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DodgyTim
11-22-2013, 02:00 PM
I’m looking at purchasing a lighter flywheel for my 818R.

My donor is a 2006 WRX with the EJ255

Standard flywheel weight seems to be 25lbs for the WRX and 18.9lbs for the STI?

A quick search online I found “lightweight” flywheels as light as 8.6lb, with common weights about 12 to 14 lb.

Also found some posts on NASIOC;
“I have a 06 WRX and just installed an F1 Racing, 13.7 lbs flywheel and a Clutch Masters FX200 today. The RPMs don't fall that fast, maybe just a slight hesitation of letting off the gas while shifting, but nothing that a week or two of driving won’t get you used to. I was also surprised to see no change at idle. The needle is as steady as it ever was. The car definitely pulls quicker and you barely have to touch the gas to keep it at 80 on the highway. I was surprised that the FX200 felt really light and gummy compared to the stocker being that it’s a Stage 2 clutch. It feels all right though and grips like a b*stard too I did upgrade my clutch line to steel braided so that could have something to do with the feel also.
The flywheel didn't throw any codes but it did misfire and stall today while casually driving down a residential street. After a rough re start and some bucking as I was getting going I was surprised to see absolutely no code at all? I have an appt to get a tune on Monday so hopefully it was just a learning process for the car and won't happen again. It drove fine after that.
I know you were looking for a STi but this is what I got. I know mine hits boost and spools even faster now than it did before, launch is significantly "touchier" but by no means have to rev to 1000s of rpms just to get it going, and you'll get put back in the seat noticeably further ha-ha. One last thing is it does feel like the top speed may have gotten decreased but I won't try that till after the tune. I can't comment on top end because I haven't taken it over 3500 yet. Hope this helps a little.”
and
“I fitted a 5kg aluminium flywheel to an '03 STi motor in my dd. The snappy acceleration and on-off nature of the motor is just plain fun. But not plain sailing. I've never seen a CEL but the first thing I got was a heap of shuddering on take-off and sometimes full on kangaroo hopping which was very hard to avoid. The only solution was to take off in a rush all the time. Might sound like fun, but gets a bit tedious for the favourite passenger!

I spoke to the clutch people about this and they said it is a common problem in efi vehicles, many people pull them out after a while as they can't live with it. Despite that it appears for all the world as if there is a gummy clutch plate issue or the like he said it will be fixed by adjusting the tune. He was right. Easy if you've got a Vipec or similar of course, as I do. The fix was to put a heap more fuel into the cells that the engine should never get to, like 500rpm. Totally eliminated the problem and I didn't see shuddering at all in any gentle take-off, much to the delight of the chick when the car was full of shopping.
So now I can just enjoy the boost the seat of the pants dyno gets with the snappier acceleration. But my advice would only be to do a lightened flywheel if you are able to adjust your tune or happy to take it to someone that will.

Fidanza Aluminium flywheel LAF8006 (5kg)
RPM2133SSCC Stage 2 Clutch, pressure plate, throwout brg & spigot brg.”

My questions are;
Does anyone have a light flywheel in their donor or DD?
What weight is it?
How liveable (is that a word?) would it be for 50/50 DD/track use?
Any thoughts on what will be the effect of the much lighter 818 R or S, can we go lighter than the equivalent flywheel in a WRX due to the 818’s weight reduction?
Cheers
Tim

Mechie3
11-22-2013, 02:15 PM
I ran a 12lb flywheel, a 1.3lb crank pulley, and no AC. It did rev very freely. Taking off required some relearning as it took a little more gas. I didn't have issues with full on bucking or poor running.

For others reading this, cars with AVCS have a cam sensor on both heads. Non AVCS cars have a single cam sensor and tend to trigger ghost misfire codes.

metros
11-22-2013, 02:21 PM
I purchased the ACT street light flywheel along with ACT HDSS clutch for my 818 build. The shop I was purchasing from really enjoyed the prolight on their shop car but I went with the slightly heavier street light for ease of driving on the street.

This will be going into the 818 as it's built so I don't have any experience with it yet to report back to you.

Rasmus
11-22-2013, 03:35 PM
I daily drive an

http://i162.photobucket.com/albums/t278/RasmusHansen/SubaruParts/IMG_3768.jpg
ACT Prolite Flywheel on my 2004 Wagon. That is my photo of my flywheel. That's 4.254 kg (9.38 lb). I run it with an OEM clutch.

