Hey guys, im a newbie to this forum, so forgive me if this has been discussed already, but i was a little confused on how the evo outhandles the sti. When you look at their awd systems, the sti shifts torque bias in two modes, either 50/50, distributing the torque equally between the front and the rear, or 35/65, giving the rear more bias for torque, which allows the front tires to do more of what theyre supposed to do, which is turn the car. The evo however, splits torque either 50/50 or 100/0, which makes no sense to me because i dont see the advantage in putting all the torque to the front wheels. Somehow someway however the evo outhandles the sti and has been for awhile, i know both have horrible weight distributions, (60/40 for both) and the evo is slightly less weight, but that still shouldnt be the deciding factor since weight difference is minimal. I also heard that the evo's steering wheel lock is 2.2 compared to 2.7 of the sti, could that possibly be the reason the evo handles better, simply due to steering response? If so, then all subaru has to due to own the evo stock for stock is improve the lock on the steering wheel and they would outhandle the evo. Can anyone decifer this for me?

 

you should do a search on the forums. There are thousands of discussions on this over the past 2 years. Also do a search on the car mag websites. Since I'm such a nice guy, here is Car and Driver's most recent.

Car and Driver Evo vs. STi

Another

 

To be honest, I've been wondering about that myself.

I do know that Subaru made some "significant" changes to the '05 which improves the steering and handling response. I also believe (though I stand to be corrected) that the (JDM) STi spec C holds the record for the fastest lap of the Nordschleife/Nurburgring track, so I'm sure the USDM STi handling could be brought up-to-scratch with a few mods.

 

what throws me off is the 100/0 torque split, it just doesnt make sense to me, the subaru spec c does have quicker laptimes, but we dont know if thats due to extra horsepower and displacement or because of handling modification, i know handling modification definately has more to do with it, but the extra ponies and displacement can also factor in, it ticks me off too being such a diehard evo fan, that the subaru outhandles it, thats the evo's pride and joy, its handling prowess over subaru, subaru winning that war is a slap in the face.

 

the spec-c is a fairly specialized version of the STi, i wouldn't fret about it too much.

 

so i guess its safe to say that no one here knows why the evo splits torque 100/0 and 50/50?

 

You use this word "and." You mean between, right? It shifts torque between 50/50 split and 100/0 split.

Now are you talking about the ACD system or the prior to 05 Evos with a limited slip differential?

If you are talking ACD, the ACD computer constantly monitors inputs (steering, braking, etc, etc) and drives a motor that is continuously changing the split via the viscuous fluid. That's why it's an "automatic" center differential.

Is your question why the ACD won't do a 0/100 split? Beats me why they didn't design it to send more power to the rear than the front.

 

it can't send more than 50% of the power to the back because of the design of the transmission in a transverse mounted engine. basically the transmission and transfercase drive the front wheels. The hydraulic center diff will "share" the power that is going to the front wheels with the rear wheels. In this way it is not possible to send more power to the rear than you send to the front, because the front are the primary drive wheels, and they can't "share" more than they keep for themselves. The subaru on the other hand is a longitudinally mounted engine and can send more power to the rear wheels.

 

My understanding is that the ACD is capable of fully disengaging so no power is sent to the rear (100:0), which is what happens when the hand-brake is pulled. This is not the normal operating state of the ACD, which varies the amount of lock between the front and rear. When it is fully locked, the split is 50:50.
You must keep in mind that actual torque split varies and depends on the traction obtained at each tire, because a tire that breaks traction will have the torque taken away from it by the limited-slip differentials and given to tires that still have grip.

 

The Spec C has more power and a lot less weight than any Evolution I have seen it compared with. When Best Motoring compared the VIII and Spec C the VIII handled better but wasn't as fast in a straight line. Also the Spec C understeered where the VIII was neutral/oversteering.

It is strange because not only does the STI have a more rear torque bias but it also has the boxer engine that sits lower, but it still seems to understeer more and so far doesn't seem to handle as well.

I know that those magazine tests said that the torque distribution can vary from 50/50 to 100/0 (and anything in between) but I am sure I read somewhere (and I think it was from Mitsubishi themselves) that it can send more torque to the rear (not sure if it was all the Evolutions or just those with the ACD). Not all the power but up to 40/60 or something like that. I am sure I read this and I will try to find where.

I think that so far Mitsubishi has put more development into the suspension then Subaru, especially with the MR. I think the Evolution had the Aluminium suspension components before the STI too. And another area is the aerodynamics, Mitsubishi test and refine the aerodynamics and the downforce in a wind tunnel and they have access to facilities and research from the Mitsubishi aeroplane (or maybe you say airplane?) company. I am not sure about Subaru.

Also Best Motoring keep saying that the Super AYC improves the handling a lot. This doesn't apply to the US though and a lot of people seem to disagree.

Aston

 

thank you all for the information, looks like i got a lot more learnin to do

 

im goin the ny auto show this weekend, itll be fun askin the dumba$$ sales reps there that question and hearing how they respond, it puzzles me how you can have a marketer at your booth who knows absolutely nothing about the car try to sell it, never made sense to me, but hey, when has the marketing department of any company ever made sense? Who knows, they might even surprise me and have a technician next to the car answering questions the way subaru did in last year's ny auto show