Lighter flywheel??
Thread Starter
Shelby GT350 Member
Joined: May 18, 2010
Posts: 2,318
Likes: 15
From: CT
Lighter flywheel??
There are pros and cons to going to a lighter flywheel...
...but generally speaking, less rotating mass in an engine is better, assuming you're competent at driving a manual transmission
So has anyone done it yet? Did it make any difference in the feel or performance of the engine?
...but generally speaking, less rotating mass in an engine is better, assuming you're competent at driving a manual transmission
So has anyone done it yet? Did it make any difference in the feel or performance of the engine?
V6 Member
Joined: April 26, 2010
Posts: 88
Likes: 0
From: bham al
**** warning - long ****
My mustang is still bone stock, so I cannot comment with direct mustang experience. However, I did replace the flywheel on my g35.
The stock g35 unit is a heavy dual-mass unit (I believe the mustang's flywheel is a dual-mass unit as well), weighing 27lbs IIRC. My replacement flywheel was by JWT, and it weighs 14lbs - so almost 50% weight savings.
There were no measurable gains on the dyno, nor did I expect any. Sprited driving, canyon runs, etc, are much more enjoyable with the lighter flywheel because revmatching is much easier and predictable. But that's the only good thing I can say about going aftermarket.
The aftermarket is a single piece with no damping, so you now hear engine/transmission noises that were previously nearly imperceptible. It's loud enough that I'm actually embarrassed by it; multiple people at drive-thru's have asked me if my car was broken.
Driving around town is a pain in the ***. Because the revs drop so much faster, lazily shifting is an issue. If the a/c is on, it's even harder to drive. In the summer, I hardly ever drive my g35 anymore. It's got no ***** down low, partially due to my exhaust mods, but mostly due to the flywheel.
And at the drag strip, my sixty foots suffered horribly. After the flywheel, my launches went from 2.1's on street tires to 2.3's, with a rare dip into the 2.2's. With drag radials, I have seen a best of a 1.895, but a stock flywheel would be good for another tenth, at least.
I've considered a lightened unit for the 5.0, because even after 5 months of ownership, I still can't revmatch well. The engine revs way too slowly. I find that interesting because the gaps in gears 2 through 5 are almost identical to the same gears in my g35 - so revmatching should be comparable between the two cars. However, all the other tradeoffs simply make a lightened flywheel not worth it IMO.
My mustang is still bone stock, so I cannot comment with direct mustang experience. However, I did replace the flywheel on my g35.
The stock g35 unit is a heavy dual-mass unit (I believe the mustang's flywheel is a dual-mass unit as well), weighing 27lbs IIRC. My replacement flywheel was by JWT, and it weighs 14lbs - so almost 50% weight savings.
There were no measurable gains on the dyno, nor did I expect any. Sprited driving, canyon runs, etc, are much more enjoyable with the lighter flywheel because revmatching is much easier and predictable. But that's the only good thing I can say about going aftermarket.
The aftermarket is a single piece with no damping, so you now hear engine/transmission noises that were previously nearly imperceptible. It's loud enough that I'm actually embarrassed by it; multiple people at drive-thru's have asked me if my car was broken.
Driving around town is a pain in the ***. Because the revs drop so much faster, lazily shifting is an issue. If the a/c is on, it's even harder to drive. In the summer, I hardly ever drive my g35 anymore. It's got no ***** down low, partially due to my exhaust mods, but mostly due to the flywheel.
And at the drag strip, my sixty foots suffered horribly. After the flywheel, my launches went from 2.1's on street tires to 2.3's, with a rare dip into the 2.2's. With drag radials, I have seen a best of a 1.895, but a stock flywheel would be good for another tenth, at least.
I've considered a lightened unit for the 5.0, because even after 5 months of ownership, I still can't revmatch well. The engine revs way too slowly. I find that interesting because the gaps in gears 2 through 5 are almost identical to the same gears in my g35 - so revmatching should be comparable between the two cars. However, all the other tradeoffs simply make a lightened flywheel not worth it IMO.
Thread Starter
Shelby GT350 Member
Joined: May 18, 2010
Posts: 2,318
Likes: 15
From: CT
**** warning - long ****
My mustang is still bone stock, so I cannot comment with direct mustang experience. However, I did replace the flywheel on my g35.
The stock g35 unit is a heavy dual-mass unit (I believe the mustang's flywheel is a dual-mass unit as well), weighing 27lbs IIRC. My replacement flywheel was by JWT, and it weighs 14lbs - so almost 50% weight savings.
There were no measurable gains on the dyno, nor did I expect any. Sprited driving, canyon runs, etc, are much more enjoyable with the lighter flywheel because revmatching is much easier and predictable. But that's the only good thing I can say about going aftermarket.
The aftermarket is a single piece with no damping, so you now hear engine/transmission noises that were previously nearly imperceptible. It's loud enough that I'm actually embarrassed by it; multiple people at drive-thru's have asked me if my car was broken.
