Guest jjohart Posted July 8, 2005 Share Posted July 8, 2005 Hi, I've got an 83 280ZXT, I/C, 19lb freewheel, street performance clutch (Spec High Clamp pressure 267 ft. lb "organic"), the latter two not more than 16 months old. I have noticed that if I push into near high open throttle for power while underway in any gear, there occasionally is a noticeable revving up of the engine speeds, say from a happy linear rev in the mid threes quickly upwards by 10,000 to fours and fives. It feels by seat of pants and observation of rev counter (digital, alas), as if the clutch is slipping with the rapid onslaught of the power, the car still gaining speed, but feeling luggish. Once I notice this, if I back off and try again, after two or three times it simply doesn't happen..in fact, I drove 1,500miles this weekend to N.S, CA and back, and most of the time it didn't happen...it seems to be when the car is going to sudden ON-DEMAND with otherwise low load (i.e cruising conditions on b and a roads). I don't think it's the turbo "freewheeling", as I can hear the dentist drill noise and air it produces at WOT, and it doesn't sound strained, nor do I see any changes in the boost meters. Anyone got an angle on what this could be? I should mention that I've occasionally felt the clutch slip when the car is cold and I go from standing stop into 1st at normal loads...I've come to the conclusion that that is w.in normal limits. I also use Redline diff. fluid, as the shifter is quite balky in winter w. oem fluid. Any guesses appreciated! Thanks John Quote Link to comment Share on other sites More sharing options...
Tim240z Posted July 8, 2005 Share Posted July 8, 2005 The way I have always tested a clutch for bite is to engage the emergency brake (or use the pedal and side step), put the car in first, and slowly drop the clutch, and give it gas (just like you would if you were pulling off from a dead stop). If the car stalls immediately, you know the clutch is biting nicely. You will notice any slip immediately. HTH, Tim Quote Link to comment Share on other sites More sharing options...
EZ-E Posted October 13, 2005 Share Posted October 13, 2005 The way I have always tested a clutch for bite is to engage the emergency brake (or use the pedal and side step)' date=' put the car in first, and slowly drop the clutch, and give it gas (just like you would if you were pulling off from a dead stop). If the car stalls immediately, you know the clutch is biting nicely. You will notice any slip immediately. HTH, Tim[/quote'] Now see I have the same problem as jjohart. With one less factor, in first and second the car is fine and pulls easily and hard, after that in third above about 4k its starts slipping and in 4th, forget it. If I am hard on the throttle, it slips madly and just revs. This is with a centerforce DF clutch, not even over 18 months old. Like you said Tim I tried that and I can spin the tires off. I dont know why it only does it in the later gears. I know though that it is slipping there is no other possiblity, and I would have surely thought that the DF clutch could hold 360ft lbs of torque Quote Link to comment Share on other sites More sharing options...
JMortensen Posted October 13, 2005 Share Posted October 13, 2005 When you step on the gas either the car has to accelerate or something has to give. Your mechanical torque in 1st and second is multiplied further by the low 1st and 2nd gears, and this makes it easier for the car to accelerate. When you're in 3rd or 4th there is not as much torque multiplication making it harder for the car to accelerate. Now the clutch shows its weakness and starts to slip. The clutch test I always did was head uphill, put the car in 4th at about 40 miles per hour, rev the engine and drop the clutch. If it's weak you'll know instantly. EDIT-Forgot to say CFDF is a piece of junk IMHO. Quote Link to comment Share on other sites More sharing options...
A. G. Olphart Posted October 13, 2005 Share Posted October 13, 2005 As mentioned above, a slipping clutch first makes itself known in the highest gear under heavy load, when the most engine torque is being transferred. If/when a clutch goes away, it is sometimes possible to limp home in low gear as only minimal engine torque is needed to keep the car rolling... gear train torque multiplication again. Quote Link to comment Share on other sites More sharing options...
EZ-E Posted October 13, 2005 Share Posted October 13, 2005 Well from much reading in the archives after the fact I have found that only a few have had sucess with the CFDF clutch. I wish I would have done that before I spent the 272.00 on it with theyre claimed 90% over stock holding capacity. Whats worse is I see a lot of people talking well of Spec clutches and the fact that the stage 3 is only 317.00, and the stage 4 is only I believe 342.00, I really could have spent very little more for something so much better. Kind of disgusts you in the end thats for sure. Quote Link to comment Share on other sites More sharing options...
Sean73 Posted October 13, 2005 Share Posted October 13, 2005 I agree it's the clutch slipping. John - did you break in the clutch properly? Once it starts slipping, it's only going to get worse. Quote Link to comment Share on other sites More sharing options...
rudypoochris Posted October 14, 2005 Share Posted October 14, 2005 How do you break in a clutch, sorry for the newb question? Quote Link to comment Share on other sites More sharing options...
Sean73 Posted October 14, 2005 Share Posted October 14, 2005 500 miles of city driving. No high boost or hard launches. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted October 14, 2005 Share Posted October 14, 2005 yeh I would have to say it's slipping mine is doing it right now... but i have a n/a clutch on a modified turbo motor.. *whoops* dont worry my ACT is coming in very veyr soon Quote Link to comment Share on other sites More sharing options...
datsunan Posted October 14, 2005 Share Posted October 14, 2005 I just replaced my 13 month old SFDF with and XTD. Mine was doing the same thing but first started doing it on the dyno. When I pulled the clutch the disc looked fine but my FW had some stange spots on it like it got oil or something on it that burned and heated small spots in it, it also had some cracks so I'm glad I changed it to a 10.5 lb. Bite the bullet and buy a new clutch, to much power is not always a good thing to have when it comes to replacing new parts! Quote Link to comment Share on other sites More sharing options...
Guest jjohart Posted October 19, 2005 Share Posted October 19, 2005 Being that I have a NPR I/C boost control to 11-12, 3 inch exhaust, can I assume a return to a stock 280ZXT clutch isn't suicide, at least for a few thousand miles? I mean, it seems like all the other clutches have their own weak spots, anyway, particularly in wallet impact to longevity index! Thanks John P.S, my break in was pretty much hiway mileage, and no full boost for quite a few hundred miles (well, maybe once or twice of high boosting!). Quote Link to comment Share on other sites More sharing options...
spork Posted October 19, 2005 Share Posted October 19, 2005 yup, sounds like it's slipping to me as well. And whether you think so or ot...360ftlbs is quite a bit of torque and you'll want a good clutch (other than the one you have) to hold that kind of power. Stay away from the ACT street disk and pressure plate as well...I literally disinigrated the disk with around 300hp and 300ftlbs of torque. I ended up going with a lcutch from Superior friction (custom designed for my car) and it was right in the price range mentioned above. I do have to say that it took a couple of trys to get it to work lie I wanted, but am very happy with the results. I recently ran 125.8mph traps in the 1/4 which equates to around 466rwhp. It'll hopefully see the dyno fairly soon to verify that on paper Quote Link to comment Share on other sites More sharing options...
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