EvoX rear caliper swap

[15limited]

Originally Posted by HAWAIICALIVEGAZ

What setup are you running for the hydro? What bracket and caliper?

Voodoo13 handbrake, Wilwood master, pbm hardline/stainless kit, and the mounting brackets are Dayton One, which are for oem calipers but you can add spacers like you would the oem hub. And calipers believe it or not are the purpose of this thread

Sent from my SM-G950U using Tapatalk

[DustinS]

I know it was brought up earlier and not really answered, but why not just use the '08+ rear calipers? They bolt on and have the same 40mm piston size and fit the rotor correctly without pad overhang.

[etc]

Originally Posted by DustinS

I know it was brought up earlier and not really answered, but why not just use the '08+ rear calipers? They bolt on and have the same 40mm piston size and fit the rotor correctly without pad overhang.

Do you have a source for that? Everything I found pointed to the sti rears being 36mm which is smaller than our stock. Like: https://www.racingbrake.com/Piston-K...C-p/bs-21p.htm

I can't really find anything specific to 08+ though.

[etc]

Digging around I see it now: https://www.racingbrake.com/Save-10-...p/bs-22bsp.htm

Ya if the black brembos work go for it! Should be the same balance. Didn't know about them when I did this. Cost and availability would be the only reasons to do this instead. That said if you have this there isn't really any reason to switch to the blacks, I have no intention of doing it.

It was mentioned before and not addressed because that comment was edited a year after it was posted.

[spitsnaugle]

Originally Posted by etc

This should resolve any brake bias concerns. It will match the four front 42mm pistons with two rear 40mm. Here are the calculations used to arrive at this pairing: https://docs.google.com/document/d/1...it?usp=sharing

Reviving this thread...

Looking at doing a similar swap right now. Looking at your math, did you account for ATS's Four Pistons up front, or just two? Same with the two piston vs one for the rear caliper. Given, since you dropped 1/2 the pistons from front and rear, your balance seems to be the same.

BUT when comparing the ATS front vs stock rear, your ratio would be quite different at 82.7% front biased

[15limited]

Originally Posted by spitsnaugle

Reviving this thread...

Looking at doing a similar swap right now. Looking at your math, did you account for ATS's Four Pistons up front, or just two? Same with the two piston vs one for the rear caliper. Given, since you dropped 1/2 the pistons from front and rear, your balance seems to be the same.

BUT when comparing the ATS front vs stock rear, your ratio would be quite different at 82.7% front biased

I did the front ATS swap for a few months before getting the exo X rears figured out and installed. You will feel that rear try and pass you up under heavy braking with just enough steering input.


Sent from my SM-G950U using Tapatalk

[etc]

The bias calculators say to only use half the pistons in a fixed caliper setup vs floating. From http://www.tceperformanceproducts.com/bias-calculator/ :

Note: multi piston calipers express their values using one HALF of the caliper body. This accounts for the floating aspect of the single piston caliper. A six pot caliper would be 1.625/1.125/1.125" for example. True clamping force would be double that but also double the single piston of a floating caliper taking into account the 'pull' of the outer pad to the rotor surface. Using total area (all six for example) would require you double that of the floating caliper also- thus the net result is the same whichever way you do it.

[spitsnaugle]

Originally Posted by 15limited

I did the front ATS swap for a few months before getting the exo X rears figured out and installed. You will feel that rear try and pass you up under heavy braking with just enough steering input.

Yeah I'm definitely doing both front and rear to keep that bias in check. I'm aiming to autocross every weekend this next year with it.

Originally Posted by etc

The bias calculators say to only use half the pistons in a fixed caliper setup vs floating. From http://www.tceperformanceproducts.com/bias-calculator/ :

Womp womp reading fail on my end. Thanks for the clarification.

Now I'm just trying to research the differences between these EvoX calipers and the 08 STI calipers.

[DustinS]

Originally Posted by spitsnaugle

Now I'm just trying to research the differences between these EvoX calipers and the 08 STI calipers.

'08 Calipers are direct Bolt on and don't require any spacer or brackets. Definitely worth it. You can also do a complete '08+ STI caliper set and the bias isn't very far from stock.

[spitsnaugle]

Originally Posted by DustinS

'08 Calipers are direct Bolt on and don't require any spacer or brackets. Definitely worth it. You can also do a complete '08+ STI caliper set and the bias isn't very far from stock.

...but finding used rear 08+ STI calipers are around $700 a pair right now, Evo X are $350 a pair. Both use swaps use the same rotor at least.

[Evil Rocky]

I purchased the front ATS and finally got my rear Evo X calipers and just need my rear rotors, brake lines and will have this exact set up. Looking forward to this.

[Bripper]

Really need to keep in mind the staggered sized pistons on the front sti brembos. Trailing/leading designed to mount on rear of knuckle, when we switch to front of knuckle its all wrong for the caliper design

[etc]

You would need to dig up some specs and answers on the 6 piston calipers to know what rear calipers would balance it.

What are the sizes of the pistons?
Are they all the same or are some larger and some smaller?
If they are not the same is there a leading and trailing edge and will those still be correct when mounted to our car?

As for the rest of it, if you have already done this on a wrx than it's going to be the same here. I am curious about that setup though.

You mention that the ctsv bracket will fit the six piston calipers, which sounds right I think the corvette guys in particular are always swapping calipers around and gm keeps the bolt spacing the same. However you also mention wanting to run huge rotors. The ctsv bracket will space this caliper out for the 326mm STI rotors in the front, if you are running larger rotors you will need to move the caliper out farther to clear them and will need a different mounting bracket. What are you using to mount them on your wrx's?

Also what rotor are you using on the wrx's? The GM rotors won't be the right bolt pattern and may not be the right offset (hub face to rotor face)

[Bripper]

Bump, edited