RKA

APR did have a hand in designing the brakes for the A4. Stoptech later adjusted the pistons to the same size APR spec'd for their kits.

The R

sure do. ;-)

kylejk

RKA, that's pretty good info you've provided. I'll add:

Those paper thin openings they call vents don't do squat to help cool the rotors.

Anodizing will hold up and last longer than paint. There's a reason why aluminum cookware gets anodized (heat conduction, not insulation), and why anodizing is prefered over painting wheels in race applications. Anodizing hold up to brake dust, salt, and other crud better.

Dars, go for stasis street sport kit. It's worth the extra $100 or $200. The calipers are painted, but you get a better quality rotor shared from their tracksport kit, not passenger car low grade cast iron rotors that stoptech buys. Stasis rotor-hats have real vents. Plus they have better semi-floating rotor hardware. Oh and also, the stoptech is made from 7000 series aluminum, rather than the 6000 series of the stoptech.

Dars, stoptechs will work fine but don't believe their marketing bull. Only those with little brake knowledge believe that stoptechs are "engineered" for the S4. There's no black magic to designing brakes. StopTech does a superb job of sourcing calipers made in china, rotors made by a large passenger-car-parts manufacturor in making an affordable brake kit.

StopTech's service is topnotch from what I hear so if you run into problems with the casting of the calipers (bridge too tight or brake pads not fitting), they'll send you new calipers. My friend with WRX had problems with his bridge not fitting into his calipers. They told him to lightly grind down the bridge, but he didn't want to do it, so they sent him a new bridge. Well that bridge didn't fit either. After that try, they sent him brand new calipers.

My friend with the WRX doesn't run stoptech rotors anymore tho. He said there was too much pedal delay until the pedal started grabbing. That's probably from the low cost rotors (I heard they're made from the same company that makes them for coleman). The rotor's inconsistant growth from heat probably pushed the pistons far inward, so there was alot of pedal travel required before the calipers actually started grabbing. Plus, he would get brake stuttering when the brakes were really hot, but would go away when cooler. That's probably from deflecting in shape from not having enough float.

Cheers,

geoff

hey can you email me? thanks.

RKA

Re: Rotor venting...I agree. The cooling effect they have is minimal. As I understand it, they implemented it to solve an issue with outer pads on a Viper wearing too quickly. Rotor temps were higher on the outside of the rotor, hence the faster pad wear. The venting provided a measure of increased cooling to even out the pad wear. Stoptech has NEVER claimed that this venting was necessary on our applications. I really doubt APR would have done away with it if it was considered necessary.

Re: Anodozing
Look at some APR calipers that have taken the toll of a bad winter. They look like hell. It's true, in a racing application, anodized aluminum is preferred, but our cars are driven on the street. Anodized calipers don't seem to be the ideal solution. I'm hoping to get anodized wheels shortly, however there is no way in hell they will be on the car when the snow falls!

Re: Low grade cast iron StopTech rotors.
There are people on these forums that RACE these cars with StopTech's rotors. Not driver's eduction events...they really race these cars! The stoptech rotors have held up superbly. Their input is enough for me to conclude that the rotor material is indeed good enough to handle anything we throw at it. Can they source better quality rotors? Perhaps, but that means it's going to cost more. If we don't need better quality, why pay for it? These kits are expensive enough.

Re: Calipers made in Taiwan
It's cheaper to get goods manufactured over there. Yes, StopTech's calipers do have beads left over from the casting process. You'll never find that on a brembo caliper, but you'll pay for that detail on a brembo caliper. I've seen the fitment of the caliper bridge. It's tight, and it needs to be, because that bridge is an integral part of the structure of the caliper. Add more clearance, and you take away from the solidity of the caliper. On the calipers shipped to me, it was fine. With a little finesse, the bridge would pop out. However if you're dealing with a manufacturer that isn't capable of building parts to very exacting standards, it's very possible that some of the calipers will have issues due to the tight tolerances that StopTech specifies. The fact that the caliper is sourced from Taiwan (or China or Korea or any other Eastern country) has nothing to do with it. I have a relative that works for a major jet engine manufacturer. They work with suppliers in said countries to produce HIGHLY specialized, and HIGHLY exacting parts for their jet engines. If those parts fail, a plane goes down. The fact is, it's entirely feasible to get quality parts sourced from those countries as reasonable prices...it depends entirely on the manufacturer you work with. Neither you nor I know anything about StopTech's supplier, so further discussion would only be speculation.

