he wants to do it so he can steer with the throttle

 

The easiest way to get more rear wheel drive bias is to trade in your AWD EVO for a RWD Mustang.

 

new center diff!!!! quaife, ralliart, cusco...etc

 

What happened to the other 10%?!?


Cabo

 

Propeller

 

some of the responses crack me up. the 03 lacks a front diff, no acd, s-ayc, s-awc, etc... If a center diff will provide a 40/60 power split that would be perfect. Tire preasure, suspension setup, etc... take more time to fine tune for each track. Making the car more rwd bias would benefit me. If someone makes this part speak up, if not get to work!!!!

 

I think what you meant is the 03 lacks a front limited slip differential (which definitely contributes to the understeer in 03 evos). Lots of people don't understand (like the subaru guy from earlier) that oversteer/understeer doesn't just come from front/rear wheels losing traction from acceleration. It comes from weight distribution, chassis stiffness, and suspension geometry. Suspension geometry (mathematically) in the subaru sti==doodoo. This why it tends to understeer despite its rear wheel torque bias. Fast in and fast out is the best way through a turn, and this is why understeer is a very undesirable handling charateristic (it requires you to slow down during a turn). There are TONS of things that you can do to an Evo to introduce more oversteer in cornering, a few were mentioned earlier: larger front tires, changing tire pressure, a thick rear sway bar and also stiffer rear shocks/springs. A limited slip front differential would also help tremendously. You have to realize one of the MAIN advantages for an awd car is it's exiting speed from a corner. While a rear wheel drive (or an awd car with rear wheel bias) is exiting a turn it has to accelerate to pick up speed again which it cannot do if it is spinning it's rear wheels all over the place. After exiting a turn in a 50/50 biased awd car, maximum acceleration can be obtained because of the traction it has (no tire slippage). This is why the Evo is such a devastating road car. It is a 50/50 torque biased awd car that exhibits oversteer characteristics through the turn (which enables fast pre-apex cornering speed) and once its done with the turn, it has all the traction in the world to accelerate back up to speed.

 

I wanted to add this...

The Sti and Evo do not have "similar suspension setups" ...take a look underneath both.

STi suspension
Evo suspension

 

Well, just because a car understeers doesn't mean it's poorly designed. Both the Evo and the Sti understeer in stock format. In fact most cars are designed that way. Understeering is more stable while oversteer is unstable and therefore less safe. I'm talking from a point of view of an average driver, so any of you drifting gods please remain in your seats.

Mainly over/understeer is determined by weight distribution and in that sense both the sti and the evo are very similar. The greater rear torque bias on the sti means that on-throttle response in the sti will tend to induce mild oversteer - or reduces understeer. This allows you to get on the throttle earlier on the exit since it will keep a tighter line compared to a car that understeers more on-throttle.
[A car that neutral steers on throttle would also be nice, providing that you have set it up right for the exit. Perhaps this is what mitsu are trying to achieve with the evo.]

Anyway, there's no black and white answer as to which is quicker. It mainly depends on how you drive and the track you're at. It's largely agreed, however, that gross understeer is never going anywhere fast.

I have to second slow in - fast out. The point is that by not trying to enter a corner too fast, struggling to get around it, mess up your line and try to wobble out of it, you maintain higher cornering speed and gain exit speed. The 'slow' bit refers to the correct speed of entry which neither exceeds the limits of your car nor yourself. It doesn't mean you go plain slow, it's just that most people try to go faster by entering the corner faster and faster and end up losing exit speed. While this (slow in, fast out) is essential in heavy, underpowered, understeery cars, it also works with awd. It's not the ONLY way, but it's a very effective and consistently sucessful one.

Sabastian Loeb and Petter Solberg have spent several seasons going around corners a lot less spectacularly than many other drivers (Loeb, especially). They didn't stove and slide around a lot then waste a lot of time scrabbling out again, just smoothly in and out and the speed they carried through those corners are just phenomenal.

 

As to the original question, perhaps this will help

http://www.quaife.co.uk/catalogue/page52.htm

They do a front/centre diff as well. I don't know what the SAYC/ACD is going to cope with it. Looks very interesting however.

 

What are your trying to achieve? Are you trying to get faster on the track?
The Evo is actually very well balanced if the suspension is setup correctly. Chronohunter's car absolutely screams around the track and has just the right amount of over steer. Perhaps your suspension is not quite dialed in or it may be time to upgrade the driver?

 

Get a front diff like the ralliart/quaife.

 

Why hasn't anyone mentioned changing the alignment? If you put the rear camber closer to 0 degrees, it will become more tail happy. That, along with tire pressure increase and a rear adjustable sway bar, should be more than enough to make the car oversteer.

 

well.... the setups/hardware is quite alike:


STi
Suspension
Front: MacPherson struts (inverted) with aluminum lower
control arm, anti-roll bar
Rear: Struts with two lateral links and one
trailing link, anti-roll bar


Evo
Suspension
Front: MacPherson struts (inverted) with
aluminum lower control arm,
anti-roll bar
Rear: Upper and lower control
arms, one trailing link, anti-roll bar

* I italiced the difference, is in the rear, I am not going to pretend im a suspension expert or whatever, I wonder what could be said about having the 2 lateral links compared to the evo's upper and lower control arms in the rear.

I suppose you could note that the evo has beefier swaybars and possibly less camber hungry factory. Plus most have said that the evo's A046 tire is better than the sti's re070. * I have a set of A046 takeoffs for my STi and I will put them on come spring, I look forward to feeling them out

 

The setups are the same, the geometry is not.