Clutch slipping, stock RB26

[Marus92]

Hey guys,

So after 2 years I have come to a realization. Could my clutch be slipping under boost?

Back in 2010 the GTR was litterally bone stock, airbox and everything. I gave myself a redline of 6500RPM, so keep it mind this is my reference for gear speed. In 1st gear in WOT I would get to 50-60kph in a flash, then in 2nd gear at I would only get to 90-100 in second gear.

Two years later, after a lot of meticulously taking care of my stock engine and still abiding to my 6500RPM and no launch policy, I can only get to 30-40kph in 1st before having to shift into 2nd which doesn't fare better when I have to shift barely at 80kph. While the engine IS stock, comp is 170 through the board and I have a boss exhaust system.

Thing is, the slipping, if it is the case, is totally smooth through the powerband, enough for me to just have thought I had one slow POS GTR. Also, the engagement from standstill is normal, it grips nicely and the pedal is stiff. I even got my rear tires to spin (on wood planks) when I was removing my crank pulley in 4th gear with the handbrake on.

Anyway, what do you guys think? Also, if I do need a clutch, where could I get a decent single plate for my limited budget? It's not worth going to a super clutch since the rest of the drivetrain is stock, unbalanced and it's a fuse, after all.

[Gordoskin]

Try out 4xtoys in lethbridge. I found a minty looking used exedy single with flywheel there for dirty cheap, they even threw in a new bearing for free. 80 in 2nd is slow, I can get 120.

[93_jdm_fd]

I went from a nismo twin plate to a stock clutch and it slips under full boost in 4th and I can't get past 5000rpm. When I get close to 5000rpm is just revs up and the car isan't going any faster. Non stock engine but the clutch is brand new so yours may just be starting to wear. Try it out in 4th and floor it from steady cruise at like 60km/h and see what rpm you can get to, of coarse without going past redline. You have to floor it though so you get full boost. If it doesn't slip then it should be fine. You can tell a worn clutch though cause the pedal get's higher and higher when it engage.

[bobbo]

It's easy. Get on some open road, get into 4th at a low RPM, floor it and if at any point the tach goes up quickly and the speedo stays the same your clutch is slipping.
It seems unlikely where you drive the car like such a sissy but it's hard to know for sure what the car went through before you got it.
There are lots of clutch options out there and it isn't a hard job to change it... just a long job. I've had my trans out twice and I'd suggest putting aside about 8-10 hours depending on what you have for tools.

[GTRADDICT]

I'm pretty sure I'll get a phone call soon...

[Marus92]

It seems unlikely where you drive the car like such a sissy but it's hard to know for sure what the car went through before you got it.

Bitch, please. lol I'll try it out. Think it would take 8-10 hours on a hoist? I have a friend that runs his own garage. I don't have the hardware to do it myself (my stands wouldn't go that high anyway)

I'm pretty sure I'll get a phone call soon...

What you think I can't do it by myself!? (you're right)

[GTRADDICT]

lol But yeah your car should be higher to back out the tranny

[bobbo]

I did it on a hoist both times. We took our time and thinking about it now we did all brake flex lines too which added to the time.
The only real tricky part is getting the trans back in again. You have to obviously line up the input shaft but to get it in place you have to clock it a few degrees to the right and the trans weighs about 150 lbs or more. Don't do it w/o a trans jack. The top starter bolt is a bit tricky too. You'll need some REALLY long 1/2" extensions as well.
If you read the manual, think it through, you could get it done in under 8 hrs.

... lets assume your clutch is fine and you're just being paranoid like most of us.

[PurpleStreak]

You might as well change the rear main seal while you're down there

[bobbo]

^^^Yup!^^^