Next month i am getting TSL to fit a AP Racing clutch with lightened fly wheel.
Hoping to see a good difference with the car on acceleration due to revs dropping less between gear changes and a better harder grip on the clutch.

Anyone else running this kinda set up on an STI8? Whats it like?

 

It should lurch 1ft off the line before stalling now

HTH

Unless you last clutch was foobared, It shouldn't make that much difference, but at least it'll take the abuse of full bore starts now

 

You should also have lightened pulleys fitted at teh same time.

Simon

 

Stalling? Scoobies dont stall. They idle at 500RPM nice and easy car to drive. lol.

Yea there is a thread about my Santa Pod times and my ****ed standard clutch, Its not going to take many more high RPM starts before it just explodes i think. DOH

Its the lightened fly wheel i am interested in really.

 

Oh sounds interesting, i havnt heard of these.

Benefits? Easier to fit while clutch being done is it that seperate time?

 

Think of the pulleys as a counterbalance for the flywheel. The benefits are similar to those obtained lightening the flywheel; but Id be changing to lighter parts out of mechanical sympathy.

Simon

 

Ah fair play. I will have a look at that as well then Thanks

 

>> Hoping to see a good difference with the car on acceleration due to revs dropping less between gear changes

A lightened flywheel means that it has less weight. If it has less weight then it will have less momentum.

This means that when you open the throttle the engine sees less resistance and the rev's increase more quickly.

On the otherhand, since the flywheel has less momentum, when you close the throttle the flywheel slows down more quickly, so the rev's will drop off more quickly between gear changes.

So you might see an improvement to acceleration due to the engine spooling up more quickly but you could lose more time during gear changes due to the engine rev's dropping off.

Regards, Mark

 

What weight flywheel are you fitting?

if it is less than 7kg you will notice that the car bogs down and fast starts are no longer easy, you will probably also move your power curve up the rev range which in an STi will make it even more crap than it already is. My turbo used to kick in at 3000rpm but when I fitted my lightened flywheel and pulley I succeeded in moving it to 4000rpm before the turbo kicked in properly, you can compensate for this by getting the car remapped. Do not get your hopes up that you are going to get a porsche/Ferrari whooping monster by making these changes. initially the car will feel really different to drive but you will get used to it. You will probably also notice a higher top speed but will lose out at lower speed.

The engine will spool up a lot quicker but as has been said it wil also slow down alot quicker.

 

the engine is moving 1500kg off a start line. i don't think the 3kg of flywheel will make the blindest bit of difference. it'll rev faster in neutral maybe.

 

@tath, drive one then come back and revise your post!

If people have nothing constructive to say and/or are speaking from experience they really should not bother commenting because it only serves to get peoples back up and you get classed as troll.

 

i've got one cheers!

your opinion IMO was a load of bollocks matey. am i not allowed mine as well?

 

every one is allowed their opinion but if you have infact got one you will also know that what I wrote was perfectly factual and true.

but if you say it is bollox then you obviously know more than me.

 

Your choice of flywheel will not affect top speed - this is just plain wrong. At speed, horsepower and aerodynamics are the only things that matter. Other factors become more negligible as acceleration approaches zero (i.e. top speed).

It also won't affect where your car achieves full boost either - unless you're talking about neutral or perhaps first where the lack of inertia of the engine means that exhaust gasses will be lower at every point in the rev range? I don't think you are however. I think you don't really understand what a flywheel does tbh, outside of what Gran Turismo 2 told you.

If you can back up your points then fine - just don't accuse me of trolling.

Back to the original question, I have an AP paddle and lightened flywheel, and the car can really be launched with gay abandon! However, I've found the combination to be very very prone to bogging - moreso than anything else I've driven in fact.

I normally use 6k and a sidestep to break traction (not break clutch) and it's arguable whether this is quick but it's certainly humorous!

 

I've heard this said before but I don't understand it. How does the weight of the pulleys need to be related to the flywheel? What are the symptoms of the pulley weights being 'unsympathetic' to the flywheel - does it go in a sulk or something?

What I do know is that the standard crank pulley has a heavy outer portion coupled to the crank by rubber and that is to form a harmonic damper. The aftermarket pulleys don't have a damper but they do look pretty and probably have a high cost markup. Subaru could easily provide you with a lighter cheaper pulley if they thought it a good idea.

