is it just machineed or uprated 1? been told it a waste of £££s.

any advice

 

I have one off API in my RA, makes for quicker gear changes due to being lighter than the standard item.

It's not possable to "uprate" the flywheel only the clutch.

 

how does it make quicker gearchange? uprated 1s are made from billet steel

 

APi will machine yours for £120 and reduce the weight from around 12kgs to 7-8kgs.

From the posts I have seen on this topic before and from people I know who have these fitted to their cars, people notice little or no difference from an original one. Also factor in the placebo effect of having spent £120 on a performance item and the fact that most are done whilst replacing a slipping clutch.

Aftermarket flywheels (such as Fidanza, ACT etc) are usually made of billet steel, aluminium and chromoly. This enables them to go down as low as 4kgs. Fitting a very light flywheel will improve throttle response and acceleration. The downsides of this can be loss of engine speed on inclines, difficulty launching at medium pace, and in some cases poor idle.

They don't pop up very often for sale used, but usually go for around £150-200, and you get to keep/sell your old one.

Lightweight flywheels are not for everyone (if you use your car to tow for example). Assess whether or not a light flywheel is right for you and if it is buy a decent aftermarket item such as ACT or Fidanza.

If you must do it half-heartedly then try and save some cash and go with AS Performance who used to do OE lightened flys (7-8kgs) on an exchange basis for around £80 iirc. If you are just worried about the state of your current one a local machine shop should be able to give a fresh skim for around £20.

I run a aftermarket 4.2kg one on mine and wouldn't go back to a heavier one or OE.

 

Bob: That is a very interesting contribution as you are a good drag racer, and i would have expected the lighter wheel to hamper launches off the start.
Are Alyn's 'wheels exchange?
Box getting changed soon so this would be a good time to make the change.
Not sure if I'm brave enough to go below 8Kg though.
Thanks for the detail!
Graham

 

I noticed a differance after having an API one fitted. It revs more feely and Pick up was quicker. You also notice a differeance when coasting down hills(not that I do it often)

David's ones are to around the 7.8Kg, I thought if you went lighter than this then you would have to change to the pulley wheels as well to balance things out

 

Danny: I think you are right in a pure engineering sense to maintain the factory balance.
About 2 years ago there was an excitable debate on this with David/API!
Graham

 

Having spoken to an engineering company that's done some flywheels, the reason you can't go much lighter than 7kg on the standard wheel is due to the fact they're cast iron, and if you take too much out of them they'll eventually shatter. I run a billet steel wheel in mine now that weighs 5kg and you can feel the difference in how the engine spins up, but it did take some getting use to, I stalled the car three times getting off the drive the first time as the heavier wheels have more inertia and so help keep the engine turning.

 

Jim is correct re the reasons for the limitations of reducing the weight of OE flywheels.

Graham: New in-car vids of drag runs are up and hosted. As you'll see the lightness of the flywheel isn't a problem. I find it very consistent to launch. Only time it can be a problem is on very sticky/glued surfaces coupled with sticky tyres, where is can be difficult to get the wheels spinning in first gear. On your surfaces I think it would be fine.

YouTube - Subaru Impreza - 1/4mile 12.3secs@110mph - In-car footage
YouTube - Subaru Impreza vs Escort Cosworth - In car 1/4mile

I can only assume that Alyns' are on an exchange basis too.

 

I see what you mean. Good clean starts indeed.
Are they on road tyres?
That box sounds fine from inside the car!

A hillclimb start is just like a road surface, no compound on it at all, but i do want to try slicks next year.

Graham

 

On low profile F1s. Poor starts really (1.8s) due to poor conditions and knackered coilovers.

I think that it will still be fine if you ran a ultralight fly, with slicks on those surfaces.