I have a new crate LS3 and was considering using one of GM's OEM flywheel and clutch combo (same one as spec'd for a 2010-2015 Camaro)

This uses a huge 12" clutch disc that is the same as the truck clutch,. I've been told this setup doesn't like high RPM shifting and wears out syncros faster.

The next consider Is a smaller diameter dual disc setup, like the Mcleod RST kit. it uses 10" diameter organic discs.
I understand this design is easier on the syncros and high RPM shifts.
Both steel flywheels weigh the same 28 #

FWIW, the car will be mostly just street driven with the occasional 5500 - 6000 RPM blast through the gears on the on ramp to the highway.
Can anybody describe the overall difference in feel and performance between these two types?

 

I can't speak for those specific clutches, but I'll tell you my experience with both of my cars. My Camaro has a cammed LS3 making around 475 to the wheels. I have a Spec 3 clutch with the 6 puck sintered iron disc in that. It drives 100% like stock, no shudder, no weird quirks. I shift that at 7100 RPM and it's like butter, even with full throttle no lift shifts. Incredibly good clutch for the price. I paired it with a new stock replacement LUK flywheel. My Firebird makes significantly more power, and I have a Tilton ST-246 twin disc with sintered iron pucks. Also drives pretty close to stock, but pedal effort is much higher than my Camaro due to the Tilton master and slave. I shift it at 7500, again, like butter. I don't do no lift shifts in my Firebird, however. The Camaro is easier to drive, for sure. If you're not trying to max out your power, the Spec 3 is a pretty nice budget clutch. They get a bad rap sometimes, but if you break them in exactly as recommended, they're awesome.

 

OP, for your power and use intent, look into McLeod FW and full-face organic disc clutch kit. I also use their MC which is made by Wilwood for them

 

The twin disc clutches will hold more power while drastically reducing pedal effort over a single disc clutch. However, since you are running a crate engine, I don't think you need to go with a twin disc. You absolutely can go with a twin, in which case I would go for the Monster LT-1S because it uses a GM pressure plate and discs. However, I would just go for a single disc that uses a hybrid disc with a full face on one side and raised pucks on the other. Something like the Spec 2+ or the Monster Level 2. The Mantic ER2 is also nice, but at its price, I would just go with the LT1-S twin.

 

Thanks for your responses, I have looked at some of the suggested alternatives.
Since my crate will only be making 500hp at the flywheel, I know I don't need a dual disc for it's holding power..
At the end of the day I was trying to figure out if I would notice a substantial difference in shift quality, longevity, and pedal feel between a 12" single disc and a 10" dual disc in general.

 

Here's what I feel between my two cars, since I have one of each. The single disc has a much more pronounced initial bite. The twin disc starts to pull the engine down a bit before it actually fully engages, and I have had to get used to how it drives because of that. I initially thought something wasn't right, so I called Tick about it and they said it was normal for a twin disc.

 

I have the McLeod twin disc in my LT1 car, full face organic disc. The MC with the kit is 13/16 vs the stock 3/4" bore so pedal effort is "slightly" firmer but by no means hard and the stroke is shorter in pedal movement. After killing several clutches of various disc compounds, the twin disc is what I should have put in first

Doing a LS3 in another car with TKX and the Silver Sport kit I got has the McLeod single disc with Tilton hydraulics. That car will make around 425 hp

 

By All means stay as far away from McLeod twin disk clutches if you have a T56… there have been plenty of threads about their clutches destroying input shafts due to their poor, flawed design of the clutch hubs and excessive tolerances on the splines.

My opinion is that the ones who recommended these clutches simply don’t put many miles on their cars. Their clutches hold power just as well as the other twin disks out there. But they won’t last due to their poor major design flaw and you will likely complain about the chatter the entire time, until it fails after a few thousand miles.

i’ve done my due diligence to make detailed posts on the McLeod horror stories. But since they’re a paying advertiser, all the bad posts get moved to a different area of the forum, where they dont get much exposure.

if you are looking to go with a twin, go with the Ram Concept 10.5. Its the best for the money. Or the Tilton ST-246, which will set you back a bit more. But you will be happy with either one.

 

Thankyou for your response but I initially posted this back in May, and since then end up buying the Mcleod RST twin.
After reading your post I looked closely at the splines on the disc hubs and fitted a quality spline alignment tool that I have used for previous clutch installs.
The spline fit into the disc hub nicely with a minimal amount of play, and definitely nothing I would consider to be abnormal.
So please clarify what it was about the hub spline did you feel was not up to spec?
too loose? , not enough cross section engagement with input shaft? or other?? I also wonder how much power at the crank these cars are making that have input shaft damage.

 

FYI...Since my last post I did some research and found several negative reviews on RST & RXT as you described. (wish I saw this sooner)
I also contacted Summit about a return and exchange on the RST for the Tilton ST246. I also I emailed Tilton Engineering tech support and got this answer:
Clutch is balanced during assembly and tested flywheel is balanced to Tilton tolerance (measured in grams) Flywheel weight 19.6 lbs, total clutch and flywheel 46 lbs, disc spline hubs lengths are .600 and .650". They responded really fast. Chock one up for a company that provides awesome tech support!
I feel confident in this being a superior product.and will do a return on the RST in exchange for Tilton ST246
Thanks Chris!

 

FWIW I have had my McLeod street twin in my T56 car for 15 years and many 1/4mi passes running a tire. I only make 400 RWHP but never a blink from the clutch. Not sure if hub spline material has changed in 15 years for McLeod relative to their twins or single disc clutches as some post suggest for the RST/RXT units, for me its a non issue on spline wear.