Mad Understeer

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DoctorFool

DoctorFool

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DoctorFool
So I am currently tuning my RX7 for touge because I decided I wanted something JDM to keep the culture going. I am going to signup for that huge touge event that's going on, but not yet. I still need some help on my car.

I was reading in the tuning section that more Camber can help for understeer. My car is understeering like crazy and I would rather have it over steer. Is there anything else I can do to help my car turn better besides Camber?
 
Toe angle has a greater effect than camber.

Try stiffening up the rear spring rate to above that of the front, and up the rear roll bar value to about 6. Front roll bar perhaps about 4 or 5.

Also, set the front camber to about 1 and the rear to 0.5.

Set the front toe to -0.05 and the rear to 0.

This isn't specific to the rx7, but works across most rwd cars as a starting point.
 
Camber also depends on how much lower you've set your car - the lower it is, the more camber you'll want to dial in. I'd start with doing one thing at a time; as Mubble mentioned anti-roll bar stiffer rear, softer front will make a big difference in the way the car handles.

If you put too much camber or toe, you can actually lose grip or turn-in, so be careful - these setting effect overall grip the most. Also, the differential can help getting oversteer, try setting initial torque higher, and braking response a bit higher; that can help spin the back tires up and get the car to rotate, the braking response can induce rotation during braking and initial turn-in.
 
Thanks I will try this but I am just worried about my back sliding out now since it's going to be stiff.
 
Try Ballast to and see where the weight position of the car is try and get it balanced and make the LSD higher values
 
DoctorFool
Thanks I will try this but I am just worried about my back sliding out now since it's going to be stiff.
Click to expand...

Well, that's the downside of reducing understeer - you're gonna get oversteer.
 
If it's understeering when you're off the throttle, lower the rear ride height a few mm and/or raise the front a few mm.

If it's understeering when you're on the accelerator, stiffen the rear shocks. Increase in small increments until it's neutral.
 
So now, to help the back from losing grip (it loses grip then can easily spin out) should I add a ballast with a position of 50 and add some downforce on the wing? Or Should I soften the spring rate?
 
Here is my setup so far.

This is a 1990 RX-7 GT-X (FC) (Premium)

Aero rear: 17
Ballast:

Amount: 110 KG
Position 50
Weight Balance - 50 50

Ride height

Front -25 Rear - 25

Spring Rate

Front 5.5 Rear 7.2

Dampers (Extension)

Front 2 Rear 4

Dampers (Compression)

Front 2 Rear 4

Anti Roll Bars

Front 3 Rear 5

Camber angle (-)

Front 2.6 (-) Rear 1.3 (-)

Toe Angle

Front -0.05 Rear 0.00

Brake Balance

Front 5 Rear 3

Any help would be appreciated. Trying to make this a perfect Touge machine!
 
Raise the ride height at the back slightly and also your going to have to put more negative toe in than that to get a difference.
I will make an rx7 and see what I come up with.
I have the FD3S RX7 and that for me is the ultimate Touge car, it doesn't oversteer or understeer, it grips so well, I'll set it online for you if you'd like to try?
 
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I suggest that you increase front toe a bit more, and reduce rear aero. It usually makes the car understeer when both entering and exiting high speed turns. But it comes at the expense of stability at high speed and the braking distances become longer.
 
I would tighten the suspension up quite a bit; @ -25 front and rear, you would want much stiffer shocks or you are likely going to bottom out. Try like 9.8 front, 10.2 rear, keep the front anti-rollbar at 3 and try 6 for the rear; also, the damping should be 4 front, 5 or 6 rear - this should tighten the car up quite a bit (meaning quicker to respond to your input), while still allowing it to not understeer - also that may be too much camber, but I'm not sure about that, I'd have to check what I run mine at to be sure - seems like a lot on a stock car, but some cars just like more camber.

Set some laps with the setting I gave, then try dropping the camber in the front to 2.0, and the rear to 1.2 and see if you pick up time.
 
Try 15/25/20 on the LSD
2.5 front and 1 rear camber
-15 front and 10 rear toe
put your arb 1 higher on rear and lower front a bit more on the back
remember you can increase and decrease grip by throttle and brake control while racing
 
Your setup is not good to be honest. Assuming you've done all the modifications to the car, drop it to the bottom front and back, stiffen up the springs to 13-14, same front and rear because the weight balance is 50/50 and the shocks and ARB at 8/7/6 front and rear, leave the toe as zero for now and the camber at 2.0 front and rear and see how it feels. LSD around 8/15/5 to start. Should handle quite well with that setup.

Try that, see how it goes and I will tell you what to do from there if it's over or understeery.
 
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