Full Front and Rear 08-12 STI Brakes Swap

[jng]

Hi guys,

Have a few questions for those who did the swap with the GRB '08-'11 STI WRX Brembos (black calipers). I have a base model 86 (Asian spec), and I purchased a set of '08-'11 STI WRX calipers + rotors which had been previously modified for use on a Subaru Forester (PCD 5 x 100). The calipers are the GRB ones, which I guess are fine, but the rear rotors are WRX ones which were used to fit the Subaru Forester (5 x 100, vs. 5 x 114.3).

Base spec brakes are ventilated front discs and solid rear discs.

Question 1:

The WRX rear rotors, while 5 x 100, are not able to fit the 86 because of the 86's handbrake mechanism is larger than the rotor's inner handbrake bell. I compared this with the stock GT86 (upper spec) rotor, and the diameter is indeed less. I had read in another thread that the part number for the stock base model (Asian spec) caliper and rotor was as per the '08-'11 WRX, but not sure how this is the case as the rotor does not fit due to the inner handbrake bell.

Will this issue be solved if I just get one of the replacement DBA rotors which are dual PCD drilled for the '08-'11 STI WRX Brembos? Either DBA42656S-10, DBA42656 (XS) or DBA4655?

EDIT: Have answered my own question with a bit more reading. Will look at the DBA4654S-10 for front and DBA42656S-10 for rear.

Question 2:

The rear GRB STI Brembo caliper does not fit the base model (Asian spec) rear knuckle without a custom bracket. Anyone can confirm this? Does the original GRB STI Brembo caliper come with a bracket, or is the caliper able to be directly bolted on to the "normal spec" GT86/BRZ/FR-S rear knuckle? If original caliper came with a bracket, does anyone have the OEM part number for it? My workshop will try mounting the rear caliper direct onto a BRZ tomorrow to see if there is difference in the rear knuckle with the base spec.

I guess worst case scenario I will have to fabricate a custom bracket to get the rear caliper to be mounted on the knuckle.


Question 3:

Anyone done the GRB STI Brembo swap, front and rear, and able to fit in a Wedssport TC105N (17 x 8)?

Thank you.

[Fizz]

Originally Posted by jng

Hi guys,

Have a few questions for those who did the swap with the GRB '08-'11 STI WRX Brembos (black calipers). I have a base model 86 (Asian spec), and I purchased a set of '08-'11 STI WRX calipers + rotors which had been previously modified for use on a Subaru Forester (PCD 5 x 100). The calipers are the GRB ones, which I guess are fine, but the rear rotors are WRX ones which were used to fit the Subaru Forester (5 x 100, vs. 5 x 114.3).

Base spec brakes are ventilated front discs and solid rear discs.

Question 1:

The WRX rear rotors, while 5 x 100, are not able to fit the 86 because of the 86's handbrake mechanism is larger than the rotor's inner handbrake bell. I compared this with the stock GT86 (upper spec) rotor, and the diameter is indeed less. I had read in another thread that the part number for the stock base model (Asian spec) caliper and rotor was as per the '08-'11 WRX, but not sure how this is the case as the rotor does not fit due to the inner handbrake bell.

Will this issue be solved if I just get one of the replacement DBA rotors which are dual PCD drilled for the '08-'11 STI WRX Brembos? Either DBA42656S-10, DBA42656 (XS) or DBA4655?

EDIT: Have answered my own question with a bit more reading. Will look at the DBA4654S-10 for front and DBA42656S-10 for rear.

Question 2:

The rear GRB STI Brembo caliper does not fit the base model (Asian spec) rear knuckle without a custom bracket. Anyone can confirm this? Does the original GRB STI Brembo caliper come with a bracket, or is the caliper able to be directly bolted on to the "normal spec" GT86/BRZ/FR-S rear knuckle? If original caliper came with a bracket, does anyone have the OEM part number for it? My workshop will try mounting the rear caliper direct onto a BRZ tomorrow to see if there is difference in the rear knuckle with the base spec.

I guess worst case scenario I will have to fabricate a custom bracket to get the rear caliper to be mounted on the knuckle.


Question 3:

Anyone done the GRB STI Brembo swap, front and rear, and able to fit in a Wedssport TC105N (17 x 8)?

Thank you.

Answer 1: You'll need to get the correct DBA rotor to suit the handbrake mechanism. I forgot the part number but what you've mentioned seems familiar. Only thing you'll need to do is trim the stock heat shield to accommodate the larger rotor....easy job.

