Stoptech vs. Brembo BBK?
 

I would appreciate some input from fellow track freeks about which Brake kit will hold up the best. My car is a track car only. I have the 99 spec rear brake set-up and ordered the stoptech BBK (race version). Problem is; the kits are back ordered from the manufacturer and has caused me to take another look at the Brembo kit. The Brembo kit is $1,000 more than the stoptech +/-. But Fritz has told me that the Brembo set-up was the best and smoothest he has ever run. My brake system upgrade has been thought out after a lot of reading on the forum:

a) 929 master cylinder
b) 99 spec (RZ) rear brake rotors/brackets
c) Stoptech or Brembo BBK (front)
d) keeping ABS intact ( flat spotted too many expensive R-compound tires)
e) Hawk DTC 70 front/ DTC 60 rear (pads)

Just want a set-up as reliable as possible and the least expensive in the long run. I logged a bunch of track time as instructor this season and plan on ton of track time next season. Needing more confidence in the "WO" so I can work on more "GO".

Dave:nod:

Dave, if you are done tracking for the year, wait for the stoptech's. I don't think there is a $1000 difference in the two. It'll only take an hour or so to put on once you have them. Also, the rotor backing plate/dust shield for the RS/RZ front brakes is a perfect fit for the stoptech kit(prob. the brembo as well). If you go that route, you can always go ahead and install them while waiting on the brakes. Another route is getting a backing plate with a flange for a hose so you can do brake ducts.

You also may want to get speed bleeders for them as I'm sure you know... makes track prep just a touch easier. I *think* the part number for the stoptech's 1010S.

Everything else looks good man! Hope to make it to VIR in the late spring/early summer and run into all the usual suspects!

Vir
 

Hey Brent...Thanks for chiming in. Yeh; hard to justify an extra $1,000 with little difference in the set-ups. I now have a pressure bleeder and catch bottle so I can bleed everything by myself. Are the front and rear backing plates available @ Mazda Motorsports? I did order the rear rotors from them. Still have my stock brake set-up on my car until I collect all the needed parts. Only thing missing is the fronts and backing plates/dust shields. Look forward to seeing you @ VIR. I could seriously use some coaching to help my lap times. Fritz did a ride-along with me and vise versa. Holy shit! I have some seroius cathing up to do. If you guys can get me under 2:10's this next season...Beer and Pizza @ Millie's on me! :icon_tup:

Dave,

My set up is similar to yours:
929 Master Cylinder
99 spec rear rotor
Wilwood 4 pot dynalite calipers rear
Brembo GT calipers front
I've used both Brembo and Stoptech rotors on the Brembo hat
proportioning valve
ABS delete
Hawk DTC 70s front and rear
titanium backing plates on front calipers

I get about 12-15 sessions on the front pads and twice that on the rears. The front rotors (Stoptech) lasted the entire season (13 races) and the rear rotors have gone 22 races so far.

As for the Brembo versus Stoptech question I'm not sure what to tell you. My setup just flat out works, no fade, no screwing around, the brakes are always there.

Guy

Pete and I are now considering the Endless kit for the same reasons the Brembo kit is better than the stop tech kit and of course the Endless kit cost about 80% more than the Brembo kit cost but brakes are not the place to save money :)

Possibly if the 4 of us go with Endless kits we can get a group discount. However I need a user friendly kit which both the stoptech and Brembo kit are so we are waiting on answers from the Endless camp.

Why spend 5k plus on the endless kit because you'll spend 1k less per year on replacing pads and rotors (I expect they'll last twice as long if the #s I've seen are accurate), a hell of lot less time worrying about brakes (the number one spot I like to decrease worries) and of course time is money too and although swapping pads isn't bad messing with rotors is a major PIA.

Yup. StopTech is a really nice kit, especially for the money, but the bottom line is, I have a fully ducted setup, and put new rotors on for WGI last hear, and have 7 days on them now and they're getting there (maybe a weekend left, possibly two). And, I get about 4-5 days out of a set of PFC pads before they are a little thicker than the backing plate, and if I go past that, it starts to trash the caliper seals from heat—and rebuilds aren't cheap. I don't suspect any of that would be any better with any of the existing kits, so you might as well do the StopTech because it looks nice and the price is right.

