R33 Gtst, Clutch & Flywheel Impressions.

[insu]

Hey all, not sure if this should be in this section or handling or whatever, but here we go. Just thought I'd give my impressions of fitting a lightweight flywheel to my car as when I was investigating the modification there seemed to be alot of conflicting information about the results of said modification.

Car's specs:

1993 GTSTML (twin bags, active diff etc)

Manual

Catback exhaust

GFB Stealth FX Bov (for rice factor, although I always have it turned to 100% return)

Apexi powerintake pod

And that's it, I had the car Dyno'd at Mercury about a month ago, and the car put down 165.9rwkw.

The Clutch:

Exedy H/D Organic kit incl:

* Exedy H/D Organic clutch plate

* RPM Brass Button Pressure plate

* New Bearings

This kit can handle 240rwkw

Bought off C&B off of this forum.

The Flywheel:

An Xclutch Alluminium flywheel with steel? face plate (see pic).

Weight: 4.8kg

Installation: ABS at Springwood.

Thanks to Dave (3lit3 32) for getting me a good price on install.

Impression:

Now at first it was hard for me to get over the new clutch to really feel what the flywheel was like because my old clutch was so badly slipping and the balance point was so high on the pedal that the new one was incredible (compared).

Strangley even being a higher rated pressure plate the clutch pedal is now (at least) twice as light as old??

The first thing I noticed about the flywheel is that you do need to be a little more conscious about holding your revs on take off. Its not that you really need more revs to move off the line when you are releasing the clutch, its just that when the clutch starts to engage the revs rop alot faster so you need to be quicker accelerating in order to keep the revs optimal.

This is sorta amplified when you have the aircon on, but it is in no way unliveable or annoying, you just have to adjust your driving style is all, and once you get it, its really quite smooth.

Now its time for an episode of Myth Busters:

Myth: Lightened flywheels make your car vibrate horribly.

BUSTED

I haven't noticed any difference to the cars handling/vibration/feel etc through idling, accelerating lightly and heavily, cruising at speeds of: 40, 50, 60, 80 and 100.

Now i'm not saying that all cars will be the same as mine, but what i'm saying is that if you buy a good quality flywheel that has been correctly crankshaft balanced (and if need be mated to the pressure plate and balanced) there is no reason why your cars driveline should vibrate.

As for general driving feel, apart from getting use to the new clutch feel and point, the flywheel is very easy to live with. Taking off from the lights is easier and accelerating through the gears when both hitting boost and even changing before 3000~3500 rpm is easier. The car seems to feel like it has more torque available off boost, and winds around the rev range much easier (and hence hitting boost faster).

Upshifts require a bit faster action in order to keep the car smooth, but I believe this comes down to the revs dropping faster when the clutch is in, and hence has to climb higher once the gear has changed and the clutch is being let out.

Again this isn't really anything bad, just something you have to change in your driving style.

Downshifts on the other hand are an absolute breeze. You don't have to blip the throttle if you don't want to on down changes, the car just feels and sounds much more willing to meet the revs when changing.

Its hard to explain, but the easiest way I can is to say that you want to change back up again, just so you can feel and hear the car change down again .

One of my reservations about getting the lightened flywheel is that I thought it would adversly affect highway driving as without the extra reciprocating mass, the car would have to work harder in order to cruise along the highway.

Thusfar this fear seems to be unfounded and if anything the car seems to 'feel' and sound happier and more 'revvy' and from what I can tell at vacuum reading before and after hasn't really changed, ergo my throttle position at 100 hasn't had to increase in order to maintain the same speed (read: more fuel use).

As for stop-start driving and general fuel economy, i'm sorry to say that I can't give you any figures as I haven't had it in for long enough. But give me a couple of weeks and i'll update this post with my findings.

As for the flywheel improving the acceleration of the car, well by the seat of the pants o' meter I'd have to say it has. More downlow I'd say than uptop, but the car also 'feels' faster I guess because of the fact it revs through the range faster.

