rough acceleration

[teamo2t]

Okay... After 14 long months of working on my GST off and on I have finished... I have a bit of a problem (I think). When I start to engage my clutch it feels very rough almost like it wants to misfire or shut off... Once I get to about 1.5-2k rpm I am fine. It only happens in 1st gear...

Let me tell you what I have done... The car was stock. I installed full exhaust (2.5 in o2 housing and 3 in the rest of the way back with no cat), new valves (with valve job), evo III 16G, intercooler piping, DSMlink, 880 cc inj, 190 lph walboro, fidanza aluminum flywheel and Kevlar clutch, removed balance shafts, and prothane motor mounts. (Profile is up to date)

Any way part of me says that I just need to get used to the new clutch, flywheel, and motor mounts... Can anyone tell me if this sounds like it is even close to normal? I am not bucking or misfiring... it just feels strange.

I know this is vague, but any help would be great. Buy the way I did a boost leak test and I have a small leak at the throttle body...

 

[peypey's ride]

First off, take care of that boost leak at the throttle body. Whats your vacum pressure reading? How does your clutch feel? Any problems going into our out of gear? Your car will feel alot different from stock now.

 

[teamo2t]

Vac reading at idle is about -17 at higher rpm slowing down it goes to about -23. I will be fixing the leak very soon. I just got excited to be finished!

The clutch itself feels good. Shifting is very nice (also installed a short shifter). Engagement seems fine.

 

[teamo2t]

A friend of mine rode with me and said it feels like it could be just a matter of getting used to the clutch. It takes off fine if I rev to about 2k and release the clutch. it is just when I try to ease into the clutch that it gets jerky... Does any of this make sense?

 

[DGajre777]

A friend of mine rode with me and said it feels like it could be just a matter of getting used to the clutch. It takes off fine if I rev to about 2k and release the clutch. it is just when I try to ease into the clutch that it gets jerky... Does any of this make sense?

Yeah, that is called chatter. It sounds like some usual 1st gear 800-2000RPM chatter on a non-organic disc. I get that on my car when I don't slip it.

Is the clutch new? How many miles on it? What kind of 'kevlar' clutch? Are you still in the break in period?

If you aren't in the break in period, try this - do a launch to heat up the disc and then come to a stop. Then do a normal acceleration and see if the same thing happens.

 

[teamo2t]

It is the Fidanza 3.2 Clutch. I only have 92 miles on it... still breaking in. I do notice that the disengagement point for the clutch seems very low to the ground. I will be adjusting that this week end to see if that helps a bit. I will also try your "go crazy and see what the car is capable of hoping that it fixes itself" method after break in. Overall, I am pleased. I am just being cautious.

By the way the clutch description says "However, since it has no marcel (cushion) this disc sacrifices a little bit of its smooth engagement. " I guess this would lead to what you are describing as well.

Thanks for the advice... I need it!

 

[DGajre777]

By the way the clutch description says "However, since it has no marcel (cushion) this disc sacrifices a little bit of its smooth engagement. " I guess this would lead to what you are describing as well. !

Yes, and it would be worse if you got the Fidanza 4.3 which uses a ceramic button disc like the ACT 6 puck sprung hub discs.

 

[teamo2t]

Well thanks. I guess my question has been answered... "Yes this is to be expected"

I have noticed as I get better and the clutch breaks in the problem is getting better. I think engagement is a little low on the clutch. I noticed in reverse yesterday. It is almost to the ground. Well I will be going home and fixing that tonight.

As always thank you for lending your expertise everyone...