Lightweight solid flywheel and clutch install and review

[Breeze91]

So after having my car off the road for almost a month while I got the heads done I just got it back on the road. While the motor was out I took the opportunity to do the clutch.

The old clutch did 127,000kms and would slip very occasionally. On removal and inspection there were a couple of hotspots on the flywheel and the clutch plate was pretty worn especially toward the edges. Not quite down to the rivets but almost.

So I ordered a new clutch and flywheel. Not the easiset thing to do but eventually got one.

As I picked up my motor with the fresh heads on it I asked them to rattle off my old flywheel with the torx T50 plus impact socket I had special ordered. FIRST MISTAKE! All over the legacy forums the T50 is supposed to fit. It is loose in the bolts though. I didn't see this and by the 4 bolt the tool was stuffed and they stripped the internal teeth on the bolt.

These bolts are hardened steel and very hard to drill. After snapping heaps of bits I went to my specialist tool shop and bought a carbide and diamond tipped bit which turned the bolt into butter. At that stage I got a warranty T50 bit as well.

I took the motor round the corner to Australian Clutch Supplies and asked them to rattle off the other three intact bolts (with the new T50 bit) it just managed to do that and finally the FW was off. Incidentally the correct tool is a square edged spline drive. Never found out which one though. Maybe get it from Subaru if you don't want the headaches I got.

While at ACS they asked what I was putting back on it. I showed them my new clutch and flywheel. They looked at it and said it was one of theirs, how on earth had I got it? It hadn't been released yet. Then they said the supplied pressure plate probably wouldn't hold it. For those interested this is why.

The 5 speed box in the liberty GT is the only one to get a 245mm clutch (all the 6 speeds get a 245). When they retro fit a non dual mass flywheel it is a 225mm clutch like all the other subaru 5 speeds. The 245mm liberty pressure plate is rated at about 800kgs, the stock 225mm OEM wrx plate is 850kgs but on the smaller clutch. So overall you need a much stronger pressure plate with a slightly smaller clutch plate. Hopefully that makes sense. In the end I walked out with the 1050kgs spec pressure plate (this will be the one on all "standard street" clutches for liberty from now on).

Oh and I got a spiggot bearing because my kit didn't come with one. MAKE SURE you get that.

So install as per normal all went well.

Driving impressions.

At first I thought it was as light or lighter than the stock clutch but I think that is because I lubed all the pivot points. Driving it is slightly heavier but my partner didn't really notice the weight.

The feel is MUCH better than my old one.

I stalled it when I first took off and have a couple more times since BUT it is easier to drive off in when you engage slowly, just if you pop it you will stall.

In every other driving situation at any revs the car is more responsive and the engine more tractable. The only possible exception is 60 in 5th (which is bordering on lugging anyway even with the DMF).

My partner asked why it is so much faster. The car does accellerate so much better! Her butt dyno is less biased than mine.

There are no NVH issues. Nothing is louder when driving. If you have the window down and your foot on the brake and bounce on the clutch without engaging fully you can hear the slop in the box and clutch springs being taken up, but that is being really pedantic. I had read horror stories about all this extra noise but there is nothing.

I was going to send in my box for new syncros as the shift was slow and notchy. I don't know if it was the new oil or the clutch or a combo but in the end I couldn't afford the preventative maint of new syncros. Thankfully I didn't. The shifts is buttery smooth in every gear now. Awesome! For the record I just used Castrol Multitrax as recommened by CASTROL for sub boxes.

Was this simply the best mod I could have done? Hell yes! No additional strain on motor, extra accelleration and much better feel. Of course if my old clutch wasn't so worn it may be different. If you are thinking about a new clutch on your 2.0l GT give ACS a call in Adelaide. Amazing!

Clutch is exedy 1050kg performance pressure plate, organic clutch plate and billet 6.8kg WRX 2.5l (06) flywheel. But it is all packaged as a DMF replacement for liberty from now on.

After 200kms and some spitrited driving my fuel consumption is pegged on 11km/l. At just over 60 in fifth the instantaneous consumption is 18/20km/l (my car is the jap spec so reads km/l rather than l/100kms) but this is as good/better than normal. About 9l/100kms.

[teK--]

Thanks for the post.

Out of the three things I hate about my car (Drive by wire mapping, clutch, lack of telescopic steering column), the clutch is the thing I hate the most. The DMF lacks so much feel it's like stomping on marshmallows.