A $5-6k kit sounds ridiculous, but if it REALLY didn't trash rotors and calipers, and the pads were thicker and lasted longer (and weren't too much more expensive) it actually might work out over time... plus the "confidence" and less hassle factor.

Btw
 

Brent, watched your vid @ VIR with NASA Octoberfast. Nice work! Fritz is a fast MOFO for sure. Congrats on winning the time trial. Nice write-up in Grassroots Motorsports as well. See you @ the track.

Dave

Thanks Guy! I'm thinking DTC 60's for the rear just to help keep brake balance even since I'm keeping ABS (not as much experience as many responding to my post...lol). Appreciate your input!

Wow! I know you've put the research in Fritz! Don't know if can go that much, but let me know what you come up with from Endless. Maybe I can sell the stock seats from my base model to get me closer...? Thanks again for the pointers on track! I definitely have work to do!:nod:

Thanks for the input Peter. Nice lap times @ VIR bud! I guess its' Stoptech until you and Fritz come up with that Group Buy with Endless. BTW; did you get your exhaust sorted out?

Dave

Right backing plate - F138-33-261A
Left backing plate F138-33-271A

about $30 a piece.

Thanks for the kind words! The VIR TT video was from 2010. Wish I could of made that event this year. I ended up with a 2:05 later on in the weekend of the UTCC after adjusting my gears and shift points on some older tires and in the triple digit July heat(I always have all kinds of excuses). I wish I could of been around for the October NASA event on some fresh tires. Maybe next year.

I've had the same set of stoptech rotors on my car since I first put it on the track in March 2010. I suspect they'll last another year. Pads have lasted around 20 days or so for the front.

For the 99spec Rears, I just replaced the rotors... prior to that, I had the same set since 2008. The pads last around 20-25 days.

DTC 70/60 is a good combo. If you feel you have too much front bias, you can try 60/60(because they don't make the 70 for the rear unfortunately).

Thanks Brent...

Ran out of edit time from leaving work to getting back to my hootch.

I'll be happy to help any way I can with your driver progression. Alot of my time drops have come from a well set up car though, not the driver. What little driver skill I do have comes from Fritz(the man who taught us all to drive and drive fast at VIR) is the jedi master, I'm just the mere padawan.

I'm not really interested in the endless set up. Too rich for my blood. I also don't think the cost is going to be justified for the return. I could be wrong, but I don't see them having a pad that is also made by hawk or PFC(I could def. be wrong on that). The stoptech/99's don't give me any brake issues and I think they're plenty economical enough for me(99 rear rotors did increase by $70 each since the last time I purchased them 3 years ago though :D). I plan to duct the StopTech's when I get the time to, but hasn't been an issue thus far. We finally cracked the code on the manual, dual master cylinder set up mid year and my brakes stop just as fast as anything on track I've compared data too. Now it's just a matter or erasing muscle memory from the last year of having crappy brakes and start braking deeper and deeper.

Oh yeah, the 2:05 at VIR was also with literally no brake pad left and two severely cracked rotors. Confidence was not high. I did a kamikaze lap(maybe two) and came in. Alex in his GT3 ran a 2:03 though and Danny Popp ran a 1:58 or something silly fast.

As mentioned to you before super lap time in July :icon_tup:

I suspect the DTCs last a lot longer than the 01s so I may have to give those a try. Great rotor life as well so clearly ducting isn't necessary.

Yep the 99 rears on these cars running moderate power last a long LONG time.

Maybe I'll try the DT70 fronts—I tried the PFC 06's this time, and not sure they really wore better than 01's, and perhaps had not quite as much bite.

Thanks for the props but it's easy when you have a quick study who's willing to really put the work in and the balls of steel help as well :D

Can't wait to see what's in store next year and hopefully you can make a trip back to the EAST some time or maybe "Almost Racing" can get together at Barber :icon_tup:

I have stoptechs on one of my cars, no track time on them yet but had an issue with one of the calipers from a past owner and stoptech's customer service was top notch they went above and beyond the call to help us.

