Caliper option, maybe not
 

Went on to Ebay today to search 06 WRX calipers and found what looks like 4pot calipers that are remanufactured. Currently Im already running Stoptech Sport pads, Sport rotors, Radium cylinder brace and Stoptech stainless lines (already enough for my taste). I felt something was missing so I searched for a caliper upgrade and those showed up on ebay along with used JDM calipers which I already planned on possibly picking up from Upgarage on my trip to Japan later this year (thumbs outta breathe)

https://www.ebay.com/itm/392587153939

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If you ever plan on driving the car in a performance setting, make sure the brake balance is appropriate for the car.

still havent had the chance to put real stress on the brakes to know if I really need the upgrade. Ill wait til after a couple Auto X events...if they ever start up again

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The factory calipers can take you pretty far with a decent set of pads and fluid.



I've been autox-ing mine for two seasons on 200tw tires. I had Hawk HP+ and ATE Type 200 for the first season and a half. Never needed more than that for autox. They're not enough for track, though(the HP+). Then I stepped up to DTC-60 pads and Motul 600 and I didn't have a problem at track again. This is while running a semi-decent intermediate pace with just a header and tune. (2:10 Thill East, 1:30 West, 2:08 BRP 13CW)

My 0.02.



Side note, I'm in the SF Bay Area as well. I'm hoping to hit Lotus Club again if their event next month happens as well as Santa Clara Corvettes at Cow Palace. Perhaps I'll see you out at an event.

advice from the both of you appreciated[emoji3]

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The 06 WRX calipers use the stock rotors. It's a decent caliper...but not a significant upgrade over stock. It does shift some mechanical brake bias to the rear so it may not be the best choice for everyone (I would not recommend that caliper with stickier tires). I may swap to them on my car because rally-x reasons.

EDIT: I'm wrong on the bias change, the rear FHI 2 pots shift bias forward. Front FHI 4 pots have no effect on bias.

I can't remember but I don't think it clears stock 2013-2016 wheels.

- Andrew

I have the 4 pots on my 04 WRX, with H6 rears. Certainly better than stock, but nothing earth shattering. I would stick with stock until you need more and start saving, because it is not cheap to get a good BBK and wheels that fit. And for me I do summer/winter so I need two sets of wheels that fit. Don’t want to do spacers.

currently running the 20/25 spacers on the stockers now. Ill be installing my 18" Nt03's soon once I get the suspension all dialed in

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My understanding is that the brz 2-pot has smaller front caliper pistons than the regular wrx/impreza part. Which by my spreadsheet moves the bias forward a touch.

Also with EBD I wonder how much it's really going to matter.

For pistons I had 42.8 mm for BRZ front and 38.1 rear non-PP USDM calipers...and after all these years it turns out I was wrong. Those numbers still come up most places you look but I think they're wrong now.

So front FHI 4 pot is same rotor and about the same piston area as OEM BRZ (40.4mm), but the rear FHI 2 pot has smaller pistons than OEM BRZ (38.1 vs. 40.46). So a frontward shift with the front and rear FHI set up due to the rear calipers.

Damn it. I'm embarassed. Gonna go back and edit like 50 posts.

- Andrew

Pretty sure I've made a few comments about brake bias with the assumption front calipers had the bigger pistons.

Yeah the wrong piston sizes are all over the place. Next time I'll measure myself! I think I (like others) assumed they were the off the shelf WRX slider front and I guess LGT rears or whatever based on rotor size.

- Andrew

Andrew,,, any chance you post the correct numbers?? These are the numbers (42.8 and 38.1) I see in most post. I recall seeing a post where a guy had a picture of the pistons with the digital caliper on it,, dam if I can find it today.

I measured a stock 2016 piston as 40.4mm (granted with a cheap HF caliper, but it's been pretty accurate). Didn't measure the rear (only rebuilt the fronts), but the subaru parts catalog shows the rear caliper using the same part # for the piston as the front -- just 1 rear vs 2 front...

https://www.ft86club.com/forums/show...1&postcount=16

In post #10:

Front:
Hitachi CL25VD Caliper with Dual 40.4mm Pistons (1.591 in.) x 2
FA300 Pad Material with 48.3 cm^2 pad area (7.487 in.^2)
294.0 mm x 24.0 mm Ventilated Rotors (11.575 in. x 0.945 in.)

Rear:
Hitachi CLA12V Caliper with Single 40.46mm Piston (1.593 in.)
FN360 Pad Material with 23.0 cm^2 pad area (3.565 in.^2)
290.0 mm x 18.0 mm Ventilated Rotors (11.417 in. x 0.709 in.)

- Andrew

That was the picture I was looking for,, thanks!!!









Thanks you sir!

Sorry for the bump on an old thread but just to make sure I am understanding correctly. We should be able to use the front FHI 4 pot calipers (off 06/07 wrx) with no changes to the brake bias at all, correct?

So would this be an okay OE+ upgrade? It should be a stiffer caliper right?

Minimal if any change to brake bias with just the front calipers.

It would be okay. Stiffer caliper and a tiny bit lighter.

- Andrew

How far forward would adding the complementing rear brakes shift the balance forward? How detrimental if at all would the balance shift be and why? :thanks:

The 4-pots make slightly more brake torque (about 6%), while the 2-pot rears have slightly less (~9%).

My numbers are
65.3/34.7 %f/r for the stock brakes
66.6/33.4 with just 4-pot fronts
68.7/31.3 with 4/2 pots

There are a lot of factors that might make a bias change an improvement, or not. Put on stickier tires, and you have the ability to transfer more weight to the front. Lower the car, and less weight is transferred for a given braking rate. Do both, and maybe it cancels out? Addtionally, EBD and ABS are there to try and sort things out.

I would just stick with stock till you need better brakes. Better pads/fluid. CSG has great pads for our stock brakes that work really well!

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^^^This. I am not overly impressed with the 4pots on my WRX.

As a few others have pointed out the OEM calipers are pretty good. Just need better pads and fluid for track duty.

I only went up to AP sprints for the heat dissipation and thicker pads that last longer and are usually cheaper or same price, but longer life, than the OEM front pads due to a common size and being thicker