I recently replaced my cheap discount auto brake pads after experiencing some significant fade when braking repeatedly from higher speeds. I replaced the pads with R4S pads and stock replacement rotors, thinking they would be sufficient for my needs. However last night I again experienced a similar issue with the new pads (about a month old now).

After braking moderately from 120-0, accelerating back to 120 and braking to 0 again there was significant smoke/smell and noticeable fade on the brakes. Is this realistic after just 2 back to back drag style runs? Maybe my expectations are just too high, but this certainly wasn't something I would expect from $150 worth of pads in non-emergency braking.

I initially considered that I may need to change my fluid, but the smoke pouring out from under my fenders after the 2nd stop led me to believe it wasn't a fluid issue. Is it worth looking into a proportioning valve to get more bite from the rear? Or would I be better off with another pad? Any other suggestions?

 

That is some pretty heavy punishment for a street pad, even under moderate braking. The R4S, according to FM is "great braking for street or mild track use." Sounds like you might just need a more race-spec pad, esp. with the power you are putting down (as listed in sig).

 

If you are running stock calipers with >300hp, you are over-reaching the capabilities of the stock components. I have a pretty wimpy setup on my car, and initially thought R4S would be "good enough". I got 3 track events out of the car before the pads did the taper wear. I have switched to R4 pads, and although the braking is better, I don't have a lot of confidence in hitting the binders hard from 110 or so. I intend to ditch the stock front calipers for a TSE Willwood front kit and upgrade the rears and proportioning valve. Hopefully this will give me the confidence I prefer when slowing from triple digits.

Moral: If you are boosted at all, you need better brakes than Mazda provided.

 

this is why they are rated as a street pad.

 

Thanks for the replies. I thought for sure the pads would be capable of handling a couple consecutive hard stops. Even "mild track use" seems like it would be way more stressful than stopping a drag race, maybe I need a parachute.

 

120-0-120-0 is a bit beyond "street use" or "mild track use" rarely on the track will you see back to back 120 MPH braking differentials (esp. in a Miata). On the street ...

 

^ What he said - I've used my R4S's for "mild track use". They started to fade after about 6 laps, with the largest differential being 100-50.

Was the pedal still firm when this happened? Then pad fade - rotors, tires, and venting all play a role too.