I'll be back to VIR next year at some point, come hell or high water.... chasing low 2's and trying to keep you in sight as always. Hopefully we can do a little planning and get you and Pete down to Road Atlanta next year as well. It's worth the drive.

Sounds like a plan on RA

At the rate you and that car are coming along you'll be the rabbit and I'll be the tortoise :)

Happy V day and keep your powder dry :icon_tup:

ptrhahn, Fritz Flynn,

If your main concern is the rotor and pad life, why dont you guys purchase the endless rotors and their pads for your existing setups?

Do you want the endless caliper because it allows you to run a thicker pad material for more brake pad life?



John

Pad thickness is really important to reduce heat to allow for long rotor and caliper life however the thicker the pad the more weight and knock back so there's always give and take but I'd much rather tap up the peddle and carry some extra weight than deal with replacing high dollar overheated pads.

Thick rotor (ideally floating) to deal with the heat but again give and take it's HEAVY

Caliper stiffness to deal with the huge space and offset from the spindle/upright that the thicker pad and rotor will need which is the same reason we can't just run a thick pad and thick rotor because it won't fit a caliper opening that's too narrow. If the caliper isn't stiff enough you'll get lots of tapering which means flipping pads to deal with the unequal wear, unequal pad temps from unequal wear causing rotor damage etc...etc....

I understand the endless setup is around 5500 and I'm guessing stoptech could come up with a killer brake setup for the FD for much less. Once I use up the rotors on my stop tech kit and my Brembo GT kit I'll probably make a call to Stop Tech and see what they can come up with and possibly we can do a group buy :icon_tup:

I've heard good things about Endless pads but so far for my money PFC is hard to beat. I'll give the DTC 60s a try once I wear out my PFC 01s but I'm guessing I'll be buying O1s again after the 60s.

PS From what I can tell Stop Tech is the up and coming brake company because of their excellent product/value and customer service.

PSS Regarding pads Grassroots motorsports did a pad test with James Clay at the wheel (He's an 11 10nths driver if there ever was one) and he said the DTC 60 was great but Hawke gave him a 60 front and 70 rear because most cars are front biased but most race cars are setup to run the same pad so that put the Hawke pad setup at a disadvantage and I think he gave the 01s the win. So with that said the 60s may be the ticket and they are less expensive so I'm excited to give them a try and also based on Brents info they last too which tells me they are NASTY or eat rotors which isn't bad because I've never replaced a rotor from being too thin it's always due to heat cracks. HAWKE as always has been a great value I love the blues which are easily the best pads for the money and I have used those in the rear for a long time.

If I may, if your looking at spending this sort of money, go with the Performance Friction caliper/rotor setup. The price point will not be much different even than the Brembo setup and these are serious calipers meant for track duty.

I personally refuse to use Stoptech brakes period, and I have told Dino and his techs that. In the RX8 World Challenge cars I run the STOCK brakes with Cobalt Friction pads and there is nothing on the track that can outbrake my car, lap after lap. Even Meyers car with the Stoptechs could not outbrake us, although it was not a fair comparison as they were using Hawk 60's and not the Cobalts.
Let me repeat- on the Touring Car RX8;s which run 1:36's at Mid-Ohio with Dan Clarke driving, used the Cobalt XR1 front/XR3rear pads, stock calipers and discs with good ducting and we have zero issues with fade.

Fritz,
It would be nice if Stoptech made a rear setup (even just 2-piece rotors). I thought it ironic that they make a "Race Version" front BBK to be used specifically for the 99 spec rear brakes; but don't make the larger rear 2-piece rotors or caliper adapter brackets like Racing Brake. I would be interested in a total kit from Stoptech instead of a "piece-meal" set-up.

D Walker,
Really appreciate your input from the racing world. I did search the web for Cobalt pads and couldn't find anything for the FD. Let me know if I missed something? I'm not sure if our 93' brake calipers equate to 2003+/- Rx8 calipers. If they are similar; it would be awesome if we could get great track performance out of STOCK calipers/rotors with the simple addition of Cobalt pads and adequite ducting. Cheers!

I don't think we FD folks have much luck running the stock brakes for very long—as with the RX8, a lot has happened in terms of the quality of brakes cars come with today, so I'm not surprised that in some cases the "upgrades" are no longer an upgrade. Some Nissan GTR guys have told me the same.

