ok so i hear that with the lightweight pulley plus the lightweight flywheel the revs die too quick on an xa/xb is this true?

should i go with a hideously expensive lightweight flywheel or get a stock one back-cut?

i'm poor . lol .

in case i don't buy a hideously expensive lightweight flywheel i will :

to reduce downtime i will probably buy an oem flywheel then get it cut and back-cut so i
dont loose down time when they're replacing my clutch by re-using my stock one.

oh and can anyone tell me the cheapest lightweight flywheels they've found?

 

They (a shop) can lighten your OEM flywheel, but you will end up using more clutch to get moving. Lighter flywheels are great, but only for higher revs. If thats what your after, go for it! Your engine will 'slow' quicker too, if that makes sense. I mean, when you use the engine to 'brake', it will actually slow the car quicker too. Less rotating mass, meaning a quicker RPM drop. Umm, I hope I didn't confuse you.
It's funny...when I was racing MX, we always put weighted flywheels on the bikes to smooth out the powerband, then when I moved up to cars, we always lightened them...LOL.

 

so guys... will the back cut flywheel be a good compromise or should i pony up and hope that the lightweight flywheel doesnt kill revs too much between shifts?

 

That is actually not true,
with a lighter flywheel, it becomes easier for the car to turn the engine under engine braking, so when you try to slow the car using the engine the effect is less than it would be with a heavier flywheel. It will drop revs between shifts easier though and give you better throttle control.
I am saving for an Exedy Single Carbon clutch and flywheel combo.

 

Maybe so...I am wrong a lot, but I was thinking back to my race truck and how it would tach super quick and also seemed to slow quicker after the flywheel was lightened using engine braking after a run. Here's my theory though...the more rotating mass (heavy flywheel), the harder it is for the engine to SLOW THAT WEIGHT. Physics...LOL. But like I said, I've been wrong before and could be wrong here too.

 

Go with fidanza, I never go wrong with fidanza, they back the hell out of their ____. It's a small motor, lighten the flywheel, free up some of that lost, um, 1/2 horse, just kiddin.

But ya, fidanza.

 

This may be a dumb question however, I must ask: Could the Light Weight flywheels that are mentioned in this thread be used on a Automatic trans or are they strictly for use on Manual Transmissions?

Any info will be apprieciated.

 

strictly for manual trannys

automatics have torque converters, you can get a higher stall torque converter

 

yeah but torque convertors are bolted to a flywheel

 

even if you back cut it....the revs will drop faster.

lighter is lighter no matter how you get it done. (lighter metals or back cut)

 

torque converters are not bolted to a flywheel, they are bolted to a flexplate which already weighs next to nothing.

This is a flexplate



This is a flywheel

 

YA _____es. just kiddin.

Just get a kick in the pants shift kit for your auto, or just call my buddy, Tom Gahl, he is and has been an engineer for GM forever, he knows more than just GM though. he is an instructor at Glendale Community College here in phoenix. He can tell you exactly what valves in the valve body to add washers to. We did it with a few different trannies for a project. The washers take place of the fluid in the valves that cause a nice slow shift, it doesnt hurt the car at all, just shifts faster, nice crisp fast shifts. Give him a call.

 

From my experience, a high stall converter is usually lighter than a stock converter, due to being smaller. Of course it depends on how small the converter is too. So to put one of these on an auto tranny would lighten up the rotating mass on an auto tranny. Finding one might be difficult on our applications though and the effects wouldn't compare to doing the same on a manual tranny.

 

ah this i know but i figure if i back cut it will be lighter but not so light as to kill revs as much as a much lighter aluminum fidanza.

 

I know saving a few bucks is VERY important to a lot of people, but it you ARE going to do it, you better just get one like the fidenza. It's engineered for this purpose and I would hate to see you either go through with it and realize it wasn't enough and have to take more off or maybe take too much and have something break or not like it. If you buy one, you can always go back to the OEM. Like I said, I know money is tight, but having to do things twice or even more is a PITA. You will be getting one designed for its specific purpose too.

 

no i can't always go back to oem i cant afford labor twice.


my biggest fear is that dropping down to an 8lb flywheel will lose too many revs....

if i knew how much a stock wheel weighed i could make a better decision.......

people have been back cutting flywheels long before lightweigh ones hit market and yeah...

cuz if i spend upwards of 360 for a fidanze and then once installed i can't keep up the revs between shifts i will be THE most ____ed off scion owner....

 

Well, I know they have been backcutting flywheels for years....on chevys and mustangs and other cars where parts are a dime a dozen.
If you don't want to risk losing too many RPM or 'revs' as you refer to them, then don't do it at all. You have to outweigh the good VS bad on this one...If you take too much off the OEM one, your screwed in more than one way because you won't be able to go back to OEM without buying a new one.
If you're that worried about the aftermarket one being TOO light, then don't do it at all. 8 LBS is rediculously light too...way too light for street use IMO. I'm sure you can get different weighted flywheels. Also, as far as the RPM dropping between shifts...I don't think thats what you need to be worrying about. The lighter the flywheel, the more clutch you are going to have to use just to get rolling. You are going to be worrying about replacing a clutch soon too.
To each his own though.

Good luck with it.

 

Great info, thanks!

I've had two cars now with AL flywheels and your acceleration is much faster than stock. It doesn't add any HP but it frees up some from your engine crank not having so much intertia to overcome.

I will definitely replace the stock one on my tC when I upgrade the clutch.

Less weight = Better.

 

You guys are making me love my auto box even more...

 

<----Auto too...LOL