Clutch choices
 

This will be the first clutch Ive ever purchased and Im trying to narrow down my choices. Right now its an LS7 (quite heavy but cheap) offset with a lighter flywheel or a Monster stage 2. V8R has a Competition Clutch kit but I cant seem to find any reviews about it elsewhere online.

Anyone have experience with lightweight flywheels? Im asking you guys because with as light as our cars are Im not sure about taking too much weight out of the rotating mass and its effects to driveability.

The car will have around 450 wheel hp and will be mostly street driven with as much autox as I can (Probably 3-4 a year).

I really don't want a clutch that's an on/off switch and hard to drive around town but also don't want to replace a clutch once a year. Is that asking too much? :dunno:

What setups are you guys running?

I drive a 2200# car with over 600hp. Mostly on the street but as much road racing as I can cram in. For a few years Centerforce Dual Friction clutch hat and disc. The flywheel is a lightweight alum Fordenza.

That worked out really well for a long time, and then I broke the clutch hat. This time around I installed a Ram HD series. A bit heavier spring, but exactly the same hat, right down to the color and tooling marks.

Anyway, I'v raced the same car with an alum and a steel flywheel. I much prefer the light weight aluminum. When I stomp on the gas, there's no hesitation or delay at all. The engine shoots to red line in the blink of an eye. Off the gas and there's no coasting - it engine brakes almost as well as it accelerates.

On the street I find it very easy and comfortable to drive. I don't really understand why people complain about the low rotating mass. I think it drives great.

My new engine gets a similar set up for the LS1 - Ram HD clutch and Fidenza alum flywheel.

My experience is with bikes, but I know plenty of people that can't get comfortable with the increased engine braking. The chassis gets all upset and they have traction issues going back on throttle. Boils down to throttle control...and their lack there of. Wonder if it translates to cars? I really like the snap of less mass.

Excellent feedback, thank you boB. I really want a responsive feel so Im leaning toward the lighter flywheel. Any idea on the mileage you got out of the Ram HD? Do you have a wilwood or similar MC? I picked up a .75 bore hoping it will work well with the heavier clutch.

Ive spent the last 15 years on a sportbike so maybe that will help in anticipating the throttle and chassis control.

I'm running an LS6 clutch on an LS1 and like it. On your LS7 clutch what slave are you using? I ask because I just left my LS1 slave in and it started leaking last year...

Bob do you have to tune different for the light flywheel to?

Since I beat the car so hard on the track, I overhaul the engine every 2 years. That's about 24 track days, and another 6-8K street miles. Since I have the engine out, I just replace the clutch.

It's a Ford based car, so I use the standard Ford cable clutch. Easy, leak free, and dead on reliable.

No, same tune.

I went with a Centerforce HD (one step below the dual friction) with a billet steel flywheel 20K miles ago and love it. I engine brake like mad at the track and it's held up awesomely.

The car is a Ford so take my advice for what it's worth.

-Jason

What kind of power are you putting out? After quite a bit of research Im now leaning toward a twin disc. Too many damn choices...

Anyone got any experience with texzilla?%
I heard good things but never experience myself

290 hp, 309 torque at the rear wheels on a Mustang dyno. Add another 18% to 20% for crank numbers.

-Jason

Something to think about is the relationship between flywheel weight and vehicle weight. The flywheel is a mechanical device for storing kinetic energy. When you rev the engine just a little and slip the clutch to take off from a stop, the inertia (stored energy) from the flywheel helps to initially move the car, allowing a smooth process. So a heavier flywheel as a fractional mass of the car helps get it moving smoothly. If the flywheel is lighter, it is a lower fractional mass of the car, stores less energy, and it's a bit harder to get underway...or at least there is less "safety margin" of stored energy to help with an imperfect technique.

When you release the throttle while moving, the heavier the flywheel, the more inertia it has, which the decelerating engine has to overcome. Therefore, a heavier flywheel as a fractional mass of the vehicle will reduce engine braking; a lighter one enhances it.

The point here is there is definitely a relationship between the inertial mass of the flywheel (the amount of energy it can store at a given rpm), and the mass of the vehicle.

So, I'd submit if you pull a V8 drivetrain from a 3600 lb. vehicle that has a steel flywheel, and install that V8 drivetrain in a 2500 lb. vehicle, replacing the steel flywheel with an aluminum one that weighs 30% less, the relationship between flywheel mass and vehicle mass is actually unchanged. In that case, I'd expect the V8 drivetrain with the new, lighter flywheel to act about the same from a driver's perspective as the heavier flywheel did in the heavier vehicle.

Which is why I have a Fidanza aluminum flywheel for my '94 build. It's all about balance, Grasshopper...

^ Very good point.

LOL you always come up with the most brilliant insight to stuff that never even crossed my mind!

I'm forever sold on Spec clutches. My Spec Stage 2 was GREAT!

So I decided on a Mcleod RST twin and aluminum flywheel. Thanks Sunshine Guy for the informative post. Although Im a bit under powered for it, it leaves me room to grow which I like, along with the stock like pedal feel. I'll update here once I get it installed.

Thanks for the help guys!

Please do. My clutch let loose on me the other night pretty dramatically. Hasn't done it again since, but if it happens once its bound to again.:eek4:

You'll love the twin clutch! I have the Spec super twin which is about the same diameter and overall weight (35-ish pounds) as the McLeod twin. Once you get used to it, it's easy to drive around in traffic. And since they are rated at somewhere north of 1000 hp, you'll likely never have to worry about it slipping :)

Dave could you post up exactly which clutch and flywheel you went with? Mine is playing the same song as Gators....

I ordered the Mcleod RST Twin disc with matching flywheel. Mcleod builds their clutches to work with oem flywheels so you could use any flywheel from another manufacturer, a lot of guys do it. I opted to go with Mcleods aluminum flywheel, albeit a bit more costly, since Mcleod builds to order their clutches and gives you alignment markings for a properly balanced install. The RST is rated for around 700 street hp. Their next level up is the RXT, which has a higher rating for street and strip.

Theres a guy on the corvette forum that sells them for the best price I could find. His screen name is TPSMAK.

Cheers