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Hi all,

Installed a brand new OS R3C clutch with OS fitting kit into the GTR, and the clutch is LITERALLY on/off.

Is there any adjustments that can be made to make this clutch at least a tiny bit drivable?

I realise that this is a solid centre clutch, but is it supposed to be next to impossible to take of without stalling?

thanks for any help!

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i had an os giken quad plate and sold it for a npc twin plate, best decision i ever made. This NPC unit drives like stock its so smooth and handles over 450rwkw no dramas :cool: The os giken was a pain its just too light flywheel wise i reckon so u need to keep the revs up to take off or it stalls or bunnyhops. Definately not a street friendly clutch.

Edited by unique1

The OS clutches are really just that on or off. If you can get the left foot finess down pat you have approx 2mm of balance point - even then it can get the whole shudder happenin. Bear in mind I still have the dapening springs in mine.

I am considering swapping my OS for a NPC clutch as the whole taking off experience on the street can be a real painful experience.

Os clutches, twin and tripple plate.

Make sure some material is taken off the front of the thrust bearing carrier snout, approx 4mm otherwise it actually contacts the rear clutch plate center, and will cause some serious issues down the track!!

I found out the hard way, and I've had both twin and tripple now. Now running an extreme carbofibre twinplate.

Thanks for all the input guys.

I was running an OS twin before with the HKS2530 twin setup. It was rebuilt and i think was made a bit heavier than original.

Whilst we were aiming for 800hp we ended up making 760hp, and i got the R3C as I usually prefer to go for a little overkill vs a little underkill. I figured it wouldnt be THAT bad but this is really not gonna work as its a street car.

The NPC unit sounds amazing if it really does drive like stock!!

I think I may have the old twin plate lying around, that was at least drivable with a bit of focus, and its not really going to get launched so it should most likely be fine.. i was thinking of potential launches before, hence more reason i went for the R3C.

And btw i think the clutch unfriendliness is compounded by the fact that im running the OS gearset with tall first gear!

Edited by SLY33
Thanks for all the input guys.

I was running an OS twin before with the HKS2530 twin setup. It was rebuilt and i think was made a bit heavier than original.

Whilst we were aiming for 800hp we ended up making 760hp, and i got the R3C as I usually prefer to go for a little overkill vs a little underkill. I figured it wouldnt be THAT bad but this is really not gonna work as its a street car.

The NPC unit sounds amazing if it really does drive like stock!!

I think I may have the old twin plate lying around, that was at least drivable with a bit of focus, and its not really going to get launched so it should most likely be fine.. i was thinking of potential launches before, hence more reason i went for the R3C.

And btw i think the clutch unfriendliness is compounded by the fact that im running the OS gearset with tall first gear!

If you are going to consider NPC, tell Doug to tell you about his common hub twin with the cushion button front plate.

It's a cushion button top plate and solid centre bottom plate with a common hub like a Nismo twin with nylon retainers. It will hold 1000hp to the ground and comment from my customer on it was 'hey it drives nicer than my Hi-ace van'

He also does the twin sprung centre clutches which also hold 1000hp to the ground and then the mac daddy that's found in M. Jacobsons GTR which is the original solid centre twin.

All priced around the $2000-2400 mark, local guy, local warranty and a clutch you'll never break.

From memory, he has these clutches tested by exedy in Japan and they spin them to 16000rpm and apply 1000ft/lb of load. Apparently they haven't broken one of his yet.

so you definatly used the supplied os giken bearing and carrier? i find mine really easy to drive..

one clutch the is hard is the nismo g-max spec3 tripple solid centre 1200ps over... imposible. i exploded me rear diff when launching. it stalled a 26 with a t04z on 20 pound and shatterd the diff side beaings..

i didnt like my npc experiance.

the clutch didnt slip. but when it did it welded itsself to the flywheel but eventually broke free..

apon replacement to a r3c i noticed a major flaw with it.. namly the soft chrom molly used for the friction plate splines..

i believe i got it thru you elite.. was a mate of bunts and anna..

one was fine one was near on stripped, and jes the input shaft was a ok.

this was after a handful of launches and roughly 3000km.

post-19586-1257579718_thumb.jpgpost-19586-1257580053_thumb.jpg

i didnt like my npc experiance.

the clutch didnt slip. but when it did it welded itsself to the flywheel but eventually broke free..

apon replacement to a r3c i noticed a major flaw with it.. namly the soft chrom molly used for the friction plate splines..

i believe i got it thru you elite.. was a mate of bunts and anna..

one was fine one was near on stripped, and jes the input shaft was a ok.

this was after a handful of launches and roughly 3000km.

post-19586-1257579718_thumb.jpgpost-19586-1257580053_thumb.jpg

Ahh yes, I remember this one. Did you send it back to Doug for inspection?

