Help with high rpm hesitation and/or clutch slip

StalkerStang

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Long read sorry, but I'm at a loss and don't know how I should proceed......

My 2011 GT had a stock clutch in it and was just intake and tuned after I first bought it. Never encountered any high rpm issues but then again I shifted it probably around 6700 rpm most the time.

I installed a GT350 manifold with the MMR adapter and stock TB. Made great power, 421@7200 on a Mustang dyno. The very first time I tried shifting it above 7K, the pedal only came back halfway. After doing a bunch of research and found all the clutch issues related to high rpm I started changing parts. I started simple and switched to DOT 4 fluid and a Mcleod clutch line. No change. I figured I was gong to have to change the clutch.....

Ordered a Mcleod Extreme street kit and a brand new Ford flywheel. Installed those parts along with all new bolts and a new Ford slave cylinder. After the clutch was broken in, I ran it up to 7500 rpm, and same exact issue; pedal came back only halfway. Happens in every gear. At this point I popped out the pedal assist spring, and no change either.

After dealing with Mcleod tech for a few weeks, they decided they would take back the Extreme Street and give me credit towards a RST kit. So, now it has a twin disc RST, Mcleods steel flywheel, and all new ARP bolts and hardware. At the same time I added Kooks shorty headers and a Lethal off road X pipe. Got the clutch broken in, back to the dyno for a revised tune (439@6600 rpm), and ran her up to 7500 rpm........ and still exact same issue.....

Literally the last part left; the clutch master cylinder. Today I changed it out for a 14 GT500 CMC. I romped it up and down the road a few times blasting it to 7K+ and still no change at all......

I've even verified that I have the "revised pedal assembly" that some of the early model 11's had issues with.

What is going on with this thing? I have tried it with the Advanced track completely off, just the TCS off, with everything on, no change. It goes into the gears just fine, no lockout, but the pedal hangs halfway up for a second or 2, and I can hear the engine hesitate for the same amount of time before it has full power again.

Is there anything in the PCM that could be causing this? It spins right up to 7K+ smoothly, I don't know what else to do......
 

StalkerStang

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So it seems my clutch issue is gone. Its possible that I associated the high rpm hesitation I currently have with the clutch slipping issues I had before the RST.

It does indeed shift at 7500 rpm with no slip but there is still a hesitation getting back into the powerband after shifting. I may be able to get my tuner to do some data logging on it Friday.
 

StalkerStang

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I data logged with my tuner yesterday, and in short it's my fault lol.

He asked me to go drive it and replicate the problem. After he reviewed my logs, he asked what I was shifting at, which I said 73-7400 rpm...... Nope.... data logs showing me turning it up to 77-7800 rpm! I'm smashing my 7600 rpm limiter lol.

Not my intention to rev in that high but now I know and need to adjust my tach watching skills!

Sent from my SM-G950U using the svtperformance.com mobile app
 

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