race clutch (LSx)
 

Has anyone driven a 5.5" twin disc ceramic/metallic clutch on the track?

I have a heavy/huge MOI oem ls7 clutch right now and want to replace it with something that doesn't wear incredibly fast and I can still slip onto the trailer and up the driveway. Hoping that our (relatively) light cars will make a quarter master twin disc 5.5" work. I'm just not sure what to expect. Swapping up to a 7.25" twin or triple is straightforward, but I was thinking of trying a 5.5 first. Maybe the difference between a 5.5 and 7.25 twin isn't worth it for HPDE?

I dont see why it wouldnt work. just get one with sufficient torque capacity. expect it to be a bear in low gears.

I have the 949 twin-disc in my '99. It's awesome. Not sure what else to say. It does exactly what 949 says it will. It is not hard to drive, slip on a trailer, or anything else, once you get used to it.

robert

I am running the tilton twin 5.5 clutch. The disk looks to be carbon. Very abrupt engagement. The only real problem was driving it on the trailer. On the track its awesome!

I would recommend the 7.25" Twin, typically most V8 people prefer to run a 10.5" twin because it holds the power and is easier to drive with better MOI suited to that engine. The 5.5" are typically for very high revving small cars with 4 cylinders with not a lot of torque. If you get a carbon material, it will be an on/off engagement, cerametallic have some slip once worn in, at first they will grab more but eventually slip quite nicely.

Mike do yourself a favor and get a trailer winch. I figured the wear and tear from slipping it going onto the trailer was the worst thing for it. I bought a Warn 93700 off Ebay for $180. I figure it would pay for itself by saving the clutch.

I drove a C6Z with a Tilton/LG clutch and it was daily drivable I think.

I would not go 5.5 but instead 7.25; I've got a 7.25 triple disc on my LS1 and wouldn't want any harsher engagement than I already have.

I don't expect you would notice much difference between the 5.5 and 7.25 in your car as a HPDE driver, but could be wrong since I haven't actually driven a 5.5.

Be sure you get your hydraulic throwout bearing set up correctly. My first try I had a hard time finding one that was short enough to work with my frankenstein setup (meaning clutch was always partially dis-engaged); second try at the shortest slave I could find and it wasn't spaced close enough to the pressure plate so I wouldn't get full dis-engagement.
Depending on what height you need for your setup, I have a Quarter Master 710-Series hydraulic throwout bearing that I am no longer using.

The 7.25 twin if its rated to your torque level sounds like the ticket, if not the 10.5 twin. I like all carbon friction surface (IE the pressure plate, flywheel, intermediate disks, and friction disks all have carbon pucks on them) so easy to modulate. Supposedly the racier versions only work well once hot.

Trailer winch. Why wouldnt you do this? It saves you from having to do the "I can only get the door 4 inches open" dance.

What discs do you have? metallic or ceramic-metallic? I'm probably going to use a 730-series if I get a quarter master.

The tilton carbon twin/triple like the LG unit look perfect, except they cost $4000-6000. Not willing to spend that type of money on a clutch. I still track a miata and want cheap stuff.

I'll probably end up going with a triple disc 7.25" quarter master with ceramic-metallic discs. The c5z nasa people I've talked to say it's overkill for them and can be slipped. The MOI on the ls7 clutch is so high that pretty much any 7.25" with flexplate and button flywheel is going to be noticeably better.

I am using a Tilton OT-II triple disc, nascar take-off. ~$200 on eBay
They are sintered metallic discs.

Agree completely on the outrageous prices of the LG units, although they do look nice. That were my inspiration to find a cheap-as-hell 7.25" triple disc.