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Discussion Starter · #1 ·
So I went out to a vacant parking lot which had been rained on to see how my stock WRX feels in the rain.

It understeered like crazy. I could not get the rear end to break loose. I would turn sharply, and smoothly apply alot of gas and the front tires wouldn't steer the car at all. It would just acclerate in a fairly straight line even with the front tires turned. Massive understeer.

I have already ordered lightwight wheels and Kumho tires. What else within reason, can be done to make my stock WRX feel more neutral.
 

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The problem is setting up the drift to kick the rear out or get a 4 wheel drift. You are turning sharply and hammering the throttle....ie the weight is shifting rearward upon acceleration and the front end tends to lift(ie why an ALK kit exists) so it understeers. Try liftoff oversteer, when you enter in a low gear in relatively high rpms....as you flick into turn in, you let off the throttle quickly and use engine breaking to put load on the front and the rear breaks loose. Left foot braking is somewhat similar to this, where you are constantly shifting weight forward and giving quick stabs of gas to control the disruption(ie how long the drift lasts). Power oversteer is all about unweighting the outside while slowing, flicking it in and slamming the throttle to disrupt grip.
 

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As a general rule most car manufactureres build understeer intio a vehicle for safety reasons- your average person in sharp corner is better off having the front end plow vs the rear coming around. However most WRX owners are not your average owner and wnat a vehicle that handles as close to neutral as possible.

Your purchase of stickier tires and lighter wheels is good investment in the suspension dept, but will not help w/ understeer- in fact stickier tires tend to exasperate it as your tires don't want to break loose.

There are ways to influence how a vehicle handles. Here are some general guidelines:

-front tire pressure higher than rear (if you go real high-sometimes the opposite- as used by some of the D-stock boys as they can't change rear sways)
-front sway bar thinner, rear thicker
-front camber more negative, rear more positive
-front strut softer, rear firmer
-front spring rate lighter, rear heavier

I'd reccomend a thicker sway bar in the rear- adjustable prefered as there may be times you want more understeer (ie winter). The thicker sway bar will induce less understeer and as a bonus reduce roll. I'd also reccomend increasing front camber- oe camber is -.25 degrees. I'd increase that to -1.0 minimum, you can get -1.5 w/ stock camber bolts. This will also decrease understeer as well as give you a better contact patch through corners.

As schischwein mentioned there are driving techniques as well to help overcome understeer. One that works well for me is turning the steering wheel towards center (momnetarily) in a sharp turn- very counterintutive, but lets the tires regrip helping you get around a corner. If your tires are squealing in a turn, they are loosing traction- turning them back towards center lets them regain grip.

Big Sky
 

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Discussion Starter · #4 ·
"-front tire pressure higher than rear (if you go real high-sometimes the opposite- as used by some of the D-stock boys as they can't change rear sways)"

Is this correct? It seems if the front tires have more air pressure in them, that the contact patch will be less as compared to the rear tires with a fat, flatter contact patch. Am I mistaken?
 

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First us let me state that using tire pressure to adjust handling characteristics is not the best choice- tire pressure should be selected on best grip, but sometimes a person has no choice. Lower tire pressure (than optimium) will distort the tire more and have a higher slip angle. Increasing pressure (to a point) resists distortion more and will result in smaller slip angles. If you continue to increase pressure beyond the values that give best grip, tread will bulge and less rubber in contact w/ road resulting in higher slip angles.

That is what some of the D stock folks have done- increase tire pressure in the rear beyond the best grip (some are running 50lbs or more) and a resultant higher slip angle in the rear=more oversteer.

Hope that makes sense.

Big Sky
 

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It makes sense, I think you just said it backwards. Make the REAR tire pressure much higher than the front and this will make ther rear-end come around easier because they will be overinflated past their maximum grip pressure.
 

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That's it. It's a tough concept, as it holds true only up to a point- go beyond that point and it starts having the opposite effect. The D stock boys have to be inventive because of the limited # of suspension mods that can be done.

I never understood why only the front sway bar can be changed- clearly a disadvantage for FWD, AWD cars. A more fair approach would be you can only change one sway bar- your choice.

One more reason why STX was a better fit for what I wanted to do.

Big Sky
 
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