FE Power Forums
FE Power Forums => FE Technical Forum => Topic started by: 427HISS on January 24, 2018, 09:17:13 PM
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For my new 428FE I have a new billet steel flywheel. I've never used a aluminum, so I'm wondering the differences between the two ?
Mostly street driven with some track days. I have a 2,400lb 427 Cobra. Not serious about changing. (or am I) hum..... ;D
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One is lighter. So your cobra can do an uncontrolled burnout sooner after you stab the throttle. Fun side benefit, will also make your wallet lighter.
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I run one in my junk, revs faster and my favorite reason, makes the exhaust note at idle much nastier. Sounds like cam is 30 % more radical
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A heavier flywheel has more inertia. So, it will take more torque from the engine to accelerate it at any given rate. This torque requirement will reduce the available power at the rear wheels of the vehicle. So, a vehicle with an aluminum flywheel will accelerate more quickly than one with a steel flywheel, assuming you have traction. The difference between a 15 pound aluminum flywheel and a 40 pound steel flywheel is about 12 lb-ft of torque at an acceleration rate of 1000 RPM/sec; I did this calculation quite a while back in this thread:
http://fepower.net/simplemachinesforum/index.php?topic=286.msg2116#msg2116
On the other hand, the clutch engagement will be smoother and easier with a steel flywheel, because it does have more inertia. The tendency for clutch chatter will increase with a lighter, aluminum flywheel. So, you have to decide what is more important in your application. For my 68 Mustang fastback project the engine is only around 450 HP and 490 lb-ft, so I chose an aluminum flywheel for that car because I didn't want to give up an rear wheel torque/HP. Recently I purchased a clutch setup for my 68 Shelby, which will have an 800+ lb-ft torque supercharged FE; with no shortage of torque available I decided on the steel flywheel for that car.
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With an overpowered car(basically any Cobra), it won't make difference in overall performance(it's going to blaze the tires no matter what), but I think the steel wheel will be "smoother" to drive around town. The alum wheel will be real snappy on throttle response and make the car more difficult to be smooth driving/shifting.
I've only driven one car on the street with an alum wheel. Buddies '62 Gal with 410/4 spd. It was cool, but definitely tell the difference in driving manners compared to my pickup(428/4 spd).
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Is there a 27-30 pound steel flywheel available? Wouldn't 27-30 pounds be just right in a light to medium weight car with a warmed up street FE? Snappy acceleration and still shift gear to gear easily?
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Isn't there a rule of thumb based on vehicle weight? 1:100 ratio? 3400 lb. car works well with a 34 lb. flywheel? Obviously there are other factors, but is that rule of thumb useful?
paulie
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My 13 LBS Flywheel seems fine on street in my 3600 lbs Fairlane with 3.70 gear and Wide Ratio , the light flywheel helps the tires recover on the clutch drop and on gear changes , it also seems to add a lot more Braking power when you let off the gas and accelerate quicker
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I think weight has something to do with it, but here is my take. I think it has more to do with gear ratios to be successful with an aluminum flywheel on the street. That includes the first gear ratio not just the rear gear and tire roll out. I had a 2.78 first with 4.56 rear and 29" tall tires and when I switched from a 30# steel to a 15# aluminum, I was surprised that it drove so well. I had no trouble at all driving away from a stop "normally". At the track the aluminum is faster as long as you can launch it correctly (adjustable clutch tuning). Now if you have a 2.32 first gear and a 3.25 rear, that combo will not work well. You can't "ride" the clutch a little to get it going with a lightweight flywheel. And if the car was heavy or light it would make this better or worse on opposite ends of those two examples.
I have a friend that drag raced an old T-bird for 30+ years. It was a lightweight chassis car, had a 351 CI small block with less than 600HP and a lenco 4 speed. That car hauled ass, he never changed a thing over the years other than playing with the flywheel. He had a 32# a 22# and a 12# flywheel. He didn't have much torque, and a "hard lock" clutch... the 32# would spin the tires (14x32), the 22 worked the best, and the 12# would dead hook and then bog. If he had an adjustable clutch, the 12# would have been the fastest. The car ran 9.07@150+ with a 9.2 deck SVO block, old FORD Motorsport A3 canted valve heads, even had a single 4 FORD A351 cast intake and a 750 DP carb, was standard bore and stroke. All the BBC Chevy guys that had big inch BBC's had trouble running with him. He trailered a lot of dragsters and was a lot of fun to watch.
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Is there a 27-30 pound steel flywheel available? Wouldn't 27-30 pounds be just right in a light to medium weight car with a warmed up street FE? Snappy acceleration and still shift gear to gear easily?
The McCleod steel flywheel I just got is 30 pounds. The aluminum flywheel I got from American Powertrain was 14 pounds.
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I'm using a McLeod aluminum wheel in my street-driven 66 Fairlane with a TKO and 4.00:1 rear. Love it... I don't see a down side. clutch action is smooth, revs quickly, very drivable, and still runs low 11s.
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I'm going for the aluminum fly. Never had one so it should be interesting.
Since I'm a retired sprint car guy, and loving the sound of a very quick rpm ramping up and down engine (nothing sounds like a 360/410 engine) that has no weight of a flywheel & clutch bolted to the crank , I even like the idea of faster revs of mynew 428 engine. A long with my 8stack injection, it should sound quick and nasty. (If my cam isn't big enough) ::)
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Built 390, '66 428 PI cam, 780 Holley, aluminum flywheel (15#?), wide ratio top loader, 4.57 Detroit locker in a '66 Falcon Wagon.
Loved that quick winding car.
Bob
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Built 390, '66 428 PI cam, 780 Holley, aluminum flywheel (15#?), wide ratio top loader, 4.57 Detroit locker in a '66 Falcon Wagon.
Loved that quick winding car.
Bob
I had a 40# steel flywheel, and have been running a 20# RAM aluminum flywheel for a good bit in my pretend Cobra. Big difference in spool-up. I'm keeping the RAM alloy.
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Pretend Cobra ?
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I think he means it has a 'glas body. 'Real' Cobras are worth the better part of a million dollars---give-or-take-a-few---and most owners probably don't drive them much. ;)
KS
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Hi, so do the aluminum flywheels have a steel insert so they do not wear out so fast, I turned one one for a guy in the early 70's for his stock car but it was all aluminum, it had some bad grooves in it so I made it a lot lighter , after that I didn't think they would work vary long on a street car. Leny Mason
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yes on the replaceable steel insert for aluminum wheel
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Yes I would think so there is a lot of friction there, a stock car you were all ways working on them so it was not a big deal, on a street car not so much fun to work on all the time. Leny Mason
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Pretend Cobra ?
Mine is not an original.
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Well I just hope you have fun with it Original or not spin the tires any time you get, Leny Mason
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Schiefer (remember them?) made IIRC the first street/drag aluminum wheels with a sintered iron or steel replaceable
insert just for that reason. While I don't doubt in some applications (sprint cars, maybe stock cars) no insert was used, it was much more typical they were, especially in a drag car/dragster.
http://www.network54.com/Forum/74182/thread/1291213321/Schiefer+aluminium+flywheel+for+FE....-
Hi, so do the aluminum flywheels have a steel insert so they do not wear out so fast, I turned one one for a guy in the early 70's for his stock car but it was all aluminum, it had some bad grooves in it so I made it a lot lighter , after that I didn't think they would work vary long on a street car. Leny Mason