11" vs 10.5" Flywheel
Thread Starter
Racer
Joined: Oct 2010
Posts: 259
Likes: 3
From: Plano TX
11" vs 10.5" Flywheel
From what I'm reading the factory high performance 454s came with flywheel 3993827 11" flywheel. (According to Fisher re crate engines, anyway)
But there was also a 10.5" high performance flywheel 3963537 for 454 applications.
Has anyone who started out with the 11", gone to a 10.5" configuration, and what kind of results did you have?
By results I'm thinking about streetability/ reliability/ performance (due to less rotating mass). Maybe a "splitting hairs" type of question, but just curious.
But there was also a 10.5" high performance flywheel 3963537 for 454 applications.
Has anyone who started out with the 11", gone to a 10.5" configuration, and what kind of results did you have?
By results I'm thinking about streetability/ reliability/ performance (due to less rotating mass). Maybe a "splitting hairs" type of question, but just curious.
Le Mans Master
Joined: Apr 2005
Posts: 6,359
Likes: 428
From: Seattle Area WA
The 11” clutch has more clutch surface area, therefore it should handle more power. Remember if you go with a 10.5 (153 tooth) you are going to need a new bellhousing, and new starter as well. An important thing to think about is how much do you want it to weigh? A steel billet 11” can be had in anything from 10, 12, 18, 29, 30, 35 and 40 pounds. The weight of your car, power band and gearing will help you determine what weight would work for you. Example is a 3.08 rear would want a heavier flywheel, with 3.70 of 4.11s you could use a 18 pound flywheel on the street. A high quality, steel billet flywheel is a must for high RPM performance applications.
Le Mans Master
Joined: Apr 2005
Posts: 6,359
Likes: 428
From: Seattle Area WA
Basic physics would say that is not 100 % true. For the same weight flywheel yes, but the basic formula is Inertia=Mr2. The biggest variable here is the mass, the radius difference in the formula is either 5.25" squared or 5.5" squared. When you can vary the weight from 12 pounds to 40 pounds, and convert to mass, that's the big factor.
Last edited by Scott Marzahl; Aug 21, 2013 at 08:06 PM.
Thread Starter
Racer
Joined: Oct 2010
Posts: 259
Likes: 3
From: Plano TX
Flywheel
I was just going by the info in Fisher's book. He has a section that lists a multitude of factory high performance part number listings, and the LS6/7 crate information he had specified the 11" I quoted. Under a section on flywheels, he listed them individually, including the 10.5" I referenced.
I'm not planning a change, but don't mind a little extra knowledge.
I would think that the 11" reference above would certainly be a high performance unit, as it was specified for the LS7 application in addition to the LS6.
