What would cause power understeer in a RWD car. For instance, the car turns in well under braking and in short turns but in long sweeping turns it understeers when even the slightest amount of throttle is applied.

 

Swaybar setting , to light of a rear spring, what your tire stagger ?

 

You have to be on balanced throttle before the entry of the corner on long sweeping corners. Otherwise the weight transitions from the front to the rear, taking the load of the front tires, which can (will) cause understeer. RWD cars always created understeer just before power oversteer.

 

^^ Well said. It would help to know what the entire set-up includeing tire stagger (F to R) difference is, to actuall offer any type help, though.

 

if the car is stock, this is exactly how it's designed

without listing all the specs, from tires to alignment to pressure, etc etc, there really is no way to give you a 'why'

 

Setup is as follows: Front tires 245/40-18, Rear tires 275/40-18, stillen front and rear sways, cusco zero 2 coilovers, cusco a-arms. 2 deg camber rear, 2.5-3 deg camber front. front sway is at mid-stiffness setting, rear sway is at high-stiff setting, coilovers set per manufacturer, damping is level 3 front, level 4 rear. Running 35 psi on all 4 tires as this seems to be the sweet spot for my tires (potenza s-03 pole positions)

 

I should also mention there is a stillen s/c also, which adds weight to the front.

 

what tires? what pressure? what toe? how much preload? what height? NA? FI?

 

^ lol...

 

ok - well the s/c definitely is contributing to things since it adds, I'd imagine, over 100 lbs or so to the front end

here is a nice concise chart that should give you a good starting point on what to address

http://www.rogerkrausracing.com/Tech...verunder.shtml

 

245 front and 275 rear comes to mind as a wrong setup...

 

non-staggered ftw! its what all the JDM time attack cars run! lol