Topic: Upgraded clutches and light flywheels

[snaponbob]

Up until just the last month or so, only clutches could be upgraded. As far as I have seen only SPEC has some real strong clutches, and there are SEVEN choices for the 2.4 and SEVEN other part numbers for the stock flywheel equipped 2.0. CLEARLY, the clutches are the weak link on the 2.0 Kappas, HHRs, and Cobalt SS.

Clutches - SPEC has them for the 2.4 and 2.0. http://www.specclutch.com/cars/Pontiac/Solstice/2007/Single The important thing to understand while looking at that chart is that they have clutches for stock (SAC self adjusting clutch) applications as well as their non-SAC flywheel set ups.

Flywheels - There are various lighweight flywheels for the 2.4. But for the 2.0 so far there are only two vendors - SPEC (same chart as above) and Fidanza. Both are sub 12 pounds vs the factory 39 pound lump. Fidanza does NOT have clutches for us.

Word of warning - choose wisely. Lightweight flywheels are wonderful things (done this on a B/SP Triumph TR8, stock GT6, and way back when on a D/SP 1500 Civic) but the ligther the wheel the more you'll feel it during daily driving. That said, the labor on a torque arm equipped 2.0 Kappa (post mid-July 2006 production) will be looking at 9 hours billable shop time. The diff has to come out as well as the turbo to allow the removal of the transmission.


edit: corrected thread title

[Critterman]

DDM is doing some testing on their 2.4 supercharged car.  I think they are using a Spec

[G8TR]

All I have heard so far is that these clutches cause a lot of chatter. Have they gotten better since being discussed on the other forums? 

[Ben L]

Good post!  Old hat to the Founders but new to me . . . 

I was cursing the clutch again on my GXP today.  I wondered when someone on the aftermarket would come up with something.

I heard the chatter thing about alum. flywheels, and I do not know the history on the Kappa 2.0s.  But I am running a Fidanza lightweight flywheel and a Fidanza Two-Three kevlar puck clutch on the Factory Five Daytona Coupe I am building.  It also has a hydraulic clutch and lays down some serious hp and torque (500+ hp 347 ci stroker Ford Racing Boss pushrod V-8, custom solid roller cam, Vic Jr. mani., Pro Systems 4 barrel double pumper carb., Canfield 195 cc CNC heads, Jesel shaft rockers, etc., etc.). 

People told me the same thing when I selected the flywheel/clutch components for that build.  But in the test drives we have taken (giant go-kart without the body)  even with a brand new unbroken in flywheel and clutch, engagement has been smooth and no chatter.  Don't know if that experience translates here or not.

Too bad the assembly its so difficult to get to. . . .  Even still, I think is on the list for long term mods.  And if the stock clutch breaks or wears out . . . . for sure I won't look back!

[snaponbob]

I have posted more detailed input on the "other" forums. In a nutshell, if the stock flywheel is used with a new higher rated clutch the flywheel REALLY needs to be resurfaced. Otherwise you WILL drastically increase the potential of chatter. It's caused put ALL sorts of things that I won't waste your time with. Just DO IT !!!!! Even then Spec (and everybody else) specifies a proper break in. It is NO different than installing new brake pads as they need to be "bedded in".

If one goes with a light flywheel it is critical to understand that the LNF flywheel is 39 pounds and the Spec and Fidanza flywheels are under 12 pounds. That is a HUGE difference and things will change. When (not IF) I need a new clutch it will most likely be in combination with a new flywheel. So far my eyes are on a Fidanza with a Spec 2+. The Fidanza is $330 all day long on e-bay and the Spec is about the only clutch(es) available. DDM is working on something but I don't know what. Some think the Spec is a mess, others don't, and since I have used NONE of them I simply do not know any more than what folks have said.

That's it. I just finished a martini and I really am more interested in DINNER !!!!!!!!!!!!!! See ya.

[Critterman]

I'm using an Exedy state II 3 puck with the stock flywheel on my 2.4,.  Very little chatter, only if I engage the clutch at very low RPM's

It's probably less now after 8 runs at the track

[TempeRacerGuy]

It's not the flywheel that causes chatter, it's the clutch.

If the flywheel has uneven friction charactoristics (hot spots and such), that will cause chatter.  But on a correctly machined flywheel, the flywheel will not cause chatter.

Chatter comes from the clutch.  if a clutch's friction disk has a high coefficient of friction and a not so even distribution of that friction, the clutch will chatter.  So, puck style friction disks, while good for cooling and eliminating green fade on the clutch, they will chatter.  Even a full face disk will chatter, including the stock one.  To make this chatter less apparent to the user, they install a set of springs in the hub.

In other words, if you need ultra high torque handling capabilities, go with a solid hub 4-6 puck friction disk, with a high clamping force pressure plate.  Under this is a solid hub 4-6 puck friction disk with a lower clamping force.  under this is a full face friction disk with a sprung hub and a high clamping force pressure plate, under this is stock with the lower clamping force.

