I have been experiencing a loss of power lately and I think it is my stock clutch at the end of its life. Seems as thow my car will not boost as much anymore. Pretty much I can can look at my air flow percentage (MAF voltage) pulled on anyone run and that would coincide with boost pretty much. Well just before this decrease in power I would flow 87% of my MAF sensor metering capability..........know I can only flow about 70%-73% percent which is very noticable even by SOTP and boost seems to be lower to.

My theroy is that a slipping clutch can cause a loss of boost psi because there is a loss of load, spinning the clutch is alot easier than accelerating the a car, and the lighter loading on the engine reduces the amount of boost it can build. Same reason you can't build boost (very little if any boost) will in neutral no load no boost.

So you have an idea about the air flow percentage:

When the clutch wasn't an issue I could pull:
75% airflow by like 5,300rpm (feel's very nice)

Now:
60% airflow by like 6,000rpm and tends to go hand and hand with rpm until 7,000rpm then per ever 200rpm it only gains ~1% or so to a max of 70%-73% if lucky.

When the clutch was good it'll pull to 7,500 - 7,600 rpm (bounceing off the rev limiter) with increasing airflow all the way with no stall.

I'll try and explain how awesome my car was at 8psi with the fresh 6 month old factory clutch with heavy ass 17's, 1st gear would slam off the rev limiter (I mean slam off the b***h) bounce back to 6,000rpm and burn tires all the way back to 7,500rpm again, shift to 2nd gear pulling super hard and still burning tire but going forward very rapidly to 60mph, then 3rd gear it was all for most V8's Ford and Chevy's.

Know I wouldn't even dare try.

P.S. Bouncing off the rev limiter in 1st and still stay on the gas knowing it not over yet is so awesome the way it just pulls right back to redline so hard then shift to 2nd by that time im talking to myself saying GOD DAMN!!! this MOFO pulls like a b***h.

If you think you are seeing a lot of power with a stock clutch, wait until you get an ACT clutch. Even with my minimal mods I noticed a monumental gain in the SOTP feeling, where I jump out of gears. I easily chirp 2nd gear, and did so even before I had my 91 cam and exhaust. Get the ACT, its worked well for me.

Ju§tin

I think it has alot to do with the way you drive and if you break your clutch in properly. NA I didn't just chirp 2nd I got a few revolutions with my heavy 17's and a chirp in 3rd with only a SAFC and PR CAI and 17degree timing.

Turbo'ed I spin threw 2nd with the same 17's and in 3rd the stock clutch usually falls on its face and I have to feather the throttle.

I'm gonna look into the ACT clutch assembly, or I might just only upgrade the disc and keep the stock PP, haven't decided on that yet.

Hey Charlie
When are you going to bring your car down? I have known you all this time and no love. whats up?:confused:

Mike Jurado

Is this Superior Nissan Mike..............wassup my man!

How much boost have you been running to hit 87%. I don't think a stock clutch would cause you to loose boost, it just might not allow you to hit boost until a higher rpm, if your running stock boost and hitting 87% i'll be amazed, must be the fact that yours is ballbearing, and avenier, plus no exhaust, also lower elevation then me. I know when i went to california with my car N/A i was like damn my car hauls ass. Slipping clutch is a bitch and just cause it to take longer to grab but once it does grab it should go to the smae boost as before. Do you have a boost gauge yet? I understand what your saying about how a slipping clutch is like haveing the car in nuetral but i would assume that once it grabs it would hit the smae boost maybe just a little later in the rpm's becuase it has to build....In any case, yes i think its hendering you but hitting less boost i doubt. Maybe i'm wrong...if you don't have a boost gauge get one and we can see...:D

BTW my wastegate actuator is off a U12 Bluebird, and yes it is boosting whatever that is set at. I haven't got a boost gauge yet I have borrowed a friends autometer boost gauge which yeilded around 7~psi and I did a little trick and got it to a max of actually 8psi and that is what it should be at right know.

Yes this is what I hit at 8psi, 87% on a cool night, and 85-90degree weather usually no lower than 80%. But the biggest problem is how late in the rev range it takes to pull that amount of airflow know. I figure its my clutch going but I could be wrong.

Blue93G20 once the slip starts there no catching up so max boost can't be achieved is your clutch is slipping. Its doesn't being slipping then gripping, it begins gripping then slipping and then it sorta just never locks up and the possibilty for a lack of boost, I have doen a search on this and have found 2 sites that sorta back this up, I'll look for them and post the link and you can help me decide what you think it is.

Yes its me.
We need to get together and torture some civics.

Mike J.

http://www.roadraceengineering.com/projectEclipsepart5.htm

Originally posted by MIKEY
Yes its me.
We need to get together and torture some civics.

Mike J.

Talk about hidding out 5 posts. lol

Yeah, will get together soon and torture some civics and assorted V8's, hows that Nismo clutch assembly doing and your new rebuilt DET engine?

Look at the highlighted part:
http://216.239.37.100/search?q=cache:QJ_svlLREcUC:frontpage.inficad.com/~houlster/Amigo/Turbo/oldnews.htm+boost+psi+vs+slipping+clutch&hl=en&ie=UTF-8

The car is doing great. Just replaced t25 for t28
new down pipe. Im very happy with the car
:D
Mike J

DAMMM 1731 post!! Your a post aholic... LOL

I know I need a new life. lol

which act clutch is the best for having around 270-300hp that has a relatively smooth engagement but will handle that much horses. and around 240-250 horses at stock boost. So which act performance clutch will handle a range of 240-300hp with no problems and have a relativly smooth engagement. I was thinking of the act extreme pressure plate with the act street/strip organic disc. they said that clutch has smooth engagement but it doesnt say what it can handle. I know the pressure plate is a good choice but should I go with something better like the six ceramic pad disc. let me know