I must say though, due to the fact that I had a slipping clutch before the install, I cannot without resonable certainty how much of the increased 'acceleration' can be contributed to the flywheel or clutch.

After my clutch has had a chance to bed in, i'll be taking it down to test n tune to see how it goes. Probably 25th (wednesday night) at willowbank if anyone wants to come down. I think there is a test and tune on then? Correct me if i'm wrong.

I'll post up results of the times on here after that as well.

Well if you made it this far, you probably have eye fatigue and are wondering why the heck you're still reading.

Oh and if anyone completely disagrees with my findings, that's great and feel free to post your criticisms, just don't flame me because I have specifically stated this is what worked with my car and those mod's etc.

Cheers -Tom

Oh and apologies for any spelling and gramatical error's of which i'm sure there are many.

*Update*

I have noticed one ill effect since fitting the lightened flywheel.

On cold weather (read morning) starts when the car starts up and idles high while its warming up, the car seems to shudder for a while. Its a shudder through the whole car and you can see it in the mirrors. Its not really bad or anything and lasts about 15-20 seconds or so then goes away. Curiously if you then rev the car in neutral to the same point the car was revving at when cold it doesn't shudder?

This is just a guess, but I guess that much like the engine the flywheel takes a couple of seconds to get up to operating temperature and working all sweet etc. Apart from this I haven't yet noticed any other ill effects of the flywheel.

Edited January 21, 2006 by insu

[insu]

Sorry I forgot to post the picture of the flywheel:

Edited January 18, 2006 by insu

[Busky2k]

The myth that the lesser rotational mass = more fuel consumption on the highway or more throttle required to maintain speed on a hill is complete rubbish. I'm glad someone else who actually has a lightened flywheel realises this! If anything, a lesser flywheel = better fuel economy because less energy is wasted trying to turn the darn thing.

[RANDY]

165rwkw isn't bad for a pod and exhaust! You must have spent well over a thousand bucks on that clutch/flywheel setup, right?

[insu]

Here's a copy of the dyno graph.

And costwise, I spent:

$320 - Clutch kit

$470 - Flywheel

$270 - Install

So $1060.00 all up installed. I'm pretty happy with the value for money of the modification, and if you have to change the clutch anyway well....

Oh and btw as someone asked me earlier, yes that is stock boost.

The guys at Mercury said it was a good result so I was happy.

[insu]

Hey RANDY, this is off topic but I like your signature idea where you put your wtb items for your liner. Do you mind if i steal your idea? Thanks.

-Tom

[shif_tea]

Hey mate, i bought the same kit as u off C&B and was just wondering if you have the part number of that flywheel from Xtreme clutches. I've been thinking of getting one before i got it installed and this has just made up my mind.

Cheers on the info man

[insu]

This is the part number: FN1024A

From xclutch (see www.xclutch.com.au which turns into: http://www.xtremeclutch.com.au/)

And I ordered mine through one of their distributors:

GLOBAL AUTO SPARES

7 Bailey Cresent, Southport

(07) 5576 5757

The guy there I dealt with was very helpful and knowledgable.

But I'm also under the impression you can actually order them straight from them? I'm not sure, but it might save you a little bit if you can do it that way.

-Tom

Edited January 19, 2006 by insu

[insu]

Oh one point though guys, I forgot to mention. The guys at xclutch did specifically say that this clutch was suitable for street and some track work etc. But they don't recommend it for drifiting if that is what you want to buy it for. Apparently drifting can cause too much heat to build up and the alluminium has the potential to warp easier.

Don't worry though, the guy assured me it will never warp on the street or track work etc.

-Tom

[WetGTR]

Hi Tom,

A very informative post. Very well written. I have to agree on everything you have said as I used a lightweight flywheel from Xtreme Clutches on a WRX. I got the exact same resultsa as you did with your clutch, car.

cheers

Adam

[insu]

Cheers Adam.

-Tom

[shif_tea]

Thanks man, i talked to the guys at xclutch before about buying straight from them and they said the price is the same as from their dealers. I'm gonna order one from hi octane racing.

