Does any one run a light weight flywheel on their cossie lump?

I understand the theory of lower moment of inertia, easier to accelerate mass, harder accelerating car, more pronounced in lower gears etc.

I have driven and built some NA engines with very light flywheels that ran well in smaller lighter vehicles.

I was just wondering what effects it has on the characteristics of a turbo charged engine?

 

Its a motherfucker to manouver - I know that much

 

Here is mine.

 

Porkie - what effects does it have on your turbocharged engine though?

Makes mine a mofo to manouver Oh and massive braking manouvers dodgy as this is my worst point driving!

 

Dumped, I started typing and then I realised I am not really sure and out of my depth technically and so deleted what I had written

It does make it trickier to pull away smoothly.

 

Porkie,

Is your car a pain to drive round the pits with that flywheel? Looks like a full race item and with the smaller diameter AP clutch as well you should feel the full effects!

 

Yeah I was the exact same lee! I have nothing to reference it against and my driving is way too digital for me to ever be able to tell anything other than it is harder to drive!

 

Any more?

 

Not a Cossie, but ran one on my R5GTT and was quite a dramatic improvment, and no real disadvantage.

 

mines was lightned...not sure by how much tho

you can see the back has been machined quite alot.

 

The worst mod i ever made to mine , made it hard/impossible to get off the line, when used with a triple plate clutch. Took out a brand new clutch trying to set accleration figures on its first test day.
If you wish to drive it on the road forget it. Porkie can say wether the comprimises are worth it for competition work.
Rod

 

I have driven Lee's and I stalled it three times in one journey . Hated it .

 

Must admit. Lees looks like it must be a 4 ish kg flywheel and with that smaller diameter ap clutch the moment of inertia will be greatly reduced. Probably be alright in a kit car but a road car weighing 1 ton + might make life hard.

I was thinking more along the lines of a 6 ish kg fly wheel with a standard diameter clutch unit.

I reckon the stock flywheel is about 9 ish kg???

 

I have same as lee on a 7.25 twin plate tilton digital clutch - 3 times in one journey is v good mike - his must be nice Mine is much better after adjusting clutch but i have not driven it like that yet. Still think it lets the engine die too easily for parking manouvers and pulling off etc.

 

I think its the clutch rather than the flywheel you couldn't get used to Mike. I find it quite easy now... BUT its now on shorter diff ratios so that makes pulling away easier.

Put it this way. My little sister drove the car to Silverstone and met me at Trax and she did not stall it once on her first ever go. So Mike you are a just a pony driver!

 

For people like me who dont know why a lightened fly wheel makes a car hard to launch/pull away from standstill.

Could someone please explain?

 

could we use her next weekend to do some accleration runs in my motor as we aint yet mastered it .

 

Yip porkie and after that my car needs run in too - so send her up this way after that

 

Google flywheel effects and you should be able to find out.

Its all about stored energy!

 

Put it this way. My little sister drove the car to Silverstone and met me at Trax and she did not stall it once on her first ever go. So Mike you are a just a pony driver! [/quote]

 

In my limited experience of them, i have found lightened flywheels work best in ligther cars, i wouldnt personally bother on a road going cossie for example.

Lighter car means you dont need as much rotating mass to pull away smoothly, and also means that any savings you make from the flywheel translate to bigger gain in performance.

 

cant believe so many people hav so much trouble, i have a very light flywheel and would not swap it for a heavy one ever, all the problems you have with the take off is driver error simple as, because these flywheels are usually used with competition clutches , they dont slip, where as your old 10" clutch or what ever you were using actually had a load against it - the big fook off dead weight of a flywheel.

the characteristics of my engine are way more enhanced with a light flywheel and small diameter clutch. if you use a twin plate with organic plate rather than cerametalic , it would be a whole differant ball game, but thats not why we (cosworth (( big torque)) people) use them - we dont want slip, but most peoples clutches are never specced with the engine as they should be, the torque rating should be taken into account when the clutch is built, not ' well i have 400 lb/ft so , ill order a triple plate 5.5" cerrametalic rated to 900 lb/ft'

 

Me too - 4 times from the old Zoo, to Seans old house!!! Less than a mile!!!

 

A lot of it has to do with the type of clutch you are using as has already been stated. You can have two main types in 7.25 inch AP type - these being sintered which is basically metal on metal and only meant for circuit use as they have no slip at all, or ceramettalic which is used mainly for hillclimbs and rally cars where a degree of slip is available. A good hydraulic clutch set up also helps a hell of a lot if using a ceramettalic on the road

 

Is that so matey, take Sheady against anyone on here for launching a Cossie & believe me he struggled big time. Obviously you are in a different league to mere mortals like Mark. I will change my statement , Light Flywheel & Triple-plate clutch are crap on launches unless your this fellow .

 

Rod, Markk is a rally driver, so he should know what hes on about

 

Hold on , anyone with a competitive Cosworth needs a proper clutch and invaribly means a smaller diameter one . I use a twin plate AP and a suitably small flywheel , launches or take offs or standing starts , call them what you will are a part of competition , you just got to deal with it . In your average shopping car with everything matched for comfort its not an issue but my performace gains are had once im rolling , like yours and like Markks , sacrificing comfort for performance is sadly a fact !

 

Our lightweigth flywheel.





7 1/4" twin plate (very snatchy)



200mm Triple Plate....(not quite as bad)





And if you're serious about ur launches u'll 1 of these....

 

ian you barsteward lovely toys - is it ready for my shakedown yet ?

rod trust me launches are not a problem with any type of clutch/flywheel assy

 

TO be honest, I had my flywheel lightened by about 10-15% and balanced with the entire bottom end on my 370BHP saff, and it was absolutly superb, reved nicely and was really torquey and easy to drive. When My clutch died I took a while to replace it ( cos I am a lazy bastard ), so when I got round to doing it I had to have the flywheel re-faced to clean it up, and the extra weight that got taken off really made a difference, it turned the car into a bit of a pain in the arse as it was much harder to pull away smoothly and lost a fair bit of low down grunt.

IMHO if you are using it for a road car then only go slightly lighter (15% max) and balanced, and it will be superb. Anymore and the trade-offs for revability will loose out to ease of use.

 

I think the stored energy problems are relevant when balanced against something else..... the thing is, im not sure what that is.. roflol

My point:
Ive driven literally thousands of combinations, some great, some indifferent, and some, like Porkies, a real cow.

The clutch mass definately makes a difference, no doubt at all, but the question has to be, at what point do we lose the inertia required to accelerate the low comp motor somewhat and help us to move away?

Anyone noticed a difference between a 2wd and a 4wd motor? One has a FAR heavier flywheel than the other and i bet most of you have never noticed a difference.....

 

Obviously not Stu! Nobodys replied!

 

yes the 4x is a numb piece of shit to drive compared to the 2wd