My flywheel is going to a machine shop tomorrow to have the face skimmed before i fit a new clutch, but i quite fancy having it lightened and balanced, since it's all apart.

Can anyone tell me how many Kg the flywheel should be reduced to or by how much, so i can tell the chap who does the job? My car is a UK spec MY99.

Oh, and any advice on what not to do to them? Like don't machine *X* part of flywheel

Many thanks

FS

 

Sam,
I'm pretty sure you'll find the lightend flywheels about are of a different material to the standard stuff. Skimming the flywheel will of course lighten it a bit, and drilling a few holes to ballance it will reduce mass a little bit more. Must be said, pretty insignificant weight saving though. I see what you're after, but if you want a real lightend/ balanced flywheel, you'll have to fork out for one I'm afraid. If it were that easy, there wouldn't be these items on the market.

Al

 

You cannot drill cast flywheels they destroy themselves, but there is some machining that can be done further to lighten. I have had it done on mine.

Note: You will loose torque by lightening the flywheel.

 

Thanks for the info guys.

So, it's best not to touch the original flywheel then?

How come it can't or isn't recommended to lighten the std flywheel?

 

You can lighten the original flywheel.

Every group N car has had this done, as you are allowed to lighten the standard item to 7.5kg, but you cannot change it for a billet item.

If lightening the flywheel will reduce torque, so will fitting lighter road wheels. A WRC car has a flywheel of around 3kg and very light wheels. Two of the reasons these cars have virtually no torque at all

 

Pete,
What are the pros and cons of billet versus lightened standard flywheels.

Ps. if I put on some real heavy wheels will it offset the torque loss from the flywheel lightening.

 

LOL at Mr King

A billet steel flywheel can be made at approx 3kg. Most are between 4kg and 5kg for a bit of extra rigidity against the clutch cover. If you took cast down this low, it would just shatter.

 

You better off getting a new lightened flywhell..Anyway your box is down so why not do it the proper way..

 

Spent too much on car at the mo' so trying to keep costs down.

Am now getting to stage where I can't justify the cost of modifying the car against its' worth, but *retail therapy* kicks in all the time and I gotta buy something to keep me amused!!!

 

Danny Fisher recently lightened his flywheel. I think that he took too much off and had all sort of problems. Maybe drop him aline.
Mine was lightened and refaced for a reasonable sum ie less than £100.

BW Mark

 

had mine lightened when clutch was changed at scoobysport. Didnt notice any problems whatsoever, nor did I notice any spool up difference, you did do it didn you pete?

billet is better for withstanding excessive heat during use.

Less prone to crack.

Have no idea what submannz is talking about. cannot see what inertia of crank shaft has to do with torque at all.

Torque is determined by stroke, compression, timing and explosion force.

Not sure about this speed up hills lark either.

would recommend a search on 22b.com for this one. It was discussed at length just the other day.

 

Scooby Sport recently lightened my flywheel from 12kg+ to 8kg-.
Cannot say I noticed any difference.
Work done while box out for other work.
Balance after machining is VERY important.
Lighter f/wheels cannot reduce max torque nor do they reduce hill climbing ability once power is applied.

 

The standard flywheel is about 15kg,the most popular lightened one is about 7.5kg.

Pros are faster spool-up,making car a bit more pokey.

Cons are probs sitting in slow moving traffic(more chance of stalling),also the cars top speed up hill will be reduced because you dont have the original flywheels momentum once it gets spinning.

There is alot more to it than this,but this is the general idea.Like I said 7.5kg is the optimum weight but you can get lighter or heavier.

Edited because I was told you cant lighten the original wheel!Duff information!

Steve

[Edited by stevie c - 3/4/2002 9:56:49 AM]