My $600 Big Brake Kit

[The Slow One]

I noticed for the brake lines you have to pick between the S13 and S14, which one did you go with?

[mike the snake]

So, since this brake swap is regarding the 300zx calipers which are the same as the WRX calipers, are you saying that doing this swap will not be good?

If this swap does shift the bias rearward, would also going with the WRX rears fix this?

What about running the 300zx calipers with some grippier pads compared to the rear?

Originally Posted by Dave-ROR

The WRX 4 pots suck. Not saying these are comparable but the WRX setup shifts bias towards the back.

You may have meant the STI full setup though

[dem00n]

The Z32 brakes were good...better than the Z31.

But seriously?

Alright...should be interesting to watch this unfold.

[mike the snake]

Please, speak up.

I'd like to know everything I can before I jump on this. If there's no real improvement over stock with fluid/pads/SS lines I'd like to know.

Originally Posted by dem00n

The Z32 brakes were good...better than the Z31.

But seriously?

Alright...should be interesting to watch this unfold.

[dem00n]

Originally Posted by mike the snake

Please, speak up.

I'd like to know everything I can before I jump on this. If there's no real improvement over stock with fluid/pads/SS lines I'd like to know.

I'm no expert on the Z32 brakes since i own a Z31. I do know that at one point they changed the brake calipers from aluminum to iron due to heating issues.

But these brakes were engineered 20 years ago, more so 25 years ago. In turth, they are somewhat similar to the Z31 design (front only), in fact it's a common mod to change the front brakes of a Z31 to that of a Z32.

If you guys wanna run brakes from a grand touring car, go ahead. They are meant for a 3100 lb+ grand tourer, so perhaps they are more powerful then our stock brakes. But how will our master cylinder react? I don't know...and personally wouldn't wanna risk it.

[eikond]

Originally Posted by The Slow One

I noticed for the brake lines you have to pick between the S13 and S14, which one did you go with?

I got the S14 lines. Good question and thanks for bringing that up.

[Dave-ROR]

Originally Posted by mike the snake

So, since this brake swap is regarding the 300zx calipers which are the same as the WRX calipers, are you saying that doing this swap will not be good?

If this swap does shift the bias rearward, would also going with the WRX rears fix this?

What about running the 300zx calipers with some grippier pads compared to the rear?

Are they the same piston sizes? If so, why are adapters made for them to fit a WRX (honest question, doesn't make much sense if they are the same as the WRX ones)? The WRX four pots have less piston area than our OEM calipers, so given the same rear setup (we have LGT rears stock which are bigger than the WRX rears), brake bias will move further back.


If these are the same as WRX, then why run them at all? I'd rather run LGT sliders up front with the LGT rotors instead. The only benefit you'd get is brake feel out of fixed calipers.


I went from curious to maybe against this setup if the piston sizes really are WRX 4 pot sized.


Also, what problem are you trying to fix? If it's heatsink related that's one thing, but this won't increase stopping force. Bias issues are slightly less important now with these too smart ABS systems but too much brake torque on one end can still be an issue, especially if you progress to driving without ABS...

[Dave-ROR]

Originally Posted by dem00n

I'm no expert on the Z32 brakes since i own a Z31. I do know that at one point they changed the brake calipers from aluminum to iron due to heating issues.

But these brakes were engineered 20 years ago, more so 25 years ago. In turth, they are somewhat similar to the Z31 design (front only), in fact it's a common mod to change the front brakes of a Z31 to that of a Z32.

If you guys wanna run brakes from a grand touring car, go ahead. They are meant for a 3100 lb+ grand tourer, so perhaps they are more powerful then our stock brakes. But how will our master cylinder react? I don't know...and personally wouldn't wanna risk it.

Even designed 20 years ago they are just calipers. Caliper design has changed in terms of strength, materials, weight, etc but the basic design and function likely hasn't changed a great deal.


