CTS-V LS7 Clutch Upgrade How To - Confused? Read!
04-25-2013, 12:38 PM
#1
CTS-V LS7 Clutch Upgrade How To - Confused? Read! So I recently lost a lifter in my V and had to do a full rebuild. During that time it became quite apparent that there is little to find in the way of "how to's" for our cars. I wanted to do the clutch while I was in there and like many kept seeing the LS7 upgrade. The price was right, but there was lots of misleading info about what slave to use etc. After speaking with multiple suppliers and being told over and over I "needed this or that or it wouldn't work" etc I got fed up. So I just bought what I thought would work from many sources of info and put it all together. At the end of the day my clutch works EXCELLENT. So read and check out the info below and hopefully you'll enjoy the amazing LS7 clutch also!
First I ordered the clutch, and hands down this was the cheapest place at the time (even when you factored shipping in). Regardless get yours wherever you'd like: http://www.gmpartsdirect.com/results...c6ls7clutchkit
Now simply stated the "hard" part of this is figuring out if you'll do one of the following:
- Use an OEM CTS-V Slave cylinder with a Katech spacer
- Use an OEM LS7 Slave cylinder
- Use an OEM LS7 Slave cylinder with a shim
There is a lot of info floating around about all of the above. I found it incredibly hard to even find a slave cylinder for an LS7 from any parts stores. It was essentially out of stock everywhere in the country.
I ended up getting lucky and found a brand new OEM C6 slave on eBay, for $75 shipped. Regardless of where you get it or what kind you get, any and all C6 Corvette slave cylinders are the same. Again the part number for both the base model and the Z06 (LS7) are both the same. The part number is 24237634, and I installed that and it works flawlessly. I'll show you what I did to get it in nicely. First pull your old clutch and flywheel off, then replace your pilot bearing. Go to Autozone and rent the following tools:
Tool #1 Part #27128 Blind Hole Puller Set (This tool allows for the easy removal of pilot bearings without having to cut or chisel it out.)
Tool #2 Part #27119 Bearing and Race Installer Kit (This tool allows for the easy installation of your new pilot bearing without marring up the face of it.)
Extras: Be sure to get some good penetrating oil and spray the bearing. It will make the job much easier. I sprayed it and let it sit for about an hour, then it was easy to remove.
I got a new pilot bearing at Summit Racing, but its probably available anywhere and is just the OEM CTS-V bearing, I'm sure Chevy has it. (I live about 3 miles from a Summit in Reno) don't mind the plug wires:
Link to the pilot bearing: http://www.summitracing.com/parts/nal-12557583
Also didn't have an alignment tool, but they are available anywhere, again I got mine at Summit: http://www.summitracing.com/parts/sum-g1341
If you get it elsewhere its a 1.125" (1 1/8") 26 spline tool. Very common and cheap.
Pilot bearing, flywheel and clutch installed:
Now onto the clutch slave cylinder, the part I saw the most BS about on forums.
OEM CTS-V slave about to be pulled out, notice bleeder sticks out of bell housing:
OEM C6 Corvette aka LS7 Slave (24237634) mocked up, notice short bleeder and clutch line hitting bell housing:
Figured I'd just swap the bleeders, I just took the CTS-V bleeder and put it on the C6 slave (I don't buy into that speed bleeder thing, sure its handy, but if you are this deep into your engine/trans it seriously takes 10mn to bleed a clutch and its not like you do it on a daily basis):
Then with literally about 2-3mn worth of using my angle grinder I notched out a bit of the bell housing, seriously very easy, the aluminum comes off like butter:
After that it worked great. No shim, no BS. Just plugs right into the OEM CTS-V clutch line etc. Only other thing I did was use a brake line bender ($15 at Autozone) to bend the line towards the front of the car. The C6 slave hard line is a lot longer than the CTS-V one. This again took about 30 seconds. Couldn't find a link to the bender I got but any bender will work, here's one from harbor freight - http://www.harborfreight.com/tube-be...ers-95782.html
So hopefully that is helpful to some of you. I could have done a LOT better of a job with pictures etc. But at least you know for a fact those parts work fine. My clutch engages closer to the floor now, and keeps moving back towards stock, I have absolutely no complaints nor would I have done anything different. I just wished there was something out there that could have guided me a bit. Best of luck guys and let me know if you have any questions!
