01_SuperSlow

iTrader: (7)

I think the only reason that GM put a heavy flywheel in the V was to make it easier to drive.
But it was unnecessary and a huge fail in my opinion.
It is right up there with the V specific motor mounts.
Horrible ideas that the engineers were actually proud of.

FuzzyLog1c

iTrader: (4)

Dead wrong.

Between the Cadillac CTS-V FAQ (a feature that most other usergroups would die for), the LS1Tech and Cadillac Forums are bristling with an embarrassing riches of guides covering almost all aspects of modifying this car. The best part is that most of the users who wrote these guides are still around--some of them may have moved on to a second generation CTS-V, but it's easy to find them and get help.

The only misleading information that you'll find is in the back-and-forth arguments about whether the clutch needs a shim or not. There is no debate about anything else.

That's not the cheapest solution. You still have to buy a 26-spline tool, pilot bearing, and slave cylinder, and after that you're stuck with a heavier flywheel and you're playing Russian Roulette with the variable build quality on the GM pressure plate (sometimes the springs arrive broken, or the automatic adjustment mechanism is jammed). The Stage 1 F1 kit is the cheapest option, although you should really pony up another $100 and get the F1 Racing MF kit with the powdercoated pressure plate. That's the best value you'll find on a LS7 clutch kit. As a bonus, it's good for another 100 ft-lbs of torque (578 ft-lbs, as opposed to 475 ft-lbs), and F1 sells replacement MF discs for about $100.

As previously stated (and this part nobody can blame you on), the only misleading information is in the back-and-forth debates that raged about whether the LS7 clutch needed a shim to work with the CTS-V or not. If you followed the trail of discussion to the bitter end (a feat in and of itself), you would've gotten the right answer: replace your LS2 slave with a PowerTorque CS2529 slave for your LS7 clutch and torque the pressure plates to 48 (my recommendation) or 52 (manual's recommendation) ft-lbs. No shim required.

You would have also been directed to the resource that would have gotten you at least 3/4 of the way to the correct solution, by teaching you how to do the clutch measurements yourself.

The missing piece of information that settled the shim debate was what I contributed back in early 2011 (after installing and reinstalling my LS7 clutch 6-7 times): the discovery that the pressure plate torque specs were vehicle specific, not clutch specific. This is something that most LSx specific shops and tuners were unaware of at the time.

If you followed the CTS-V FAQ, you were told that the stock LS2 pressure plate torque spec was 52 ft-lbs. If you read the LS7-powered Z06 Corvette guides, you torqued the pressure plate to 74 ft-lbs. GTO guides were all over the place, since they borrowed parts from everywhere. As a result, CTS-V owners that torqued their pressure plates to 52 ft-lbs couldn't understand why CTS-V owners who torqued their pressure plates to something else (e.g. 74 ft-lbs) were complaining about partial disengagement of their clutches and talking about shimming their slaves.

Nobody realized that the actual problem was torque--it would take someone with a tendency to massively over-torque everything (I had broken over 15 piece of 3/8" drive and 3 pieces of 1/2" drive, not including two socket wrenches, overtorquing bolts before having this epiphany and learning the value of the torque wrench) to discover the answer.

Since torquing pressure plate bolts beyond 45 ft-lbs causes the fingers on the pressure plate to gradually retract, additional torque can be specified to increase the spacing between the fingers of an installed pressure plate and front face of the slave's throw-out bearing. Slight differences between the spacing in various cars resulted in various torque specifications, and in the case of the CTS-V, spawned a debate that lasted for years.

You're right. That's interesting--it wasn't like this in years prior. I did a quick check: LS3 and LSA slaves are easy to find, but they're not the same size as the LS7 slave, so future LS7 installations may require what the experts do by default: measure and adjust to compensate--either via additional torque (if spacing is lacking) or by shimming (if spacing is too great).

Be very careful with that statement. There are several LS7 slaves that have different throw out bearing lengths and diameters. Unless you confirmed that the GM part number for both vehicles is the same, I wouldn't have said that.

That was a big mistake, for which you'll be kicking yourself later. If you actually drive the car, you need to be bleeding your clutch fluid at least once or twice per year (more often if you're aggressive, or participate in track events).

There was "something out there" that could have guided you a lot, if you did your research. Don't blame the community--blame yourself.

01_SuperSlow

iTrader: (7)

Cadzilla

iTrader: (3)

true.. there are also a few 'benefits' to the dm fw that we may not necessarily care about, like noise suppression and vibration dampening... which could be said about nearly everything we change on the v.

FuzzyLog1c

iTrader: (4)

It is too heavy. 20 pound steel flywheels are the standard for LS-series engines for a reason: they're easy to drive, they're easy to launch, and they're not so incredibly heavy that rev-matching and acceleration suffers.

Our cars came with a 50 pound flywheel because GM engineers were influenced by corporate idiots. They were tasked to build a car that would shatter the 60+ year old average age of the Cadillac buyer, but as the design progressed, upper management was concerned about alienating the elderly Cadillac audience entirely. Cue the soft rubber bushings, the shallow seat bolsters, and the massive boat anchor dual-mass flywheel, which is good for only one thing: teaching senior citizens how to drive stick.