A bit of insight I'd LOVE, would be where to start in terms of PFC calipers. They make quite a few, so it's tough to pour through their catalog and know where to start... you'd likely need to be able to order with specific piston sizes in order to match it with the 929 MC, and whatever you're doing at the rear. You'd need to be able to be very specific about what you want.

Having run StopTech's for years (tracking and street, not racing), I've got my own sense of their pluses and minuses... would appreciate your insights on minuses (PM me if you, understandably, aren't comfortable dishing on a public forum). I'm at a point where the function of my system is pretty good, it's just a matter of how quickly you go through "consumables".

I spec'd up a custom ST rear kit last winter using their new mini 4-piston rear calipers. The issue I ran into was wheel clearance for the wider rotors and calipers, (which forced the mini 4-piston because it's narrower than the 2-piston), and then piston sizes. In order to "match" even the "race" front kit, you needed REALLY small pistons to not screw up the bias, since ST has gone fairly small up front to match the OE MC. I'm very particular about having a super firm brake pedal, and wasn't willing to screw that up. I'm running the 929MC with the ST kit sized for the OE MC, and with the RB rear upgrade kit, and I LOVE the feel.

The other issue of course would the deletion of the e-brake. Having just loaded my car on a wooden-plank trailer in a snow storm, I don't know what I would have done without the e-brake.

I can look today to make sure I am right, but the RX7 and Rx8 calipers are totally different. The RX7 uses a smaller disc (came with 16" wheels IIRC) and a 4-piston caliper, the RX8 was designed from the word go for 18" wheels and uses a larger disc and a sliding caliper. At first glance without taking measurements it does look like the RX8 setup would bolt onto the RX7 wiht minimum modifications.
We use a Mazdaspeed supplied duct-made by Speedsource but easily fabbed if you have the tools/talent- and the aforementioned Cobalt pads. Over this season we ran 5 Pro races, several Club races, and many trackdays on a single set of rotors. In fact, those rotors are still on the car and are good to go for at least testing purposes. We used changed front pads once this season I believe, would have to check the records. I do know that when we changed the pads they were still OK for use for say, a test day or club weekend, just not what we wanted for a WC weekend.
If I were allowed -and we are not in WC- to upgrade the brakes I would use the Performance Friction calipers/rotors or the AP setup. The AP setup is serious money, the PFC is less money.
If you guys are blowing through brake pads- especially good pads like the PFC 01's etc.- then there is an issue somewhere. I would start with ducting and work my way back from there.
The reason you did not find an FD application for the Cobalts is that they virtually custom make each set of pads on order. As far as I can tell, they only stock pads for popular applications, and even if you think it is a popular application they may not have it on the shelf. This is the only frustration I have with them, as I have to order pads weeks in advance of needing them. You might need to send them a sample for a stock FD caliperand expect to wait about 2 weeks or so for them to run them through. They are racers and they are at the track as much as anyone so they know whats up and are great to deal with.

The problem with the FD is it was designed for a 16in wheel and has a small diameter disc, and this is a serious issue for good braking. The RX8 was designed with a larger diameter rotor from the word go and the greater torque arm effect is the largest difference in braking. The ABS is better too, and FWIW I believe, having looked at both cars with an eye towards this, the RX8 Hitachi ABS (non-CANbus) would be a very easy drop-in for the RX7.

You would want to put the catalog away and call or start an email dialog with one of thier engineers. They do have a vast assortment of calipers, rotors, and pads etc. and if you give them the car weight, tracks or types of events your going to run, and your expectations they will be able to help you with at least a good starting point. The engineer there I am currently working with for the Grand AM cars is a pretty sharp guy, and I can see if its OK to post up his contact info.
EDIT- as a price point comparison, to replace the (race not street) Brembo setup on the Challengers with the PFC brakes- calipers, rotors, pads, etc fnt and rear- is abotu 6K a car. This may be a price given to Grand-Am competitors, but still should not be far off. With some street car BBK's nearly 6K for the front alone, I would see this as a good value.

