JUIC3D

My OEM stock clutch has officially given up the ghost after 140 1/4 mile passes, numerous 1.5-1.6 60fts, 27,000 street miles, and plenty of highway pulls. The car still drives ok on the street but I can no longer launch the car over 5300rpms or the clutch overheats, glazes, and sticks to the floor.
I didn't get Joe_G mileage out of it, but all things considered, I'm very pleased with how it has held up to my abuse with stock gears and almost 500rwhp.

Researching my next clutch has brought me to the ZR1 realm of clutches and now I need some questions answered.


What is the difference in the stock ZR1 clutch, the Katech LS9X, and the LS9R?

From what I can tell, the LS9 and LS9X are essentially the same as the X uses the LS9 pressure plate and clutch disks. Is that clutch even an upgrade over the stock ZR1 clutch? If not, what justifies the increase in price over a stock ZR1 clutch kit?

The LS9R clutch is said to have the same clutch disks as in the LS9X (which are the stock ZR1 disks) but an upgraded pressure plate that holds 20% more torque. Can a pressure plate really increase the overall effectiveness of the clutch by 20%?

My car is currently at 494whp and I'll be spraying 100-150 on top of it in the relatively near future so I need a clutch that will stand up to the abuse.

The car is also my daily driver and my wife drives it on occasion(New Years eve for example ) so it needs to remain streetable.

I frequent the dragstrip often and will need a clutch that can hold up to the repeated launching and associated wear/tear with 1.5 and lower 60's. With the 100-150shot, I expect to be close to the 750ftlb torque mark and will need a sturdy clutch to handle the grunt.


Thanks in advance.

turbotuner20v

Ls9x is the same as the stock ls9. You need a new flywheel to run the ls9 though and that package is bundled as the 'ls9x' kit, so I think that's where it gets the name.

The ls9r just uses a stronger pressure plate to increase the torque capacity by 20%. I'd assume since it's produced by Katech they did some kind of testing to verify this.

This will probably be one of the closest to stock feeling clutch upgrades you can do.

Joe_G

Do you have the pedal spring removed?

JUIC3D

Yes Joe, you removed it for me when we came to visit.

Joe_G

I removed two others in the last few months too. I am the clutch spring surgeon at the track.

I think you'll be happy with a ls9 clutch, but it's expensive.

Describe more fully what your clutch is doing?

paisa427

Clutch spring? Why did you guys remove it?

JUIC3D

I'll do you one better and post the video.

Basically, I try to launch and the clutch spins and the pedal goes to the floor and there's a VERY strong smell of clutch that permeates the entire dragstrip.

I had multiple people come up to me and tell me they could smell the clutch the entire pass down the strip.

I'm very good with letting the car cool between passes and the clutch fluid is crystal clear. I just think the power is catching up to it and it just can't hold consistently anymore. That's my opinion at least.

I don't mind spending money on a clutch as I'm really not wanting to do that job more than one time right now. I'd rather spend a little more and get a good quality clutch that will withstand the abuse.


First video is from my very first pass this past Thursday night. I didn't record the burnout, but it was very small, just like in the second video.

Second video is the same thing.

I launch, let the clutch all the way out quickly and it just sticks to the floor and spins.

I can launch it soft at like 5000 and still cut a 1.58 60ft but my rpms are so low my ET and MPH suffer dramatically.



First(Thursday evening 1/19/12)



Second(Saturday afternoon 1/21/2012)

Joe_G

Well, I'm going to unfortunately have to agree with your analysis. Thats a bummer.

Does it hold a 4th gear pull or does it slip there too?

JUIC3D

Eh, it is a bummer, but I'm ok with it. Most people don't get 10% of your reported longevity, and to be honest, I'm rarely easy on the clutch when it comes to racing so I'm happy it lasted 140 passes in addition to the abuse it takes on the street.

I don't mistreat it, but it is a performance car and I treat it as such.

I've not tried a 4th gear pull yet. I can drive it just fine on the street, and I can launch it gently, but that's about it. It won't take anymore 6000-6500 launches

corvet786c

Is your heart set on these clutches cause there are other options.