 

because the pulleys are bolted to one end of the crank and the flywheel to the other - it's supposed to be balanced so if you reduce the weight of one end it's an idea to do the other as well.

 

Its supposed to be balanced around its axis of rotation. Whats the point of balancing it like a see-saw?

 

read this to find out about the flywheel and pulley.

http://bbs.scoobynet.co.uk/showthread.php?t=445098

look around the end of the thread.

it is from Damian Harty at Prodrive so I reckon he should know what he is talking about

and tath I am talking about my experience with my car and my mods.

I can not make this up and would not even want to make it up I am speaking from experience and after talking to my dealer.

As for backing it up feel free to come over to germany and I will show you personally.

 

i run exactly the same set up on a p1.

RCM 4.6kg flywheel
AP organic clutch
lightened pulleys (gtspec)
car is runing maybe 380bhp

pros: it revs up quicker for sure. how much real speed this will give you is questionable, but its not a lot i suspect. this came from the flywheel. it does make the car 'feel nice' when you are hoofing it though. the pulleys i put on at the same time as a lot of other mods so cant comment on performance. fack all i suspect. idling and gear changing speeds etc are no different to o.e. you can do a drag launch as well as an o.e set up, just takes a bit of practice thats all cos its different.

cons: engine braking massively reduced. if you are still on standard scoob brakes get an upgrade first. car will not potter along in traffic anymore on a closed throttle and first gear. you get a lot of mechanical noise from the gearbox on the overun due to the lack of inertia going through it. requires a couple of hundred rpm more to pull away from lights and junctions, but after a bit you are used to it no problems.

is it worth it. on a drag car of course it is. all in all it will probably get you down the strip quicker so say no more.

on a road car. it makes the car a bit more obnoxious and racy feely for a small performance gain. i like that feel so to me it is worth it. the majority of people i suspect will not like it though. i do have a very light flywheel though and i think 7 or 8 kg is probably ideal.

if you need a new clutch anyway and you drag the car, may as well do it while you are there IMO

 

You started out with the front - back balance preconception (so in fact you did make it up). I noticed that Damien Harty was vague on what weight the flywheel should be to balance your lightened pulley. Thats because the pulley and flywheel are not meant to balance each other, just as long as the flywheel has a much higher moment of inertia than the pulley.

Don't think that saving 2kg off the pulley will have anywhere near the same effect as 2kg off the flywheel it wont. The mass in the flywheel is at a much greater effective distance from the centre than that of the pulley (see- 'polar moment of inertia'). At a guess mass in the pulley will have about 1/10 of the effect of the same mass in the flywheel.

Theres a big difference in the operation of the flywheel and the Subaru pulley and that is the flywheel is hard bolted to the crank while the pulley mass is attached with a visco-elastic coupling (ie rubber) - its a basic 'harmonic damper'. Do a Google if you want to know more about that.

Apart from a bit more NVH, using an undamped lightened pulley probably wont do any harm but I think the advice that you should use a lightened pulley with a lightened flywheel is dubious.

 

I didn't say you should use a lightened pulley with a lightened flywheel it is just something that I have done, I changed the pulley over a year before I changed the flywheel. changing the pulley made a noticable difference in perormance but it also made the engine lumpy which is why I asked prodrive the initial question.

Changing the flywheel also made a noticable difference but not the difference I was expecting.

but anyway I have done it and written about my findings if anyone disagrees with them then fine I really couldn't care less TBH.

The guy asked a question and I answered it with what I personally know and experienced.

 

Wurzel, there's no need to take the hump.

It was GC8 that said it.

I'm just trying to clear up what I think are misconceptions.

 

Dont bring me into it!

 

LOL, all we need for this thread now is PSLewis and all hell will let lose!
Whats that quote? "On my command unleash hell!"
Or someat like that

 

I reckon that it's another one of "THOSE" areas of aftermarket tuning that costs a small wedge and there are dubious gains at best for the average scoob owner. Sure, if you are a racing driver or punt ya car up and down a strip at the weekends, then fine I'm sure the differences are more noticable, but to man on the street who' s not 100% sure about how it all works (i.e. me spending money on metallic blue pulleys and a slab of metal that is less substantial than the one Subaru put in, doesn't really float my boat. Adverts should read..................