Re: Rotor hats made of 6000 series aluminum vs. 7000 series in Stasis kits.
You never mentioned what effect this has on braking performance. AFAIK, rotor hats don't do much. What impact would this change in material have on the performance of the rotors? Or are we to believe that 7000 is better because it's a higher number?

As for your friend's WRX...is this his first big brake kit? If the piston sizes are larger, the brake engagement point may be lower. Didn't C&D test a bunch of big brake kits on a WRX and find StopTech the best solution out of the bunch? It's hard to argue with results.

The vibration at high speeds...did your friend ever use street pads with those rotors under track conditions? Did he fail to bed the track pads properly (if he used them)? There are other reasons why he could have vibration issues when the rotors came up to temp. There is way too much speculation in your post regarding the source of these problems. I don't know the background you or your friend have in braking principles, but I'll bet money, StopTech has an edge on both of you.

I'm sorry if this post comes across as a flame...that is not my intention. The main reason I chose to respond are the assumptions you and your friend have made about the issues he has had with his stoptech brakes. I have no vested interest in StopTech or Stasis...I just think it's wrong to lead people down the wrong path without some substantial proof or knowledge regarding the issues your friend had. I didn't see any indication of that in your post, so I'm bringing that to light.

fka smurfette

and also, brake fluid eats away the anodization, leaving you with whitish-grey calipers that look like ***.

kylejk

That was stupid of me to insinuate that foreign made parts are somehow inferior.

When you mention that APR anodized calipers "look like hell", in what way did it look bad? Maybe they were just horrendously dirty? I can't see any reason y anodizing could be worse than paint. So what kind of wheels are you getting that's anondized? Must be nice.

As for my friend, no he's doesn't race, but he's been a die hard track junkie for 15 years. And just because someone gets sponsored to use a product doesn't mean it's great. All that says to me is that the product is good enough and the free rotors and/or $$$ is helpful because racing is $$$$$. Find me soneone who uses a product without being sponsored, and I'll listen.

And my friend's well aware of the different symptoms of glazed pads vs. coned rotors vs. warped rotors. He's replaced the rotors and mounting hardware and he no longer has issues with his rotors coning out. He's not sure if it was the rotors or the harware, but he's happy with stoptech.

Oh, the difference between 7000 series and 6000 series is small but if details are important to you, 7000 series is stiffer and harder (less flex) but more expensive.

RKA

My objection to anodizing is largely aesthetic. They look like crap after exposure to the elements. Smurfette, and a few other Chicago area folks can attest to what the calipers look like, and they have posted pics on the forums. I'll admit...for me, after spending this kind of money, I don't want calipers that look like they just got pulled from an acid bath.

The wheels...Fikse satin anodized FM5's.

Regarding racing...you're right, it's horrifically expensive, and sponsorships make it possible for people to race. So finding anyone that really races without being compensated in some form by sponsors is exceedingly difficult.

Regarding your friend's rotors...<a href="http://www.stoptech.com/whitepapers/warped_rotors_myth.htm">here is what I was referring to!</a> While you might balk because this information is published on stoptech's website...I've found their white papers VERY informative, and lacking the kind of self serving statements that can quickly errode any point they attempt to make.

Thanks for the clarification on the 6000/7000 aluminum!<ul><li><a href="http://www.stoptech.com/technical/">More White Papers on Braking...</a></li></ul>

kylejk

He says that he was getting vibrations from the rotors distorting in hard braking zones, because the rotors would be perfectly fine in lighter braking zones and when the rotors were cool. When he replaced them, he says there was no marks indicating that the rotors had expanded. Plus the contact points of the rotor and hat showed that the rotors coned because the lips of the hat weren't flat anymore and kind of "squished".

I'll do a mini unscientific survey and ask people with stoptechs that I see at the track if they get any vibrations when their brakes are hot and in hard braking zones.

That sounds like the hardware wasn't doing their job of letting the rotors expand with heat.

BTW, the stoptech article at the link you sent me is a good overview that's easy to understand by laymen, but there's some inconsistancies. The author says he's never seen warped rotors, yet stoptech says that in extreme conditions (I guess they mean track/racing) any rotor can warp. Plus they say that if the wheels are overtorqued, the rotors can warp. Maybe the author hasn't seen that many rotors. I've personally measured and turned warped rotors, and the warping isn't from glazing or overtorqued wheels.

That's too bad about those anodized calipers looking crappy.

RKA

I hadn't read that bit about coned rotors before...that's my dose of new info today! :-)