Light weight flywheel?

[Bob90lx]

Hey everyone;
In the next few months my SHO is coming out again, and hopefully not again after that for quite awhile...
The plan is to get my Mtx lsd'd and get a stronger clutch installed at the same time. Also will be looking at a full proper 60k.
What I'm wondering about at the moment is how happy people are who have light weight aluminum flywheels installed on their sho's. I'm nervous about how it will effect daily driving. This car doesn't get driven everyday, and is more of a toy than anything else, but I doubt it's going to be mostly a track car. I've heard of people not liking the effect a light weight flywheel has on drive ability, and so I thought I'd try to hear some first hand opinions and experiences about it from people who have used them on their sho's. Thanks!

 

[jayro]

I have a lightened steel flywheel from sho source. It is a nice piece. Not sure if they still carry their super light aluminium one. With less rotating mass they rev faster and aid in downshifts etc. The drawback of the reduced mass is that it is easier to **** the car from a stop. They also do not handle heat as well. In my opinion there are alot of better ways to spend the money than on a flywheel, depending on what else you have done to the car.

 

[RonPorter]

I haven't looked up that lightened SHO Source flywheel, but I'm guessing may be 15#s?

Mixed reviews on the super lightweight AL ones. Car is too heavy, with not enough torque, to be pleasant for a daily driver.

Similar situation with another car I had in the same weight class with similar engine torque issues. Stock flywheel was 28#s, with lighter ones offered at 14#s & 9-10#s. Few guys got the 9-10# one for a DD. They regretted it. I went through two of the 14 # ones, and I felt it was a reasonable compromise, and still wound up quicker.

 

[SHOspazz92]

IIRC, The SHOsource unit is 17lbs.

-Sam

 

[RonPorter]

IIRC, The SHOsource unit is 17lbs.

-Sam

About what I figured.

For DD and regular street use, I suspect most folks would be happier with something in this weight range.

 

[Irish Pride]

I have the Clutch Masters 9lbs flywheel in my car and i love it! I dont DD my car anymore, but i did for several months after the install and it didnt bother me. Once you get used to it there arent any problems. It definitly added to the fun factor.

One thing to watch out for is if you go with a really strong clutch i've been told that it can actually flex the flywheel. I have a Spec stage 2 and i dont have any problems with mine but still something to look into.

 

[rubydist]

my 92 has the 3.2 w/ 3.0 cams and an 8 lb flywheel, and I like it - revs better than the stock and I have no problem with driving it as my daily driver. I will say that the 3.2 has noticeably more torque than a 3.0, so it may be that a 3.0 w/ the 8 lb flywheel would be more challenging to drive.

 

[Bob90lx]

Cool guys, thanks for the quick response!
I'm not sure how far I really plan on going with mods to the engine. And I have t decided on a clutch for sure yet either. Ive got a parts car that I'm going to fix up in a few weeks and use the proceeds from the sale to purchase a few things for the primary project.
Also, my car is somewhere in the area of 600lbs lighter than a Taurus. I'm not sure if that would effect drive ability with a lightened flywheel or not, I thought I saw it mentioned in a previous post.
My wish list for sure is ported intake, bbb's, and tri flow cams. I doubt I'll be able to find the money for the tri flows though, but hey, i can dream lol.
So like I said, the engine will probably be out of my project in a months time, and I guess I am worried I'll regret not doing a flywheel while it's easy. Has anyone ever just taken their stock SHO flywheel to a machine shop and had it lightened? Or is that a bad idea?

Again, :thankyou:

 

[jayro]

With your mods I would stick with a clutch that is close to stock, maybe a stage 1. Check out Shonutperformance and sho source. Definitly go with a ceramic throw out bearing. Alot of stage 1 clutches are basically stock ones with heavy duty rivets and straps.

 

[NotSoSlowSHO]

The driveability issue with a lightened flywheel is not related to torque. Adding or subtracting rotating mass to the flywheel has NO bearing on engine torque. What it DOES do is effect the rate at which the motor can change RPMs

You will find that rpm drop when shifting will be the biggest change, and effects driveability a ton. RPMs drop like a rock when you push in the clutch.

Unless you like abusing your SHO, shifting with a light flywheel pretty much requires you to rev match shifts.

 

[Bob90lx]

Cool, thanks again I appreciate it!

 

[rubydist]

The driveability issue with a lightened flywheel is not related to torque. Adding or subtracting rotating mass to the flywheel has NO bearing on engine torque. What it DOES do is effect the rate at which the motor can change RPMs

You will find that rpm drop when shifting will be the biggest change, and effects driveability a ton. RPMs drop like a rock when you push in the clutch.

Unless you like abusing your SHO, shifting with a light flywheel pretty much requires you to rev match shifts.

Unfortunately, there is much mis-information in your post.

The driveability issue IS related to engine torque - an engine with a large amount of torque at low rpms is not as difficult to drive with a light flywheel as an engine that has lower torque at low rpms. Because there is less energy stored in the rotating flywheel, more engine torque is required to keep the engine turning as you release the clutch, or more finness with the clutch pedal. However, in my experience with the 8 lb flywheel, the engine does fine as long as you know how to drive.