First I ordered the clutch, and hands down this was the cheapest place at the time (even when you factored shipping in). Regardless get yours wherever you'd like: http://www.gmpartsdirect.com/results...c6ls7clutchkit
Now simply stated the "hard" part of this is figuring out if you'll do one of the following:
- Use an OEM CTS-V Slave cylinder with a Katech spacer
- Use an OEM LS7 Slave cylinder
- Use an OEM LS7 Slave cylinder with a shim
There is a lot of info floating around about all of the above. I found it incredibly hard to even find a slave cylinder for an LS7 from any parts stores. It was essentially out of stock everywhere in the country.
I ended up getting lucky and found a brand new OEM C6 slave on eBay, for $75 shipped. Regardless of where you get it or what kind you get, any and all C6 Corvette slave cylinders are the same. Again the part number for both the base model and the Z06 (LS7) are both the same. The part number is 24237634, and I installed that and it works flawlessly. I'll show you what I did to get it in nicely. First pull your old clutch and flywheel off, then replace your pilot bearing. Go to Autozone and rent the following tools:
Tool #1 Part #27128 Blind Hole Puller Set (This tool allows for the easy removal of pilot bearings without having to cut or chisel it out.)
Tool #2 Part #27119 Bearing and Race Installer Kit (This tool allows for the easy installation of your new pilot bearing without marring up the face of it.)
Extras: Be sure to get some good penetrating oil and spray the bearing. It will make the job much easier. I sprayed it and let it sit for about an hour, then it was easy to remove.
I got a new pilot bearing at Summit Racing, but its probably available anywhere and is just the OEM CTS-V bearing, I'm sure Chevy has it. (I live about 3 miles from a Summit in Reno) don't mind the plug wires:
Link to the pilot bearing: http://www.summitracing.com/parts/nal-12557583
Also didn't have an alignment tool, but they are available anywhere, again I got mine at Summit: http://www.summitracing.com/parts/sum-g1341
If you get it elsewhere its a 1.125" (1 1/8") 26 spline tool. Very common and cheap.
Pilot bearing, flywheel and clutch installed:
Now onto the clutch slave cylinder, the part I saw the most BS about on forums.
OEM CTS-V slave about to be pulled out, notice bleeder sticks out of bell housing:
OEM C6 Corvette aka LS7 Slave (24237634) mocked up, notice short bleeder and clutch line hitting bell housing:
Figured I'd just swap the bleeders, I just took the CTS-V bleeder and put it on the C6 slave (I don't buy into that speed bleeder thing, sure its handy, but if you are this deep into your engine/trans it seriously takes 10mn to bleed a clutch and its not like you do it on a daily basis):
Then with literally about 2-3mn worth of using my angle grinder I notched out a bit of the bell housing, seriously very easy, the aluminum comes off like butter:
After that it worked great. No shim, no BS. Just plugs right into the OEM CTS-V clutch line etc. Only other thing I did was use a brake line bender ($15 at Autozone) to bend the line towards the front of the car. The C6 slave hard line is a lot longer than the CTS-V one. This again took about 30 seconds. Couldn't find a link to the bender I got but any bender will work, here's one from harbor freight - http://www.harborfreight.com/tube-be...ers-95782.html
So hopefully that is helpful to some of you. I could have done a LOT better of a job with pictures etc. But at least you know for a fact those parts work fine. My clutch engages closer to the floor now, and keeps moving back towards stock, I have absolutely no complaints nor would I have done anything different. I just wished there was something out there that could have guided me a bit. Best of luck guys and let me know if you have any questions!
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Pherrera1 (01-15-2020)
04-26-2013, 10:07 AM
#4
http://www.tickperformance.com/gm-ls...-applications/ - $489 + $49 in shipping
https://ls1tech.com/forums/manual-tr...hip-today.html
Great guy and nice reviews, but was pretty set on selling me his propriatary LS7 slave cylinder for $200+, a speed bleeder for $70 and some other misc stuff. All said and done it was well over $800 delivered. So again nothing against him, I was just many thousands into my rebuild and went with the cheaper option. I crack up when they list the alignment tool as being some huge bonus, they are typically about $3 at any auto parts store. Certainly doesn't "make the sale" for me.
