Originally Posted by redbird555
Those 2 statement contradict themselves. One one hand you're a dual disk will hit harder than stock and on the other hand you're saying it will hit less because it has less moi.
I think what you're saying is that a dual disk clutch will not slip like a single when you drop it and thats true in some cases however the moi is the real reason it becomes harder to launch. A good single like a monster level 3 isnt hitting any less hard than a single when you drop it so that point is sort of moot when you get into really good frictions like a monster level 3 or spec 3+. A lighter dual disk clutch will not shock the drivetrain worse than a heavy single. Thik about it you're unloading 50lbs of inertia onto the tires at one time vs 25 maybe with the other, the slightly increased rpm wont make up that. The reason a lighter clutch is harder to launch is because it transfers LESS inertia (shock) to the drivetrain making it bog if not enough throttle is given. Given the same rpm the heavier clutch has more of a chance to spin the tires because it transfers MORE energy.
The moi thing is a tradeoff but it still doesnt mean the car isnt launchable with a little practice. Hio's car weighs the sameas a c5z and cuts 1.6 60's so ya with practice its not hard. I can easily launch my 34 lb setup without bogging as well. Have you personally tried a light clutch?
It sounds to me like you would rather have a 50lb clutch robbing you of power ever second you're running through the gears than practicing your launch. Thats an ok approach for a lot of people but I want the most performance possible with what power I make.
I'm not saying it will hit less. I'm saying it will hit harder. Just because it has a smaller MOI doesn't mean it will hit softer than a stock single disk clutch. In fact, it won't. Then you have to rev it higher and it will lock up much harder. More rpm, more centrifugal force, more heat. To answer your question and support my statement, I have an 18lb clutch as well with twin 7" disks that is setup to handle a 950fwhp n/a motor. YES it has a much smaller MOI but NO it does not grab softer than the stock clutch. As I stated very specifically above, this information is geared toward new c5 owners, like Scott, who like to drag race a lot with their street cars with 400hp or less.
But the real question here is how many c5's have you had experience with launching with different clutches?
I get that you are proud of your clutch and it can be effective in the 1/4 mile if you have the car setup well, and of course it will help down track but it's not the right clutch for a new c5z owner who needs to learn the how to launch the car. That's what I'm saying.
And my next question here is: "Why change out the clutch at all?"
Here's why you shouldn't.
1) It's a huge expense for parts and labor
2) There's a significant chance there can be an issue with the install (ask thousands of c5 owners).
3) Some clutches chatter and have other inherent problems
4) A clutch that locks up isn't good for launching and shifts
5) Aftermarket clutches are harder on the driveline
6) More prone to wheelhop
Furthermore the c5z clutch has held up to 100's of launches in bolt on cars.
Some of us have done so without parts failure on the drag strip. These clutches recover very well also.
And the stock clutch is good for 1.6x's and better with practice.
There's a c6 owner who I've helped over the years who has something like 400 passes on his stock c6 clutch and cuts 1.4x's at will with gears and around 450whp.
My advice is that unless your clutch is failing on a consistent basis in a c5 then keep it in there and learn the launch with it with less chance of wheel hop and driveline shock. Take that $2000 and get the proper tires, gears, or headers and tune or some combination similar.
I bet Doug's lightweight Tilton, besides his well thought out setup, and great driving contributes to his impressive mph in the 1/4. Now if his Tilton was cutting 1.2x's vs. 1.5'x on the stock clutch, I might say it's worth it. ( sorry, I had to, inside jk)
But I can't tell you how many people struggle to launch their vettes with hard hitting dual disk clutches. And once you break the rear in these cars and it takes out the trans you'll be gun shy for a long time if you can afford to get it rebuilt right away.
Just looking out for other c5 bruthas with no motives or agenda other than to help them not make some of the mistakes I see happen all the time. And this is all assuming the OP and other are drag racing a lot with the car and are trying to cut a good 60'.