Yes, engine rpms drop significantly more quickly when you release the clutch (and have the throttle closed) with the lighter flywheel. Because of this, shifting is actually improved because the engine has a chance to slow down to the proper speed for the new gear, so it is less ******* the syncros. (Unless you shift as slow as grandma....) Rev-matching is not required at all on upshifts, contrary to your claims. Rev-matching is always a good idea on downshifts, regardless of the flywheel weight you have.

 

[NotSoSlowSHO]

Unfortunately, there is much mis-information in your post.
.

No misinformation at all.

You simply do not understand it. :wave:

 

[dohcsable]

With your mods I would stick with a clutch that is close to stock, maybe a stage 1. Check out Shonutperformance and sho source. Definitly go with a ceramic throw out bearing. Alot of stage 1 clutches are basically stock ones with heavy duty rivets and straps.

Ceramic tob, and just get a southbend tz or dxd.....you won't regret that choice.

 

[SHOdded]

Engine spins up faster, power comes on quicker, car takes off like a jackrabbit; BUT you have to be an active driver to use a lightened flywheel in a DD, especially while coming to stops, as everyone has said. Loved every second (chirped the tires even with the Quaife) despite that. But then I had the Fidanza, maybe the 14#er mentioned earlier would be a great compromise...

 

[jayro]

So.....
1. The reduced weight causes the rotating assembly to be more easily effected by an outside force. That makes it rev and drop RPM's much faster, but also means that it is stopped much easier when it is acted upon by the stationary (or slower moving) drivetrain.
2. While torque is not increased or decreased (substantially) by a lighter flywheel, a car that has more low end torque avialable is easier to drive with a lightened flywheel. This is because there is more torque avaliable to transfer to the stationary drivetrain (trans/wheels) when you apply the throttle during clutch engagement.

Correct?

 

[NotSoSlowSHO]

So.....
1. The reduced weight causes the rotating assembly to be more easily effected by an outside force. That makes it rev and drop RPM's much faster, but also means that it is stopped much easier when it is acted upon by the stationary (or slower moving) drivetrain.
2. While torque is not increased or decreased (substantially) by a lighter flywheel, a car that has more low end torque avialable is easier to drive with a lightened flywheel. This is because there is more torque avaliable to transfer to the stationary drivetrain (trans/wheels) when you apply the throttle during clutch engagement.

Correct?

correct on all counts

Bottom line, when lightening the rotating mass, driveability is effected by the increased speed at which the motor can change revs.

This increases the amount of driver skill needed for starts from stop, launches, and any time the trans is shifted.

But once engaged in the proper gear, just jump on the GO pedal, and the lightweight flywheel will make you happy :wave:

 

[rubydist]

No misinformation at all.

You simply do not understand it. :wave:

I understand it way better than you, and explained it accurately in my post above. You could man up and admit you didn't word it right, or you could just be an *ss like you did above.

It is important to accurately answer people's questions, so they are not misled about what they are questioning.

 

[RonPorter]

No misinformation at all.

You simply do not understand it. :wave:

Nope, torque is where it's at. Usually, the lower the low-rpm torque, the heavier the factory flywheel will be.

Actually, from a drag racing standpoint, small-cube engines in heavy cars do well with very heavy flywheels to help them out with the 60' time. This would be a GOOD PLAN for someone serious about drag-racing a FWD SHO.

The 2.5 liter turbo LGT I had did well with the 14 # Streetlite over the 28 # dual-mass (with only occasional stalling), but the 2.5 liter was not driveable with the 8-10 # (forget the exact weight) Streetlite that a few guys tried.

Well, unless to want to launch off every traffic light at 2K, slipping the clutch!!

 

[NotSoSlowSHO]

I understand it way better than you, and explained it accurately in my post above. You could man up and admit you didn't word it right, or you could just be an *ss like you did above.

It is important to accurately answer people's questions, so they are not misled about what they are questioning.

"man-up"?? :laugh_ti:

And youve resorted to name calling now? Great job

How about we break this down....

The driveability issue IS related to engine torque - an engine with a large amount of torque at low rpms is not as difficult to drive with a light flywheel as an engine that has lower torque at low rpms.

Engine TORQUE has nothing to do with rotational mass.

Rotational MASS has nothing to do with torque.

Granted (as you have mentioned) rotating mass does store some rotational energy. Basic physics applies here. No energy is lost. Rotating mass does not consume energy. It stores it, then reintroduces it into the system as needed. But once used up (doesnt take much) it stores nothing. All it does id dictate the speed at which a motor can change revs.


ANY motor with a large(er) rotational mass will be easier to drive than one with less(er) rotational mass.

Its simple physics.


Engine torque has NOTHING to do with how fast the motor drops in revs when the throttle plate shuts.

.....or more finness with the clutch pedal. However, in my experience with the 8 lb flywheel, the engine does fine as long as you know how to drive.

Well this sounds familiar, quoting myself now.

Bottom line, when lightening the rotating mass, driveability is effected by the increased speed at which the motor can change revs.

This increases the amount of driver skill needed for starts from stop, launches, and any time the trans is shifted.