Joe_G

When you add power it's common for the pedal to stick to the floor on shifting when under hard acceleration. The Ranger clutch fluid method helps www.rangeracceleration.com

And if that doesn't cure it very often taking the pedal spring out will do the trick. The pedal spring holds the pedal to the floor to make the clutch operation easier for those in high heels.

JUIC3D

No, my heart isn't set on anything in particular.

I know of the McLeod RXT and the BC2 but I'm trying to gain an understanding of the different LS9 varieties.

I've heard such a broad spectrum of reviews on nearly every clutch I've mentioned at local meets and whatnot and then I come on the forums and hear another set of opinions.

It's so hard making an educated decision without trying them out first hand, but I'd rather er on the side of caution and go bigger than I need, rather than getting a borderline 'good' clutch and end up having to swap it out again in 6 months to a year.


Joe, I love the high heels reference.

I love the pedal feel with the spring removed--stiff, linear, beefy--just like a clutch should feel. My wife drives it just fine too, in fact, she said she likes the feel of that clutch more than her Mini Cooper clutch.

Katech_Zach

This about covers it.


For your application I'd recommend the LS9R because of your heavy duty drag strip use. The LS9R is a great choice for you because of the dual purpose of the car. It will drive smooth and easy on the street and be able to stand up to the nitrous on the drag strip.

JUIC3D

Thanks for the response Jason.

Any idea what kind of life expectancy is reasonable to assume with the LS9R, given my power levels on bottle and motor?

I've read of the RPS BC2 having an extended life due to the carbon disks, but that is the extent of my knowledge. Unfortunately, I have to go off the reviews posted online which may or may not always be accurate.

While I don't expect a clutch that is often launched hard at the track with nitrous to last forever, I really don't want to be forking out $1700 each year to replace it, so it would be nice if it lasted for at least a couple years. Am I way off base or is that a reasonable expectation?

Katech_Zach

It's hard to say because nobody has ever worn one out yet, but I would say your expectation is reasonable. Also one of the beauties of this clutch is that its easily rebuildable. If you wear out the disks it's not $1700 for a new one, it's only $750. If you damage the flywheel surface you can get a new insert for only around $50.

JUIC3D

Thanks for the feedback Jason, I appreciate it.

palindrome1H

That sounds like a win-win!

Streetk14

I'll add my 2-cents, for whatever it's worth...

The LS9X and LS9R are identical, except a modified pressure plate for increased bite on the "R" version. Both use a custom aluminum flywheel that allows the LS9 clutch to be used on standard 6-bolt LS motors. Because of the aluminum flywheel, they are ~13 lbs. lighter than a factory ZR1 clutch/flywheel assembly.

I just drove my car last night for the first time after installing the LS9R clutch. I was actually surprised how much stiffer the pedal is than my factory LS7 clutch. I've never driven a ZR1 (or a car with a stock LS9 clutch), so I'm not sure how it compares in this area. I'm still breaking it in, so no hard driving yet. Hopefully I'll get used to the stiffer pedal, or maybe I'm just going to have a huge left calf after a few weeks

I will say that the engagement is smooth as stock, with no noise or chatter. The engine seems to rev slightly more freely in neutral because of the lighter clutch/flywheel package.

Detoxx03

My friend has the LS9R on his s/c C6 and seems to like it. I'll try to get him in here for a review.

Slo-Poc

I have the ls9r and love it no more peddle stick and a nice responsive/informative clutch feel if that makes sence. I beat the car to death making over 600hp and run bald drs for the past year. I've slipped it probably over 100+ times on the street and track and can still pull good 60s. I've dumped the clutch mulitple times also and it holds a sticky tire, so it seems to be the best of both worlds. Also not a calf workout when in traffic and no twin disk chatter. There are plenty of 700+p zr1s tracking there car on the stock ls9 cutch without a problem but why not just get the lighter and stronger one while your in there. Hope this helps!