STi flywheel/clutch upgrade for Spec B?

According to the MY08 Service Manual for the Spec B, the 6MT flywheel is a conventional (meaning, non-dual mass) unit. Does anybody know how much it weighs? I am wondering if a cheap, light(er)weight upgrade would be to replace it with a used FW/clutch assembly from a MY04-7 STi. I'm sure there are at least a couple STi owners out there who have dumped their stockers for aftermarket ones.

 

I know that the stock STi flywheel is about 18~19 pounds. I'm hoping that's less than the stock Spec B one.

 

Thanks,

Dave

I think that if you're going to go through the effort of replacing a clutch, why would you want to put in a used one? Most of the guys who have upgraded clutches probably did it because they had too much power going through the stock clutch, and it was slipping.

 

Now, I would love to put a stock STi clutch in the car, along with a lighter flywheel, so I'll watch this thread and see what happens

What I'm really interested in replacing is the flywheel (if, in fact, the original STi one is lighter than the spec B). I'm assuming that most guys with an STi who replaced their flywheel also replaced their clutch at the same time, so I could probably get the whole set easily. Obviously if after inspection, I can see that the clutch is no good, then I'll get a new one.

 

I'm also assuming that the STi flywheel may not mate up with the spec B clutch, which means I'd have to use the STi clutch. Can anyone chime in on whether or not the spec B clutch/STi clutch use the same flywheel mounting points?

^ I would assume that the Spec. has a heavier flywheel for drivability purposes as it is a heavier car.

Does anyone know for sure if an aftermarket clutch and flywheel setup for a Sti 6MT will work with the 6MT of the Spec B?

Bump this up for an answer, anyone?

After researching it, yes it will!

just to resurrect a long dormant post....

 

what are stronger clutch options for our SpecB's without getting a leg work out?

The best option for SpecB's is STi clutches. I use the ACT HD extreme in my SpecB. Clutch and streetlite flywheel. Holds 529ftlbs.

 

I can answer your questions as well as provide pricing.

So a couple of quick questions:

1. Do the 09 spec B have a dual mass fly wheel as the stocker? If so would a xx year STi fly wheel work? I'm guessing yes but don't know if a specific year of the STi works better.

2. what kind of toque would a STi clutch hold?

3. finally, do you mind shooting me a quote for a Sti flywheel, clutch and TOB via PM?

 

thanks man

So a couple of quick questions:

1. Do the 09 spec B have a dual mass fly wheel as the stocker? If so would a xx year STi fly wheel work? I'm guessing yes but don't know if a specific year of the STi works better. No. SMFW. Actually uses what apperars to be same FW as STi

2. what kind of toque would a STi clutch hold? Anywhere from 420-700 depending on set up.

3. finally, do you mind shooting me a quote for a Sti flywheel, clutch and TOB via PM? I will send you a couple options.

 

thanks man

 

The SpecB 6MT clutch is the same pressure plate and flywheel as the STi OEM. What Subaru did to the SpecB was give it a 10mm smaller clutch disc. This was done because the SpecB has lower power levels from the factory and saved Subaru a few cents on each car. The hot ticket is to get back that lost clamping area and go to the STi clutch. Even the aftermarket SpecB specific clutches use the smaller disc, hence the lower power ratings.

 

STi in your SpecB 6MT FTW!

so it's the same fly wheel as the STi, all i need is a STi clutch and then i'm done?

 

thanks again for the clarification.

Yes, your flywheel will work as long as the clutch you choose does not require a specific flywheel combo.

 

You can always go to ACT's website and check out all the STi clutches. If it says it works with OEM flywheel, you are good. You have the same tranny minus the front diff and some electronics. Clutch difference is minimal and just a cost savings to Subaru. Until the release of the SpecB specific clutches about a year ago, all SpecB owners could do was use STi clutches. No one worried then , LOL.

that's great info. thanks a bunch! let me figure out exactly what i need and go from there.

Good luck!

 

-Mike

I think I'm about to go through this as well with my 08 spec b. I'm getting the ACT HDSS and the Streetlight FW for 04+ STIs. I didn't really want to go with a LWFW, but I want to get something new so that I can get it all installed at once and done.

 

I'm not sure if I need to look at the snout kit from TSK. Seems to be a popular mod but I don't know if I need it or if it even works with the 6mt. This is kind of an unexpected expense so I'm trying not to overspend, but at the same time I don't want to take the transmission out again. Anything else I should get or be aware of?

The TSK3 is for 5MT only. Not used in your 6MT. Clutch, pressure plate, TOB, alignment tool all included with ACT. With the Flywheel, might want new bolts. Change your tranny fluid while you are at it, LOL. You should be set.

STi pressure plate/flywheel is not the same as the Spec.B.

 

STi is a fair amount stiffer... and flywheel has larger surface area.

I went over that earlier in the thread. They are interchangeable, but Subaru gave the Spec B about 10mm less area because the motor has less power and it saved a few cents.

 

But you are correct senior sharp.

Has anyone tried this or have any info on the quality or the company in general?

 

http://www.erzperformance.com/Competition_Clutch_Stage_2_Clutch_Kit_for_04_07_Su_p/15020-2100-04sti.htm

 

Just double checking my options as I'm trying not to spend too much. I found the ACT HDSS and Streetlight flywheel for $915 shipped. The Competition Stage 2 is only $375 and the accompanying flywheel is forged steel (14lbs) and $330. Wondering if it is worth the savings..

I have no experience with it. Sorry.

Also, just FYI... the clutch assembly between spec.b and sti is pretty much identical in weight ~36-37 lbs for everything, ~18-19 lbs of which is flywheel. The sti pressure plate is stiffer and engages much closer to the floor. I like it a lot better, but that all comes down to personal preference.