04-26-2013, 10:29 AM
#7
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Yea,no doubt about that,definitely a help,looking to tackle this as soon as I get the parts in.
What was the difference in weight between the LS7 FW and the stock dual mass one?
What was the difference in weight between the LS7 FW and the stock dual mass one?
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04-26-2013, 10:33 AM
#9
I stupidly just threw the old one away prior to weighing it so I don't know its exact number but it was very heavy. Even the LS7 one weighed in at 28 or 29 pounds I believe. I don't think I'd personally go with any lighter of a flywheel with our cars though. You need a good rotating mass on a heavier car, there really is no argument to have a super lightweight flywheel in a 3900 pound car. Grab a stock LS7 flywheel and clutch, put them in and forget about it. Drives like a completely stock car and has all the capability that 99% of CTS-V owners need. If you ever need more you can always get an upgraded LS7 style clutch. Just stay away from the OEM clutch. Essentially the CTS-V is an 11" clutch, and the LS7 is a 12" clutch. That 1" makes a huge difference in TQ capability.
04-26-2013, 10:36 AM
#10
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Nice,yea I didn't want a much lighter one that that anyway,that's still a pretty good weight saving over the stock dual mass,I think they are about 45 lbs if I remember.
Anxious to get this swapped over.
Anxious to get this swapped over.
04-26-2013, 11:00 AM
#11
Stock flywheel is either 48 or 52 lbs (off the top of my head). Don't go out of your way for a GM OEM LS7 clutch--they're slightly inferior to the F1 Racing LS7 clutch series in every way. Similarly, the PowerTorque CS2529 should be your slave of choice. It's included with the F1 Racing kits, but you can buy it separately for about $90 at O'Reilly's.
The OEM LS7 flywheel is unnecessarily heavy, at 25 lbs. Typical chromoly steel flywheels weigh in at 20-21 lbs. For track and autocross drivers, consider picking up an aluminum Fidanza flywheel (13.5 lbs). You will need to relearn to drive the car with an aluminum flywheel, because it does not have enough inertia in and of itself to roll the car forward from a stop. However, that reduced inertia will pay off in spades when you try to accelerate, because less engine power is being wasted fighting that inertia.
Always remember that you're actually managing the rotating inertia of the clutch's entire rotating mass, which includes the weight of the pressure plate and friction disc. Since rotating inertia of discs is dominated by diameter, not mass, you should also note that a twin-disc system (which typically has a diameter of about 8", instead of 10.5") will be even more responsive than a LS7 clutch with an aluminum flywheel.
The OEM LS7 flywheel is unnecessarily heavy, at 25 lbs. Typical chromoly steel flywheels weigh in at 20-21 lbs. For track and autocross drivers, consider picking up an aluminum Fidanza flywheel (13.5 lbs). You will need to relearn to drive the car with an aluminum flywheel, because it does not have enough inertia in and of itself to roll the car forward from a stop. However, that reduced inertia will pay off in spades when you try to accelerate, because less engine power is being wasted fighting that inertia.
Always remember that you're actually managing the rotating inertia of the clutch's entire rotating mass, which includes the weight of the pressure plate and friction disc. Since rotating inertia of discs is dominated by diameter, not mass, you should also note that a twin-disc system (which typically has a diameter of about 8", instead of 10.5") will be even more responsive than a LS7 clutch with an aluminum flywheel.
Last edited by FuzzyLog1c; 04-26-2013 at 11:06 AM.
04-26-2013, 11:14 AM
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Stock flywheel is either 48 or 52 lbs (off the top of my head). Don't go out of your way for a GM OEM LS7 clutch--they're slightly inferior to the F1 Racing LS7 clutch series in every way. Similarly, the PowerTorque CS2529 should be your slave of choice. It's included with the F1 Racing kits, but you can buy it separately for about $90 at O'Reilly's.
The OEM LS7 flywheel is unnecessarily heavy, at 25 lbs. Typical chromoly steel flywheels weigh in at 20-21 lbs. For track and autocross drivers, consider picking up an aluminum Fidanza flywheel (13.5 lbs). You will need to relearn to drive the car with an aluminum flywheel, because it does not have enough inertia in and of itself to roll the car forward from a stop. However, that reduced inertia will pay off in spades when you try to accelerate, because less engine power is being wasted fighting that inertia.
