Hi,
I need help choosing a clutch.
I lost 5th and 6th gear earlier this year, which pretty much predetermined my next project on the car. I already sourced a "new" (to me) transmission and figured out that while pulling it out it would be a great time to rebuild the rest of the drivetrain. I will be replacing the bearings and couplers on the torque tube. I will change the rear seal on the engine and pilot bearing and all the hydraulics for the clutch.
The plan is, after I rebuild the drivetrain, to put a H/C/I on the motor with all other necessary boltons. The final goal is as close to 500RWHP as I can get.
The approach I am taking is not only making HP but reducing weight. Let me make this very clear - This is not a drag car, nor will it ever be. This is for fun, driven aggressively, carving the Colorado canyons and maybe doing an occasional Autocross once or twice a year at a car show. I want it to rev fast and since it has a few miles on it, to take it a little easier on the crank.
So I already have bought an aluminum Fidanza flywheel. It was a deal I just could not pass and it is brand new. What I need help with, is picking a clutch to mate to it.
What I need the clutch to do:
-Not brake my bank account
-Be light
-Be able to handle 500rwhp
-Be user friendly on the street
-Be quiet
-Last me for a while

Any recommendations, advice and personal experiences are greatly appreciated.

 

I have a Monster stage 3 in my 525rwhp car. It also has a Tick master cylinder. Pedal pressure is a bit stiffer than stock but still easy to drive. I don't have any chatter but as with any puck style clutch it has an on/off type engagement. I love the clutch but if I had to do it again, I would spend a little more and go with a twin disk.

Also your driving style matters. You can get by with something like an LS7 clutch but if you are going to the track, there are better clutches.

 

I have a SPEC Dual Disk but, its expensive and some people don't like them. Mine has worked flawlessly and I beat it!

Some things that you need to be concerned with.

FLY WHEEL HOT BALANCE!
NEW PILOT BEARING

Slave Cylinder critical measurements for shimming!!!!
Look at both of the pictures in the add.

http://www.tickperformance.com/tick-...im-kit-3-pack/

TORQUE TUBE DISASSEMBLE AND INSPECT!
Inspect the bearings and couplers.

Bill

 

Getting up around 500hp it seems the single disk clutches capable of holding the power are describes as on-off switches. I've read quite a few people who claim their McLeod twin disk clutches are as light or lighter than stock with very easy pedal modulation yet they also easily hold the power. A side benefit is that they are a smaller diameter with a lower moment of inertia. If I do get a build that hits around 500hp+ I'd probably use one of these clutches even though they do cost a fair bit more. I do like driving my car and having a on-off switch for a clutch with a heavy pedal just doesn't sound like any fun to drive.

 

my main concern here is what clutch that is capable of holding 500+hp would be a good match up with the Fidanza flywheel? I searched and read a lot about different clutches, but everything I found was either from years ago or not concerning my intended use.
I read somewhere that not all clutches are going to do good with this particular flywheel. Some say that twin disc clutches will have pretty pronounced chatter WITH THIS PARTICULAR FW. Some say that it should be used with organic clutches in order to work good.
I just want to gather as much feedback from different people as I can, in order to make an informed decision.

 

Nobody ever complained about a Mcleod RST twin. Great manners, light pedal, no noise....rated at 800 HP.

I had a SPEC 2+ with great manners, light pedal, no noise...rated to 782 TQ.

Either of these two clutches = no regrets.

Others that work great out there as well, best of luck in your decision.

 

The problem is that another person will hate what one person thinks is great. So, you almost have to drive it to know if you'll like it.

I would expect that a lightweight grabby puck style clutch is a really crappy combination.

On the other side, a twin disk like the Mcleod has a lower inertia and paired with a lower weight flywheel it will be a really low inertia requiring more rpm to take off and be easier to stall. It might be more likely to cause surging when cruising at a low rpm, like in a parking lot. But then, it will also rev quicker which would be good for road racing and aggressive driving.

 

McLeod RST -

Light to stock pedal pressure, no chatter, no "on-off" switch.

