Caution- If you are interested in lightweight flywheels or clutches, aftermarket master cylinders, 8.5" clutches, etc....this thread is NOT for you! Please respect this and move along as this is not a debate about the advantages/disadvantages of 1 vs. the other.

I recently found out about this newly released clutch via this thread: https://ls1tech.com/forums/manual-tr...utch-kits.html

It comes in an organic disc (700ftlbs) or metallic (1000ftlbs) disc based on needs and driving style and limits. I know I'm pushing the limit of the organic disc but elected to try it. I decided I would upgrade my single disc Ram Power Grip clutch and try out 1 of the @Summitracing twin disc clutch kits that they just released. I didn't need to replace my clutch but I prefer twin disc clutches and was intrigued by the Summit Racing kit for a number of reasons. Pricing is pretty amazing for what you're getting. Getting a flywheel included and all bolts, etc. is a nice bonus. For reference, in my various Fbody's I've tried or driven multiple Spec clutches, a Southbend clutch, a McLeod RST, and multiple Ram's so its fair to say that I've got a good feel for them. I will say that I am SUPER picky when it comes to drivability (driving impressions below). I don't want my car to drive stock-ish, I want it to drive OEM....while making double or more than stock power levels On to some pics:


Opening of the package. Major kudos that they included threadlocker for both the flywheel bolts and the pressure plate bolts.

It came with flywheel bolts which are always forgotten about and an odd size. One less thing to buy.

It's a good looking clutch kit!!! Notice how the flywheel has more of the weight towards the center to reduce some inertia.










Out with the old!


In with the new!

Driving impressions- There was about a 500 mile break-in period on my setup. For reference, the car is the turbo Z28 in my sig. It's a rebuilt LS6 (10.5:1) with a Titan stage 2 cam, rear mount billet 7875 turbo making ~15 psi in higher gears. Figure somewhere in the 650-700whp range. Initially the pedal effort was slightly stiffer than the Ram Power Grip. The Ram was very close to OEM pedal effort so the increase in pedal effort is completely reasonable given what the clutch is rated at and nothing I would consider race at all. It does not make any noise when engaging/disengaging. Since break-in there has been no chatter or shuddering and the pedal effort feels lighter as well. I am using the stock hydraulics with the drill mod only. A shim is not necessary with the kit, but I did put a very small shim in mine to allow a wider wear range before it would ever start to slip. After break-in I switched my 315/35/17 street tires that would spin 3rd gear to M&H 275/55/17 drag radials. I haven't swapped in the 9 inch yet so no high rpm clutch dumps, but it hooks 1st at WOT. No issues shifting at 7000 rpms. In short, I would have no issues using this for a daily driver. So far I'm impressed with the quality and level of detail of the clutch kit. Once the 9 inch goes it, it'll be time to try and launch it on a tire. Questions welcome!

 

Sounds like a good deal. What slave are you running? I know you said stock but ls1 or ls7?

 

Stock LS1.

 

I really like the packaging!

 

Is this a different one from the other thread? It looks much larger in diameter.

 

Nope same one and same part number. It may have just been a play on the eyes as far as photo angles etc. I haven't seen the 1000ftlb version in person, but I imagine its identical except for the disc material itself.

 

You didn't use the ARP bolts ?

ARP flywheel bolts are an odd one....awful design, very tall, poor spline engagement. Seems so strange. Flex plate bolts fit and work far nicer ( or stock as pictured )

 

I used the bolts that came with the kit for both the flywheel and the pressure plate. I don't think any of it was ARP, definitely not the flywheel bolts as they aren't funky 12 points. I believe in general the flywheel bolts are an odd size like an M11x1.5. All the local auto parts stores say they stock them and when you pick them up theyre for an old school small block chevy so it was a welcomed change that it came with new bolts.

 

First picture shows what look very like ARP flywheel bolts in the bag, installed flywheel looks like regular bolts ?

Just curious. As said, I dislike the ARP flywheel bolts design.

 

Haha good eye! I had bought flywheel bolts not realizing they came with them in the kit. The stock bolts are the ones that came with the kit.

 

Does the engine feel like it revs up quicker with this setup?

 

And add me to the list of people that thinks ARP flywheel bolts are trash. Nowhere near enough engagement on the head.

 

Its a cammed rear mount turbo ls6 so it's a bit tough to say with any detail about how quickly it revs pre/post clutch swap. You can tell from the pics what they did to keep more of the mass towards the center. It's no featherweight but I'm happy.

 

They do need a really good fit socket on them, but given they do take a decent amount of torque, the head is *****. And really, there is little reason for that odd design. And on some triples, the tall height fouls the inner disc. Not ARP's problem though, but something to note.
As said, I just used flex plate bolts last time, as they are a more normal design, and shallower in height. Although if the flywheel has a recess, they may not be suitable. Mine is flat.

But with the ARP FW bolts, after maybe 2-3 cycles, the heads/splines can be weak, and ready for the bin before they do risk getting chewed. They're just crap.

 

Thank you for posting a review! I have mine right now, waiting for my engine to come back from the builder!!

 

Congrats! I think you'll really enjoy it, just remember to break it in properly. Did you go with the organic or metallic disc?

 

I ended up going organic.. figured I’d be good going that route. I don’t anticipate my setup making more than 600ftlbs but who knows lol

 

Cool. Nice thing is you could always upgrade the discs later on if needed.

 

Looks like a solid clutch option. I'll have to keep it in mind the next time I am in need of a clutch.

 

Definitely. It's nice that its a complete kit with flywheel and all hardware included.