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Location:
Adelaide Street Racing ca...
Registered:
November 2004
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JZA80/R32 GTS brake conversion for A70's
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Sat, 09 July 2005 06:03
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Hi guys,
I dont know if anyone has seen it but in the current issue of Zoom mag they have a tech issue on how to fit JZA80 rotors and R32 GTS calipers to an A70.
They mount the rotors and calipers with a kit shown in the mag. The thing I want to know is: if you can fit R32 GTS calipers could you fit R32 GTS-T, R33 GTS-t or R32 GTR calipers as they are bigger?
In the magazine the pads/calipers dont use the full surface of the rotor (even tho 100% of their contact face is on the rotor) because they are too small. I was wondering if you used the bigger skyline brakes with the same kit would they
A)Fit using this kit and rotor set up
B)Use more of the face of the rotor
C)Provide superior braking perfomance
Thanks heaps
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Location:
Adelaide Street Racing ca...
Registered:
November 2004
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Re: JZA80/R32 GTS brake conversion for A70's
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Sun, 10 July 2005 08:45
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BUMP
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Location:
Brisbane
Registered:
June 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Sun, 10 July 2005 08:49
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why would you bother with "GTS" callipers? The stock ma70 ones would probly be better! Of course you could put GTR's etc on there. Ma70s have massive disc contact area for pads, meaning you could probly install a set of GTR's on stock ma70 discs. BUT... the only thing stopping you is that the ma70 rotors are only 22mm thick...which is why i suspect they have spec'd the bigger jza80 32mm thick rotor.
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Location:
Adelaide
Registered:
September 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 02:33
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Apart from the greater diameter and thickness, that is why.
The bigger thicker disc has much better heat dissipation etc. It would make a big difference
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Location:
Adelaide Street Racing ca...
Registered:
November 2004
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 08:13
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How could the standard ma70 brakes possibly be as good as the GTS skyline brakes? The skyline brakes are 4 piston calipers, the ma70's are single. The skyline brakes as bbaacchhyy says are also clamping down on the larger rotors further improving braking.
I can see your point however in that the GTS isn't exactly the best braked model in the range and if you were going to change brakes why not go better again?
My main question is: Will GTR brakes bolt up to the same brackets which make the R32 GTS brakes fit? Do they have the same mounting points etc? I just dont want to buy this kit and some GTR brakes only to find that they wont fit.....
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 09:04
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| RAWS wrote on Mon, 11 July 2005 18:13 |
How could the standard ma70 brakes possibly be as good as the GTS skyline brakes? The skyline brakes are 4 piston calipers, the ma70's are single.
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this is like the AE86 single vs RX7 4pots... which has more clamping force per line pressure? the AE86 single pots 
for single pot sliding caliper, take piston area, multiply by two. (equal and opposit reaction and all that)
for 4 pot fixed caliper, add area of each piston..
compare which has larger piston area.....
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Location:
Adelaide Street Racing ca...
Registered:
November 2004
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 09:37
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Yea but stopping isnt all about clamping pressure.
The reason race cars use 6-pots isn't because they have big clamping pressure or because they look cool (they do look really cool) but because they distribute this clamping pressure more evenly over the rotor with a larger pad face which in turn stops the car a lot quicker without neccesarily increasing clamping pressure at all.
They also generally have larger rotors which dissipate the heat better, keeping the bigger pads cooler which all leads to a massive improvment over shitty single piston brakes... 
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Location:
Brisbane
Registered:
June 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 10:00
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| RAWS wrote on Mon, 11 July 2005 18:13 |
How could the standard ma70 brakes possibly be as good as the GTS skyline brakes? The skyline brakes are 4 piston calipers, the ma70's are single. The skyline brakes as bbaacchhyy says are also clamping down on the larger rotors further improving braking.
I can see your point however in that the GTS isn't exactly the best braked model in the range and if you were going to change brakes why not go better again?
My main question is: Will GTR brakes bolt up to the same brackets which make the R32 GTS brakes fit? Do they have the same mounting points etc? I just dont want to buy this kit and some GTR brakes only to find that they wont fit.....
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GTS ARE NON TURBO MODELS AND DONT HAVE 4 POT CALLIPERS. THAT IS GTST.
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Location:
Brisbane
Registered:
June 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 10:02
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oh and to re-iterate what i said before, YES the ma70 discs are better than the 280mm r32 "GTS" ones. They are 6mm thinner, but are 20mm larger in diameter. Thickness has no comparison to diameter.