 

Both clutches mentioned are in a similar weight and not that much lighter than the stock LS7 clutch used with the same flywheel. The SPEC 2+ is not a puck style clutch, it has a standard style disc with a hybrid carbon/kevlar facing on one side and an organic facing on the other. Its slip well in stop and go traffic and holds power well. The Mcleod RST is a little lighter but still in around 45 lbs with aluminum flywheel. It's as friendly of a "driver clutch" that you'll find that can hold power and shift well at higher rpm's. The Spec 2+ comes in slightly heavier (2-3 lbs) I believe with the aluminum flywheel attached. The bucking (with a lopey cam) you mention does increase as weight decreases but that generally occurs in the less than 40 lb clutch/flywheel combos. If surging occurs with combos over 40 lbs chances are that it will surge with a stock LS7 clutch with steel flywheel that tips the scale close to 60 lbs.

 

But it is not mass that matters. It is inertia. Moment of inertia of a disc is 1/2 times mass times radius squared.

McLeod is 9.5" clutch. Radius squared factor is 18.

Monster is 12" clutch. Radius squared factor is 36.

So, if both had same mass then the 1/2 and mass terms are the same. This means the Monster would have twice the inertia of the Mcleod.

See how keeping the diameter down makes such a big difference now?

 

I know what you're saying, I currently have an RPS BC2 that weighs 26 lbs clutch and flywheel. With my 232/236-113 cam it surges at low rpm's around parking lots or any slow / low rpm driving...but it would still surge even with a ~58 lb oem LS7 clutch. A lower moment of inertia works to your benefit when shifting at higher rpms, rev matching for downshifts and in general frees up power and allows the engine to build revs quicker. The Mcleod RST would be an excellent choice even with the aluminum flywheel. The RST is designed as a street clutch with full organic facing and easy to slip if needed in traffic, loading onto trailer, etc...but added surface area of twin discs allow it to hold 800 crank hp.

In my 2002 C5Z I had a smaller cam without surging and a 12" SPEC 2+ clutch with aluminum flywheel AND aluminum pressure plate that all combined weighed in around 36 lbs. The clutch worked flawless without issue.

FWIW, the C7 comes with a twin disc clutch.

 

My current clutch is the RST with a stock flywheel, it works exactly as advertised. I've others such as RSP twin carbon street lite, Monster conversion & the LS7.

I've learned really super lite clutch flywheel ***'y are not for me, extreme pedal pressure isn't either. Hi rpm quick shifts are, nice modulation & near stock pedal pressure make the team!

I'm 600rwhp & 518rwt, the McLeod has never blinked from day one.

I experienced the vibration issue's that has been mentioned, some good threads regarding that.

 

For what you want out of a clutch, I would recommend the Monster LT1-S street twin. Its rated for 700WHP/TQ, it will out last any aftermarket single disc or multi disc clutch, and it drives like a stock clutch.

Give us a shout if you want to go over details. (817-750-2000)

 

I have a Mantic ER2 and am making ~600whp. Pedal feels very close to stock and slips like a stock clutch with only occasional and very minimal chatter. Would definitely recommend! Doug@ECS hooked up a great price, too!

 

The Monster twin disc gets my vote. The twin disc is by far the way to go. It will last longer, it has light pedal effort, and it can handle alot of power.

Most automotive manufactures are starting to go to twin disc setups due to there ability to withstand higher power levels and for the longevity that they offer.

 

Such a subjective discussion.....

I'm a h/c 346" and make over 500rwhp, I also happen to run a Fidanza with a RXT.
Fidanza = 13lbs
RXT PP = 17lbs

When you dynamically balance it....I like to remove weight to achieve balance. Flywheel first, then bolt them together and do a final balance.

As some have alluded to...MOI and OD play a big role. Not all weights are created equal.

Another big thing no one has mentioned is gearing. More gear will help tremendously with the bog/ high rev issue of leaving from a dead stop.

Remember, it's all about coefficient of friction through....clutch disc material, surface area and applied pressure. It's a fine balancing act...and not all clutch manufacturers subscribe to the same philosophy....that is why there are so many choices on the market.


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