I have a 1998 Max. Most recently I added a centreforce dual friction carbon Kevlar Clutch and a still B-Pipe. (Clutch feels just as light as stock by the way) Since then on quick throttle the car starts choking almost like it's going to stall and it shakes the crap out of the car. I know it's not the clutch as it engages and disengages silky smooth with tremendous holding power, I begining to believe that it's because of the lack of back pressure. Any comments. I have everything else done Flywheel, UDP, Y-Pipe, HKS superflow intake, etc.

The dealer thinks it's a sensor, or the silencer on my Apex-i exhaust. Please help.

 

Replace your 02 sensors with all that airflow you should have replaced them with the y-pipe install.
Try that first and install them yourself dont pay the dealer to do it.

 

Today I replaced the O2 sensor by the CAT and I'm still getting the fluttering on hard throttle. Can it be that I should have a resonator installed to have some sort of back pressure!

 

Do you think this may be caused by the clutch not being broken in properly?

 

Well dang the 02 sensor should have fixed it. The lack of back pressure does not really have anything to do with it. With a lack of back pressure you will lose some low end thats all but not a chug chug thing. But heck you never know ask a muffler shop a good one will know the answer. Sorry I could not help further

 

My friend has the centerforce dual friction clutch carbon blah blah blah, and has the aluminum flywheel, with a short shifter... after taking it out on it's maiden voyage, there were no probs, it gripped great and it felt fine... besides the stifness of the S.S.

 

So you definitley dont think it's the clutch!!! One other thing I noticed to day as I'm reversing if I press the clutch is seems like the B-Pipe (Stillen) is hitting one of the heat shields. I noticed the since this installation most of the problems started. I think my next step is to put the factory B-Pipe on and see if this corrects the problem.

 

Hmm... I don't know what to tell you... A problem I realized on my friends Max is that there was a knocking in the rear if we hit a light bump or any slight movement in the rear of the car, turns out the "Rear Stabilizer Bar" was set wierd and it hit the car in one area... As far as the clutch thing goes, I don't know what to tell ya...
Figuring you didn't instal the clutch yourself =Þ take it to the place of installation and YOU take them for a spin in it...or something...good luck.

 

I think that the O2 sensors on the Y-pipe have a lot more to do with engine control than the one on the cat. Your car is probably running rich, which would cause the stutter on heavy throttle starts. My car has been doing the same thing since I added the Y and intake, and I know it is running rich because I can smell it. If anybody knows better, please let me know before I blow $$$ on new sensors.

 

I'm not sure if its the same feeling but my friend had that on his skyline, blowing crap out of the exhaust and feeling hesitation when accelerating. He found that his coils and spark plugs where the cause and the engine wasnt getting enough spark.

 

I brought my car to a race shop that's very well know with Nissan's. The problem is the lighter flywheel that's causing the vibration on abrupt throttle. He explained it as less inirtia is required to spin the flywheel because of the fact that it's half the weight, it throws the balance off when you stomp on the peddle from a coasting position. It was also confirmed with Stillen that this is a normal occurence which will eventually fade away. Basically I have to live with it.

Now I've completed the installation of my Stillen B-pipe with an aftermarket resonator and a Car Sound Stainless performance Cat. It sounds pretty good aside for some droning at 2.5k - 3k and some knocking on the rear heat shields over bumps and hard acceleration. I'll fix this on Wednesday.