Today is the first time i really noticed it. Starting at low rpms, in 3rd/4th/5th gear, go WOT and as rpms build and boost starts to come on. Right when it hits boost and peak torque the rpms 'hold' for a second then continue on as normal. I think its the clutch starting to slip, its a stock at 41k and ive never launched it or abused it. It loses all acceleration when it does it, falls flat. It was cool and kinda of rainy today. I didnt have the lappy to run Evoscan so i could be knock from bad gas and its cutting me off. Im going to go out after dinner and do a run with my neighbor and see if its knock. Also my tires are pretty worn and its been wet today, so i could be breaking traction, it did feel like the back wasnt planted when it happened. Im not to heavy on the xfer case and how the vcu works so i dont know if only the back can break lose. any help / ideas!! and what kind of clutch can i buy, i dont need a 4 puck crazy drag clutch. something just stronger than stock would be nice. Thanks.

 

act street clutch, MB7-HDSS, check em out

 

Ok so ive done some diagnostics and its not clutch slippage. its weird. Look here as airflow spikes and cuts back. same with rpms. Im blaming the wastegate. Its sticking shut, causing boost spike. then ecu puts full duty on wastegate solenoid, it pops open 100% and boost drops. I saw my boost gauge go from 20# down to 17# back to 20# when this happened, all within a second and a half. Look at the charts and tell me what you think.


Its not as pronounced in the second one.

 

Well, a clutch slipping is unique sort of problem. It is not going to leave you stranded and it will diagnose itself as you keep driving.

 

Today i got another data point, all windows rolled down so i could hear better, it is wet again today and i distinctly heard tire spin. sounded like rear passenger side. Which explains the rpm surge and hold (my tires have around 1/8 inch tread left, they're old). but why is my air flow spiking? You can feel it too, comes on hard with the boost then loses power, then gets it back.

 

So the roads are dry now and its warm out. no slipping, no tire spinning, no air flow spiking. I think the air flow spike is related to the loss of traction and the sudden rpm increase. not wastegate related. the car preformed fine now that its dry. that means i need new tires... only 1/8" tread. they're getting old. I have nitto 555 now, any suggestions about tires? i was looking to spend around $450-550 for tires. I might just stick with the 555's they lasted a long time.

 

I like Toyo. How many miles did you get with the 555's ?

 

yeah so it went away or i stopped noticing it, but now its back and its worse. So i know the clutch is slipping. I dont want to spent a lot of money on this bugger cause i just bought a laptop and im broke. lol. i found the oem clutch disc for $100, and the pressure plate for $130. So do i need just the disc or the disc and the pressure plate. Im pretty sure the pressure plate can still clamp 100% Every one at work tells me to get a crazy race clutch, but i dont need that at all, im slightly mod'd (Intake/ exhaust) so im sure that didnt put my clutch out to die. I got it used with 2nd gear synchro blown out, so im sure the previous owner was a bad driver. Thanks for any help! -- Jeremy

 

Interesting info ... usually when the clutch slips the rpms climb for a while and the car stops/reduces accelerating and then the rpm drops to catch up and the car continues accelerating ... If it is starting to slip you need to change out the clutch soon ...

 

yeah it like 'lets go' and rpms hold and then it grabs again, after its thru the peak torque region of the rpm range. im babying it a lot now i need the clutch to still last a little bit so any suggestions about just buying the clutch disc and keeping the old pressure plate and TO bearing? they appear to be fine.

 

Clutch slippage is very easy to diagnose. If your RPMS shoot up and the car doesn't accelerate, buy and install a new clutch. Also, if you smell the clutch burning (or smoking) this is another clear indication. Good luck!

 

You are correct it usually happens around the peak torque rpm range. Depending on your power level you could either replace it with a cheap stocker or go with an ACT clutch.