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not12listen
02-13-2008, 12:31 AM
ok. i've done more than my fair share of driving and in many, many different types of cars. the most effective combination i've found, is not a commonly used setup.

it boils down to using a brake pad in the rear, which has a better 'bite' than the front brake pad. the idea is simple: shift more braking duty to the rear to help balance it out.

from the factory, most vehicles have roughly 70% of the braking duty performed by the front brakes. i've spoken with a few people about what i've done, brake setup wise, and some have suggested brake bias adjusters, which serve to shift the brake duty via the pressure from the front to the rear (or whichever ways you choose).

there is one major thing that the bias adjuster cannot compensate for: the bite characteristics of the pads.

you can adjust a brake bias adjuster to be '50/50' and you could EASILY still have a setup that locks up the front wheels.

my initial setup consisted of:
blank rotors from Napa Auto parts
Axxis Metal Master front pads
Axxis Metal Master rear pads
Goodridge Braided Steel Brake Lines
Castrol DOT3 brake fluid

i really did not like the braking characteristics. the front grabbed really soon and the rear did virtually no work (i would purposely test this by braking MID turn).

so, i then did a bit of reading and discovered that the EBC Green Stuff pad does not have the as broad of a active heat range as the Metal Master pads. basically, they're a 'lesser' pad.

so, brake setup v2:
blank rotors from Napa Auto parts
EBC Green Stuff front pads
Axxis Metal Master rear pads
Goodridge Braided Steel Brake Lines
Castrol DOT3 brake fluid


i would drive thru the same 'test' turns as previous, and noticed that not only was the car more easily controlled with braking during the turn, but also that i felt less nose dive under hard braking.

the rear pads were FINALLY starting to do there job, and because of the specific setup, the braking duty had shifted noticeably rearward.

the test vehicle for this:
1986 Toyota Mr2

with its mid engine layout, braking during a turn is a very touchy (and potentially very, very dangerous) maneuver. because there was less nose dive (weight transfer forward), the rear was not lifting nearly as much as previous. this allows mild braking during just about any portion of the turn (if needed), whereas previously it was nearly asking for an accident to happen.

so... how does this all relate to the impreza? this weekend, my 99RS will be undergoing a very similar brake setup.

the current setup:
OEM blank front vented rotors (99RS)
OEM blank rear vented rotors (94 Legacy GT)
OEM front calipers and brackets (99RS)
OEM rear calipers and brackets (94 Legacy GT)
OEM brake lines
ATE Super Blue DOT4 brake fluid
Monroe Semi-Metallic front brake pads
Monroe Semi-Metallic rear brake pads

the future setup:
Brembo blank front vented rotors (99RS)
Brembo blank rear vented rotors (94 Legacy GT)
OEM front calipers and brackets (99RS)
OEM rear calipers and brackets (94 Legacy GT)
GoodRidge Braided Steel Brake lines
ATE Super Blue DOT4 brake fluid
EBC Green Stuff front brake pads
EBC Red Stuff rear brake pads


now... 2 details have not been brought to light. brake bed-in and bleeding.

http://zeckhausen.com/bedding_in_brakes.htm
http://zeckhausen.com/bleeding_brakes.htm


i follow the steps on those pages. i figure that its a german school of racing, they ought to have a pretty good idea of what they're doing. :)

one note though, on the brake bed-in process, i do NOT hit the triple digit speeds... :) this is just my daily driver after all. :)

anywho... if anyone has any questions or comments, PM me or just reply. and, i will be reporting back on here on my findings with my 'future' setup (ie. this weekend) with the good and bad.

my01rs-t
02-13-2008, 10:46 AM
Interesting. I removed my proportioning valve and the abs completely and like the extra rear pressure. I'm using the same pads all the way around though with wrx rotors up front. 2001 RS.

not12listen
02-13-2008, 12:01 PM
i'd love to remove the ABS, but i'm making monthly payments for my RS... if i get into an accident, it'll register in the ECU if the ABS was disabled or not... :/

anywho... doing the different pad setup would allow you to keep your ABS and use the stock proportioning valving as well.

greddy
02-13-2008, 01:13 PM
i'd love to remove the ABS, but i'm making monthly payments for my RS... if i get into an accident, it'll register in the ECU if the ABS was disabled or not... :/

anywho... doing the different pad setup would allow you to keep your ABS and use the stock proportioning valving as well.

Replace the ABS fuse by a ''burned'' one, if insurance ask, just tell them that the fuse have recently burn;-)

not12listen
02-13-2008, 02:11 PM
depending on how the testing of the new brake setup goes this weekend, i MIGHT consider doing just that.

but, i'd rather just swap out pads to get the braking characteristics that i want. i prefer mechanical tuning over electronic. good or bad, its more predictable. :)

not12listen
06-21-2008, 02:17 AM
well, its been a long time.

i did the swap, bleed and bed-in. near the end of the the bed-in process, there was LOTS of smoke coming from all 4 corners and the pedal felt like a wet sponge. :)

after 15 minutes of 'cool down' time, i touched the brakes... if it werent for the fact that i was wearing my seat belt, i would have been shot thru my windshield. :)

2 days later, i had my boss test out my brakes. his words were along the lines of: "WHAT THE F*** WAS THAT?!?!?!?" just after his head nearly came in contact with the steering wheel. :)

since that time, the brakes have become far more 'reasonable' in their reaction and bite. now they just feel like grippy OEM pads that do not fade, and get even MORE grippy when heated up. :)

i am still getting more nose dive than i'd like, but a big part of that is my stock springs and struts.

once i get my suspension firmed up, i'll definitely be testing the brakes more... :)