background info:
OEM brakes wore out so i got new pads (Axxis Ultimates)
at the end of an HPDE last season i cooked the fluid so got new ATE blue put in by a shop (i was tired of bleeding brakes from working on another car)

track day last weekend
little bit of fade (to be expected with street-ish pads)
in the last ~3 laps of the last 2 sessions of the day
^ only going to get worse as i get faster
signed up for 2 more autoX and 1 more track day and 1 week at the dragon over the next 2 months... see how they hold up

cooking the OEM fluid wrecked the pedal feel completely
but even after the new fluid i still have a feeling that it should be harder...
first idea would be air in the system...
but i had the brake fluid replaced by a shop with a good reputation...

could it be the pad is just softer material than OEM? (i keep thinking that the pedal felt softer after switching from the OEM to the Axxis pads before the OEM fluid was cooked, but i am not sure this isn't my brain making things up cuz i don't have a good memory of the OEM pedal feel anymore)

or is it just a case of need to re-bleed the lines?

i would love to get a bbk but i am not ready for that cost yet
would brake ducting aimed at the calipers help with stock calipers and streetable pads and maybe getting ferodo 2500s or similar next time around (marketing info says they are supposed to be stiff pads) be good or useful with these issues?
issues being:
fade with Axxis pads and softer than ideal (for me) pedal feel

i know the pedal feel can be better because i had the chance to drive a prepped nsx and the pedal felt like a rock and the stopped FAST!!! <-- but that could be a lot of things

basically i am looking for ways to improve the pedal feel other than changing the brake system completely and bleeding the lines again... if any exist

that got long fast, sorry!

 

What year is your car? A set off SS brake lines and the Tyrol Sport caliper stiffeners may be just what the doctor ordered.

 

I was concerned of this exact issue even after a full brake flush with Motul brake fluid. I have carbotech ceramic pads and I am wondering if its just the nature of ceramic pads. On the street the initial pedal feel is softer than it was with OEM pads. However at my last auto x when the brake system heats up the pedal feel becomes rock solid.

 

It is a 2004 and oooo that is something that might be in the budget!

hmm, good to know that i am not crazy... in theory anyway

anybody else have this happen to them?

 

There are only four things you can do to change pedal feel assuming other things are working as they should- sliders are lubed, pads are fairly new and backing plates not bent, fluid has not boiled etc.

1. Fit a BBK which come with fixed mount (not sliding calipers) and other related parts that effect feel and response.

2. Install ss braided hoses which reduce hose swelling. (included in the BBK purchase)

3. Replace the caliper with something having smaller piston area thus requiring more pressure to clamp. (included in the BBK purchase)

4. Replace the master cylinder with one having a larger bore- thus lower pressure requiring more effort to push. (not needed in the BBK purchase)

 

so would you say the pad's material wouldn't make a significant difference to feel then?
^ if that is probably just in my head, i think a better bleed job might be necessary...

bbk is definitely in the future...
just a matter of saving up a bit more

thanks for your input!

 

I believe a pads material will effect bite or abrasiveness onto the rotor translating into a more rapid decel (that's its Mu effect) and can change as the temps do which is why race pads work better when heated up.

But the materials itself I do not believe will be compressible enough in any form to be felt as pedal stoke or fluid displacement. Even the street mateial won't be like a sponge when squeezed.

I think you may be overlapping "feel" to be both responsiveness of brake torque- the pad bite, with lack of firmness which would be related to the fluid issues and sliding nature of the caliper design. And if the pad were well worn down you may have had some plate deflection also as a single piston caliper tends to bend the plate under high pressure- why race calipers have two or more per side.