This is supported by the fact that that GM has never utilized a flywheel with more than half that weight since. Most of the rest of your paragraph up there is uneducated babbling about flywheel weights that you really need to experience before you shoot your mouth off. For instance, the "4k+ powerband" statement is complete gibberish. Moment of an inertia is not influenced by rotational speed. Therefore, a lighter flywheel has the same effect at 4 RPM as it does at 40,000 RPM.

Supplemental Weight and Rotating Inertia Comparison (rough):

GM LS7 Clutch Assembly (#24255748): 33.0 lbs
Fidanza LS7 Aluminum flywheel: 13.5 lbs
Total LS7: 46.5 lbs

McLeod Clutch Assembly (6932-07): 21.5 lbs
McLeod LS1 Aluminum Flywheel: 13.5 lbs
Total McLeod: 35.0 lbs

Diameter of LS7 friction disc: 11.50 inches
Diameter of McLeod friction disc: 9.69 inches



Moment of Inertia of LS7 clutch: Iz = (1/2)*(46.5 lbs)*(11.50 inches / 12 inch / ft)^2 = 21.35 lb-ft^2
Moment of Inertia of McLeod clutch: Iz = (1/2)*(35.0 lbs)*(9.69 inches / 12 inch / ft)^2 = 11.41 lb-ft^2 (47% less)

(The above assumes entire assembly is impossibly thin and has a diameter equal to that of the friction disc)


There you go with those assumptions again. Define "super lightweight," and I'll guarantee you that your idea of lightweight is not, in fact, light compared to the 8 lb flywheels frequently installed on imports. LSx engines, in stock form, aren't considered powerful. In fact, in today's LSx modding world, you're not even interesting until you're making more than 700 RWHP.

There are NO benefits to inertia, other than getting the car started from a dead stop. Gear to gear, that inertia makes it harder to shift, because your transmission's synchros have to overcome all of that extra rotating mass to equalize the input and output shaft speeds.

Literally the same as the stock clutch? Ha!

At some point, you've got to realize that you're new to this car and the community. Your opinions are not shared by the community. Hopefully, at some point, you'll look back at this post and wonder how you could write something so misguided. But we won't hold it against you--most of us were in the same shoes as you at one point. Including me--especially me.

DACTARI

iTrader: (1)

Fuzzy, I have to wonder where you get the energy to put into this forum, and whether you put the same intensity in your day job. There are some personalities out there who are always on, are you one of them? Just wondering. Hope you use your powers for good.

With regard to flywheel weight-- I've been doing some reading myself lately. Isn't a lighter flywheel harder to shift because the engine RPMs can fall off too fast? This is in the context of up-shifting, not down-shifting. I've also read that a heavier flywheel is better for turbos to keep them in boost between shifts.

FuzzyLog1c

iTrader: (4)

I'm definitely of those people that burns the candle at both ends. ENTJ (if you know your Myers-Briggs). Aggressive and occasionally confrontational everywhere I go. I have plenty of strong friends and strong enemies. I definitely put the same amount of energy into work and grad school.

A lighter flywheel can have that problem, but you shouldn't be giving it time for the RPMs to fall far. For what it's worth, I've missed a shift from 4th-5th at 4500+ RPM a couple of times and hit 3rd instead. With the 13 lb Fidanza LS7 flywheel, the car barely hesitates. If I did that with the stock flywheel, I would've broken something.

Moon Cricket

iTrader: (1)

Fuzzy you have way too much time on your hands for arguing. My so called "mis-guided" thoughts and so called "lack of information" have proven to work quite well. I'm not here to argue with you about the best flywheel ever made. Simply stated you and I both know a 25 pound flywheel works VERY well for almost anyone. It is not too light, it is not too heavy. Internet physics is hilarious to me. I do not doubt one bit many of your arguments hold weight. What I find interesting is that you literally say "if you had read through the (amazingly long winded and many opinion based answers) threads you would have found the information you needed".... Well Fuzzy, I did indeed read those, and that is precisely how I came to the decision that I did. Its not dumb luck that I picked the correct parts and it all works. My goal, rather than arguing about theoretical advantages and all the BS is to HELP other members that maybe don't have the time, mechanical ability or whatever other reason to scour over the internet for hours and hours trying to determine if "new information about the tq of a bolt changed in 2011". I mean come on man, what I did was provide a simplistic, easy to follow way to install your clutch. If you don't like it, then don't read it. None of it is inaccurate, I personally used those parts exactly as described and my car drives and shifts brilliantly with its insanely over weight, 25 pound flywheel and "sketchy" GM clutch assembly.

