brake booster upgrade

[SIMO888]

Good afternoon all,

just wondering if upgrading the brake booster and to an STI brake boost and break master cylinder if there is a noticeable difference and worth it at all

[bigBADbenny]

No idea, my Brembos work fine on the stock GT-B MC.

BUT:
Did you take my advice and read Hyrax' member profile?
https://www.google.com.au/search?q=site ... PxNbaIiqw4

viewtopic.php?f=10&t=15482

Have you ever read any FAQ's eg on Nasioc, eg a brake FAQ?
http://www.google.com.au/search?client= ... 8wfDioCIDQ

If so you'd be asking what tyres might improve your braking distance if you're looking to decrease that.
Or if you are cooking your brakes, you need to increase the heat management of your brakes, either through better driving technique, or GT brakes with slightly larger rotors.

[SIMO888]

hey Benny I have read some of Hyrax' profile but when I was speaking to a guy at the brakes place in Alexandria in Sydney he said that when putting on more improved disks pads brake support bracket stainless steel braided lines 5 dot braking fluid the wrx sti Monoblock 4piston Caliper that id need to to them booster and master cylinder

[HyRax]

There is a noticeable difference in performance with the STi booster+MBC. I even recommend it for those with stock calipers, but this alone does not fix a poor tyre/pad combo to begin with.

The net effect is that you pump 13% more brake fluid for the same amount of pedal power. In other words, you can brake with the same level of force as before with less force applied to the pedal, but that's all you're doing. If the pads are already struggling under heat, or the tyres run out of grip, this will simply mean you meet those limits under less pedal pressure than before.

Get some better pads and tyres and your actual braking performance will improve. Get the STi Booster+MBC for less effort in the brake pedal. I've personally been using Kuhmo KU36 tyres (a little bit noisy on the highway, but perform quite well on the track) and QFM pads (for daily, spirited and track day use - surprisingly versatile and very tolerant at the cost of some reasonable dust on the wheels) and am very happy.

[SIMO888]

Tyre's I have on the car atm are Pirelli P7 and have a lot of treat still on them

[bigBADbenny]

Thanks Hyrax.
Yours came from a preFL tbSTi which had GT brakes stock?
Or is JDM or something special?
Simo, I suggest making a member profile so you can descibe the current state of your car, and you can outline the scope of your project.

Then we'll all be on the same page and will better be able to provide relevant advice

[HyRax]

My BB is from a 2005 WRX STi and the MBC came from a 2006 WRX STi from memory. Nothing special with regards to origin. Both were from wrecked ADM stock.

[RX25SE]

Do the STi's run a larger or smaller diameter master cylinder bore when fitted with Brembos?

[HyRax]

The WRX STi MBC bore is 1+1/16" (17/16ths of an inch) in size - 13% larger than a non STi MBC.

I don't know if the MBC in an tbSTi Liberty (or even the JDM Legacy STi models) use the same size MBC as the WRX STi.

If someone is willing, get a small mirror and your camera, and take a photo of the underside of the MBC where its bore size is written.

[norbs]

Pads make a huge difference. I at one point had Endless CCA pads (ceramic) with brembos and DBA rotors. Once up to temp your eyeballs would almost pop when you hit the brake pedal with some vigour. No fade at all (spirited driving down mt hotham). But they were squeely and crap when cold so I swapped them for more streetable pads.

[Bennoz]

Curious, has anyone done the Booster/Master upgrade on a Gen V?