Fishhawk

Hi guys. I don't know if this has been discussed or not but here's my question. I own an 85 GT that has dyno'd 300 RWHP with 310 RWT. I have been running the original 10" clutch and am planning on upgrading to a 10.5 this winter. I have been getting conflicting advice on which flywheel I should go with. Lightweight aluminum or a heavier steel? The car is a street driven car with the occational run at the local drag strip. I have heard that aluminum flywheels are not very streetable but will alow the engine to rev quicker at the track. I've even been told by a couple of clutch shops to just go with a stock replacement steel piece. I've also been told by a couple seasoned racers to go heavy.
The car weighs around 3200lbs with me in it. At the track I run a 275/50/15 BFG DR.
Any ideas here? Thanks in advance.

5.0mustang5speed

i think that with your power level a stock flywheel is fine, i have a 347 motor that is built to run hard(soild roller, and all the good stuff) and i use a stock flywheel which was ballanced with the motor but i also use a blow proof scatter shield in case. unless you just want to spend the money on a alumiun unit , go steel

Guest

Not streetable lightened flywheels is a crock.

I have seen MANY, and I mean MANY Honda owners with lightened (between 6-8 pound) flywheels who have testimonials that lightened flywheels are perfectly streetable.

Sure. It WILL take some getting used to, and you have to watch your tach... but it's no harder than driving stock.

The bonus is there is less rotational mass, meaning you're putting your engine into the powerband just that much faster. On the street and on the track it's always beneficial to get a performance product that is also lighter and stronger.

downwardspiral

dont do a lightweight flywheel. It will give you top end horsepower, but takes away torque. Lightened flywheels are more for rally driving and riceballs, because they run at high rpm's most of the time. Unless you want the top end power, I wouldnt reccomend it.

kartracer55

Hot rod had an article with this. Heres the thing...

Aluminum flywheels are lighter, so they will allow the revs to pick up and drop faster than a steel one... this is good for autoX and stuff when the motor is all over its powerband.

Steel flywheels are heavier, so they will keep the revs up because of more rotating mass, and this is better for drag racing and launching the car in general.

The verdict: unless your doing road racing, an aluminum flywheel is a waste of time.

Jim

Guest

Exactly how does a flywheel add horsepower and subtract torque?

That makes absolutely NO sense. All you're doing is rotating a lighter mass. You lose and gain no horsepower or torque.

downwardspiral

its not technically adding or subtracting anything, its freeing it up. the more rotating mass an engine has, the more inertia it has. hence, a lighter flywheel will decrease the inertia, allowing the engine to rev up quicker. I didnt phrase that right.

garygreen211

Lighter flywheel also means faster clutch engagements. You'd be shifting faster, revving faster, engine braking will improve. Idle quality will suffer, won't be as stable. There is an article in MM&FF they swapped a ligher flywheel into cobra and shaved 1/10th off the quarter, not bad. While driving you can't just let the clutch out easy and expect it to move, it will stall, so in heavy traffic driving will be a beotch, and perhaps increase the wear and tear on the clutch as you add some gas. Under normal driving wear and tear on the clutch will be less, and you will increase MPG due to lesser rotating mass. Due to the positive qualities associated in here, this mod is a must for road racers. No doubt drivability will suffer, but we aren't in a type of hobby where drivability is a big issue.



Gary

vfast

pretty much all your answer are wrong..I'll answer 200si....your right in a way it don't add horse power so to speak to the engine , but it does to the wheels due to less rotating mass quicker......a steel flywheel should be street because it holds per say the revs up while shifting in a 4-5 speed in v-6..v-8 apps...the reason for the 4 banger is the flywheel is smaller so when you go to a alum..your talking under 10 pounds and they don't have the driveshaft power loss from more mass...as well as most don't redline til atleast 7k but still make it harder in traffic on clutches and the heat that will in turn lead to some stress cracks,warping

garygreen211

No drive shaft, eh? Do you really think rear wheel drive setup take more drivetrain loss than a front wheel? (are you serious?) Ok. Let's take a rear wheel or four wheel drive focus. (yes, there is such a thing as rear wheel drive focus) Or saab, BMW, Lotus, many European cars are rear wheel drives and many are 4 cylinder. They put a lighter flywheel in to make car more revable, lighter mass also means faster clutch engagements, and less wear and tear under normal and high speed shifting. You gotta realize something, when you upshift, and let go that clutch, the damn thing is not engaged yet, it takes time for engine revs drop to match tranny revs. The extra rotating mass does not help there, take it away and the added engine braking will make the clutch engage faster.

A flywheel is there to help the engine rotate. The rotational mass of the flywheel keep the engine rotating smooth at idle. Reduce the weight and you have much more revable engine, a must for road racing, can be useful in drag racing too. However, slow speed and heavy traffic driving will suffer, since now you have to add more gas into the equation just to get moving.



Gary