuck

here is a chart that shows all the simple things like tire pressures, alignment, sway bars...I don't know if you have adj sway bars but you can swap for a stiffer rear or softer front...good luck...at speed an RS with cup tires will have a lot more grip due to aero, suspension, alignment and tires...you might be aiming too high

That's gotta help me with Forza on the XBOX360 - thanks

[NorthVan]

Tim, I think that you need to be more agressive with your driving. The OEM MPSC are no better then your PS2's. Try accellerating more out of the corner, in othe words induce more oversteer, this will reduce your understeer. To practice this go to a safe track and start throughing your car around and you will find that these cars rotate really easily.

[utkinpol]

Originally Posted by NorthVan997C2S

Tim, I think that you need to be more agressive with your driving. The OEM MPSC are no better then your PS2's. Try accellerating more out of the corner, in othe words induce more oversteer, this will reduce your understeer. To practice this go to a safe track and start throughing your car around and you will find that these cars rotate really easily.

Ed,

you have H&R sway bars - I just wonder - do you keep them at same setting most of the time or do you adjust it often according to each track conditions, what are general rules about this part?

[GT3 Chuck]

with sway bars you start at the end of the car that is the problem...if it is understeer then you would soften the front bar...if it is already at full soft then you can stiffen the rear...if the rear is already at full stiff and the car is still understeering then you need to look elsewhere or change one or both of the swaybars to bring the car within the range of adjustability...as in the chart above if you can't sort the car out adjusting the sways, tirepressures, tire sizes or alignment there are other methods with springs and shocks...

[NorthVan]

Originally Posted by utkinpol

Ed,

you have H&R sway bars - I just wonder - do you keep them at same setting most of the time or do you adjust it often according to each track conditions, what are general rules about this part?

I do have H&R bars, I have them set as neutral as they can go. I have never touched them since the install, if I need to adjust the car I do it with tire pressure or adjust with the brakes and gas as you drive. There is no substitute for seat time and learning how this car handles under different circumstances.

[utkinpol]

Originally Posted by NorthVan997C2S

I do have H&R bars, I have them set as neutral as they can go. I have never touched them since the install.

Are those sway bars in neutral position any different from stock ones?