14 replies to this topic

[micky_vr4]

So, looking at doing a bit of a brake upgrade at some point for the VR4: 4 pot calipers and bigger rotors...

I'm in no immediate hurry to complete this stage of the project but found some R32 GTST Skyline 4-pot Sumitomo calipers (similar to those on a 3000GT) really cheap and that got me questioning whether they provide a viable option for the old faithful VR4 (fabricate some caliper adapters, find disks with the right hat height/disk thickness and redrill to suit)?

Has anyone else even remotely thought about this or is it a completely crazy notion?

Cheers,
Mike.

Edited by micky_vr4, 15 April 2013 - 01:40 PM.

[evo-gsr]

Easier to just buy the kit on ebay for the galant and your done.

[Velocity Racing]

there are gravel rally Evo 3's that run with Nissan 300zx turbo 4 spots, which are not that different to the R32 brakes. They fit under 15" wheels, hence the reason to go down that path. But if rim size doesnt matter there are probbaly easier bolt on soulitions as per above

[micky_vr4]

Yeah I would like to just chuck on at kit and be done with it but when the option is there to get a set of fronts for under $100, it's pretty tempting to give it a try...I'm also looking at having them fit under 15" and 16" wheels, so the smaller size is important.

[jack be nimble]

You need to check piston surface area is similar to what is standard or you may have less brakes than you had

[micky_vr4]

I believe that the 3000gt calipers and r32 calipers are basically the same model from Sumitomo, just with different mounting points...not sure on this though

[micky_vr4]

Ok, just had a look at the different total piston surface areas for calipers from the following: stock e39a vr4 , 3000gt calipers and r32 gtst.


Model Caliper piston (diam x qty) (mm) Total piston surface area (mm²)
2pot e39a 41.3 x 2 2679.29
4pot 3000gt 40.4 x 2 + 42.8 x 2 5441.24
4pot r32 gtst 40.4 x 4 5127.58

So, there isn't too much of a difference between the two sets of 4pots (~6% difference in total surface area), which indicates that the setups would act quite similar.

With the smaller total piston surface area of the r32 gtst calipers when compared to the 3000gt ones, I think you will get the system acting closer to the stock setup with less front bias (assuming similar rotor size to stock) and less reason to get a brake bias proportioning valve.

Still unsure of bolt hole spacing and suitable rotors though...

Also, if anyone has any corrections or experience with similar setups, pipe up now!!!

I'm after something which will provide good braking characteristics for hillclimb but also take a beating on the track without being quickly effected by heat soak.

Edited by micky_vr4, 16 April 2013 - 01:06 PM.

[jack be nimble]

Ok cool for looking into piston areas. Somene like dougmo will be able to give you insight as th the feel of these calipers, compared to stock. But as you say, they are quite similar to stock.

I assume these calipers will not bolt on and require adaptors. So that means a custom set up. You need to decide that you are going to do it and buy the calipers then sort it out.
I have wrx 4 spots and thats what I am building for.. simple. I will make them fit.

break the fitment down into steps.
Put the caliper inside the rim and measure what diameter discs are the maximum to fit. Also look at the required hat height for the caliper to clear your rims. Then download the brake disc catalogue and try to get some standard discs that will suit. buy the discs, bolt it all up. Then sort out your caliper mounting and design the brackets. I suggest 12mm plate as the vsb say that you need the caliper thread engagement to be at least equal to the bolt diameter...
Good luck

[JayRome]

R32-34, 300ZX, Some S14/15's & GTO 4pot Sumitomo Calipers, from doing research they all are the same minus the mounting.. They have the same brake pad part number (in most books)

you will have to upgrade (or if you have already) to the larger brake master cylinder, and while you are at it, might as well change all your brake lines to stainless..

Brake bias will also have to be looked at, or you will lock up under heavy braking..

3000GT/GTO have 2 different 4pots, they have the same calipers but 2 different brake disc's. From memory something like: 216mm and 314mm. Early models came with 16" wheels, later came with 17" wheels..

My front set up on VR4:

Edited by JayRome, 17 April 2013 - 11:34 AM.

[micky_vr4]

Brake bias will also have to be looked at, or you will lock up under heavy braking..

Jay, with your setup, how did you factor in the brake bias adjustment? Did you get an aftermarket bias adjuster or just stick with the stock setup, or did you upgrade the rears as well?

Like you Jay, I noticed in my research that Nissan's r32/z32/r33/r34/s14/s15 all had the same Sumitomo calipers with less total piston surface area than the 3000gt, whereas most of the gtr's (except for the brembo optioned ones) appeared to have almost exactly the same calipers (same piston surface area) as the 3000gt...interesting stuff...

[evo-gsr]

you will have to upgrade (or if you have already) to the larger brake master cylinder

Brake bias will also have to be looked at, or you will lock up under heavy braking..

I disagree.
I have these exact same brakes on my Evo (which is much lighter than the galant) and I have done neither of these things to mine and Ive never had lock up issues or lack of pedal issues.
And the rotor size is 296mm, which you were trying to recall.

[micky_vr4]

I disagree.
I have these exact same brakes on my Evo (which is much lighter than the galant) and I have done neither of these things to mine and Ive never had lock up issues or lack of pedal issues.

What are you using your car for? Is it a track, rally or street car?

I have the 1" master cylinder on all of my vr4's so that's a start.

[evo-gsr]

Street and the occasional track day here and there. I have a 1" master too..but have used this setup without it also and still had the same pedal feel etc.

So you dont " have to upgrade" it and in my case it made no noticable difference.

Edited by evo-gsr, 19 April 2013 - 07:49 AM.

[ce9aevo2]

on my evo 2 i used r33 calipers and redrilled r32 vspec-r33 gtr rotors (324mm)
with a custom bracket (i still have a pattern for it) works really well but will only fit under 17in wheels.

[JayRome]

I disagree.
I have these exact same brakes on my Evo (which is much lighter than the galant) and I have done neither of these things to mine and Ive never had lock up issues or lack of pedal issues.
And the rotor size is 296mm, which you were trying to recall.

Ah yes thats is 296mm for the smaller one, cheers for that..

Actually you are better off upgrading to the 1" master on the VR4's if the master had never been rebuilt/changed. Correct you dont have to, but its a good upgrade for either twin pot or 4 pot fronts. The 1" upgrade did change the feel on the pedal with a lot of the guys with VR4's, but i cant speak for the EVO/GSR platform..

Edit:

you can go another way and ask Bazz about his braking system on the AMG, uses larger twin pots from camaro with 330mm rotors..

Edited by JayRome, 19 April 2013 - 03:55 PM.