Cheers again for the information mate. Good thread

[dangerous_daveo]

Few questions, simply out of interest from doing the opposite of what you did, which was going to a less harsh clutch, on to a stock fly wheel. From what the car orginally had which was a 9 puk ceramic on to a 4-3.5kg fly wheel.

So my questions are, stock pressure plate? And how much does the fly wheel weigh in at?

[Bass Junky]

Hey there.

I have an Ogura Light Weight Steel Flywheel and Exedy Super Heavy Duty clutch.

When you go to the drags, you are not going to like it that much.

It tends to jolt around between gear changes unless you are super hard on it. I lost 0.5 seconds on mine affter the fitment of the clutch and flywheel and an intercooler.

I was told that I should pick up 0.4 off seconds, and I didnt.

BUT, with and extra 70 odd rwkw now from then, I haven't got that problem.

You'll need to launch higher and be SUPER fast with your shifts or the decellerating engine will jolt around as you come back on the throttle.

Word to the wize

BASS OUT

[insu]

Few questions, simply out of interest from doing the opposite of what you did, which was going to a less harsh clutch, on to a stock fly wheel. From what the car orginally had which was a 9 puk ceramic on to a 4-3.5kg fly wheel.

So my questions are, stock pressure plate? And how much does the fly wheel weigh in at?

Dave- I'm sorry, do you mean how much does the stock pressure plate and flywheel weigh in together?

The stock flywheel weighs around the 9kg mark (correct me if i'm wrong).

As for the stock pressure plate wieght i'm not sure? I don't think it could be much more or less than standard though?

Or were you refering to wether or not you should use the stock pressure plate or not when going back to a stock setup?

-Tom

[insu]

Bass- Thanks for the words of wisdom, this info should help me to understand how to launch the car and drive it down the track better, instead of having to do 20 thousand runs to find the best way to drive the car!

-Tom

[insu]

Hey all, me again. Just for any of those following this post, i've confirmed the test n' tune is on wednesday 25th from the willowbank website, so if anyone else is bored that night and wants to come down, it could be a fun night.

I'll probably be getting there around 6pm, gates open at 5pm and racing starts at 5.30pm.

On that note, does anyone know the entry fee for night? I had a look on the website and couldn't find anything. It's probably somewhere in the Queensland section, I just couldn't be stuffed looking.

I'll post my results up once i'm done, though I don't know if it will help anyone for three reasons:

1) Every car is different.

2) Every driver is different

3) The car hasn't done any runs before, so there isn't really anything to compare it too, but i'll give you guys a run down on how the car feels and responds when you take it down the track eh?

-Tom

[predator]

It's $35 for willowbank..give or take a dollar or two.

anyhow, go post in QLD area, some people may attend.. I'm out though

I'm fitting an xtreme lightened flywheel, and cushioned ceramic xtreme clutch behind an RB25det, and rb20 gearbox.. the cushioned ceramic rather than the button or full face clutch in the hope it may hold the gearbox together for a bit longer. Shall see whether my thoughts are correct(?) or not soon enough.

Interesting reading though on all that.. good when people post up their experiences other than the "big blank" after the initial "should I?"

The way SAU used to be!

[insu]

Thanks Predator, i'll go make a thread about going down to willowbank, and see who'll come out. Thanks for the entry info too.

-Tom

[rev210]

Hey there.

I have an Ogura Light Weight Steel Flywheel and Exedy Super Heavy Duty clutch.

When you go to the drags, you are not going to like it that much.

It tends to jolt around between gear changes unless you are super hard on it.  I lost 0.5 seconds on mine affter the fitment of the clutch and flywheel and an intercooler.

I was told that I should pick up 0.4 off seconds, and I didnt.

BUT, with and extra 70 odd rwkw now from then, I haven't got that problem.

You'll need to launch higher and be SUPER fast with your shifts or the decellerating engine will jolt around as you come back on the throttle.

Word to the wize

BASS OUT

<{POST_SNAPBACK}>

Dude!

What the is going on there?

You have to be shifting pretty darn slow for that to happen. I never had that problem.And I had the same flywheel as well?