HP and torque relationship in a light car

[RACERAL]

My motor which is still sitting on the stand is 447H with 500tq at 5000. I'm thinking about going with a aluminum flywheel just so it will rev quick... Good or bad idea

[Grubby]

Al,

I am also seriously considering a light flywheel because the engine has serious torque and the car is light. I would say a 30 pounder is about right.

John

[RICK LAKE]

RACERAL Aluminum flywheel is great, How about a 22 pound flywheel? The rotating assembly in the motor was setup guessfor "0" weight needed or removed. This is one thing a have always done with bottom ends and had the whole thing setup and checked. Have we looked at a clutch setup yet?? If you are an easy driver, go with a stock 11" setup. If looking to be a little silly, I recommend a street twin. Lite pedal, good feedback, last the life of the motor if setup right with a hydro TOB. IMO The abuse part I want to break or take the most abuse is the clutch. Cheapest thing to replace or other parts and takes alot of abuse too. If you go with stock setup get the spring hub disc. Rick L.

[DanEC]

I used a medium weight McLeod flywheel of around 20 lbs and my 459 does seem to rev very quickly with it. Also, very smooth in clutch takeup on starts. I would consider a 30 lb flywheel to be pretty heavy - at least in a Chevy 427 that would be a stock GM flywheel.

[mikeinatlanta]

I don't remember the exact figure, but I was thinking my flywheel was around 10 pounds.

[DanEC]

Originally Posted by mikeinatlanta

I don't remember the exact figure, but I was thinking my flywheel was around 10 pounds.

That would be a light one.

[Gaz64]

You should take the weight of the clutch into account when selecting a flywheel weight.

If your stock flywheel is 30lbs and your clutch in 10-15 lbs, then halving the weight of the flywheel doesn't have that much impact.

I ran a billet steel flywheel (2.7kg) in a 700kg street car.

My V8 weighs 2900lbs, and runs a 18.5lb steel flywheel, sprung centre single disc clutch, T5 5 speed, 3.5 diff gears, 245@.050 cam. Easy to drive

[mikeinatlanta]

I'm running a quartermaster twin disk with integrated aluminum flywheel. Idea of the twin disk was the reduced inertial of the smaller assembly when compared to the same weight single. I don't remember all the specifics, but I recall everything being about 1/2 original weight with calculated inertia being even less.

[lovehamr]

Originally Posted by Gaz64

I ran a billet steel flywheel (2.7kg) in a 700kg street car.

WOW! That's a 6# FW in a 1500# car. What the heck is it and what engine uses a 6# FW?

[Anthony]

For a normally aspirated engine, I think torque is mainly determined by engine displacement, and the efficiency of the engine for any given rpm, so there is basically a maximum attainable torque for any given engine. HP is torque X RPM, so the more HP you want, the further up the rpm range you want to shift the torque curve. As far as semi's, yeah they make only 500 HP, but they make it at 2000 rpm's, all day long, while your roush 427 makes maybe 200 hp at 2000 rpms.

[vector1]

I gave up my torque wrench and now use a horsepower wrench, much faster.

[Dominik]

Build a 427/428 cui with 390hp and the corresponding torque, able to rev to 6000 and be happy :-)

Spend the balance of your cheque book on a driver course, part throttle settings - and suspension adjustment.

Hit the #2 North out of La Canada/Flintridge (CA). And don't look back ;-)