 

Oooooo I understand now, I think you may have hit the nail on the head. I think it might be a combination of a tiny air bubble and less initial bite with the ceramic pad when compared to OEM. all i know for sure is squishy pedals are no fun. pad still has >50% of its material so hopefully my backplate isn't bending yet

I assume the race pads you sell to go with your bbk have awesome bite etc when warm

how are the streetable ones like bp-10 compared to OEM or ceramic (if you know)?

also how easy is the pad swap compared to with the oem caliper?

sorry to swamp you with a bunch of questions like that, i prefer to research for months, buy once and be happy :D

and last random question will brake ducts help the street pads last longer before fading? or are street pads just not going to cut it even with that <-- i figure the ducts would be a good investment as they would work with the bbk too and not be redundant like steel lines when i eventually get a bbk and as i get faster temps will only go up...

thanks for the useful info!

 

I'll try to answer what I can without sounding like a sale pitch.

Two kinds of "feel". First is bite- that aggressive nature of the pad clamping on the rotor and slowing the car without huge amounts of effort. Think 40 grit paper and not 120 grit paper. A pad with a higher Cf bites harder. Most track type pads are of this nature. Second feel is pressure related and comes from compressing the fluid. A "firm" pedal is common when the entire system is fully bled out and has no air which can be compressed. Combined with the caliper design, rotor run out, hub run out, bearing wear etc you can experience some "longer pedal" than you may like at times from oe parts.

This leads to two types of "fade". First is almost always pad fade. That's the pad giving up due to its inability to function well as the temperature range you ask of it. This is the critical point as now the whole system begins to suffer. As the pads fade the car does not seem to slow down as well as before....so you push harder on the pedal to make up for loss of bite with an increase in clamping. But alas the pads are cooked and the rotor can no longer manage the cycling of the heat as it should. That usually leads to fluid fade- all the heat generated goes to the iron caliper and the fluid passes its boiling point and bubbles form. Now along with longer stopping distances you have a spongy pedal feel also. All that pressure also leads to the plate flexing which goes to lessen the contact point and work the center even more. Think banana shape. It's all just a slippery slope...

You're done.


Most BBKs work on the basic assumption that more is better. By using a larger rotor the thermal threshold is elevated and the efficiency is up because you use more leverage in the braking rather than clamping. And that added mass helps to control the heat build up. Combined with alum calipers which shed heat rather than absorb it and pads that are more tolerant of 1000f temps you have more stable braking, longer.

Yes pad compound effects the performance both hot and cold. Most race pads are crap on the street and eat rotors from being too abrasive at low temps. Street pads will break down soon on the track from too much heat. No pad does both real well. That's why most race calipers do have easier means to change the pads. Quickly. Pads like BP10 are similar to pads like HPS and others in that they are a good, stable, mild street pad that meets the demands of daily use.

Nothing wrong with working the stock parts hard. Just learn their limitations and do your best to control it. Ducting on the track may help but not on the street. And some pads may not want that low a temp to work at so experiment.

Hope that helped.

 

how i achieved harder brake pedal:

brembo bbk and stainless lines

 

that is some great info todd, helps alot, thanks a bunch

also glad to hear that it worked for you Alpha Motoring

looks like ultimately the bbk path is where i will end up
i will try a couple experiments first (don't really want to replace the brakes before this set wears out)

one last question
you mention that race calipers are designed to allow for fast pad changes
^i assume the DynaPro calipers are included in that
how long would it take someone to change from street to track pads (with solid mechanical skills)?

thanks again

 

Not long.

Pull the clip, pry pads back to retract pistons (one pad at a time) replace pad and repeat. Even for the mechanically challenged....maybe 5min.

 

5 mins eh, SWEET!
takes me longer to rotate tires... FWD has issues with even tire wear

so does that mean the only thing holding 2 halves of the caliper together is the clip? so no bolts to undo/re-torque? <- that is pretty nifty

thanks for putting up with all my questions, but it really is helpful to me
don't tell my significant other but i will probably call you when my current setup is cooked... :-X

 

Are there Wilwood options for the rear that allow for quick pad changes also?

 

Resurecting a dead thread here, but so far I love my Wilwood DynaPro's like the ones TCE sells. Yes, pad changes are really easy and require no hardware removal other than the clip you can undo easily by hand.

I notice that TyrolSport stiffeners haven't been mentioned much on NAM in a couple of years. What has the long-term experience been for those who are using them? I might get a set for the rear.