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Location:
Adelaide Street Racing ca...
Registered:
November 2004
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 11:41
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my apologies V8_MA61, the mag just said GTS calipers, they obviously meant GTS-T. I then carried this over calling them GTS calipers also not realising that GTS calipers aren't 4 piston. The ones in the kit are 4 piston.
About the rotors tho if u read the thread from the top I never said anything about the r32 rotors being better or considering fitting them to my supra. I said the R32 calipers on the JZA80 rotors were far better. The kit is to fit the MK4 rotors and run gts-t calipers. The mk4 rotors dwarf both the ma70 and r32 rotors in both thickness and diameter.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 12:00
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| RAWS wrote on Mon, 11 July 2005 19:37 |
Yea but stopping isnt all about clamping pressure.
The reason race cars use 6-pots isn't because they have big clamping pressure or because they look cool (they do look really cool) but because they distribute this clamping pressure more evenly over the rotor with a larger pad face which in turn stops the car a lot quicker without neccesarily increasing clamping pressure at all.
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i thought it was for more even force distribution to promote even wear, prevent the pad from moving around in the caliper as much (ie not twisting), and reduce caliper distortion... meh same same 
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Location:
Adelaide
Registered:
September 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 12:25
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In the end, as long as the brakes work, who cares.
But a point to note (as pointed out by Stewart) 4/6/8 potters are not necessarily better than even a single piston caliper.
Look at a BMW M5, that has twin piston calipers, and no-one has EVER complained about the brakes on that.
In the end, it is a function of disc diameter, mas, thickness, disc material, pad material, operating conditions, booster size, pad size, caliper stiffness, suspension geometry etc, etc, etc.
So, at the end of the day, if you cab lock your brakes in the dry, they are powerful enough, but will they suffice over a long period at that level of abuse ?
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Location:
Canberra
Registered:
September 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Mon, 11 July 2005 22:26
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Anyone have any ideas how we can contact the guy in ZOOM that is making the caliper mounting kit ? They mention a place and contact number in zoom but the guy making the kits has left the company and the Mobile they supplied has been out of service foe weeks ?
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Location:
Adelaide
Registered:
September 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Tue, 12 July 2005 03:33
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| 1200det wrote on Tue, 12 July 2005 07:56 |
Anyone have any ideas how we can contact the guy in ZOOM that is making the caliper mounting kit ? They mention a place and contact number in zoom but the guy making the kits has left the company and the Mobile they supplied has been out of service foe weeks ?
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Wasn't snail on this forum coming up with a similar/same kit a while back ?
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Location:
Brisbane
Registered:
June 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Tue, 12 July 2005 06:12
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obviously the more pistons in the calliper the better its braking response though. Its gonna take a lot less time for 4 small pistons to move than it is for one big one.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: JZA80/R32 GTS brake conversion for A70's
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Tue, 12 July 2005 06:34
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| V8_MA61 wrote on Tue, 12 July 2005 16:12 |
obviously the more pistons in the calliper the better its braking response though. Its gonna take a lot less time for 4 small pistons to move than it is for one big one.
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if they have the same cross-sectional area (per side of caliper of course), the same amount of fluid will produce exactly the same result in terms of piston movement and force applied
Edit: this is cos when the single piston has the same area as one side of the 4 pot caliper, the same volume of fluid produces same extension.... but with 4 pot, you have to double the amount of fluid as you have to take up pad knock on both sides of the non-floating caliper. but on a sliding caliper, only one side moves, but it has to take up the pad knockback from both sides, so it DOES move twice as far, but the total piston movement of each caliper, and the amount of fluid required to displace the pistons is EXACTLY the same....
so for equivalently sized 4 pot and single pot, the only difference should be the eveness of force application...
But, with a 4 pot, you also have more piston circumferential area = more friction from piston seals etc.... is this good or bad?
[Updated on: Tue, 12 July 2005 06:47]
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Location:
Brisbane
Registered:
May 2002
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Re: JZA80/R32 GTS brake conversion for A70's
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Tue, 12 July 2005 23:26
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| oldcorollas wrote on Tue, 12 July 2005 16:34 |
so for equivalently sized 4 pot and single pot, the only difference should be the eveness of force application...
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Don't forget the 4-pot caliper is likely to be bigger and have more mass, which means it will dissipate heat quicker and be a better heatsink. Both of these things are good to prevent your brake fluid from boiling (which is BAD).
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