I am very confused. After reading the information from Mitsubishi on the Evolution VI and VII I was under the impression that the 50:50 split was just a starting point and the center differential adjusted the split to send more torque to the wheels that could handle it (according to all the sensors they use)? If the rear wheels started to spin or slide then more torque is sent to the front etc. so it could theoretically vary itself from a 100:0 to 0:100 split. Is this what you guys are talking about? I also thought the tarmac setting in the ACD set it to about 40:60 starting split and snow was 60:40 or something (maybe not even that much difference, I think I read the exact figures in an EVO magazine)? While typing this I thought maybe it was the ACD I was thinking about (first part of post) but I remeber reading a magazine that said the Evolution VI could do this too?
Aston

 

I dove a prelude SH around Waterford Hills Race track (near Detroit) and it does work, almost unaturally so! Ideally you would have some form of EBD (electronic brake distribution) to work side to side (measuring stearing angle, lateral load etc.) so it would bias breaking to the inside tires on turn in eliminating understeer then the active diff(s) would send the torque to the outside wheels. EVO IX anyone? The trick is making this stuff seamless and consistant. Everyone here has heard the almost universial hatered for the AYC system when used hard at the track (not just because it is prone to failure) because you never new what it was going to do next.

There is a lot to be said for a well tuned mechanical system.

There will be a day that a 30k car can have perfectly tuned electronic active diffs and brakes, but judging by the comments of track day users of EVO's that day has not yet arrived. may have done us a favor decontenting the VIII (except for the front limited slip )

 

My point was that it's not quite fair to compare the front-rear distribution in the Skyline to that of the Evo since the Skyline was designed as a touring car and the Evo was designed as a rally car. Your post made it sound like "rear-bias is best because the Skyline does it." Sorry if I'm misunderstanding you.

 

Indeed!! A lot of things to talk about. The main problem is that doing it through the email, takes away a lot of good things. I think, that just after this post of yours, I realized that we are talking about the different kind of usage or racing if you will. All of your points are from the road racing perspective, while I have mine through the autoX experience.For you medium speeds are mid-top of the third, which goes between the 60-100 mph. When I use the same range, speeds are in the 40-55 mph range. High speed for the autoX rarely go over the 65 mph, although I did see a few events where I was at the top of the third (even hit the rev limiter once, which happens around 105 mph), but those are rare exceptions that shouldn't really happen in this sport. And, most of the autoX courses are covered in a 2nd gear, so floored 400 HP car behaves somewhat different when the same is done in a 3rd or 4th. And the last big difference that I see here is that autoX setup has to be much more loose than RR once would desire.

So, going over this keyboard sharing experience and thoughts is still a lot of fun (especially when you have someone over there that likes the keep things in the right spots), but still nowhere close to the discussion that could happen over the or

Later!!


Fedja

 

Sti, EVO7 in Tarmac mode.....
On a dry road course rear bias is preffered.

It's: "Rear bias is better, that's why Skyline (and others) are doing it".

 

Generally speaking the greater the surface grip the more rear bias you want all the way up to 10f/90r on a good surface with "R" compound tires.

The reasoning for this is the greater the grip of the surface the greater the tendency for any car to understeer so we would ideally counter that by shifting torque to the back.

On a lower grip surface (rain, gravel, snow, etc.) car is much "looser" ( ) so more even torque split even a slight front bias (60f/40r) depending on how slippery it is. The Ford RS200 group B rally car had a lever that let you go from full RWD to 60f/40r !! I'm sure they can do even more than that now with electronics and all

The 35f/65r Cusco mechanical center diff is a nice compromise. Much more predictable than a slow reacting dim-witted viscous. Gotta find a source for a group buy

 

Keep me in the loop there too!!

Fedja

 

So you're not getting the STi?

 

What is STi??


Fedja

 

 

who is better viscous coupler or the ACD