Hi Guys,

I finally got ahold of the engine shop and they have finished lightening my 325i flywheel. :) Opinons on this mod? I will post pictures when I get it.
I am having the 325i head ported and polished, and my cam reground to 272.
Anyway, I know the 323i e21 is lighter to begin with, and I got my 325i down to 12 pounds. Bav Auto/BMP wants a lot of coin for this.

My cousin lightened his in his porsche and he took me for a ride, and I think it really made the car feel faster.

Later
J

i would seriously look at the single mass flywheel from the 323i if available before bothering to lighten an existing one.

Why didnt you use it since you had a 323i to begin with?

lightened flywheel.......excellent and mostly forgotten mod.

my eta motor is getting that treatment no doubt.

and i have a m10 lightened flywheel just sitting about awaiting a new home *hint hint*

i would seriously look at the single mass flywheel from the 323i if available before bothering to lighten an existing one.

Why didnt you use it since you had a 323i to begin with?


http://www.bavauto.com/assets/product_images/bas/alumflywheel.jpg
(this is bav auto's picture)
When you replace your stock steel flywheel with our Lightweight Aluminum Flywheel, you're upgrading in two important ways:

* Quicker Acceleration. Our Lightweight Aluminum Flywheel is between 8 and 18 pounds lighter than its OE counterpart. Because the rotational mass is reduced, less engine power is spent changing the speed of the engine and more goes directly toward accelerating the vehicle. This also helps your BMW decelerate more quickly when you take your foot off the throttle.
* More precise gear changes. Since engine RPMs change faster, the engine revs down faster between gears allowing you to get in the next gear and back on the gas faster. You can also down-shift faster with just a quick 'blip' of the throttle to match revs and smoothly engage gears.



My 323i one is in the car with the orginal engine.
I can not get to the engine yet. So with the build up of the second motor,
I had the 325i flywheel already. I think its a single mass flywheel also, and
Tyler also ran a 325i lightened flywheel previously with a sachs clutch.

PS: Matthatter -DJprofessor - anyone - what is the weight of the stock e21 323i one?

something like 12 or 13 lbs i think.

You could have just waited till you were ready to drop the new engine in, unbolt the one off the standard motor, bolt it onto the new one with some new bolts :)

something like 12 or 13 lbs i think.

You could have just waited till you were ready to drop the new engine in, unbolt the one off the standard motor, bolt it onto the new one with some new bolts :)

Mathatter, I thought the 323i one stock was greater than 12 or 13 lbs, I will have to check and see. I have not been able to touch my car, and had the 325i flywheel so I fiqure why not?

no, im pretty sure its equivilant in weight to the lightened flywheels you can buy from people like fidanza, its only for the single mass one, its much lighter. I didnt want to, but i guess i can remove one and weigh it if anyone wants to know 100%.

The dual mass ones are heavy, over 25lbs i seem to remember.

I think that stock weight is 19lbs by the way, and 12lbs seems very light, usually they are about 14lbs when lightened.
You will have to compensate a little in your launching technique, a little higher launch rpm will be necessary, it definetly takes getting used to. Your shifts will be better with the engine rpm now better matching the next gear. A lightened fly wheel does not necessarily make the car faster. When mine was lightened it made the revs easier to match, and when you reved the motor it would rev up faster than stock and would also decelerate the revs faster than stock. The butt-dyno voted that the car did not get anyfaster but felt different. It was worth the $40.

My 323i flywheel is sitting in the garage, I'll weigh it a post the #.

My 323i flywheel is sitting in the garage, I'll weigh it a post the #.

Jay Thanks. I thought for some reason that CJ is right and its around 19lbs or so. Also do you have a wiring diagram of how you put together the module to convert 323i to 325i wires. I thought this was on the internet but i forgot where it was. Did you wire directly into the 323i fuse box?

later,
J

http://www.e21bmw.net/tech/motronic.php

from tricords site in the links section. I cut the plug off my 323i harness and 325i harness and solder my 323i plug onto the 325i harness (7-8 wires). So when I'm ready it should be a plug and play as long as I got everything right. Also extended the wires by about 2 feet.

Has any e21'ers bought the aluminum flywheel? Or hell even some 02 guys, it will be interesting to see just how much a difference it make in my cars reaction/driveablity, stock is what 19lbs vs. 8.8lbs how much higher rpm would you have to launch at? The bavauto. one is the one I have, JB racing makes it and they send you a mini-catolog w/it they even make ones that are lighter$$ 6.5-7lbs 215-228mm. Anyone got an aluminum crank pulley? Free's up some rotateing poundage on the bottom end 8lbs vs. less then 1 pound + 20% underdrive, does anyone here know anyone w/lighter internals in their motor/bottom-end? I want gritty details, just how bad of an animal will it be with a bottom-end assembly that is 30% lighter rotateing mass, I have yet to run into m10 like that.

Has any e21'ers bought the aluminum flywheel? Or hell even some 02 guys, it will be interesting to see just how much a difference it make in my cars reaction/driveablity, stock is what 19lbs vs. 8.8lbs how much higher rpm would you have to launch at? The bavauto. one is the one I have, JB racing makes it and they send you a mini-catolog w/it they even make ones that are lighter$$ 6.5-7lbs 215-228mm. Anyone got an aluminum crank pulley? Free's up some rotateing poundage on the bottom end 8lbs vs. less then 1 pound + 20% underdrive, does anyone here know anyone w/lighter internals in their motor/bottom-end? I want gritty details, just how bad of an animal will it be with a bottom-end assembly that is 30% lighter rotateing mass, I have yet to run into m10 like that.

I would be careful runing a M20 or anything less that 11 pounds.
According to JIM over at MM - Metric Mechanic this is tough too drive and stalls out.
For my car 12 pounds is fine. And vibranthenarot they want way too much money at BMP and Bav Auto for the alumium fly wheel.
$600 is too much for me.

Jay did you get a chance to weight the stock 323i one? I am curious what it comes in at.

I had not heard that much about the pulleys, but I know in the VW world
they also make these for the MKIV GTI, and Unorthodox racing makes them.
Not sure what they do? Some people swear by them.

My 323i flywheel came in at about 13-13.5 pounds.

My 323i flywheel came in at about 13-13.5 pounds.
Its the stock 325i one that weighs a lot more. Thanks. It appears Matthatter was correct. :eek: :confused :mad :stickoutt

My stock 323i flywheel is 12.8 lbs.
I have a 1982 528e flywheel that is just like the 323 and it is 13.2
I used the JB racing alum. flywheel with a Sachs sport clutch with my 3.0 stroker and it is just right.
Takes a second to get used to but it revs so quick and uncaped it sounds scary. :buttrock
The rods and pistons are a bit lighter than stock 2.5 so that helps the fast rev. also
I don't feel the 8 pounds is to light at all.
I think you can pick this flywheel up from JB racing or Ireland enginering for like $450. They are less duckets than they used to be!!
Jeff

Hate to say i told you so :stickoutt So ive got 3 323i flywheels, anyone want one? :laugh

Its just the single mass units which are light, the twin mass ones are heavy bastards.

hatter what would mine be?

A stock 323 flywheel is a little ovr 13lbs. Mine was taken down to 11 lbs. No launch issues.

it should be the same.