lightweight flywheel, turbo, and stock tranny?
 

For my GSL-SE , i will eventually go turbo. What i'm wondering is, can i put a lightweight aluminum flywheel on it? I'm goign to be keeping the tranny stock, and with the turbo on it i'm wondering if its going to be worth it.

I'm thinking that if i ever blow the tranny i can always just sell the flywheel.....

Peace
Geoff

I have a lightened flywheel and stock tranny. Works good. I use a 4 puck brass button clutch with it and I have the stock diff (S2). I've had no problems.

When I got the clutch put in, the dude that did it, wasn't going to let me have the clutch if the car didn't have a lightened flywheel. :D

Hey, if you have a 13b turbo motor, and non-turbo tranny, which flywheel do you buy?

For the non-turbo right? Otherwise it wouldn't fit in the bell housing correct?

Flywheel and it's required rear counterweight match the engine's rotating assembly (e-shaft, rotors, counterweights), otherwise rotating assembly is out of balance and bad bad things happen.

Buy the turbo light flywheel. Bellhousing clearance with flywheel isn't a problem.

-bp-

Correct!!!


When mix-matching motors and trannies, you need to buy the flywheel and clutch for the tranny. Buy the counter weight for the motor. Make sense??

Ryan

Well what if the clutches are different sizes between the engine year and the tranny year? You know, the diameter?

~T.J.

Use a TII engine, TII counterweight, NA light flywheel, and NA clutch. You can't use a turbo clucth with a non turbo trans or vice versa, the input shafts are different.

Oops... Double post. :cool:

I believe (someone correct me if I'm wrong) that when using a lightened flywheel, you use the auto counter weight for the engine in question.

So, in my case I have a S5 13BT, S5 auto counter weight, lightened aftermarket flywheel, pressure plate and clutch plate to suit S2 (9.5" isn't it?) and a S2 tranny.

Could be wrong though.

The auto counterweight does have to be the same series.

uhm.... ok.....

so get the lightweight alum. N/A flywheel?

You're using you're GSL-SE engine and SE Tranny correct?

You can put the N/A light flywheel. I don't recommend the aluminum flywheel, it's too light. Even in an N/A form.

I think there is there is a 16lb N/A lite flywheel for the SE's that should be nice.

The recommended one is usually the 17lb Racing beat Light Flywheel, but it won't work with your engine and tranny combo. It's sold for the TII engines.

I am running a 17lb flywheel with a TII tranny.

Thanks you guys for the confirmation.

Actually the weight of the flywheel depends on a couple things. If your gears are really short(mainly modified by the final drive ratio), and you need to rev from low to high very quickly, like on a BP, the lighter aluminium flywheels will be great, even for drag racing. On the other hand, most street cars don't have very short gears (mostly because highway driving on a short final is annoying), an so the rate of rpm increase isn't significant enough to warrant an extremely light flywheel. This can be compounded by the fact that NA rotaries don't have tons of low end torque.

Just remember the more the flywheel weighs, the more energy it will deliver upon clutch engagement, and the more energy it will pack away for storage during quick accelerations.

The setup I have is a 4.38 rear end and a long fifth gear.

Kind of like an overdrive.

What 5th Gear? What Tranny?

I have an 83 tranny, but an 87-88 5th gear. At least that is what the guy who sold me the car told me.

It does not seem like the other 5th gears that I have had in other 79-85 Rx7s.

Well slap my wrist I stand corrected! SORRY. :-(

Is it from a regular N/A car? The 86-91 N/A FC had a 5th gear of 0.697.



US SPEC MAZDA DRIVELINE RATIOS

*** FIRST GENERATION ***
……………………………………………………………….…….………………………………..AXLE..FINAL.TIRE......TIRE..ENGINE
VEH.. YEAR. 1ST.. 2ND...3RD.. 4TH...5TH...RATIO RATIO SIZE……....RPM...RPM @ 60 MPH
RX-7. 79-83 3.674 2.218 1.433 1.000 0.825 3.909 3.227 185/70-13 892...2878
RX-7. 83-83 3.674 2.218 1.433 1.000 0.825 3.909 3.227 195/60-14 891...2875
AUTO. 84-84 2.458 1.458 1.000 0.720 N/A...3.909 3.909 185/70-13 892...3487
GSLSE 84-84 3.622 2.186 1.419 1.000 0.758 4.083 3.097 205/60-14 878...2719
RX-7. 84-84 3.622 2.186 1.419 1.000 0.807 3.933 3.175 185/70-13 892...2832
RX-7. 85-85 3.622 2.186 1.419 1.000 0.807 3.909 3.156 185/70-13 892...2815
GSLSE 85-85 3.622 2.186 1.419 1.000 0.715 4.077 2.914 205/60-14 851...2480
RX-7. 85-85 3.622 2.186 1.419 1.000 0.697 4.444 3.099 205/55-14 910...2820

*** SECOND GENERATION ***
……………………………………………………………….…….………………………………..AXLE..FINAL.TIRE......TIRE..ENGINE
VEH.. YEAR. 1ST.. 2ND...3RD.. 4TH...5TH...RATIO RATIO SIZE……....RPM...RPM @ 60 MPH
Base. 86-91 3.476 2.002 1.366 1.000 0.711 4.100 2.917 185/70-14 855...2494
GXL.. 87-91 3.476 2.002 1.366 1.000 0.697 4.100 2.859 205/60-15 841...2404
Turbo 87-91 3.483 2.015 1.391 1.000 0.719 4.100 2.948 205/55-16 828...2441
Conv. 88-91
GTUs. 89-91 3.476 2.002 1.366 1.000 0.758 4.300 3.261 205/55-16 828...2700

*** THIRD GENERATION ***
……………………………………………………………….…….………………………………..AXLE..FINAL.TIRE......TIRE..ENGINE
VEH.. YEAR. 1ST.. 2ND...3RD.. 4TH...5TH...RATIO RATIO SIZE……....RPM...RPM @ 60 MPH
(FD). 93-95 3.483 2.015 1.391 1.000 0.719 4.100 2.948 225/50-16 829...2444

I think a basic fact has been grossly overlooked in this post and that is the fact that the stock n/a trannys are essentially 5-speed POS's. If you're serious about making power (200+), that n/a tranny will toast quicker than wonderbread in a convection oven. The n/a tranny's were designed to hold back an n/a engine (read: not much power, minimal torque). When an n/a tranny gets turbo power being spun into it (let alone with a lighter flywheel and high perf clutch), something's gonna break (except for fourth gear, that will never break :D).

Obviously, someone will chime in to say that "my n/a tranny has held back my 287rwhp for 5 years without a problem" or something. My advice? Get a TII tranny. They aren't overly expensive and it almost guarantees you won't be running through trannys every couple of months.

Please, someone else with a decent reputation speak up and second my point (or counter it, just give some good reason). All experience/knowledge/logic leads to a distrust of the n/a tranny's in my book. I'm planning to get a TII tranny for my n/a simply for reliability and to put my mind at ease when I drop it from 7k :D

Right now I just have to get the car running, then I can worry about breaking trannys, hahaha.

Of course the TII tranny would be the way to go....But he specifically said that he was going to keep the tranny stock.

Going turbo with little boost, the stock one will probably take the beating for a little while, but if you push more than 200 hp, I bet you're going to be asking for trouble.