R32 GTR clutch master cylinder adapters

[weikleenget]

Hi again all, I’ve tried doing some searching on the topic but couldn’t find the answer I’m looking for.

 

I deleted my clutch booster because it had an air leak and was squealing like a hog, and now my clutch has very poor pedal feel and the friction zone is way too small, so I believe I need a bigger diameter clutch master cylinder to compensate for not using the booster. I found a Wilwood option that’s 3/4” for a good price and will fit my 3AN clutch line, but all the firewall adapters I see online such as RB factory or Chase Bays are listed as RWD only (GTST/GTS). Link below.

https://rbfactory.shop/products/nissan-to-wilwood-girling-clutch-master-cylinder-adapter

My question is if these adapters will also fit a GTR, and if anyone has experience using a 3/4” CMC without the booster, my clutch is a Nismo coppermix twin plate.

 

Thanks, always appreciate the advice!

Edited Wednesday at 10:31 PM by weikleenget

[GTSBoy]

I've not looked at a GTR without the booster there. Is the hole and mount on the firewall not just the same as GTSt? I would have expected it to be. Nissan don't change panel stampings if they don't have to, and you'd think they'd just order/design the booster to mount to the same place.

[Duncan]

Yeah 4wd (boosted) has a recess in the firewall for the booster, and 2wd is flat - the example in the link shows the flat surface.

When you deleted the booster, did you just attach the factory slave cylinder directly to the recess in the firewall with no adaption?

 

[weikleenget]

51 minutes ago, Duncan said:

Yeah 4wd (boosted) has a recess in the firewall for the booster, and 2wd is flat - the example in the link shows the flat surface.

When you deleted the booster, did you just attach the factory slave cylinder directly to the recess in the firewall with no adaption?

 

We just disconnected the vacuum line if I remember correctly, booster is still there. Is there a rebuild solution for the booster or a different adapter that will work for GTR chassis?

[r32-25t]

There are adaptors that allow you to delete the booster and use an s15 clutch master cylinder. 
 

if you want to keep the booster they are still available brand new 

[GTSBoy]

And boosters can be rebuilt by the same sort of brake shops that will rebuild a brake booster.

[weikleenget]

12 hours ago, r32-25t said:

There are adaptors that allow you to delete the booster and use an s15 clutch master cylinder. 
 

if you want to keep the booster they are still available brand new 

I saw the s15 version but will it be enough force for my clutch? I guess just repairing the booster is the best option 

[GTSBoy]

5 hours ago, weikleenget said:

I saw the s15 version but will it be enough force for my clutch? I guess just repairing the booster is the best option 

Dude - we all run massive clutches on the original non-GTR master on everything other than a GTR.... The boost was never required.

[weikleenget]

4 minutes ago, GTSBoy said:

Dude - we all run massive clutches on the original non-GTR master on everything other than a GTR.... The boost was never required.

Is the problem that we just disconnected the line, does it need to be plugged? I’d rather not buy another master cylinder

[GTSBoy]

No, you don't want to plug the vacuum line, as that will turn that side of the booster into an air spring and probably make it feel worse.

I'm not saying that the GTR master itself doesn't need a booster. I haven't paid attention to the GTR one to know what size it is cf the non-GTR ones. But when you think about it - they have to do the same job, which is to move a little slave piston a few mm to do what it is supposed to do, and that final action is the same on all the cars. So, it is very unlikely that the GTR MC is any different than the others, because it has the same pedal stroke and the same output requirement. The booster just makes it feel easier.

I'd suggest you probably have an actual hydraulic problem. It's totally common on these old shitboxes.

[r32-25t]

6 hours ago, weikleenget said:

I saw the s15 version but will it be enough force for my clutch? I guess just repairing the booster is the best option 

I’ve got one on mine and it’s fine, 

[weikleenget]

2 hours ago, GTSBoy said:

No, you don't want to plug the vacuum line, as that will turn that side of the booster into an air spring and probably make it feel worse.

I'm not saying that the GTR master itself doesn't need a booster. I haven't paid attention to the GTR one to know what size it is cf the non-GTR ones. But when you think about it - they have to do the same job, which is to move a little slave piston a few mm to do what it is supposed to do, and that final action is the same on all the cars. So, it is very unlikely that the GTR MC is any different than the others, because it has the same pedal stroke and the same output requirement. The booster just makes it feel easier.

I'd suggest you probably have an actual hydraulic problem. It's totally common on these old shitboxes.

What could be causing my clutch problem besides a bad master or slave then? Both those parts are new