R33 Gtst Brakes On R34 Gt

[NISMO.SKYLINE]

Hey guys,

I'm looking to increase the braking power on my R34 25GT Coupe which has the basic factory brakes all round at the moment. It also has factory standard smooth 280mm x 26mm rotors on the front and 297mm x 18mm on the rear.

I want to upgrade the front brakes to the bigger and stronger R33 GTS-T brakes. I can acquire the necessary calipers and rotors off ebay but i'm still not sure if it is a direct replacement. I have been told that it is not as simple as a bolt on upgrade and that you must also change the brake lines and brake master cylinder as well to compensate for 4 pistons instead of 2. I have also been told that it may screw up the ABS installed in the car.

Trust me, i have read around on many posts and forums but cannot seem to find a simple straight answer without conflicting posts.

The alternative is to simply replace my rotors with some new slotted ones and get new brake pads but i would still rather upgrade to the more powerful R33 GTS-T brakes.

Any help would be much appreciated,

Thanx

[GTSBoy]

R33 turbo brakes are only 296mm diameter. The R34 turbo brakes are 310mm diameter. Given that the caliper bolt sizes are different between the R33 and R34 brakes, you'd probably be better off aiming towards using the R34 brakes.

And yes, it would probably be a good idea to use the matching master cylinder, and yes, it is quite likely that you'll need the lines too. Any brake upgrade deserves the use of braided teflon lines anyway, so you're up for those regardless.

And it is quite possible that the short length of hard line that actually connects to the caliper is different between the two types of caliper, so you'd need to get those. But they can be bent up by any decent brake shop (from an example, or working direct on the car), so that's not a huge issue. The rest of the lines on the car should be fine. The connection to the master cylinder should be the same, or close enough. Why don't you go look at your master and measure the location of the brake lines relative to the firewall or other convenient landmark, and then go do the same on a turbo R34 as an exercise in doing this stuff for yourself?

[Hanaldo]

The 34 GT is somewhat of a mutt though, the 34 GTT brake stuff doesn't fit straight on. I've got 33 GTST calipers on mine, and from memory the GT uses a 12(I think) mm bolt same as the R33, whereas the GTT uses a 14(again from memory) mm bolt. So to fit the GTT stuff, you would need to drill out the holes. HOWEVER, I believe this even varies between early model GT's and late model GT's. Early models use the 12mm, late models use the 14mm.

In my case (1998, early model) the GTST calipers fit straight on. I went with HEL braided lines (for the sake of ~$100, why wouldn't you?) and upgraded the master cylinder at the same time as well. Definitely not hard. I would recommend just going and measuring your caliper bolt holes though.

[NISMO.SKYLINE]

The 34 GT is somewhat of a mutt though, the 34 GTT brake stuff doesn't fit straight on. I've got 33 GTST calipers on mine, and from memory the GT uses a 12(I think) mm bolt same as the R33, whereas the GTT uses a 14(again from memory) mm bolt. So to fit the GTT stuff, you would need to drill out the holes. HOWEVER, I believe this even varies between early model GT's and late model GT's. Early models use the 12mm, late models use the 14mm.

In my case (1998, early model) the GTST calipers fit straight on. I went with HEL braided lines (for the sake of ~$100, why wouldn't you?) and upgraded the master cylinder at the same time as well. Definitely not hard. I would recommend just going and measuring your caliper bolt holes though.

Yeah, i'm pretty sure using the R33 GTST stuff for my upgrade is the better way to go instead of the R34 GTT stuff. To many size differences with the R34 GTT and i would rather not drill new holes. Also, just to clarify, my 25GT Coupe is also a '98 model. Getting my hands on some R33 GTST calipers and rotors is easy enough off ebay but the brake lines and master cylinder is where it becomes difficult for me.

So Martin, where can i get the necessary brake lines and brake master cylinder for this upgrade because i have absolutely no idea. I'm in Melbourne if that helps. Also, when you upgraded your R34, did the ABS system give you any problems because i have been told that this upgrade can screw up the ABS in R34's.

Thanx for your help, really appreciate it.

Phillip