For those of you that want a "race car" setup, by all means, buy the super lightweight flywheel (of whatever weight you desire) and the 8" twin disc etc. For ME, and I am certainly assuming here, and the vast majority of CTS owners, there is a trade-off between "race car" and "daily driver". In my eyes, you didn't buy a 3900 pound luxury sedan to have the 'fastest shifts', 'fastest revving' bla bla bla car in the world. You bought it because you wanted a fun, fast, reliable, track ready but ultimately very streetable car. If you don't fall into those catagories then I completely agree, you should probably buy the F1 stage whatever clutch you'd like. However I believe you and I can agree that there is no reason to argue whats best for every person out there. The OEM LS7 clutch does indeed work very well.

As for me being wrong about the clutch slave cylinder, I have called and spoken with every major parts distributor I can think of, and even the local Chevrolet dealership, each of which told me they had ONE listing for an 05+ Corvette. Thats not at all to say there is only one, however that the vast majority of people that sell the parts sell one for all, and regardless of that being right or wrong, the part number I listed does indeed work flawlessly in my CTS-V. Maybe everything I did was wrong and all coincidence but it sure worked out swell for me.

Sorry for helping others!

TeamSorad

iTrader: (2)

Not to jump in the middle but I agree with with MC. I have searched no bs at least 10 hours of browsing the net searching both forums for information on the LS7. As I mentioned in my own clutch thread there is 10 pages and almost 250 threads. So the just search thing just doesn't work. One thing I don't understand, I have read from searching that the clutch flywheel replacement is one of the best mods but there isn't a sticky (or one I have seen) but there are sticky threads from almost 10 years ago fixing the rear end.

I literally was confused and even posted my own thread just to get the info quick and easy without all the ''other" stuff. I really think the mods should just search ls7 in the cts v forums and just delete everything or save the few threads that actually make any sense to the "noobs" like me. I don't know **** about corvette anything.

I'm one of those people that don't want a race car but hates the chatter when I push my clutch in. My clutch grabs fine so I would be basically changing out my clutch for the reported better drive ability, faster revs and getting rid of the chatter hopefully.

Fuzzy I recall in an earlier thread I searched I believe you were saying the F1 clutches were basically stock LS7 clutches that were just painted. This is def the first thread I have ever seen saying gm makes inferior clutches.

I would love to save some money and buy the complete "luk" clutch kit on ebay for 500 with slave but I am still getting conflicting info.

I just want my car to pull harder without any chatter

I didn't post to get involved with who has more corvette knowledge, I have read your stuff Fuzzy no doubt you know a lot, was just posting to confirm this **** is confusing.

Lbar

Thanks Moon Cricket, I'll save this thread in my favorites. Then I won't have to waste time sorting through the others when the time comes to replace my clutch.

As far as flywheels, I wouldn't hesitate to run an aluminum flywheel in these cars if it was not a track car. I would do it reduce the shock on the drive line when I'm tearing through the gears. The stock aluminum flywheel in my 03 Cobra convertible weighed 12.5 pounds. That car was very easy to drive and weighed 3780lbs, with a longer first gear and taller rear gear. If I accidentally had it in 3rd instead of 1st pulling away I didn't bother to shift back because the car did not struggle at low revs with a light flywheel.

DACTARI

iTrader: (1)

My wife is an ENTJ. We are having 2 people over tonight, so she's been cooking all day, baking cakes, etc. When they come over, it will be a full scale hyperactive production. Goddam, what happened to relaxing with your friends?

FuzzyLog1c

iTrader: (4)

By the way, after doing some more poking, it appears that the PowerTorque CS2529 is no more. However, the good news is that it has been replaced by the Dorman CS650109. $103 on Summit. If you check Dorman's site, they will confirm fitment for the 2006 Chevrolet Corvette, which is the same compatibility that was listed for the CS2529.

1BADCTS

iTrader: (17)

Damn... I bought the slave on Ebay but it didn't come with a hard line. Is the line available by itself from the auto parts store? Guess I'll find out tomorrow!

And how long did it take for your clutch to come in from GM parts direct?

Moon Cricket

iTrader: (1)

I don't know about the hard line but it took about 5 business days from east coast to west coast

jsnm

iTrader: (6)

I was hesitant on GM parts direct,but I got my parts within 3 days,not too bad,definitely best price ive seen,thanks mc for the link

IdriveaV

iTrader: (5)

Thats not the right part number CS650129 is the right part number for the 06 vette.
not that cheap either ha.

FuzzyLog1c

iTrader: (4)

My bad on the part number. I'm not sure what happened earlier--I ran the Dorman configurator. You're wrong about the price, though--the CS650129 is only $87 on Summit.

http://www.dormanproducts.com/p-2114...ave%20Cylinder

http://www.summitracing.com/parts/rnb-cs650129

IdriveaV

iTrader: (5)

Thats amazing, rock auto has it for 200.
I have an account with dorman and can buy directly and they want roughly 160.
I think i might just buy one to have when i need it at that price

MN_V

iTrader: (5)

Thanks a lot Moon Cricket Dude. Nice write up and pics! Fuzzy man take it easy on people just cause they slightly differ from your opinion and don't spend an hour writing a response doesn't make them uneducated or babbling. Some of us have kids and **** jumping on our laps when typing telling us to get off the computer!

Moon Cricket

iTrader: (1)

Welcome sir, just doing what I can to help others!