$600 Brake retrofit, Cadillac ATS brembos, STI rotors.

[finch1750]

Originally Posted by etc

Ya that was the more info I was going to add. Using the calculator on the 300z swap site I ran the numbers, but left that at work

Basically it is shifted forward slightly by the larger rotor and larger brake pads. And offset back rear slightly by the 1.6mm loss in piston size, lower hydraulic force.

From what I remember stock was something like 69.8, this is something like 70.1.

I am working from home this week watching my son but when I get back next week I will update with the actual numbers.

First off thanks for posting. I was wondering about this swap myself

Based on the STi rotors and 42mm piston size you gave these actually shift the bias to 73.7%. OEM is 69.7%. Z32 is 70.9%.

front piston size (inches) = 1.654 and 1.654 (42mm)
front pad cf I left at .48 (street performance example)
front rotor diameter 12.8
front pad height (I left at 1.875.. not sure how to calc this so I left it at the prefilled value)
rear piston size = 1.49999 (38.1mm)
rear rotor diameter = 11.42
rear pad cf = .48 (same as above)
rear pad height = 1.25 (left at prefilled value)
Result = Front brake bias 0.737 or 73.7% to front.

OEM
Front piston size (inches) = 1.685 and 1.685 (42.8mm)
front pad cf I left at .48 (street performance example)
front rotor diameter 11.575
front pad height (I left at 1.875.. not sure how to calc this so I left it at the prefilled value)
rear piston size = 1.49999 (38.1mm)
rear rotor diameter = 11.42
rear pad cf = .48 (same as above)
rear pad height = 1.25 (left at prefilled value)
Result = Front brake bias 0.697 or 69.7% to front.

Z32 brakes:
front piston size (inches) = 1.5925 and 1.5925 (40.45mm)
front pad cf I left at .48 (street performance example)
front rotor diameter 12.44
front pad height (I left at 1.875.. not sure how to calc this so I left it at the prefilled value)
rear piston size = 1.49999 (38.1mm)
rear rotor diameter = 11.42
rear pad cf = .48 (same as above)
rear pad height = 1.25 (left at prefilled value)
Result = Front brake bias 0.709 or 70.9% to front.

And just to clarify as well the Z32 calipers are made by Sumitomo, not Nissan. They are good enough for R32-R34 GTS-T, S14&S15, and R32 GTR so they aren't garbage. This isn't to say Brembos aren't better just clarifying info for everyone.

The Legacy GT rotors are also $57/ea on Amazon compared to $89 but there are no two piece options if looking to shed weight.

[rixter145]

sub'd

[etc]

Originally Posted by DAEMANO

Thanks for the write-up!

Do you have links for 2 piece options that you found. Trying to get an idea of cost and weight differences.

Also any idea as to how much this affects F/R brake bias?

I didn't dig too deep into the 2 piece options, you are going to spend 650+ for a set but the weight drop will be significant (~8lbs per rotor). You can start on the $190 blanks and work up to the 2 piece later if you decide you need them.

Most manufacturers drill their hats for both 5x100 (04 sti) and 5x114(05+ sti). So you have the roughly same options any sti has.
http://www.girodisc.com/Girodisc-Fro...Ti_p_5514.html
http://www.racingbrake.com/WRX-STi-F...-11-p/2017.htm
http://www.evokiller.com/product.php?productid=16913
(I am sure there are others, this was a quick google search)

[etc]

Originally Posted by finch1750

Based on the STi rotors and 42mm piston size you gave these actually shift the bias to 73.7%. OEM is 69.7%. Z32 is 70.9%.

front piston size (inches) = 1.654 and 1.654 (42mm)
front pad cf I left at .48 (street performance example)
front rotor diameter 12.8
front pad height (I left at 1.875.. not sure how to calc this so I left it at the prefilled value)
rear piston size = 1.49999 (38.1mm)
rear rotor diameter = 11.42
rear pad cf = .48 (same as above)
rear pad height = 1.25 (left at prefilled value)
Result = Front brake bias 0.737 or 73.7% to front.

Thanks for doing the legwork That looks about right, the only thing missing is the pad height, which I actually used because hawk lists it for their pads on both calipers. I think the difference from setting that is nominal this is probably correct.

Honestly I looked at a lot of these numbers that day and they kinda muddled together. I was running the numbers to try and work out a good match for a rear caliper to shift the bias back without using a larger rear rotor, as they seem to handle the heat well enough.

Anyway a 40mm piston would do it well, I was going to start down the road of determining if we could mount the 40mm piston'd fixed calipers from a 964 C2. But that will be a whole separate project (that I will probably never end up actually doing).

[DuMa]

should also be noted that the $600 price in the title does not include pads.

[etc]

Originally Posted by DuMa

should also be noted that the $600 price in the title does not include pads.

