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halik008 halik008 is offline
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Car: E90 335i
Default N54 FBO clutch slipping into 2nd gear from WOT 6.5K 1st? Possible? - 06-14-2019, 03:19 PM

About 10K ago I replacement the clutch with another stock LUK unit when I had the engine out. Flywheel looked fine surface wise. So I think clutch wear while I thing I am as good as it gets.

I am FBO on stock turbos, JB4 w/ E85 BEF & ///M3 LSD rear end.

I am almost positive that I am getting clutch slip from 1st gear redline WOT into 2nd gear. Basically shifting from first right into second and flooring the throttle again I just get raise in RPM without any acceleration sensation. IT doesn't happen all the time but it does happen.

The clutch delay valve has been long removed but it almost feels like the pressure plate isn't fully clamped down when the max torque hits so the clutch disk just spins?


All the usual test for clutch reveal no issues: Starting from 4th gear = stalled car, WOT from 50mph in 6th gear = angrily slowly accelerating car.


Is that possible? Perhaps i need to slow my left foot/right foot coordination?

Last edited by halik008; 06-14-2019 at 03:27 PM.. Reason: tbd
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landshark92 landshark92 is offline
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Default 06-14-2019, 11:54 PM

Try hitting it in 5th or 4th gear on the freeway at the speed and rpm that gives you the torque peak. I think that is a pretty good test. What rpm is our torque peak, something like 3,500? If that doesn't cause it to slip, I doubt it will in 2nd gear unless your powershifting it.

Sometimes it is hard to tell the difference between wheelspin and clutch slip in my car in 2nd gear if the tires are slipping ever so slightly. Sometimes they spin without noise and the sensation is very much like clutchslip, i.e. a raise in rpm and no forward acceleration.


2013 335is N54 / 6MT / JB4 G5 ISO "E85" BEF map 5 / Fuel: E40 / Phoenix Racing charge pipe / Diff lockdown / 70K miles

I'm addicted to meth but E85 gets me by...
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halik008 halik008 is offline
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Default 06-15-2019, 07:26 AM

Quote:
Originally Posted by landshark92
Try hitting it in 5th or 4th gear on the freeway at the speed and rpm that gives you the torque peak. I think that is a pretty good test. What rpm is our torque peak, something like 3,500? If that doesn't cause it to slip, I doubt it will in 2nd gear unless your powershifting it.

Sometimes it is hard to tell the difference between wheelspin and clutch slip in my car in 2nd gear if the tires are slipping ever so slightly. Sometimes they spin without noise and the sensation is very much like clutchslip, i.e. a raise in rpm and no forward acceleration.

For sure dont have a problem in those conditions.

Nah it's not tire spinning, my tires like to squeal when spinning and I get no noise plus the rear is well planted with no sense of looseness.
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