SleeperZ Posted September 6, 2003 Share Posted September 6, 2003 New best time - R/T 0.162 60' 1.944 330 5.558 1/8 8.481 @ 84.08 1000 10.990 1/4 13.081 @ 108.56 Haha, I bet you're thinking "what's this post doing in the drivetrain forum?" Two things: I have a steel strap mounted over the nose of my diff, and it is getting noisier and noisier. The diff is beating it up, and now I notice there is about a 1/2" clearance above the diff and it's vibrating under torque application. I am gonna tie in some more steel and reduce that damn gap, I'm sick of taking it apart - although I need to check to see if my new factory diff mount is sheared - I hope I limited the travel enough to save it. So once that is tightened and quiet, I will hammer the 60' a bit more, and 12s will be in the bag... The ClutchMasters stage 4 clutch is definitely holding the torque, but the release is halfway up the pedal, and I'm used to my Centerforce II release which was close to the floor. So on my powershifting, I was close to hitting the rev limiter. Here is my question: It seems the L28 turbo Z people are using any old pressure plate (Jersey with the 2+2 PP, LJ with the Z32 PP) and the common theme is the ACT modified street disc. I understand this disc is mounted on a sprung hub, and it has 4 or 6 pucks. What could I expect running this disc with the Centerforce II PP? I'm thinking I should get good holding pressure, and the higher friction material of the puck disc should work well - and I get my pedal travel back. Opinions, questions, comments all welcome. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted September 6, 2003 Share Posted September 6, 2003 Uh... clutch engagement height is adjustable at the pedal. I think you need a 8mm and a 12mm wrench to adjust it. 12mm for the locknut, and 8mm to turn the shaft. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted September 6, 2003 Author Share Posted September 6, 2003 Uh... clutch engagement height is adjustable at the pedal. I think you need a 8mm and a 12mm wrench to adjust it. 12mm for the locknut, and 8mm to turn the shaft. I realize this, and I adjusted it until there was slop in the rod. The pedal travel it takes to disengage the thing is so much less than the old clutch. There isn't much thread left in the adjuster, but I suppose I will run it in some more...thanks. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted September 6, 2003 Share Posted September 6, 2003 24mph gain in the 2nd half is nothing to sneeze at. That is a strong indication of serious HP. Corrected for sea-level, it is about 12.23 @ 116.1. Get that 60' down to 1.80 and you have an 11.90 car at sea-level. Quote Link to comment Share on other sites More sharing options...
spork Posted September 6, 2003 Share Posted September 6, 2003 How do you correct for sea level, is there a formula somplace that you would pass on to me? Or maybe an on-line calc. that does it for you? James Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted September 7, 2003 Share Posted September 7, 2003 http://www.gnttype.org/techarea/misc/altitude.html Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted September 23, 2003 Author Share Posted September 23, 2003 Uh... clutch engagement height is adjustable at the pedal. I think you need a 8mm and a 12mm wrench to adjust it. 12mm for the locknut, and 8mm to turn the shaft. Appreciate the reminder. I finally got some time to work the adjustment - I had to adjust the pedal about 1/2" at the stop to get the clutch release close to the floor. Does anyone have any opinions on my clutch setup ideas? When I renew the clutch, I'm thinking about just getting the ACT modified street disc, but use the Centerforce PP. This CM stage 4 pressure plate has about the same pedal effort as the Centerforce PP, but about 40% less throw, so I'm thinking the clamping force is not as much. I could also get a possibly smoother engagement with more pedal travel, not sure if this a good thing.... Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted September 25, 2003 Author Share Posted September 25, 2003 Bump! I know there are many folks running 12s with a 5 speed. Does the problem people have with Centerforce more related to the disc? Aren't most pressure plates made of similar materials? I'm thinking I like the travel of the CF pressure plate, and if the material is the same, it should clamp a puck style clutch material better than a stock pressure plate. AFAIK, the clutch is the main issue with the turbo L28 over 400 hp... Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted September 29, 2003 Author Share Posted September 29, 2003 Bump! I know someone has a useful opinion here...anyone? Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted September 29, 2003 Share Posted September 29, 2003 Ohh, two bumps... you rarely see this here. Anybody care to help SleeperZ? !M! Quote Link to comment Share on other sites More sharing options...
Z-Gad Posted September 29, 2003 Share Posted September 29, 2003 I have never run a CF clutch in my turbo car, however, I do have one in my n/a daily driver. The clutch disk appears to be the same material as any stock clutch. The material will make a difference, but for me atleast, the clamping force of the pressure plate is what really made the difference. I had a stock 240mm pressure plate modified by removing the stock material and replacing it with ceramic buttons. I put the new disk in with a stock pressure plate and although it held better, it would give up ~15psi. I ordered the 512 ft/lb pressure plate from ACT and problem solved. It engages smoothly since I am still using a sprung hub, and stays engaged due to the clutch material and pressure plate. I do notice that my knee begins to ache if I am driving in traffic for long periods of time though. The price to pay for engagement Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted September 30, 2003 Share Posted September 30, 2003 Nathan is your clutch fork bent? Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted September 30, 2003 Author Share Posted September 30, 2003 Nathan is your clutch fork bent? No, I don't believe so. My CF clutch was working perfectly with full travel. The ClutchMasters PP and disc I'm running now just has less travel, so I had to adjust the pedal closer to the floor to release at the same spot. The pedal effort is about the same, so I'm thinking the CF has greater pressure combined with a longer throw. It does have those funky weights on the diaphragm to increase pressure at higher RPM... Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted September 30, 2003 Share Posted September 30, 2003 I've had the same proublem that your having also. I happen to still have been able to adjust the pedal to an acceptable level still. Seems like everytime I change my clutch the pedal moves more and more. Although I haven't confirmed it I had decieded in my head that the clutch fork must be bent. Now ith you having similar proublems maybe that not the case. Quote Link to comment Share on other sites More sharing options...
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