R33 Brembos

[Luke_ENR34]

Im going pedal box so i'll choose my own masters for the calipers i have.

Pretty sure its something to do with vacume. Theres only a few bolts holding them on so see if you can borrow one off a GTR to see if it does anything.

[Jap_star]

well its not like Lukes car is going anywhere in a hurry. may have a good look

[BOZ22N]

Luke, what does this thing do? You said it's a separator, so it separates vacuum? air? from what?

And I don't think it would feel any less spongy with this thing on.

Boz22n, what diameter BMC did you end up using? What bias adjuster? Ever had any troubles with adjustment range being insufficient, i.e. too much/not enough front/rear bias?

I think it is a 1"1/16 ? the bias is great the prob with the GTR master is the proportion is out for a GTST F/R weights etc.

[Legionnaire]

So BMC is equal in size to GTR's - 17/16".

Thanks for info!

[Jap_star]

Bm57 didnt change it one single bit

The thing on the left is the thing i didnt have which i think may fix it if i did keep them.

IT WORKS!!!!!!!!!!!

borrowed this off a mates 33gtr today and plugged into my stock BM40. with the lines it comes with as you still need the one way valve , pedal feel was fantastic, a huge improvement, even with stock master

now too get my own

[Tony de Wonderful]

I think it is a 1"1/16 ? the bias is great the prob with the GTR master is the proportion is out for a GTST F/R weights etc.

How does the size of the master cylinder effect bias?

[Legionnaire]

It doesn't. But I think he meant proportioning valve that is built into master cyliner on GTRs, has wrong bias for weight distibution of a RWD skyline. 

Patrol has no integrated bias adjuster in its BMC, so external adjuster is necessary.

I found this "vacuum can" in FAST. It's called "tank-assembly vacuum" in there and has a partnumber 47110-24U01. Must be inexpensive, so if it really improves pedal feel, it may be worth spending a couple of $ on.

[Jap_star]

Have sourced one. $30

[Tony de Wonderful]

Looking at the manual it doesn't show a proportioning valve on the GTR master cylinder just on the GTST/GTS ones.

[Legionnaire]

You can see it in the  pic in one of earlier posts it this thread.

I've highlighted the valve part on BMC body.

[Tony de Wonderful]

You can see it in the pic in one of earlier posts it this thread.

I've highlighted the valve part on BMC body.

Ah ok so it's integrated rather than the GTST one which screws in?

[KiwiRS4T]

How does the size of the master cylinder effect bias?

Only guessing here but I would say the diameter has nothing to do with it but if you pull one apart you will see there are two pistons inside and i would guess its the relative travel of those pistons and perhaps the size of the apertures that makes the difference. My car is not quite running yet but I don't expect any problems in my heavy Stagea. Relative size of brakes also makes a difference - whether you are just putting big brakes on the front and by how much you are beefing up the rears.

[Legionnaire]

Ah ok so it's integrated rather than the GTST one which screws in?

It is integrated  in that the BMC body is cast with provision for the integrated prop valve. But the valve internals themselves are then screwed in. Attached are pics of disassembled BM44 prop valve.

BMCs with no integrated valve, like on Patrol and Pathfinder have no valve body cast with them, as seen on the third attached pic.

Actually, I would suppose that other than piston diameter and bias-controlling spring GTR BMC is identical to GTST and GTS BMC.

i would guess its the relative travel of those pistons and perhaps the size of the apertures that makes the difference

Since on tandem master cylinders like ours both pistons are attached to the same rod and has same travel for a given pedal input, I'd say it is only piston size that may be different