R32 Gtr Brake Upgrade Advice

[MYRB30]

I'm still trying to source the control arm air deflectors

Once I've worn everything out, and if my improvements are not enough, I'll invest further in larger rotors / dog bones / new calipers etc by which time I'll be too old for this and sell my GTR for half of what I spent on it.....

p.s. is anyone still interested in this sh*t?

Hell yes, I'm hunting around for a brake upgrade for my Zilla now. I'm currently doing the whole tie rod and rack end thing on her so I can put my Enkei's on (17x9) with out screwing them on the inside. Once they're on I want to put larger rotors on. I wanna keep the GTR calipers (sounds like they are a good caliper), just fill the rim a bit more, and really, these brakes were designed in the 80's. 16 inch was a big rim then.

What I would like to know is:

a: Has anyone changed their brake bias/proportioning valve to suit the greater leverage from the larger rotor? If not, do the front brakes wear quicker?

b: Has anyone looked at changing the rear rotors?

Thanks for everyones words so far

[MYRB30]

Will 343mm rotors fit in a 17 inch rim?

Also do the r33 brembo GTR rotor fit an R32, Is the hand brake part the same between them?

[MYRB30]

Sorry bout post above, I meant to ask do the rear r33 gtr rotors suit the r32 gtr, as in are the handbrake drum sections of the rotors the same?

[Roy]

The hand brake assembly of the R32 GTSt and R32 GTR rotor is the same as the R33 GTR. The brackets for lines and calipers need a little tweak for the caliper, and bolt pitch is different...but hand brake is the same or at least within the range of factory adjustment for normal use

[Rowdyr32]

If your mechanic said not to cut the backing plates off due to air flow around the disk I wouldn't take anything he says seriously. All the backing plates are there for is to stop dust and stones and water. Performance cars in the 70's would cut the backing plates off so if the mechanic doesn't know don't listen to him about brakes and would question his knowledge about performance cars. Cutting the plates off expecially the rears as rear rotors crack, is the cheapest brake mod you can do. As for castor rod ducts I just got some cardboard and tape. Bent it all up and made sure it cleared everything then wrapped it in foil to turn it into a mould and fibreglassed over it. Attach it with hose clamps and your done. Same could be done with some 1.6mm aluminium and a few hours. Might cost you $30. I've seen some of the so called caster rod deflectors and there 50mm high and 100mm long and would most likely do f/a for the price.

As for semis the benifit on the street wouldn't be worth it. Spend the money on suspension. My car is maybe 1 or 2 seconds slower on the track on streets but my tyres last 5 time longer and there cheaper. If you are driving to the limit of semis on the steet you'll end up around a tree eventually. My guess is you won't even be pushing the semis to the limit so streets would do atm. A fair few guys at the track don't even push the semis to the limits. They only have them because everybody else does! Do you really need them???

It is easy reading the forums to think you need big and fast everything but really a nice street/track setup isn't that expensive or hard to achieve if you do it right with a gtr as their such a good platform and you already have 300rwkw.

[MYRB30]

Thanks Roy!

With my r32 GTR I intend to fit the 33 gtr front rotors and use the caliper brackets to suit.

Is it worth fitting the 33 gtr rear rotors and doing the same with the caliper?

[Roy]

It would be an absolutre head fark to try and make an adaptor to space out the rear std caliper. Lots of grindign woudl be involved

[Ronin 09]

It would be an absolutre head fark to try and make an adaptor to space out the rear std caliper. Lots of grindign woudl be involved

yeah don't do that it's painful...

[LotusGTR]

Well I went to Phillip Island on Friday and had a ball but the brakes were shite. Set up was:

Brake booster brace

Castrol SRF

Braided lines

RDA slotted rotors

QFM K750 pads

As soon as they got hot, they vibrated to buggery, so I had to drive slow for the day (2.01). Rotors are not warped as when they were cool they were fine. Someone came up with the idea that the pads were depositing on the rotors when they were hot???? causing them to vibrate? Wheels are balanced, all suspension and brakes bolted up how they should be. Small play in upper control arms.

When I say hot, we all know how relatively easy PI is on brakes, and really I never stomped on them as I just couldn't. Only really stood on them a bit at Honda, but even then it was far from full pedal.