It's a little touchy getting use to such a low mass flywheel at first. But in about 3 days you get accustomed to it. I still tend to kill the motor about once every 4 months. Usually while backing up, up hill.

It doesn't like to be launched like a 25 lb flywheel. In fact, I wait to get on it until the clutch is fully engaged otherwise I get slippage and then smell clutch. All the other gear changes are easy.

One downside: there's a bit of gear chatter noise from the transmission when on a slight down hill while under no load. That is, coasting on a slight down hill while in gear. I do one of three things to combat the chatter: 1. put up with it, 2. push the clutch in, or 3. take the car out of gear.

I also tow with the pro-lite installed:

http://i162.photobucket.com/albums/t278/RasmusHansen/SubaruParts/IMG_1372.jpg

http://i162.photobucket.com/albums/t278/RasmusHansen/SubaruParts/IMG_1489.jpg

http://i162.photobucket.com/albums/t278/RasmusHansen/SubaruParts/IMG_2530-1.jpg

I like it so much I'm gonna run one in my 818r. I'd recommend it for your application.

C.Plavan
11-22-2013, 04:22 PM
I picked up and installed a Clutch Masters FX400 6 puck for my 818R with their Aluminum Flywheel. You can also replace the friction ring later on down the road on the FW. However, I didn't weigh before install.

longislandwrx
11-22-2013, 05:06 PM
A streetlight flywheel ~15lb with a lightweight pulley is a great compromise. Faster revs, but with less of the nuisances Rasmus brings up. But hey this isn't a WRX and comfort ain't the name of the game, so you might be fine with a prolight




Just noticed this is pretty much what Metros said so +1 that.

RM1SepEx
11-22-2013, 05:21 PM
I put a 12 lb chrome moly flywheel in my 818 based on the wrx discussions online Subaru forums and possible errors as a compromise

metros
11-22-2013, 06:32 PM
A streetlight flywheel ~15lb with a lightweight pulley is a great compromise. Faster revs, but with less of the nuisances Rasmus brings up. But hey this isn't a WRX and comfort ain't the name of the game, so you might be fine with a prolight




Just noticed this is pretty much what Metros said so +1 that.

Yup, hoping to get most of the best of both worlds.

Mitch Wright
11-22-2013, 09:17 PM
Rasmus, I have been eyeing the ProLight for my R, I assume you have been able to tune out the misfire code? My donor is also a 04.

longislandwrx
11-22-2013, 09:57 PM
Some people never get misfires. You never know.

Silvertop
11-23-2013, 12:40 AM
I went with a moderate 13 lb Exedy flywheel and Stage 1 Organic Clutch, along with a Grimmspeed lightweight crank pulley. I don't expect to have any ECU misfire issues and touchy launching or clutch engagement problems with this not-too-wild arrangement, but I won't really know until I get it all installed in my 818S and get it running.

My mail-order ECU tuner (Delicious Tuning) tells me that he has resolved related ECU misfire issues for the ECU I am using, so if I do have a misfire problem, he'll be able to fix it.

Rasmus
11-23-2013, 11:04 AM
Rasmus, I have been eyeing the ProLight for my R, I assume you have been able to tune out the misfire code? My donor is also a 04.


Some people never get misfires. You never know.

Every time I have this discussion on NASIOC I get shot down by people telling me it's not possible that I don't get the misfire code on my '04 running a 4.3 kg flywheel. I don't. I know how easy it is to make the ECU ignore the code but I figured I wait to see if it actually fired. Nope. Not for me.

What really boils their noodle is when I show them I'm running these too:

http://i162.photobucket.com/albums/t278/RasmusHansen/SubaruParts/IMG_4585.jpg
Lightweight crank and accessory pulleys in tandem with the Pro Lite flywheel.

Never had a misfire code. Your mileage may vary.

DodgyTim
11-23-2013, 12:10 PM
Thanks to everyone that posted, I was thinking about going to the lighter end of the range as my 818 will be track focussed and the odd Sunday drive, where I won't be doing too much stop start driving.
The misfire codes don't worry me too much, there will be other codes I need to delete as well, like secondary air

Mitch Wright
11-23-2013, 10:17 PM
Thanks Rasmus,
I am planning on replacing the OE wiring harness an aftermarket EMS, if I don't overshoot my budget to bad. I have started de-contenting the stock harness just in case. Either way I decided to go with the Pro-Lite.

Thanks for the info,

Mitch