Light weight flywheel for street use ok?

dklitzke

Registered User
I have a '95 SC 5-speed which I am planning on doing some mods to when I get home from Iraq. I have already gotten great responses from youse guys on my MP Inlet Plenum question thread. Here's one for you: Bill at SCP has an 11 lbs aluminum flywheel, made by SPEC (whom he highly recommends for quality). It sounds like a really cool, howbeit a little pricey way to improve performance. My question is how will this effect street drivability and longevity? Will the lighter weight flywheel put additional stress on other components such as the clutch or transmission? I know it'll cause the car to rev quicker, but how will it effect torque, or will it? One thing I don't want to mess up is the great torque this car has. If it turns out that this is a safe as well as beneficial mod, I'll do this and go ahead and install a SPEC clutch as well (either Stage 1 or 2). What say ye?

:D

Don
 
You may find the SPEC clutch a bit stiff, and grabby, for everyday street use. My 95 5-speed is just a hobby car now, otherwise I would be considering taking out the SPEC Stage 2 we installed this summer.

I'd second David's recommendation for a CenterForce Dual-Friction unit.

An aluminium flywheel is fine. The only detrimental effect I noticed for street driving, is that you can't lug the engine down as much in the lower gears when driving on slow residential streets. I guess the lost inertia is the culprit. It's not terrible, I can just feel that it's not so happy at 1200 rpm any more. BTW mine is a McLeod 11" flywheel, but I'd assume the same results with the SPEC unit.


cheers
Ed N.
 
With the stock flywheel, I could go with low revs like that, and idle around a corner rather than downshifting to 1st (I have 3.27 gears). With the light flywheel, it will still do that, but I can feel a bit of "roughness". So I try to avoid that now. ;)

cheers
Ed N.
 
A third for the Centerforce Dual friction clutch.:) I have been using them for many years with excellent life expectancy. I went with a Spec lightweight Steel flywheel from SCP, (18lb I think...) for my daily driver. Personally, I am not a fan of aluminum flywheels, the reason is that Al does not have an infinite fatigue life, but steel does. So, to me steel is a much better choice for a street car. Also the Spec steel units still have the bolt on friction surface like an Al unit.

The difference compared to the stock flywheel is remarkable without being unstreetable as it can be when you go to light. Especially with the vehicle weight that we are all dealing with...

Charles
 
I cannot seem to find the Centerforce DF listed for a 95 SC. Now maybe it's the way the listings are shown that I just don't see it, but everywhere I try I find the CF I and II but no part numbers for the DF. I would appreciate it if someone could give me that information.

Ira
 
Centerforce does not make a DF for the 94-5. The 94-5 is actually a 11.5" clutch, where the 89-93 is a 11.0" There is no gain running the 11.5" so just go with the 89-93 clutch, just use the corresponding flywheel.

The 11.5" package is naturally heavier than the 11", so even that change will be a step in the right direction. If you want lighter...

The two sizes are completely interchangable as a unit. The trans is the same input spline, etc. and the flywheel end of the crank is the same. So there is no mods at all.

Also a DF 11" will hold more torque than the Centerforce II 11.5"

Charles
 
Charles Markman said:
Centerforce does not make a DF for the 94-5. The 94-5 is actually a 11.5" clutch, where the 89-93 is a 11.0" There is no gain running the 11.5" so just go with the 89-93 clutch, just use the corresponding flywheel.

The 11.5" package is naturally heavier than the 11", so even that change will be a step in the right direction. If you want lighter...

The two sizes are completely interchangable as a unit. The trans is the same input spline, etc. and the flywheel end of the crank is the same. So there is no mods at all.

Also a DF 11" will hold more torque than the Centerforce II 11.5"

Charles
Excellent. Thanks a whole lot! So you're saying that when I swap the clutch I should install the 89-93 flywheel also and not leave the stock flywheel in?

Ira
 
irar said:
Excellent. Thanks a whole lot! So you're saying that when I swap the clutch I should install the 89-93 flywheel also and not leave the stock flywheel in?

Ira

No, all OE flywheels are the same. Ira, your clutch is already an 89 clutch and flywheel anyway. But I would still go for an aluminum flywheel and DF clutch. It's stiffer but not too bad and engagement is smooth like stock.
 
Did I miss something, but why would a 95SC have a 89 clutch?:confused:

As far as not leaving the stock flywheel in... That comes down to how many miles are on it? How many times has the stock flywheel been resurfaced? If you cut a flywheel to many times, it gets thinner, so the travel of the throwout bearing can be limited, so it won't disengage properly. That problem can be corrected with flywheel shims, but personally they scare me... I'd rather change the flywheel.

Also, how much are your feet worth? With the M5R2, you can't put in a scattershield to protect in case of explosion (rare, but posssible). You can put a ballistic blanket around the bellhousing to contain the explosion, but I'd stick with an SFI approved flywheel, Steel or Aluminum and avoid the explosion altogether So it might as well be lighter...

And while you are in there, replace the flywheel and pressure plate bolts. And swap out the slave cylinder/throwout bearing and pilot bearing. They are cheap insurance!

Charles
 
if i recall right he is wrong, the flywheels have a different surface aread for the clutch, the 89-93 are 11" and the 94-94 are 11.5" i'm pretty sure the 94-95 flywheel has .5" bigger surface area for the clutch... also i have a spec clutch stage 3 with lightened pressure plate, if you go spec have it lightened, i also have a spec alum flywheel, i have the ffrp aluminum 3.73s posi rear also in my 91 i love it, but the clutch is a little hard :) just get a bigger left leg, but when you want it to catch it goes :)
 
Charles Markman said:
Did I miss something, but why would a 95SC have a 89 clutch?:confused:

As far as not leaving the stock flywheel in... That comes down to how many miles are on it? How many times has the stock flywheel been resurfaced? If you cut a flywheel to many times, it gets thinner, so the travel of the throwout bearing can be limited, so it won't disengage properly. That problem can be corrected with flywheel shims, but personally they scare me... I'd rather change the flywheel.

Also, how much are your feet worth? With the M5R2, you can't put in a scattershield to protect in case of explosion (rare, but posssible). You can put a ballistic blanket around the bellhousing to contain the explosion, but I'd stick with an SFI approved flywheel, Steel or Aluminum and avoid the explosion altogether So it might as well be lighter...

And while you are in there, replace the flywheel and pressure plate bolts. And swap out the slave cylinder/throwout bearing and pilot bearing. They are cheap insurance!

Charles

The OE flywheel for the 94/95 and the 89-93 is the same. Only the clutch is different. Some aftermarket flywheels have an 11" friction surface and some have 11.5". So there may be a difference depending on manufacturer.

However, since it is recommended to use the 11" clutch when going to an aftermarket source, it follows that it doesn't matter what flywheel you use.
 
The OE flywheel for the 94/95 and the 89-93 is the same. Only the clutch is different. Some aftermarket flywheels have an 11" friction surface and some have 11.5". So there may be a difference depending on manufacturer.

However, since it is recommended to use the 11" clutch when going to an aftermarket source, it follows that it doesn't matter what flywheel you use.

Bring this back from the dead, but I have some input. I installed a dual friction on my 94 with the 11.5 stock flywheel. The car will not disengage the the clutch very well. I had to pay the guy to drop the trans again and put the Cent II in and it worked fine after then. Maybe if I machined the surface of the flywheel it would have worked. But it didnt so 1 more for the flywheels being different. .02
 
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