How much was the kit that you purchased, and if it wasn't from ACS then who was it through? I may look at contacting ACS direct to get what I need, also to ensure that I don't accidentally buy the wrong parts since I want to convert to a solid flywheel too.

[Breeze91]

Go direct through ACS. I don't know the finished price from them but mine was around a $1000 for everything. They have a special clutch plate that has three different types of springs in it to manage the harmonics (apparently). I could see the different types of springs. It all seems to work nicely. I did get a bit worried when they said "we measured it all up and built the kit from scratch, it should all go together..." They want to see how the car drives, but my impressions give it a very big thumbs up. The stock DMF weighs a tonne.

The engagement is so smooth.

[teK--]

Is the friction point well defined? On mine it is so subtle that wearing a different pair of shoes can make the difference between feeling the clutch engagement or not. Other times I have to either feel the car moving or watch the engine revs drop.

[Breeze91]

The pedal feel is pretty consistent throughout the stroke. If the car wasn't running you'd struggle to pick the point where the clutch engages. When the car is running the friction point becomes very apparent with no chattering or shudder.

[teK--]

That is what I want .

It's a catch 22, waiting for a clutch to wear out so I can replace it with something better. Or intentionally wearing it out more quickly to reach that stage. In both scenarios the ~$1500 cost is killer

(My clutch has only done 57,000kms so it could still be going for a while)

[Breeze91]

Tell me about it! This was a $4500 service with me doing all the work (except the heads).

[maj]

Excellent info Breeze91

I'm starting to notice more slip in 3rd gear now (done 165,000kms on original clutch), previously only had occasional 5th gear slip.

Will give ACS a call today for pricing on their replacement kit.

[Breeze91]

Quick Update. I have done several thousand kms on this now and still love it. I do need to mention that I do get some rattling noises that are only apparent if I have the window down and I am in a building. The sound is like noisey injectors or a bit like the lifters on an early subaru when they get noisey. That is the sort of volume.

The rattle occurs when;
Car is in neutral, not in gear and the A/C compressor comes on and drops the revs a bit
Car is in first, second, third at low revs between about 1000-2500rpms. Accelerating.

I need to state again I can only hear this noise if the window is down and no radio etc and I am in a builind or going close to a fence.

At first I thought it was my gearbox input shaft bearing but this is commonly reported on legacy and wrx with light flywheel. In fact some wrx Sti owners report it with stock flywheel (which is also light).

EDIT The Torx Plus T50 does work. Turns out the bit I got was a T50 Torx. MAKE SURE YOU STATE THE "PLUS" and that the tool guy knows there is a difference.
So I am still very happy and I find once the car is warm it is actually better in fifth at say 60km/hr than it was.

[teK--]

Thanks for the update, I imagine the vibration may be from the lightened flywheel causing something similar to resonance. I'm still keen to do this mod though for all the other benefits.

My clutch has just survived another track day so at this time not in need to do the changeover just yet

[maj]

Hi All,
ACS gave me part number of KSU24503 for the Lib GT 2.0T kit as well as name of local stockist (since I'm in Canberra), which is Canberra Brake and Clutch. Gave them a ring asking for a price for the kit, they've quoted me just shy of $2100 which sounds suspiciously like the install price to me.

Also gave subaru another call since they've briefly mentioned to me the solid flywheel conversion is possible and should be cheaper than their price of $3000-3300 for the OEM DMF replacement. Waiting to hear back.

[teK--]

ACS quoted me $738.00 to supply the kit for my 2.5i. I imagine your price is fitted but even then that's a lot of money for fitting. I wouldn't expect to pay more than around $600-$700.00 for the clutch and flywheel to be changed over.

[Breeze91]

Yeah the na is much cheaper than the turbo. Mine was just for supply. Originally I thought they were going to be about 600-700 but the turbo ones are way more, sucks for me, good for you.

They reckon they have done heaps of NA ones as there are much more on the road. Don't know if they use the same flywheel. Not even sure if the non turb is push or pull style clutch

[maj]

Actually on further investigation this appears to be a DMF kit:
http://passenger.clutchpro.com.au/data/ ... y/3596.htm

[Breeze91]

Whoa missed the post from Maj. Mate if you like I can buy one for you locally and courier over if it saves $1000. That is pretty dear. They may have quoted you on the replacement DMF kit which is much more expensive. It is a Daikan copy of the sachs DMF. Be really clear about the single mass conversion kit.

Charles