It was a rebuilt triple OS right?

He doesn't use soft chrome molly for the friction plate spline. They are genuine exedy centres.

The clutch wouldn't have welded itself to the flywheel, but may have given that feeling. Something else has caused those splines to flog out.

So when you say you didn't like your NPC experience, do you mean you weren't happy that the clutch broke or were you unhappy with the service provided? I'm sure the situation was resolved as I never heard any more about it until now. Doug covers all his work under warranty so if something has gone wrong, he would have covered all costs involved if the clutch was faulty.

i never got around to sending it up. so its abit late now. but is clear its not rite. just having that happen made me abit wary of converted clutches.

so to be acurate i have never delt with them at all.

im asuming there own complete clutches are much better. and this must of been a faulty hub. non the less not to good.

any sugestions? will they still fix it?

i never got around to sending it up. so its abit late now. but is clear its not rite. just having that happen made me abit wary of converted clutches.

so to be acurate i have never delt with them at all.

im asuming there own complete clutches are much better. and this must of been a faulty hub. non the less not to good.

any sugestions? will they still fix it?

If I remind him about it he probably still would. If a hub has failed I'm sure it's through no fault of his own. That is not the only converted triple-twin OS clutch he has done. I did mention it to him back when it happened and he said he had not heard from you. Anna confirmed this when I spoke to her also. I assumed you would have wanted to do something about it.

If you have it lying around, send it up to him and I'll see that he takes care of you. He would anyway but at least this way he will know someone isn't just stitching him up. Provide a story with the clutch and a timeline of events also.

The R3C is not intended to be used for putting around the workshop.

The first thing you will notice after getting car back from workshop, at any stage of the R3C life ie old/new, where the car has been shuffling in/out of the workshop, will be instant on and off. This is worst if the mechanic doesn't know how to use the clutch.

It is designed for race condition. Once you have a bit more heat into the clutch it will be easier to drive.

The best way to relieve your current problem to do a few high rpm launches :(

That's what the clutch is designed for.

I have a r3c.. i find it ok, it is rather on and off like you've noticed but you get used to it after a little bit. as 9k said.. get some heat into it, as i do find after a bit of a drive it gets better.

since the cars been out of action i have been at the gym working on that left leg to keep it in shape :/

Thanks for the input guys, for now ill put the old twin plate back in, and keep the R3C for when I sell the beast, in case the new owner wants to take it to the strip/track.

However if anyone wants a brand new condition R3C let me know :(

Key thing with any OS Giken clutch is to make sure you have the right movement kit or bearing carrier for the clutch. A lot of people who have trouble with drivability are not using the right length carrier. Too long and the clutch may not engage properly, causing slip. Too short and the clutch will release very close to the floor, making it very jumpy. Also just generally having the wrong length (wrong by +/- 2mm or more) will have the fork on the wrong angle, so it takes more pedal effort and the take-up seems more sudden.

Hi all,

Installed a brand new OS R3C clutch with OS fitting kit into the GTR, and the clutch is LITERALLY on/off.

Is there any adjustments that can be made to make this clutch at least a tiny bit drivable?

I realise that this is a solid centre clutch, but is it supposed to be next to impossible to take of without stalling?

thanks for any help!

ive used a few over the years but have reverted back to using twins, as most want to drive in traffic traffic.

The ORC twins drive like stock and have a light pedal but the tripples are too agressive for a daily in peak hour traffic IMO. I lived with one in a supra for a year before i retrofitted a twin and never looked back, car was only making mid 400's though so it was not really stressing the twin.

what sort of power you making?

Edited by URAS

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