So I topped off the tank, pads, tires, oil, and set out for an all-too-seldom b5 s4 drive -- been down for wtf turbo/timingbelt issues for most of the last few years. Car rips, 034 tune stage 3 on 91 craptane -- the smoothest tune I've had since stock (build). felt great in the canyons, cold, 40degrees, patches of frosty runnoff around.
handling:
great, I've got the car rotating quite nicely in the corners, although takes a bit to get used to the awd again, the center diff setup on our cars is difficult to predict right out of the box -- if you pin it too early, when the car's loaded up in the front, you get push, but on exit, with the 4-1, you can put all she can eat in and only the slightest rear spinup.
then I got to the skidpad, came in, brakes glowing, pulled the fun lever at 40-50 mph, got sideways, fed in the power as I stopped countersteering and turned the steering wheels straightish, the front end began to push as I popped the clutch, so I turned the wheel more into the turn (opposite of countersteer) and fed in some go juice. The front inside tire lit up like a christmas tree. Repeated a few times, could even smell the brakes from the 'EDL' trying to slow the wheelspin on the inside front. I need a front diff, and/or a better center diff. The only thing allowing me to do continuous donuts is re-initiating with the e-brake.
I took a subaru sti '06 through the paces earlier this month, and the diff system was far better sorted... I could drift for days. It seems a front LSD may be required for my driving style, but I'm not certain if that would fully resolve the issue. One thing is certain, in that post about Farah's review (page 7), I went into some of the details about how our diff system works. And while for most driving, it doesn't matter -- but when you push the car beyond its limits, the open diff system is just bleeding power into the atmosphere, and only the braking system is preventing the spinup from getting worse (it was so bad I smelled brakepad, but this just puts heat in the brakes while simulating load to the center diff, allowing slightly more power to transfer rearward; but ultimately, this is a half-assed patch that ultimately ruins the drive as I wasn't planning on stopping and my brakes were already glowing on entry).
*edit* contributing factors: front tires were probably already a little cooked from the drive before i started drifting, front camber may reduce contact patch of inside front. regardless, i've always had the complaint that under power the car tends to send too much power to the front.
The 4:1 only helps late corner exit -- otherwise it has zero impact.
the rear LSD helps a ton. but under extreme driving, be it drifting or rallying, the front needs an LSD as well.
I wonder if the Type 3 Torsen center diffs like that on the later audis can be fitted somehow... or maybe the R8 style viscous coupling (primarily rwd bias, which is what I want). I've heard that the ALM guys were running a welded center... if anyone has any ideas on this stuff let me know (yes i'm aware of the 944 parts used to convert to RWD, not interested in RWD on this platform).
Audi AWD systems link
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Originally Posted by james 408
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