Driving around town is a pain in the ***. Because the revs drop so much faster, lazily shifting is an issue. If the a/c is on, it's even harder to drive. In the summer, I hardly ever drive my g35 anymore. It's got no ***** down low, partially due to my exhaust mods, but mostly due to the flywheel.
And at the drag strip, my sixty foots suffered horribly. After the flywheel, my launches went from 2.1's on street tires to 2.3's, with a rare dip into the 2.2's. With drag radials, I have seen a best of a 1.895, but a stock flywheel would be good for another tenth, at least.
I've considered a lightened unit for the 5.0, because even after 5 months of ownership, I still can't revmatch well. The engine revs way too slowly. I find that interesting because the gaps in gears 2 through 5 are almost identical to the same gears in my g35 - so revmatching should be comparable between the two cars. However, all the other tradeoffs simply make a lightened flywheel not worth it IMO.
My mustang is still bone stock, so I cannot comment with direct mustang experience. However, I did replace the flywheel on my g35.
The stock g35 unit is a heavy dual-mass unit (I believe the mustang's flywheel is a dual-mass unit as well), weighing 27lbs IIRC. My replacement flywheel was by JWT, and it weighs 14lbs - so almost 50% weight savings.
There were no measurable gains on the dyno, nor did I expect any. Sprited driving, canyon runs, etc, are much more enjoyable with the lighter flywheel because revmatching is much easier and predictable. But that's the only good thing I can say about going aftermarket.
The aftermarket is a single piece with no damping, so you now hear engine/transmission noises that were previously nearly imperceptible. It's loud enough that I'm actually embarrassed by it; multiple people at drive-thru's have asked me if my car was broken.
Driving around town is a pain in the ***. Because the revs drop so much faster, lazily shifting is an issue. If the a/c is on, it's even harder to drive. In the summer, I hardly ever drive my g35 anymore. It's got no ***** down low, partially due to my exhaust mods, but mostly due to the flywheel.
And at the drag strip, my sixty foots suffered horribly. After the flywheel, my launches went from 2.1's on street tires to 2.3's, with a rare dip into the 2.2's. With drag radials, I have seen a best of a 1.895, but a stock flywheel would be good for another tenth, at least.
I've considered a lightened unit for the 5.0, because even after 5 months of ownership, I still can't revmatch well. The engine revs way too slowly. I find that interesting because the gaps in gears 2 through 5 are almost identical to the same gears in my g35 - so revmatching should be comparable between the two cars. However, all the other tradeoffs simply make a lightened flywheel not worth it IMO.
Thanks for sharing your thoughts!
Mach 1 Member
Joined: May 24, 2010
Posts: 873
Likes: 1
From: MA
If I remember correctly GT flywheel is single mass and V6 is dual-mass. Going to a single mass flywheel on V6 may cause the NVH that t-ray described because V6's are by nature not very smooth but with a V8 don't believe you will have the same problem.
Mach 1 Member
Joined: June 17, 2011
Posts: 606
Likes: 0
From: Youngstown, Ohio
I cannot speak for NVH but I can say that clutch chatter and the driveability issues posted above are for sure things to consider.
Thread Starter
Shelby GT350 Member
Joined: May 18, 2010
Posts: 2,318
Likes: 15
From: CT
Great input here...lighter brakes are out of the question so what are guys running for lighter wheels? Seems like they're all boat anchors for these cars...or shockingly expensive.
V6 Member
Joined: April 26, 2010
Posts: 88
Likes: 0
From: bham al
FYI - according to this post, the OE flywheel is 21.5 pounds. That's quite a bit lighter than I expected.
*****
Edit - after further reading, this particular bit of information is fascinating:
I guess that's part of Ford's aggressive fuel saving strategy, but I don't know for sure.
*****
Edit - after further reading, this particular bit of information is fascinating:
Originally Posted by vorshlag
The "heavy flywheel effect" is all in ignition timing. The OEM tune adds 66 degrees of ignition advance in "engine deceleration mode" (off throttle, falling RPMs), which slows the engine responsiveness. He changed this to a normal 12 degrees and wow, what a difference. The engine response SO much more lively! Its easier to rev match downshifts, too. I had no idea that could be in the programming.
Last edited by t-ray; Sep 9, 2011 at 01:29 PM.
Mach 1 Member
Joined: June 17, 2011
Posts: 606
Likes: 0
From: Youngstown, Ohio
FYI - according to this post, the OE flywheel is 21.5 pounds. That's quite a bit lighter than I expected.
*****
Edit - after further reading, this particular bit of information is fascinating:
I guess that's part of Ford's aggressive fuel saving strategy, but I don't know for sure.
*****
Edit - after further reading, this particular bit of information is fascinating:
I guess that's part of Ford's aggressive fuel saving strategy, but I don't know for sure.
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