Hey guys, I'm probably going to end up needing a clutch soon and am wondering what everyone here is liking. Right now I've got the stocker but it's at 111k miles and takes quite a bit of slipping to get the car rolling from a stop with the AC on, once I'm going I don't have any slippage but I'm pretty sure it's fairly worn in the engagement range.

With that in mind, the car is lightly modified with a Manic stage 2 tune, Wagner intercooler and W/M on the way for power adders/maintainability. I am tracking it and it is still my daily so I don't want a straight race clutch but am wondering how people are keeping up with increased power with the various clutches available to us.

I don't know too many clutches for these cars but so far OS Giken seems to be a popular name, but I've never run one so I don't know what they're like to live with. I find the stock clutch very light so a heavier plate isn't the worst thing. With 110k miles on mine currently I'm expecting an engine replacement relatively soon considering my use basis and when it goes I'll be swapping in a prebuilt long block from Sneed or similar with forged internals and some head work. The stock turbo is definitely lacking in the top end and on the long straights so a billet upgrade is in order when that goes.

What're people running with a mix of street and track and how do they feel about them? I do not like the dual mass flywheel, I don't mind a lighter setup at all but I don't want a setup so light the car stalls.

 

Here's one more recommendation for OS Giken. First installed about 60K miles ago, with 280WHP in 2011 and just keeps on grabbing. Currently up to 383WHP and during last rebuild it looked like it was good for another few years. A little chatter at launch in town, but nothing I can't live with.

I'd recommend you wait for the engine swap before you replace the clutch / flywheel --- save a bunch of labor hours. Think about their LSD too, put all your new found power to both wheels.

 

Are you running the STR or GT series? Dual or single plate? I don't really launch my car, are you referring to leaving stops like at a light?

When the time comes for the clutch replacement an LSD will be going in, haven't quite decided which one yet but the wavetrac is looking really good.

 

STR1CD --- single plate. It's also a lightened flywheel --- all kinds of top end acceleration.

By "launch in town", I'm referring to getting away from a stop light. Since I live in the boondocks, there's minimal city driving and stop lights, almost all hiway.

 

I'll have to see if I can dig up some examples of the chattering. I drive a 50/50 mix of highway and city when driving on the street so chattering when leaving stops and with the clutch depressed could be irritating.

Also looking forward to a slightly lightened flywheel, the dual mass is irritating in town and for quick shifts.

 

Found some examples of the rattle, pretty similar to the multi plate dry clutches on Ducati's. Not a fan honestly.

How are the clutchmaster kits? Anyone running these with much luck? I'm not looking to push power boundaries here, but we all know how the HP bug is.

 

Well I've been looking around some more on this and think I'm going to end up leaning in the direction of the OS Giken Grand Touring series as they're reported as having very minimal chatter. Has anyone run the Hard vs Soft plate and have comments on how much of a change in pedal pressure vs stock they are?

As it was also mentioned earlier in the thread I will be doing an LSD at the same time, think I'm gonna end up going with the Wavetrac.

 

So would you mind tell us why you decide to to go with OS giken vs Helix or any other brand?And why you decide go with STR1 and not GT1 for instance.
Reason im asking you is cause i'm also as searching for a semi road(not daily just fast drive/fun 2-3 times a week) and track use 4-5 times per year. My setup will be almost exactly like urs.
Wagner+Aquamist+Ohlins+AEM+Decat+Wavetrac around 300hp not forged for start.

 

Sure thing, OS Giken is well-known name in the motorsport world. I haven't personally heard of helix before.

• I did actually decide to go with the GT series over the ST series, as the former has a dampened floating hub assembly that greatly reduces the chatter effect when the clutch is depressed. I don't care for the chatter noise at all so this was a large deciding factor for me.
• The OS also has the timing hole machined which is the only way to set the timing chain properly, not sure if the Helix or which others have this.
• From what I've heard the customer support with OS is excellent, which is a large deciding factor for me when purchasing any product.
• I expect my car is currently floating somewhere around the 200 ft/lb range so the soft diaphragm rated at 280 should be sufficient enough for a modest improvement such as a larger billet turbo when mine goes. Depending on how much of an increase in pedal effort the hard diaphragm is over the soft I may opt for the 30 ft/lb capacity increase.

 

If going with the Giken I would go with the GT soft since you are still using it on the street as it will make it easier to drive in stop and go traffic and pulling away from stops.
https://www.waymotorworks.com/os-gik...-cooper-s.html

For the diff I would still go with the Quaife as it is the original and bulletproof with a lifetime warranty. I don't like the extra parts Wavetrac put in the diff to try and make it lock as those will add wear over time and failed diff is too much labor to ever do twice.
https://www.waymotorworks.com/quaife...ferential.html

If it was a more track car I'd go with the Giken diff.

Also when doing all this I would make sure to do the powerflex front control arm bushings since you'll have the subframe out.

 

I'll add the Quaife diff to my list to consider when the time comes, they were my original consideration but I really liked how the wavetrac will still distribute power to both wheels if one lifts entirely. I'm hoping to put this off until middle of next year at least to get some other projects out of the way and hopefully have the engine back in my other project car to drive while the Mini is down.

I'm actually doing the front control arm bushings and sway bar this weekend already so knocking that one out early.

 

I run an OSG twin which is the noisiest of the bunch, the STR and HTR would be next but they're really not bad at all. The GT is the quietest but will still chatter a bit when cold. It's to be expected though with a full metallic sintered clutch. That construction is also why they are so durable. The more you drive these, and the harder you push it the quieter they become. So feel free to drive it like you stole it. Also don't let the OSG rating fool you. These clutches are under rated by the factory. I'm also running the Wavetrac and love it.

 

What is the longevity of that GT OSG clutch? I’d like to get another 100k miles out of the car without having to worry about the clutch again.

 

Any updates?

 

Haha none yet, with everything that's happened this year and now that I'm working from home I haven't put nearly the mileage on my car that I was expecting so the clutch is still hanging on. That being said it's gotten VERY slippy in the beginning of the engagement range and now that I'm towing my kart to the track I'm sure it'll give up sooner rather than later.