R32 Gtr Vs R34 Gtr Brakes

[tacker]

I have been offered a set of R34 brembos and disc's.

i am wondering if that would be a step up from the slotted R32 disc's (new) and standard calipers?

[Roy]

R34 Calipers are better then the R32 GTR calipers. The rotors are bigger as well, 296mm for the R32 and 324mm for the R34. (Though the std R32 GTR rotor is 32mm thik compared to teh R34 which is only 30mm...though just about every replacement R32 rotor i have seen is only 30mm ...so)

If you can its better to get the R33 GTR caliper and rotor as its a vbolt on affair. The R34 GTR calipers use bigger bolts to mount to the hub, so if you are going to use them on your R32 then you will need to drill out the hub to suit the larger diameter bolt. Not a big deal, but somehting to keep in mind...and be very careful when doing it to make sure the re-drilled holes are true

[ezi09s]

as he mentioned. the 33gtst and 32gtr brakes are the same, as is the bolt pattern for 33gtr 32gtst etc...

33gtr much easier option.... depending on how cheap your getting the 34 brakes for of course.....

[adznight]

R34 Calipers are better then the R32 GTR calipers. The rotors are bigger as well, 296mm for the R32 and 324mm for the R34. (Though the std R32 GTR rotor is 32mm thik compared to teh R34 which is only 30mm...though just about every replacement R32 rotor i have seen is only 30mm ...so)

If you can its better to get the R33 GTR caliper and rotor as its a vbolt on affair. The R34 GTR calipers use bigger bolts to mount to the hub, so if you are going to use them on your R32 then you will need to drill out the hub to suit the larger diameter bolt. Not a big deal, but somehting to keep in mind...and be very careful when doing it to make sure the re-drilled holes are true

What he said

[tacker]

They have been offered for free.

I dont think it would be a big issue to drill and tap the mounting points.

Are they better brakes i can alway get new slotted discs to suit the r 34 calipers.

Edited June 28, 2006 by tacker

[Roy]

The rotors are the same between R33 abd R34 GTRs. 324mm x 30mm thk. If he is giving you the rotors for free its not a big job to get slots machined in them.

Oh, and you dont need to tap the hub, just drill it out. The high tensile bolt comes from behind the hub and screwsa into the caliper, so the thread is in the caliper, not the hub. SO only have to worry about it being concentric with the original hole

[tacker]

Cheers Roy,

your coments are very well received i think i will take him up on the offer.

Regards

[BHDave]

It's not a particularly difficult job to drill them out. I just bought a new 18mm (i think) drill bit and drilled them on the car to fit some r34 gtt calipers to my 32 gtst.

I didn't realise the 34 gtr also used the larger mounting holes.

[tacker]

By the sound of it the hardest part will be to find a 18mm drill here in Dubai.

my kingdom for a decent auto and hardware shops

[tacker]

Ok brembo's are now off the radar. I have made contact with a company call precision brakes in the states and they are willing to build a 14 or 15 inch 2 piece rotor to suit the R32 GTR.

My question is if i have a mounting bracket cut on the water jet would the standard caliper do the job. From what i can tell from reading as many threads as possible is that is not the pressure of the stanard caliper which is a problem as the standard brakes work fine for the first half of a 20 minute track session. It is in fact the heat retension that causes the brakes to fade.

If i give the calipers more rotor to work with and more mechanical leverage plus project Mu level 900 brake pads would this help with disapating the heat build up and therefore reduce the time it takes for the fad to occur.

[djr81]

If i give the calipers more rotor to work with and more mechanical leverage plus project Mu level 900 brake pads would this help with disapating the heat build up and therefore reduce the time it takes for the fad to occur.

Yes, but not for the reasons you think. Assuming you are not braking any harder than before then the amount of heat going into the rotors will be the same as before. Remember when braking the kinetic energy (equals half mass times the square of velocity) of your car is bing converted into heat which goes into your rotors. The difference is that a larger (effectively a heavier rotor) can "store" more energy at the same temperature as the smaller rotor. So you should see the rotor temperatures reduce. This is not a function of the mechanical leverage of the system, however.

Best bet is to put effort into cooling ducting as this will help you dump the heat.

As for 900 degree pads, well have a think about the temperature beyond which your cast iron rotor will start to really suffer. No point having (for example) pads that work to 1000 degrees c when the rotors turn to shit at 700 degrees....

[tacker]

DJR,

could not agree more with what you say!

What i should have said was are the calipers up to the task of increased mechanical leverage applied by the larger rotors.

And as you say the larger rotor can store more energy but it can also effectively remove heat efficently due to the larger surface area.

I have run some ducting to the front discs and it seems to pass more air then i thought it would. I tested it with an electric fan and it was surprising how much air was passing through the rotor.

But your right i hope to never get near 900 o C but i am told these pads work great from 500 through to 700. i will check with the infra red temp gun first chance i get as to how hot they are getting on the next practice day.

[djr81]

Couple things:

The clamping force applied by the calliper will not change regardless of the size of the rotor you put on the car. It only changes depending on how hard you put your foot on the middle pedal. The tangential (lateral, radial, call it what you will) is a function of the clamping force and the brake pads friction coefficient. Nothing else. The braking torque going into the hub via the rotor is affected by the rotor size, but this isn't a concern because at the end of the day the hub is stronger (much) than the forces generated in any amount of late braking.

Your infra red pyrometer (thermometer) won't work on your shiney brake rotors. These things work on the emissivity of the object being measured & need a matt black object. So you can measure tyre temps, tarmac temps, but not the temp of anything shiney. You will have to relay on old fashioned temperature paint. It doesn't matter in any case, because the temps of the rotors on the track matter, not after you have done a cool down lap tend not to matter.