JasonS4+Festicle

So, I've posted in the past about this issue:

My car doesn't stop so well with these brakes.

First, I thought it was a bleeding issue so I bled them (including the ABS pump) over and over and over and over - the pedal is hard.

Not better.

Then, found a small leak to the vacuum canister - slightly better but not great by any means.

Then, maybe a master cylinder issue - replaced - still the car won't stop correctly.

Then, tried different pads (started with Hawk HPS) - went to Porterfield R4Ss - no better.

Checked the pressure at the caliper itself - 1700psi on both sides - should be fine.

(Oh, they have been bedded using the standard procedure.)

<b><u>Put track pads in - Mintex C - AWESOME. So, the brakes are awesome with track pads in which tells me it must be a pad issue.</u></b>

I can't imagine that Hawks and Porterfield both suck that bad (the Porterfields were great with my stock HP2 calipers).

I'd run track pads all the time if they weren't so noisy...the sound is killing me.


Oh, I've had 2 different people drive my car and comment how the brakes barely make the car stop - can barely lock up ABS. It's that obvious.

Last PM, I had enough and put the Mintex Cs back in there just to affirm for sure they worked well - they do. Even when ice cold (located in Chicago where it's ~35F) they work better than the other pads. When I went to change them, they barely had any wear, which tells me that no friction material is being worn off - glazed maybe? But 2 sets of street pads got glazed?

Is something wrong here?

Any ideas of an agreesive street pad to try?

I'm about ready to pull the brakes and go back to stock or try a differnt BBK - I just think it's my pads and hate to keep buying new ones to find the same issue.

ryans4

i hated Porterfield R4S pads, especially in the rain. Try Ferodo DS2500 or Pagid 4-4's/4-2's...

O.W. Kenobi

Did you spill anything on the pads, perhaps?

JasonS4+Festicle

Also, which pad is a more agressive pad - Ferodo or Pagids?

I'd like the best "bite" - a little noise is OK, track pad noise is less OK

ryans4

find the pad writeup by RYOUNG, probably in A8 or Motorsports forum...

JasonS4+Festicle

thanks - found it &lt;starting to read&gt;.....

Johnny Bravo

Dusty, but aggressive.
there friction coef vrs temperature is very flat, and very high ~.55+

My thoughts would have lead me to the Brake booster and possible leaks. ( seems like you addresed that issue )

Otherwise, the rotors.
Im not hot on the metalergy of cast iron as it relates to brake rotors, but i think since you;ve exhuasted almost all other options, i would take some time to check the rotors.

-----------------------------------------------

Besides the guessing:
Can we calculate the amount of brake force / torque you are able to generate with this ecs setup.

and compare them to stock, ST's, Brembos, and Stassis setups.

Need some basic numbers:
Number of pistons per caliper
Piston Diameter(s)
Effective radius of pad on rotor ( usually, this is the distance from center of rotation to the center of the annulus)
friction coef ( set it to .5 since you are comparing other setups to each other and you want to remove pad compostion from the variables )
Line pressure: again set then all to the same value, lets say 1200 psi. ( we are just comparing the mechanical advantage of each system, so this variable also gets thrown out )


Then see if you are able to generate the same forces in relation to other setups on the market.
If you find that you way off the chart ( need way too much pedal force to generate comparable brake torque ) then you need to compensate with different piston dia, different size rotors, or both.


If you find that the ECS kit is grossly mis engineered, present your data to them - reminding them that family also rides in the car. and see if they can remidy this issue.


( you can use vag comm to do some 60-0 tests, and compare them to stock or other s4's )

www.stoptech.com ( if you need some good honest advise, call Matt Weise )


http://www.turnfast.com/tech_brakes/brakes_balancing2.shtml

JasonS4+Festicle

RYOUNG as ryans4 suggested below!

anyway, they were shipped today and will be on all 4 corners as soon as I get them.

Hopefully, it's not a rotor issue causing my pads to glaze prematurely. If it is, I might have just spent some $$ on new pads that will get glazed.

I can't imagine that's the issue as the Mintex C pads make your eyeballs pop out when you hit the brakes (and your eardrums hurt when they squeel like a pig).

Johnny Bravo

Im still interested in a quanative analysis. Do you have any info off hand?

JasonS4+Festicle

no, don't have the #'s off hand...anyone else maybe?