So basically   (higher torque handling capability = greater chances of chatter)


Now, onto flywheels :-)

I have a GREAT knowledge of flywheels, and have used every type...  standard 304 stainless, lightened factory, Chromoly, and multi-piece alluminum.

the lighter the flywheel, the quicker your engine will rev (both up and down), and more energy will be transfered to the wheels, but there are a couple drawbacks...  a flywheel is designed to store energy, the heavier the flywheel, the more energy is stored.  This stored energy does two things, first it smooths the engine and second it helps your car move off from a dead stop.

Smoothing out the engine...    your engine has two forces that affect the rotation.  The first is the power stroke, which "kicks" the engine into rotation, the next is drag, which tries to slow the rotation down.  The flywheel uses it's stored energy to maintain rotation speed till the next "kick".  The heavier the flywheel, the more energy stored to combat the drag and thus a smoother engine

Starting off from a stop.  The energy stored in the flywheel is what helps to start you off from a stop...   When you let the clutch out, the energy stored in the flywheel, is transfered through the transmission to the rear wheels to help you move off.

Thus, with a lightweight flywheel...  the engine ("MAY") run slightly rougher on a 4 cylinder engine.... though on my past experiences with MR2s, Hondas, and Nissans, this has been a non-issue and was not noticeable.   Also, you have to rev the engine slightly more when taking off from a stop because there is less energy stored in the flywheel.

Now, here are my experiences with light flywheels.

professionally Lightened and heat treated stock (customer used against my judgement)  - exploded while reving in the garage, destroyed the engine block, transmission case, put a 8" round divet in the concrete floor, and a 3" hole in the roof 20 feet up.  The only thing that kept the tuner in the driver's seat from being injured was that when the ring gear came apart, the part heading to the driver's seat hit the starter motor and bent into a roller coaster shape.  It's pretty cool and I have a picture of it somewhere.

Light 304 Stainless - was OK... not much lighter than stock, but worked well

Fidanza multi piece construction...  Light weight, reved well, has replaceable friction material....  However, the dowel pins on one customer car came out, rattled around the bell housing and destroyed the transmission case.  On another car, the ring gear came off, and buzz-sawed through the tranny case destroying the case, wiring harness and some hard pipes.   Through past poor experience, I will NEVER use nor recomend multi-piece flywheel designes, especially with different metals as they have different expansion rates with heat, which mean that they can work themselves loose and come apart.  All the Fidanza supporters always say how they are safe because they meet SFI specifications...  However the SFI also says that they can only be used with a scattershield in case they come apart.

Chromoly...   Absolutely the BEST, light, strong, and last...   and when the starter disengages, the flywheel makes this ringing sound that's pretty cool :-)  They handle the heat well, they are single piece design, there really is only one drawback... they are expensive but worth it.


So, for a car under 450 ftlbs or so of torque (to the flywheel), I would recomend a chromoly flywheel with a full face, sprung hub friction disk and heavy pressure plate...   ACT makes pretty good products, but they don't list anything for our car....  I'm going to give them a call next week to see what they can do.

[TempeRacerGuy]

OK, actually just got off the phone with Mike at ACT (Advanced Clutch Technology)

He said that the Sky redline/Solstice GXP clutch and flywheel is currently in testing, and here are the specs:

Heavy Duty Pressure plate + full face sprung hub has a 411 ft lb torque handling capability with a 49% increase in clamping force  (about 10-15% increase in pedel pressure)
Heavy Duty pressure plate + 4-6 puck (solid or sprung hub) has a 526 ft lb handling capability with the same 49% increase in clamping force.

He said they also have a 1 piece Chromoly flywheel in development, but he did not have weight specs on it.


He said that these will be released in about 2 months.  If you go to their website and select your vehicle and input your E-mail address, when it's released, they will send you a press release.

This is perfect timing for me :-)

[shabby]

Lotsa good info there, i had an act 2600lbs clutch on my talon, it took a beating with my awd launches and held up fine. The only downfall was the pedal pressure... my left calf muscle was 1" bigger than the right one, but i got used to it even in stop and go traffic.

[RUTurbo]

Thanks for the info TRG, nice to know LNF owners will have some more options in the near future!

[TempeRacerGuy]

Lotsa good info there, i had an act 2600lbs clutch on my talon, it took a beating with my awd launches and held up fine. The only downfall was the pedal pressure... my left calf muscle was 1" bigger than the right one, but i got used to it even in stop and go traffic.

Yes, on my Evo, I am running the Extreme Pressure Plate with full face disc.  It's very streetable, and yet when you pop the clutch with launch control, the car claws at the ground for traction like a cat on a polished lenolium floor.  ACT has really proven to be a great company for us Diamond Star guys... they have supported us well and their products have taken a beating.

However with the Heavy Duty Pressure plate, you won't have that huge left calf... 15% heavier on this car is still light enough for my 3 year old to depress with no problems.

OK, yes, I sound like an ACT fanboy, and I am... but that's because on ALL of my cars ACT has proven to be the best...  I have tried:  RPS, Centerforce, TRD, Clutchmasters, Exedy, Tilton, and OS Giken.  Other than the OS multi-plate clutch (at 5X the price), ACT has been the best!