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Automatic diff options for autocross

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blasterracer817

10+ Year Contributor
71
3
Jun 29, 2012
Winona, Minnesota
Alright, I've been trying to find this and am having minimal luck with the answers. I have a 95tsi awd I am going to start building for autocross/ road race. I would be building the trans and all that fun transmission related stuff. However I want to run eather a paddle or slapstick style shifter rigged up off a roads urge so I have complete control of shifting so it's like a manumatic. Now my questions are. Can we run the same diffs as manual guys. For example I want to run an evo 9 rear diff with the tre mod. A 4spyder center and lets say a kaaz front. Is that even possible or am I screwed? Otherwise ill have to buckle up and five speed swap. But I'd rather use the auto for it. Thanks
 
Quaife or Wavetrac front, you can use a 3.8 front diff, 1.074 tc, 3.545 rear with mech rear lsd. Redlines quicker than the 3.307 rear auto setup.
Convertor likes the gearing more, yet it only sits at 50rpm more at 110kph on the freeway compared to a 3.307 setup.
Cheers
 
blaster, you dont want to run a kazz or cusco front diff as they are clutch type and require special fluids to work. As AWD stated you want to run a torsen style diff. The quaife and wavetrac are torsen as well as factory mitsu LSD when you can find them. The evo 8/9 rear can be used as it is the same 3.3 as auto setups. I am pretty sure a 4 spider can be made but it is least important of the puzzle. you do want to run a torrington bearing mod for the center diff.
I believe that is far more important than four spiders.

AWD, you may want to clarify what stock is and what you are recommending. It sounds like you are recommending a custom ring and pinion for front diff so he can run the quicker 3.54 rear ends.
 
In Jap land they have RVR SG non turbo awd autos. We have a few here in Aus.
They run a non lsd 3.545 rear, 1.074 tc & a 3.8 57/15 front std. Same centre
line measurement as a turbo auto box. But the casing of the box is narrower
to make the starter motor line up with the ring gear on the 3 bolt convertor.
You can scavenge a few bits off the box like valve body, end clutch etc.
For the price of an anchor non turbo auto box, you get a pinion, crown & bits.
Custom front diffs I do get made here for specials & they are expensive.
Like the VR4 turbo auto 3.6, 1.090, 3.307 the 3.8 setup is out by 0.007
The RVR turbo auto is 3.55, 1.074, 3.307 only out by 0.002 better for locked.
Cheers
 
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Wow thats very cool. yes the price of the box would be worth the ring and pinion. do you have the numbers on the box that would have the that 3.55 or 3.60? I would like to try to find one here in the states. I have long since wanted to setup an auto with the 3.55. car would be sooo much more fun around town. do you have any video links of a car setup this way?
 
Last edited:
Check out the 92 Expo yous have over there. Auto with a 3.545 rear. Dunno what tc & front diff is.
I will look at the code on the non turbo auto anchor I have here in the daylight. 1:40am here now.
Maybe tomorrow if I have time. It's not legs for big mph, but it's a great DD. Fuel is not too bad.
Read your PM about my hybrid turbo.
Cheers
 
94awdcoupe the N/A awd auto has the usual W4A33 on it & W4A32 on the overdrive cover.
The turbo box has W4A33E on the side & the N/A has W4A32EF on it.
Cheers
 
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