old motorhead

I had about 20K miles and more than a few trips down the qtr. mile on my ZR1 clutch. That's behind a Maggie at 650rwhp along with all that stupid *** Maggie torque. No problems. And when I be shiftin' on the streets, sumtime I be shiftin' hard too I hope every clutch that I own from here on is as good as that one was...and still is. I sold the car to a neighbor and he's lovin' it too.

Streetk14

I probably had 8000 miles on mine when I sold that car, and no issues with slippage or failure. Did a good number of 1/2 mile airstrip events with it at over 700 rwhp. Now, I'll admit I didn't abuse the thing and that I try to avoid slipping my clutches in general, but no OEM clutches are made to handle that sort of thing.

Maybe it's a luck of the draw sort of thing with that clutch? I dunno.... but I think if it's treated like an OEM clutch it will last a long time. If it's being raced every weekend, then it probably isn't the clutch of choice.

travis1693

Once again, AWESOME ADVICE from everyone. Gotta say I am bumming on the clutch comments as it's already here. Thought I bought the best one out there for my needs. Was just going for good drivability and something that could handle the HP. All the other reviews (not on this site) that I could find were pretty decent.

NormWild

I've seen quite a few regrets dropping the CR too low, it makes the car suck to drive low in the RPM range. When I do my rebuild I plan to keep it in the 10s.

NormWild

I finished up my Mantic Twin install last week, drove it all weekend and I am in love with this clutch. Glad I got talked out of going with a single disc by ECS.

Unreal

I would sell it and buy something else. The ls9, if it was $600-800 maybe would be ok for a lower HP car. Your new build should be 700-800rwhp easy if you do it correctly and there are just better clutches for the price. Mantic, RXT, LT1R, etc.

Detoxx03

Like Unreal said I'd return it and buy a real clutch.

02402ramair

So the motor lost several ring lands and closed the gaps on the plugs but graph does not show any dropping of cylinders.

I would bet this IS NOT the graph when motor let go.

travis1693

All new punched and stroked 408 ready to go back in!! All forged and balanced internals, JE pistons, Mahle keyed crank, new valves, milled heads.

schpenxel

Please don't let them blow this one up too. It'll probably survive more "inexperience" than the last, but they can kill it just the same if they don't know what they're doing

(good luck, hopefully it goes well..)

travis1693

No doubt, I definitely agree with you. The owner of the shop is doing all the work on this one, and the guy who was tuning it is no longer there. This time, the responsibility is all on them, so I am very confident that they will take the utmost care and tune on the side of caution. Due to the clutch break in period, it won't even go on the dyno for a while, just data logging on the street with me driving at less than 50% throttle. Keeping the AFR's in the 11.5 range per everyones suggestions. I'll be running 92 octane with 32 ounces of Torco to 18 gallons of gas from now on, and keeping the boost to 10 psi max. When all said and done, I'll be into this thing for a little over 20 grande, I will take no chances with her.

NormWild

$20K for a forged motor install?? What are you putting in that sucker?

schpenxel

I assume he means for supercharger, new motor, clutch, labor, tuning, etc.

M M Alexander

20K is still about 8K too much

DOUG @ ECS

Glad to hear you're happy with the Mantic twin!

Unreal

Clutches don't mind WOT. I would get it on the dyno as soon as it heat cycles and leaks are fixed. My motor has 12 miles when it hit the dyno. Clutch won't care about WOT pulls, just launching/engaging/etc.

07_C6_WPB

Some times you just have to give up on someone because they are not taking advice. That is this thread. There is NO WAY IN HELL this shop should be attempting such a build. They have NO CLUE what they are doing. They are pushing for MAX results with ZERO care for the owner's wishes. He wanted to be slightly conservative and they went max effort in a dangerous way, either because they don't know what they're doing or they're wreckless and just wanting some obscene HP number to use for marketing.

Now the wrong clutch is going in the car for the build. Clutches are a PITA, do it right the first time! The simple fact the shop said ok to a ZR1 clutch into a 408CI supercharged motor @ 10 lbs is silly..... unless they want to bust your *** for labor in a few months on a new clutch......

I give up!

Pitufina

schpenxel

I didn't say it was a good deal.. just that I HOPE he at least got that out of it. He could have gotten the same package, or better, from a reputable Corvette shop for that price

Ah well, live and learn. I do hope it works out well.

Streetk14

I think the clutch will be just fine. I had the same one for several years. It took the abuse of half mile roll racing and other shenanigans on the street at over 700 whp. I tried to avoid slipping it and didn't do any drag racing on slicks, but gave it plenty of hard shifts, clutch-dump burnouts, etc.

I do think there are better options these days, but I also think there isn't too much to worry about as long as he doesn't beat the living crap out of the car.

Low to mid 11's is a good place to be as far as the AFR is concerned, but you might want to think twice about that Torco. Just know that it contains MMT, which is that orange junk that collects in the combustion chambers, on the valves, 02 sensors, and in the cats. MMT has been banned for use in pump gas in the US because of it's effect on emissions system components.

I used to run the NOS Racing Formula octane booster (which contains MMT like Torco) in my twin-turbo BMW to help supplement our crap 91 octane, but stopped doing so after I saw what the inside of my turbos looked like after running. I'm sure it takes a while for any harmful affects, but it wasn't something I wanted to keep putting in my engines after seeing what it did and doing some reading on it. It's actually a metallic coating that accumulates as the MMT is burned.

Ethanol is a better octane booster IMO. There is obviously more cost involved to safely run E85 blends in an LS motor, but it's a better choice in my opinion.