For the track definitely not. For the street you can get the stock pads for like $35 [ame="http://www.amazon.com/ACDelco-17D1050M-Professional-Semi-Metallic-Front/dp/B000IZ1J3O/ref=sr_1_1?ie=UTF8&qid=1461197156&sr=8-1&keywords=17D1050M"]Amazon.com: ACDelco 17D1050M Professional Semi-Metallic Front Disc Brake Pad Set: Automotive[/ame] So depending on how nice amazon's prices are being that day you could possible squeak in at $600.

But ya, the xp10s I plan to run on the track are over $200 if I remember correctly. But again the stock frs xp10s are around $200 as well.

[etc]

Added a couple more photos to the top post, with the wheel on and one of the back and the mounting bracket.

The request for more photos has forced me to expose my dirty car to the world

[ryoma]

Originally Posted by etc

Just to be clear this is only for the fronts. The rears would remain stock with this setup.

Oh I thought it was all 4 so I was screaming to myself at what a deal this was lol. Still cheaper though compared to other front BBK's

Sent from my VS986 using Tapatalk

[PandaSPUR]

Almost cheap enough to make me want them just for the look lol.

How'd you get the brembo logo on there after painting? Is it just a vinyl sticker?

EDIT: And I guess this isnt reversible since you're drilling out one of the stock mounting holes to a bigger size?

[etc]

Originally Posted by PandaSPUR

Almost cheap enough to make me want them just for the look lol.

How'd you get the brembo logo on there after painting? Is it just a vinyl sticker?

EDIT: And I guess this isnt reversible since you're drilling out one of the stock mounting holes to a bigger size?

It is painted on as well with vht flameproof (2000f) paint. The usual recommended way is to.put a decal on then clear coat over it but I didn't trust that to handle track temps, especially with white letters. I used a vinyl stencil (link in first post) then painted using that.

Reversible is a little more.tricky. worst cause you would replace the knuckle. Alternately you could find a spacer to put around the factory mounting bolt to bring it up to 9/16ths. If I ever need to go back I am not too worried.

[Calum]

Originally Posted by PandaSPUR

Almost cheap enough to make me want them just for the look lol.

How'd you get the brembo logo on there after painting? Is it just a vinyl sticker?

EDIT: And I guess this isnt reversible since you're drilling out one of the stock mounting holes to a bigger size?

This is from the instructions, just to ensure accurate info.

"For this next step you will need a drill

and a 9/16” drill bit. You will need to

drill out the top caliper mounting

hole to accept the larger 14mm bolt

that the ATS caliper requires.

In this step you will take the included

M14x2.0 tap and tap the bottom

caliper mounting hole. This will hold

your bracket stationary. If you do not

wish to tap you spindle you can pick

up a M12x1.25x55 bolt and a

M12x1.25 nut to secure the bracket."

[propulsion1]

I wonder if there is a GM rear brembo that would also fit our platform with some modifications. Any one has any clues?

[PandaSPUR]

Originally Posted by etc

It is painted on as well with vht flameproof (2000f) paint. The usual recommended way is to.put a decal on then clear coat over it but I didn't trust that to handle track temps, especially with white letters. I used a vinyl stencil (link in first post) then painted using that.

Reversible is a little more.tricky. worst cause you would replace the knuckle. Alternately you could find a spacer to put around the factory mounting bolt to bring it up to 9/16ths. If I ever need to go back I am not too worried.

Ah my bad, completely missed that last sentence with the link.

Hmm this seems fairly DIY-able too.. even for a guy like me who has no garage or driveway.

[etc]

Originally Posted by propulsion1

I wonder if there is a GM rear brembo that would also fit our platform with some modifications. Any one has any clues?

I looked around a bit for this, the ATS uses sliding caliper so that doesn't help. There are the camaro ss / ctsv brembos but they are much larger, around 14" diameter. The other option are corvette brakes but they are also closely matched front/rear and larger. Also all these are four piston rear if you want to try and keep stockish bias you will need to keep the rears two piston and around the stock diameter (I think it is 36mm, don't recall offhand).

Alternately you could consider the larger rear pistons a boon. From what I gather if you want to get into trying to adjust brake bias and find the actual ideal bias (not just try to match stock) you would overspec the rear brakes until they are able to lock first then install proportioning valve(s) in the rear lines and start backing off hydraulic pressure until you have the bias you want. I am not certain how well this process works with ebd, not well I would imagine.

The other problem is if you want to stick with economical oem rotors, ours are the largest that subaru makes so you need to find a donor car with a similar diameter rear rotor.

Also the parking brake makes the rears trickier too as it would have to happen to be the same size as ours, or you could just drop it all together.

Short version is that rears are actually tricker than fronts and heat-wise the stock rears aren't too bad. I haven't seen over 450f on mine, where my fronts would regularly be over 750f coming off track.