Fastest on day was a R33 GTR running massive Alcons which I now envy......Very frustrating not being able to use the brakes to their full extent. I switched out the fronts and went slow and sideways, though, so all was not lost.

p.s. Rowdy, how could you advocate street tyres for the track. They're totally inadequate.

[LotusGTR]

Another thought, I still have some DS2500 pads and I'd be interested to see how these perform and whether it addresses the vibration problem. I won't be able to replicate the problem on the street so need some easy to get to / affordable track time to check out the new pads. Calder / Sandown? Any thoughts on how to most easily get some track time?

p.s. Winton = too far at the moment.

[luke james]

Bought DBA 4000 series slotted rotors front and rear with lucus pads .....pads were $75 front and $75 rear $946 all up for rotors and pads they are rated to 650 degrees are easy on the rotors and ill get 15 laps at mallala in a r32 GTR that runs low 11's down the 1/4 mile and mallala is very harsh on brakes these brakes are awsome could not fault them best up grade I have done hope this helps....

PS: still got stock lines brake lines and no special brake fluid yet so brakes should only get better....

posted this in another section on braking good luck....

[LotusGTR]

Right. So on a track that is hard on brakes, with slightly less invested than my set up, you've had good results. Others seem to be saying they've had great results with a slightly modified std set up too, so perhaps I need to persist.

Thanks for your input.

[luke james]

Right. So on a track that is hard on brakes, with slightly less invested than my set up, you've had good results. Others seem to be saying they've had great results with a slightly modified std set up too, so perhaps I need to persist.

Thanks for your input.

Yeh brakes are awsome id say better than good results and I still have to put braded lines and better brake fluid and they can oly get better this is a fast gtr so they have been put to the test (brakes that is)

[phunky_monkey]

Did you bed the brakes in properly?

[luke james]

Did you bed the brakes in properly?

???????Is this a question for me?

[LotusGTR]

Did you bed the brakes in properly?

I think this may be for me? The answer is I think so. 8 hardish stops from 120 - 60, then drove normally on them for 500kms before getting them on the track. How does that sound? Let's assume this is not adeque running in, what now in your opinion?

[Roy]

Personally, you need to do stops from about 140km/h down to about 20km/h. Really get the heat into the pads and rotor and deposit that pad onto the rotor. Problem is 140km/h is speeding, so the idea of sayign Winton is too far ? Well the Winton track days are the ones where i try to line up a pad change as the drive up there is the perfect opportunity to do a crazy amount of stops from 110km/h to basically the speed where i can grab 1st gear again( 10-15km/h). Then cruise for 20mins and let he brakes cool down again, then jump on the bastards a few times more. Fact that you leave Melb at 5am means you get a pretty good run with traffic and can be left alone to do bed the pads. You cant do it on the drive to PI, Sandown etc. So you end uyp sacrificing your first session just bedding brakes.

[luke james]

you can even bed in at 80-100 km and hit the skids do this about 10 or some time youll be right good luck with the brakes ....

[LotusGTR]

Well, this saga is likely to end with me buying some tasty and expensive as all get out AP calipers and all the associated bits'n'pieces. I'm sick of rooting around with this so this is the 'final solution'.

My likely set up will be 356mm fronts and I have a choice of 343 or 356 for the rear. The vendor tells me that they have a brake testing rig and on some track Commers they find that contrary to their expected theory, having 'larger than wisdom would suggest' rears gives an overall better balance under hard braking. Hence the 356 option on the rear. He's not trying to up sell as he aint that kind of guy. My query is that perhaps the weight distribution on the Commer is quite different to the old GTR and therefore these results aren't 100% applicable. I'm guessing the GTR is more nose heavy?

Any thoughts on this final choice for me?

[Roy]

Personally, i think get the fronts and then play a game of wait and see. To improve stopping distances tyres and suspension are perhaps more important then the actual brake hardware.

Since you are doing some track work and street driving i think AP 4 pot rears with big rotors is a premature. See how the std rears go with sme good pads and then make the tough decision.

Personally i think the weight distribution, suspension geometry, vehicle weight and CoG is all significantly different between the Commodore and R32 so wouldnt guess that what works for one will work for the other.

What wheels have you sussed? Before paying for the APs touch base with me...i may have a far cheaper and equally good solution