[dothackRAVE]

Okay, let's say I have a Lexus IS-F. Let's say this beast makes 431 horsepower at the crank, and 384 lb-ft of torque. Let's say this baby weighs 2989lbs, and has a weight distribution of 47% rear and 53% front.

Problem: This thing oversteers like a mofo under braking into a corner, and its barely controllable. That means weight shifts forward, and there's no weight in the rear to keep it in check. Under braking, the rear suspension lifts about 0.3 inches. I don't know how badly the weight moves.

Solution: I have the option to tune the following:

• Tire pressures. Currently at 28psi front and back on R compounds.
• Camber/Toe/Caster
• Anti roll bar stiffness
• Spring stiffness/ride height
• Damper rebound stiffness/bump stiffness
• Brake balance and braking force.
• Can also add aerodynamics, however I'm not sure if it's useful when turns come along since they tend to happen under sharp corners, i.e., not enough speed for aero to be useful.

P.S.>> This is for Forza 3, all aids turned off, etc., and I'm using it as a tool to learn about how cars react to tuning of suspension and aerodynamics. I know it's a video game, but I'm just going to assume it's at least correlative to real life.

Advice? Please assume that the driver is a god, so driver mods are not an option.

Thanks.

[Optical Toxin]

make the front more stiff than the rear. that should help a little if i remember correctly. i don't know if it correlates from fwd to rwd, but my honda had understeer. i corrected it by making the rear more stiff than the front.

[TRD]

I would try moving some brake bias to the rear.

[dothackRAVE]

Thanks Optical, that helped a little, but it still oversteers like a bitch and now there's some understeer. Some fine tuning will definitely be needed.

TRD, I did as you said, but I'm curious about the physics behind it. Care to elaborate?

[Optical Toxin]

it could just be how you are controlling the throttle. there are a lot of articles online which talk about throttle control to correct oversteer/understeer options.

[Tri-Power]

get a different car. The G8 murders in that game! Anybody drag race online in forza?

[dothackRAVE]

Originally Posted by Optical Toxin

it could just be how you are controlling the throttle. there are a lot of articles online which talk about throttle control to correct oversteer/understeer options.

Yeah, I'm well aware of the throttle control business. In most cars if it slips, it's quite easily controllable with some countersteer.

But this IS-F is behaving like the engine's hanging out the ass end like a 911. Uncontrollable oversteer to instant spin out.

Tri-Power, I have a Mustang Cobra that I use to drag race. Add me to your XBL! Name for Forza 3 is DaAznKnight.

[LightningTeg]

I played with the ISF and I thought it was an awesome car.

[vettehardt]

Originally Posted by TRD

I would try moving some brake bias to the rear.

That was my first reaction. If the clamping force on the front is too great, it will force all the weight to the front and leave the rear unsprung (probably causing some wheel hop). If you lessen the force on the front and increase on the rear, it will keep the rear more planted an the weight shift less dramatic.

[GrandChero4WD]

Originally Posted by LightningTeg

I played with the ISF and I thought it was an awesome car.

I was disappointed. I expected better to be honest.

[s2klover]

brake balance 47 front pressure at 110. how much downforce are you runnin?