Our current brakes are from a heavy arse station wagon up front and a heavy arse family sedan in the rear. :shrug:


MC is a valid question, goes back to the piston area.

[mike the snake]

Not trying to fix anything. Just interested in a cheaper alternative if there's performance to gain.

Lookie what I found!

http://forums.nicoclub.com/akebono-1...s-t545946.html

It looks like the Q45 brakes also swap, and might be a better choice for our cars. Apparently they have 25% more braking force, so they might not cause the rearward bias.

http://www.ka24development.com/brake_upgrades.html

[Dave-ROR]

Originally Posted by mike the snake

Not trying to fix anything. Just interested in a cheaper alternative if there's performance to gain.

Lookie what I found!

http://forums.nicoclub.com/akebono-1...s-t545946.html

It looks like the Q45 brakes also swap, and might be a better choice for our cars. Apparently they have 25% more braking force, so they might not cause the rearward bias.

http://www.ka24development.com/brake_upgrades.html

Any bias shift (in either direction) can cause a change in braking. Often, it's longer (not shorter) stopping distances.


If by performance you mean stopping distances, buy stickier tires and move on since the OEM brakes are capable of locking up with R compounds and decent pads.


The only functional reason (outside of feel) to run big brakes is if you need a larger heatsink for repeated high speed braking (ie track use with a fast enough car and driver to fade sintered pads) and to remove unsprung weight, but that's only a benefit IMO if you don't change something else negatively.


Plenty of other reasons for a BBK that are less functional, but you have to pick carefully to benefit. These reasons can include pad choice, pad expense, pad lifespan, rotor expense and rotor lifespan. I run different brakes up front partially for heat reasons when I was tracking the car often and for consumables cost. Pads last so much longer in my setup and are cheaper than the OEM size so over time it pays for itself - IF you track the car a lot.


Most people upgrade brakes for looks, which is fine, but it's worth mentioning that sometimes those upgrades are downgrades functionally...

[Racecomp Engineering]

nm

[JasperNoone]

Originally Posted by dem00n

I'm no expert on the Z32 brakes since i own a Z31. I do know that at one point they changed the brake calipers from aluminum to iron due to heating issues.

IIRC it was a caliper flexing issue, not heat.

[mike the snake]

Piston sizes I believe are 30mm.

Originally Posted by Racecomp Engineering

If the piston area is smaller like it is with suby 4 pots, you are still adding a larger diameter rotor with the LGT rotor. So the brake bias point may be moot. Maybe.

I dunno what the piston sizes are on the Z32 calipers so whatever.

- Andy

[eikond]

Originally Posted by Dave-ROR

The WRX 4 pots suck. Not saying these are comparable but the WRX setup shifts bias towards the back.

You may have meant the STI full setup though

I'll state again for the record that I am not an engineer.. physics was not my strong suit in school. So I'm learning all of this as I go.

I haven't had enough time in the car to determine how much I like the new brakes. I certainly haven't driven it on the track yet.. I've literally driven it like 30 miles.

I will say that during the bedding process it felt like they had more grip and really helped slow the car down faster. But, that was also in a straight line.. So I couldn't feel much in terms of brake bias.


Dave: Where did you read that WRX 4-pots suck? Have you tried them? I've read one review on this forum where the guy said he loved them. Where did you hear that they move the bias toward the rear?

Here's my math:
The stock BRZ calipers have 48mm pistons
if my high school geometry is correct, that would make for a radius of 24mm. Pi x R ^2 = 1810 x 2 pistons = 3620

The Z32 calipers have 40.45mm pistons
same math gets me 1282 x 4 pistons = 5127

So, in theory the Z32 caliper should inpute more clamping force right? So I'm not sure why that would result in moving the brake bias toward the rear?

Again, i'm not a physics expert..

One thing I noticed is that the Z32 pads are slightly smaller surface area than the BRZ stock pads. I don't know how much smaller though.
Does a larger pad surface area increase stopping ability? It seems logical that it would.. but I'm not sure about that.