7A Transmission...dare I commit heresy?

Jordo! · 12-08-2011, 04:49 AM

Quote:

Originally Posted by wstar

Re: Osiris tweaks to the 7AT Torque Map: IMHO you should really only do that to adjust for engine torque, and even then on NA we're talking +10-15% over stock values at most. The guideline is to monitor slip under what should be lockup conditions (slip meaning RPMs vs wheel speed isn't stable), and tune the torque values just high enough to reliably kill slip.

When you set them massively higher than they need to be, it does exactly as you describe: every time you click the button it slams everything and kicks you in the butt. You're just causing excess wear all over your drivetrain, and more importantly for track stuff, you're upsetting the balance of the car. The last thing you want while upshifting out of a corner and still pushing to the side a bit is to suddenly shock the drivetrain and rear wheels. It may feel "faster", but the quick, smooth engage at a lower torque map value is better.

If memory serves, I've got it around 25-30% higher across the board after about 1.5K, and it is definitely much faster off the line. 3-4 can be a bit rough, and could potentially upset the chassis if you aren't careful, but I found that a gentle relaxing of throttle input on the shift will cause it to read a slightly lower load value, and soften the shift without losing engine speed or road speed.

That said, I imagine a slightly lower setting would be a good compromise for optimal straight line driving and cornering. Feels good to me as is -- but it's definitely something that would have to be experimented with by anyone tracking the car to get it just right. I think for a road car you can have it set be a bit more aggressively safely.

Also, the faster shifts should put less wear on the clutch bands, while only marginally increasing shock to hard parts. Overall, you probably break about even in overall wear and tear.

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