R32 GTR front brake disc size upgrade!!

[Ronin 09]

Right, have just come back from the land of GTR and picked up the GTR bible - has just about every tuning part for GTRs with pics

I have found a mod that I am considering, and it seems quite tasty indeed.

They are machined spacer plates to move the 32GTR standard calliper out radially, and the best part is that all you need are JZA80 (supra?!) discs at 324mm diameter.

This will obviously have to wait until I get some bigger wheels, but for 39,900 yen with discs (I think, can't read it), approx $550 aussie dollars, that's pretty good value... or have i interpreted it completely wrong?!

Anyone done this yet?

Seriously, this magazine was about 30 bucks but sure was worth it. Below is a scanned cover if you can get your hands on one too

Mag cover:

[Sydneykid]

A good idea in theory. Adds a bit more leverage to the braking. Will also add some more feel as the disk (being larger in diameter) travels further with each wheel revolution. So it will be easier to modulate for best retardation. The Nissan 4 spots are good callipers, so they are well worth keeping. Something I was considering for the R32GTST a bit later on. It will also "fill up" the space behind the wheel for the appearance conscious.

[Roy]

Yeh thats the same brake upgrade as i have on my GTST, though i have no idea if my rotors are std replacement R33 GTR, DBAs or perhaps even Supra?!?!?!?!

I was very happy with the upgrade...my brackets were made by Race Brakes in Sydney, but were more expensive then the kit your looking at:( What is it they say about hindsight.

I imagine the larger rotor also helps dissipate the heat better. Rather then get the single piece Supra rotors, i reckon the kick ass setup would be some DBA5000s, or get soem 2nd hats from Japan, even if the rotors are shagged, and ill PM you a place to try for rotors that are very good prices. Something else to consider

Perhaps an idea whilst the brakes are all apart...i had a torn boot on one of my piston calipers. So they are currently off getting HPC coated, and im also getting the caliper pistons HPC coated to try and minimise the heat transfer from the caliper/pistons to the fluid. Probably a waste of time:) But its cheap so why not, and also improves appearance and on paper may have some merit. Then im getting another new seal kit put in them, so should be like new for the WRX day:)

You can see the difference in rotor size in these pics...pissy std rotors:(

And big and shiny new rotors:)

[lwells]

Is there any issue with brake balance when simply increasing the rotor size?

Cheers,

Lucien.

[Roy]

I did notice that heavy braking on cold brakes tyres my car has a tendency to lock rears:( But that goes once you get some temp into them...i have always suspected its a pad combination problem more then rotor thing.

[RichyR32GTR]

Just wanted to say, nice car mate!!!

Cheers

[RichyR32GTR]

Just wanted to say, nice car mate!! You got taste!

Cheers

[Duncan]

roy, your car looks hot.

on fire hot.

lwells, you have abs on the gtr, so you wont be locking brakes....they may hit the ABS earlier though.

I upgraded mine to the n1 brembos front only, and the other car has the porsche 6 pots but we don't have noticable trouble with bias

[Roy]

Just wanted to say, nice car mate!! You got taste!

Cheers

If only my GTST would grow up and one day become a silver GTR:)

And Duncan, Clader must be my lucky place...went drag racing with no probs, and went to a WRX sprint there the other day with no fire:) New bonnet on way then no one ever be the wiser;)

As for brake bias, unless your thing has std supsension with R-compund tyres...i think you will be fine.

Std susp with sticky tyres might see the car do hand stands and unload the rear tyres..in which case it is more a braking / tyre improvement that needs to be addressed with chassis/suspension upgrade-tuning rather then adjusting brake bias.

Keeping in mind the more grip you have at the front under brakes, the more weight transfer so the less tge rears need to do...so i think it becomes as much a suspension thing as bias

[yogi000]

hey guys,

sorry to dig up an old thread, but i wanna put 296mm discs on my r32gtst type m, so i would need a spacer plate to use my orginal calipers with the dba 296mm slotted rotor from either a r33 gtst or r32 gtr (DBA4963 or DBA4926), how much do these plates cost? and does race brakes keep em in stock or does it have to be custom made???

I'm trying to get fit all this in a r33 16" stock rim, which should work since the r33 came out with 296mm discs. Correct me if i'm wrong

Cheers

George

[Roy]

Sell your brake calipers to an S13/R31 owner and just buy R33 GTST or R32 GTR calipers as that way they will be all bolt on and save the agro of using an offset bracket

[Chunners]

Hey Ronin 09

I have global 324mm rotors on my R32 GTR with standard callipers. They were already on the car when i imported it, had no problems at all with them. You are right you do need at least a 17" rim with the rotors.

Chunners

[yogi000]

will my brake lines need any modification to put r33 gtst or gtr calipers on ????