Always remember that you're actually managing the rotating inertia of the clutch's entire rotating mass, which includes the weight of the pressure plate and friction disc. Since rotating inertia of discs is dominated by diameter, not mass, you should also note that a twin-disc system (which typically has a diameter of about 8", instead of 10.5") will be even more responsive than a LS7 clutch with an aluminum flywheel.
The OEM LS7 flywheel is unnecessarily heavy, at 25 lbs. Typical chromoly steel flywheels weigh in at 20-21 lbs. For track and autocross drivers, consider picking up an aluminum Fidanza flywheel (13.5 lbs). You will need to relearn to drive the car with an aluminum flywheel, because it does not have enough inertia in and of itself to roll the car forward from a stop. However, that reduced inertia will pay off in spades when you try to accelerate, because less engine power is being wasted fighting that inertia.
Always remember that you're actually managing the rotating inertia of the clutch's entire rotating mass, which includes the weight of the pressure plate and friction disc. Since rotating inertia of discs is dominated by diameter, not mass, you should also note that a twin-disc system (which typically has a diameter of about 8", instead of 10.5") will be even more responsive than a LS7 clutch with an aluminum flywheel.
04-26-2013, 01:51 PM
#13
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I would be scared to try another F1 clutch setup,I tried one on a WRX back in the day,didn't seem to hold up too well.
They could have changed the design though,I don't know.
Good input though.
They could have changed the design though,I don't know.
Good input though.
04-26-2013, 02:03 PM
#14
Fuzz is spot on for the most part, except I believe that the stock LS7 flywheel is more like 28 lbs.
I remember the whole LS7 setup being about 56 lbs. I'll have to look that up.
My stock dual mass setup weighed 74 lbs(flywheel, pressure plate, and disc).
I went with the Mantic single clutch which weighs 49 lbs total(21lbs flywheel, 23lbs pressure plate, 5lbs disc)
Lighter flywheel is not a problem at all, I always take off almost at idle.
I remember the whole LS7 setup being about 56 lbs. I'll have to look that up.
My stock dual mass setup weighed 74 lbs(flywheel, pressure plate, and disc).
I went with the Mantic single clutch which weighs 49 lbs total(21lbs flywheel, 23lbs pressure plate, 5lbs disc)
Lighter flywheel is not a problem at all, I always take off almost at idle.
04-26-2013, 02:08 PM
#15
It's a different design--an improvement on the basic LS7 design. I have my used one sitting right here. 21,000 miles of having the s**t beat out of it and it never faltered. Many other CTS-V owners have it and can say similar things.
04-26-2013, 02:14 PM
#16
Stock flywheel is either 48 or 52 lbs (off the top of my head). Don't go out of your way for a GM OEM LS7 clutch--they're slightly inferior to the F1 Racing LS7 clutch series in every way. Similarly, the PowerTorque CS2529 should be your slave of choice. It's included with the F1 Racing kits, but you can buy it separately for about $90 at O'Reilly's.
The OEM LS7 flywheel is unnecessarily heavy, at 25 lbs. Typical chromoly steel flywheels weigh in at 20-21 lbs. For track and autocross drivers, consider picking up an aluminum Fidanza flywheel (13.5 lbs). You will need to relearn to drive the car with an aluminum flywheel, because it does not have enough inertia in and of itself to roll the car forward from a stop. However, that reduced inertia will pay off in spades when you try to accelerate, because less engine power is being wasted fighting that inertia.
Always remember that you're actually managing the rotating inertia of the clutch's entire rotating mass, which includes the weight of the pressure plate and friction disc. Since rotating inertia of discs is dominated by diameter, not mass, you should also note that a twin-disc system (which typically has a diameter of about 8", instead of 10.5") will be even more responsive than a LS7 clutch with an aluminum flywheel.
The OEM LS7 flywheel is unnecessarily heavy, at 25 lbs. Typical chromoly steel flywheels weigh in at 20-21 lbs. For track and autocross drivers, consider picking up an aluminum Fidanza flywheel (13.5 lbs). You will need to relearn to drive the car with an aluminum flywheel, because it does not have enough inertia in and of itself to roll the car forward from a stop. However, that reduced inertia will pay off in spades when you try to accelerate, because less engine power is being wasted fighting that inertia.