Answer 2: If you've got the GRB "black STI" calipers...then it's direct bolt on no brackets required whatsoever on ALL GT86/BRZ/FRS variants regardless of model....because the mounting holes on the hub carriers itself are all identical.

Answer 3: Yes they fit perfect. In fact that's exactly what I have.

[gtishtar]

Originally Posted by Fizz

Answer 1: You'll need to get the correct DBA rotor to suit the handbrake mechanism. I forgot the part number but what you've mentioned seems familiar. Only thing you'll need to do is trim the stock heat shield to accommodate the larger rotor....easy job.

Answer 2: If you've got the GRB "black STI" calipers...then it's direct bolt on no brackets required whatsoever on ALL GT86/BRZ/FRS variants regardless of model....because the mounting holes on the hub carriers itself are all identical.

Answer 3: Yes they fit perfect. In fact that's exactly what I have.

i found this Japanese web paged http://ameblo.jp/kitservice/entry-11932876981.html with google translate. we can use this with 08+ sti caliper w/o trimming shield, is my understanding correct?

　純正品番　バックプレートRH　26704VA000　定価￥５４７０
　純正品番　バックプレートLH　26704VA010　定価￥５４７０
　純正品番　レバーRH　26708AJ020　定価￥８７０
　純正品番　レバーLH　26708AJ030　定価￥８７０

[woojukim116]

https://blog.racetechnologies.com/20...ubaru-brz/amp/

[churchx]

So? Caveats of messing up brake bias and alike were known before. It still won't keep from doing brembo swap those that want to put brembo branding for cheap via retrofitting calipers from other cars, as looks and cost to such people matter more then performance & safety. That didn't matter to them in past, and won't change in future, whatever vendors say.

[jamal]

The bias and pistons sizes, are close enough IMO, but it does go forward slightly. The rear 08+ sti calipers use 40mm pistons, which is the same size as the stock calipers (well, almost, stock are 40.5). The older 04-07 rear brembos only have 36mm pistons though and would not be good to use.

This, however, should be more of a cause for concern:

Subaru WRX STI calipers are made to be mounted in the trailing position (behind the axle). If mounted in front of the axle, by exchanging positions of the plugs and bleed screws on the caliper, it is not possible to bleed all the air out of the system because the fluid crossover in the caliper is the highest point and will trap air.

However, a number of people have done it and seem to have been able to bleed the brakes?


Also, that article's figure of a 25% increase in front brake force is not what I come up with. The total brembo piston area is only 1.5% more and the total change in brake force about 10%

The total bias I get for stock brakes is 68.3:31.7 and with brembos 69.9:30.1, so about a 2% shift. The proportioning system works the same on both cars, providing even brake pressure front and rear until a speed difference begins to occur.

[Bones36]

is it alright to use stock brake lines with this upgraded calipers?

[Turbo]

Originally Posted by jamal

Also, that article's figure of a 25% increase in front brake force is not what I come up with. The total brembo piston area is only 1.5% more and the total change in brake force about 10%

You need to factor in changes to the effective radius and the changes in piston area. I'm not sure if you've done that, as I had looked at going this route but ruled it out early when I ran the numbers.

[KevLows]

Question

Maybe it’s been asked but what’s the purpose of switching the bleeders around? Wouldn’t it just be easier to swap the Calipers left to right?

[mrderp]

Originally Posted by KevLows

Wouldn’t it just be easier to swap the Calipers left to right?

Yes it's easier, but it puts the pistons in the wrong order, leading to tappered pad wear.

[KevLows]

Originally Posted by mrderp

Yes it's easier, but it puts the pistons in the wrong order, leading to tappered pad wear.

I see might explain the issue I’m having then

Thank you

[Butterman]

Edit: Redundant post

[Bripper]

Im looking to put some 2018+ sti (Rear) brakes on, already have Alcon 6 piston front 355mm setup. My question is. Specifically what rotor do i need to fit over the ebrake assembly. Ive heard 08--17 sti dba fit our car in rear. But 18+ is a larger rotor by about 10mm.

Another question. Incase i dont do this setup. I have some 04-07 sti rears im about to pull off my 2015 wrx. Already have the bracket to run them on either car. Will my 04-05sti dba 4000 rotors not fit. Because the hat needs more clearance to fit over the ebrake?

Im looking for a cheap solution for my rear upgrade and dont want wilwood. Seems either of the 3 gens sti or evo x with washers and pad overhang or brz performance package rears are going to be reasonable. Especially the gold calipers i already have. Even if i need new dba for 08+ sti i can get both for 220. But gold caliper are 38mm pistons i think. 08+ are 40mm. And 18+ are 326mm rotors vs 316mm