[Duncan]

nope should be fine thanks Nissan

[yogi000]

thanks duncan. Just jap quoted me $295 for a pair of r33 gtst calipers, what do u guys think?

[GTRgeoff]

Not a bad price but look for soome in the for sale section as it may work out cheaper to get them reco'ed. When they first started coming in they were asking $600 a pair.

[BoOsTeD_RB26]

I know this might put lots of people off, but I'm going to say it anyway.

After a quick phone call to Racebrakes in Melbourne, I was basically advised NOT to perform this mod as its basically, as he deems it, "a shitty and dodgey way of doing things," and to finish off, he basically refused to sell them to me. Each to their own I say.

I can't see how this is dodgey; so I've come to the conclusion that the guy I spoke to was a dickhead basically because he kept on trying to sell me an Alcon brake kit worth 4.8k.....No.

Does anyone know where I can source these adapters/spacers from (apart from UAS?) I just called them and the kit for the GTR has not yet been developed

Ronin 09: Are there any brand names or any details as to where we can source this kit?

[GTRgeoff]

Depends who it was. Howard is the only one there I will deal with, but he can be blunt, and is no dickhead. Also his preference is the AP Racing setup. At about $4K all up. Nice but a bit pricey.

I suggest taking a look for Roy's thread on this very mod and determining it's pros and cons, which it has a few of each. In fact it's in his sig above.

[Roy]

I can't see how this is dodgey; so I've come to the conclusion that the guy I spoke to was a dickhead basically because he kept on trying to sell me an Alcon brake kit worth 4.8k.....No.

 

Ok, Howard (Race Brakes Melb) is an absolute champion guy who knows brakes on cars. He has run a well respected shop for years in Melb, and has a good name for engineering great brake setups. So if something isnt 100% right, then he wont be involved, as its his reputation at stake. A good thing, as id rather wait and spend 4k then burn 2k.

But the upgrade we are talking here is a lot less then 2k. And the reason he would have said dont do it as we were only looking at my car with the same setup the other day....and it is a compromise, and not 100% right. And even before havign a close look at my car he wasnt a fan of the setup, incidentally done by another brake specialist:(

That said it is an improvement over the std GTST brakes, and i suspect an improvement over the R32 GTR setup. So whilst it isnt quite right, it is still a step in the right direction as far as improving stopping.

Despite Race Brakes never being big fans of this sort of setup, i stuck by my guns that the setup worked really well, which it did for 3 years.

December past i changed form my usual RB74 pads to harder / racier Comp 9 pads. At first they were great, but now that i have had a bit of pad wear im encountering a few problems with the harder pad.

Essentially the pad hangs just off the edge of the rotor by about 1mm. Not big deal, but the problem is that the caliper pistons surface area do not come in complete contact with the rotor face, but actually overhang a bit of the rotor.

This mean once the pad wears a little, that there is the possiblity that it will rock on the edge of the rotor when you apply the brake, and also cause a bit of pad knock off. So the result is a slightly soft pedal, and instead of the pad wearing/heating evenly accross its face, there is a heat concentration reducing stopping performance.

With the softer pad they seemed to readily taper with the rotor face still providing good performance. With the harder pads, they dont wear with a taper, they just bight into the pad and wear poorly.

So the fix may be to use an R32 GTR, R33 GTS25T, or R34 GTT caliper which come with larger rotors std then the GTST caliper. If i can get my hands on a set ill check.

But Howard sells the best solution to the questions you are asking, and he doesnt cut corners as that could hurt his reputation. And he would have been recommending AP, not Alcon calipers.

Depends on what you asked for...but at 4.8K im guessing the following:

343mm X 32 or 355 x 32mm vaned 2-pce rotors with custom hats to ensure the caliper clears the wheel etc without spacers etc, not cheaper DBA 5000s measuring 324 x 30mm.

You will be getting top quality braided lines, pads, radial mounts and 6-pot AP Calipers. Good quality gear costs money.

You can still get a good result using DBA5000s, some 2nd hand GTR Brembos and some lines and pads. It will be cheaper, but the brake performance wont be the same either. But people are asking the same money for 2nd Hand GTR Brembos as brand new 4 pot APs. Difference is the Brembos bolt on, the APs still need a radial moutn bracket.

A good alternative that will still give stella brake performance would be 330 x 32 rotors with AP 4 pots. You will still need the radial mounts, possibly new lines depending on what you currently have etc etc

Or just run DBA4000 heat treated rotors, std diam, run nice pads, good fluid, it depends what you want to be doing with the car.

[Roy]

I should also mention when i waffle on about brake performance im not talking about stopping distance.

I mean its abiltiy to run nice and cool and consistant, with good pedal feel and control. Running cooler allows you to run a lower temp pad saving rotor wear etc etc