Always remember that you're actually managing the rotating inertia of the clutch's entire rotating mass, which includes the weight of the pressure plate and friction disc. Since rotating inertia of discs is dominated by diameter, not mass, you should also note that a twin-disc system (which typically has a diameter of about 8", instead of 10.5") will be even more responsive than a LS7 clutch with an aluminum flywheel.
Also I can't really say I agree with the 25 pound flywheel being too heavy. Few people out there would EVER see a real world benefit from a lighter flywheel in OUR cars. Our 3900 pound cars came with a 50 pound flywheel for a reason, not just that GM was randomly picking whatever sounded best. Already dropping that weight in half is quite the difference. At some point you see diminishing returns on a super lighweight flywheel. Similar to going with a huge cam, sure on a "race" car a huge cam is a great thing to have, however when I did the cam in my CTS-V I took into consideration that I actually DRIVE this car everyday. I don't want a car that has lost a huge portion of its overall drive ability just so I can have a great 4k+ powerband.
What I'm trying to say is that while in some applications, i.e. dedicated race car etc, sure maybe a super lightweight flywheel has its advantages. However in a heavy car, with a powerful engine such as the LS6/LS2, I don't think your engine has ANY issue spinning the 25lb flywheel at all. I also think the added benefit of having that inertia going from gear to gear far outweighs the 'faster revving' you may get by removing some mass.
Now on the 3rd point of the smaller diameter twin disc setup I'm not sure how I see that. Overall the OEM clutch is 11", and the flywheel is probably 13" or so (clearly bigger to contact the starter). The LS7 setup is the same overall diameter, as the starter needs no modification to contact the flywheel. So I'm not sure how you get 10.5 vs 8 inches. But either way the rotating mass, while it would be closer to the center of the rotation still is the same overall diameter. I know that does make a difference, but with something static like a flywheel, i.e. it only has one axis of movement (unlike a wheel that changes direction) I think the benefits vs the loss of driveability and assumed cost would again be null.
All in all, the LS7 clutch drives literally the same as a stock clutch, and was built by GM for 500 horsepower factory cars, and sees millions of miles with setups well over 500 horsepower with no issues. At some point you've got to realize that a CTS-V isn't a full out race car for most people and maintaining its creature comforts and pleasurable drive will typically outweigh theoretical advantages, although they do have their time and place.
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04-26-2013, 02:17 PM
#18
I don't mind it really, its not overly hard, I left a nice little clear hose coming off of it, takes all of about 10mn to bleed, and I just do it once or twice a year at most while already doing an oil change etc. I don't disagree that they are nice, but for me the added cost paid for my slave cylinder.
04-26-2013, 02:27 PM
#19
Now on the 3rd point of the smaller diameter twin disc setup I'm not sure how I see that. Overall the OEM clutch is 11", and the flywheel is probably 13" or so (clearly bigger to contact the starter). The LS7 setup is the same overall diameter, as the starter needs no modification to contact the flywheel. So I'm not sure how you get 10.5 vs 8 inches. But either way the rotating mass, while it would be closer to the center of the rotation still is the same overall diameter. I know that does make a difference, but with something static like a flywheel, i.e. it only has one axis of movement (unlike a wheel that changes direction) I think the benefits vs the loss of driveability and assumed cost would again be null.
04-26-2013, 02:31 PM
#20
All flywheels are the same diameter. It's the pressure plate and discs that vary, some are 11", some are 12", and in the case of the Mcleod, 8.5" to 9". The Mcleod comes with a pressure plate adapter to bolt on to a stock(non dual mass) flywheel. Just wanted to clear that part up.
Its really no different than saying our cars would be faster if lighter, absolutely correct, no doubt about it. However to become lighter you'd have to remove creature comforts (seats, sound deadening, a/c etc) whatever it may be. And I would assume that the overwhelming majority of CTS-V owners have that car because they want a nice car to drive every day, not some all out race car (ok we all do WANT that) that has bad manners. Just like the cam I was speaking about earlier.