im looking to get a lighten flywheel for basically a street car with minimum street use .. it will be mostly street racing and track oriented car ..

question is for my needs will a stock weight flywheel be better than a lighten flywheel ? or the other way around .. dnt really want my revs to drop much in between gears , and before in other cars with light flywheels it felt like that was what was goin on , it did rev up faster and was definatly noticable but it did feel like while in between shifts the rpms droped alot more than before ..... or was it me just imganing it ? thanks in advance !

 

i think lightweight flywheels arent the best for drag racing with the morn weight the flywheel has more i guess momentum to get the whole drivetrain goin. thats just wat i think i may be wrong

 

https://ls1tech.com/forums/ls1-domes...s/t-97304.html

 

https://ls1tech.com/forums/manual-tr...-mile-car.html

You have to theories rivaling each other

Oldschool- Hit the tires as hard as possible with a 60 pound flywheel, putting the nose in the air and planting the tires

New school- Conserve the power that was once wasted by having to turn the heavy flywheel, and convert it to forward momentum, also saving your drive train from the lethal shock of all that momentum all at once

You have to bring your RPM up a bit higher with an aluminum flywheel, but you gain it all back with less possibility of breakage, more HP to the ground, and a more free revving engine. It just doesn't make sense to spend all that money for an ultra trick high dollar lightweight rotating assembly when you are just adding weight back with a heavy flywheel.

 

i believe that once you get the heavier flywheel movin it wont take much to keep it up there. im goin billet steel one because of price and also because i believe the lightweight isnt good for drag racing.

 

alum flywheel is the way to go. a GOOD driver can 60 just as well with the alum flywheel

 

I hope more of those with experience in both will post up there results and not the "wishful thinkers". I've done both and will never run another heavy flywheel again.... Unless I'm racing an Impala SS

 

When i had my 6 speed, i had a aluminum flywheel and would not have it any other way. But now i run a 4l80.

 

I just went 11.13 @124.6 1.62 60', but had several 1.55-54's that day also, just bad runs, with a 4130 chrome moly flywheel, which is about the same weight as an aluminum. I used to have a billet steel, but I switched to the light one and will never go back. Actually, I still have to dial my suspension in, and get better tires on, because I was blowing the tires off on those 1.55's.

My car is just a little stage 1 patriot/torquer II car, with a roll bar, 12 bolt and boltons, if I can 60' that decent with a light flywheel, some of the more powerful, lighter cars should be able to.

 

1.30 60ft 9.94 with an aluminum flywheel.

 

I never knew you had a Alum. flywheel Barry...

Either way, I remember a few years back one of the CARTEK Vette guys going to an Aluminum flywheel and not liking it, going back, and getting better results.

Barry can 60' like nuts with a Alum flywheel because he is spraying, so the lack of momentum in the flywheel, will be overcome by the torque of the juice coming on.

Yes, the responsiveness of the motor will be less with a heavier flywheel, but if you are stable at, lets say 7000rpm at the line, then let off the clutch, the heavier flywheel'ed car will loose less RPM on the launch, cary the car harder out of the whole and so on.

If the same car, now has an Aluminum flywheel, you will have to launch higher tio get the same effect and result in the 60' But what if you can't? What if you rev limiter is 7200, and you need 7800 to overcome the weight diferential, that RPM may not be realistic and so, the car will never run as well as a iron flywheel'ed car.

If however, you are leaving at 5000, going to 6000 ro overcome the weight will be fine.

I think the flywheel debate is on a case by case basis, there is no one correct answer.

For instance, I fall into the previous example. I have launched my car as high at 7200rpm and "hooked" lol with a bit of spin, but nothing major. Usualy I launch at 6500+ rpm if the track can hold it. I am guessing, that with a Aluminum flywheel, I will have to go to 7400+rpm launch to equal my 60's, that is imposible for me, so the Alum. flywheel is not the right choice for my car.

Just my $0.02

 

Heavy cars favor heavy flywheels. Light cars can use lighter flywheels.


Just one more reason to gut the pig

 

I've read that the lighter flywheel cars will have less rpm drop on the shifts.

 

well i have a forged nitrous 347 in my rx7 and that has a lightweight flywheel as well as a spec 5 clutch .

and in my z28 .. wich is why im asking now its just a bolt on H/C/I and a 150-175 but stock internals minus katech bolts and arp hardware .. is what im looking .. back when my rx7 was t88 rotary i have a act flywheel and it always felt liekit would loose too much rpm in between shifts .. actually even my bov didnt sound the same as before when i replaced it ..

i think ima jus get my stock flywheel resurfaced and call it a day .. launching with mt et radial and a stock rear end on say myabe 600+rwhp isnt gona last too long ..lol .

 

How could that posibly happen?

Mechanicaly, it is imposible.

Lets play with some numbers:
If you are at 5000 RPM in 2nd gear for instance, and you shift to 3rd, mathematicaly based on the ratio of teeth on the gears you should be at 3650RPM in 3rd gear.

There is no way around it, the ratio of the gears does not change because of your flywheel's weight.
Yes the clutch can slip a bit on shifts and keep the RPM up a hair while everything catches up, but you can not cheat mechanical interactions between two solid objects [ie gears]

The only way to make your RPM drop less is to shift faster, preventing your rear wheels from slowing down, which will slow down the output shaft, which will slow down your imput shaft, which will slow down your motor.

Why do you chirt your tires when you shift fast? Because your motor is faster than the gearing needs it to be, there for you drive the rear wheels faster than they are mechanicaly enclined to do in their current MPH. Same reasons apply here.

Based on this, if anything, a lightweight flywheel will slow down your motor more on a shift that a heavy flywheel. If a flywheel weighs more, it has more inertia, therefore, it takes more force to change its velocity, therefore it will be more difficult to make is slow down, in the same way that it is more dificult to speed it up. So if you are a slow shifter, and allow the motor to be in a state where the trans is in nutral for a longer period that normal, a heavier flywheel, will resist the slowing of the motor better, and keep the rpm up longer.

Honestly, in my oppinion, a light weight flywheel is a disadvantage in drag racing. In road racing, it is a big bonus, it shows more power on the dyno, might be easier on parts and so forth. But I dont think its needed in a drag car.

 

Backwards

They make rev matching WORLDS easier though

 

How do you like the stage 5? I had one, but didn't have the ***** to try it

You need to post some pictures of this RX7! I assume your on V8RX7FORUM dot com?