Not getting into specific details there are issues with the Stoptechs when used as anything other than a streetcar fashion brake upgrade. I really do not like thier caliper design. Meyers I know tried two different setups and still was not able to gain any advantage over the stock caliper other than the two-piece rotor acted as a heat barrier and kept some of the heat out of the hubs, which he felt allowed his ABS sensors to live longer. I never had any such issues myself. The thing I would stress is that no matter what is says on the box, these are kits designed for streetcars as a fashion statement first and for a performance advantage second. In all seriousness you would be better off to get a set of Wilwood calipers at half the price
Dino is smart however and a great businessman, Centric (who owns Stoptech) also owns a lot of other brake companies, and there is now some tie-in with Cobalt. It would really not surprise me at all if he made a push for further development.
I will be glad to go into specific details of why not to use them over a phone call or in person, but that is about the limit of what I feel comfortable putting in writing, PM or no.

I've heard issues with cooking seals and I think Pete had that problem as well but as always you get what you pay for and for 1500 the ST kit is a much better kit than some of the other budget kits out there.

Not surprised you are out braking your competitors on stock brakes which are probably lighter and perfectly matched to the ABS setup but I'm guessing you are also blowing through pads and rotors. Doesn't matter at the pro level but us no budget amateurs do everything possible to save are equipment from damage. If you guys don't have ABS then I'm VERY VERY surprised you are out braking your competitors especially with Cobalts (not a fan) so it can only be the driver has a good shoe or Mazda built a hella good stock brake kit for the RX8 :icon_tup:

PFC is pricey on all their equipment but IMO it's the best brake stuff out there dollar for dollar but like Pete said I don't have a clue about which caliper to use and Stoptech would know what the FD needs. The current Stoptech kit I have bolted on my car has better bias than my GT kit but that's the only place there's an improvement. I'm sure I could call Brembo and explain that there's is just a little bit of front bias and they'd come up with a good solution but I also feel it would be expensive because Brembo products have a well deserved reputation surcharge.

Pete,
I did like that about the RB kit (keep the e-brake). I don't think I'd want to be without it either. Since I already had an RZ rear end here at the shop; I decided to go with the 99 spec rotors from Mazda Motorsports and just swap out the caliper brackets along with the larger rotors. It just seems to me that Stoptech could at least do what Racing Brake did and give us 2-piece rear rotors and brackets for the OE rear calipers. I will be installing the 929 MC I got from Ray Crowe along with my total upgrade. I want the same "super firm" brake pedal you describe and that Fritz was going-on about @ VIR a couple of weeks ago.:icon_tup:

Pete's car is a freak it's the only FD I've been in with such a hard peddle. It's basically abi normal in a good way :) If I tap up my peddle which I have to do anyway because the front pads wear quickly my peddle feels great.

No need to fix something that isn't broken. Our rear brakes are fine for the power levels we have. My rears last twice as long as my fronts and work well.

Two piece rotors are a PIA with much greater chance of warping etc.... so as long as we can get the 99 parts I see no need to change.

Take the money we save on rear brake rotors and pads and lighten the car somewhere else or add safety etc.....

PS if you really want some two piece rear rotors Precision Brake can help you there but again IMO it's a waste of money.

No we do not blow through equipment :) see here:

I should also mention they are the set of rotors that came on the car when I picked it up from Tom and he dcould not remember how many races they had been on the car, and yeap, they are still on there and still in awesome condition.

It is probably also helpful to poitn out this is a 2650lb (empty) car that starts the race at just over 2900 (fuel and drover) and finishes at 2800-i
sh

The weight is a big difference but more importantly is the speeds we'll see versus the RX8. I hit 160 both front and back at VIR. I could buy a 25k ceramic move it kit and still probably wear em out :)

As you know there's a huge difference in brake wear from 100 mph and up and from 140 to 150 is probably 2 times the wear, 150 to 160 4 times etc.....

Yup... my car with me in it and a full tank of gas is about 2930 lbs, and we're pulling down twice a lap from 160, using 285/30 Hoosier DOT tires. Still though, that's no more than the GT3's and Z06's out there that are heavier.

I am willing to believe, though, that there's something more to it—including a technique issue. It DOES seem like the rate that I/we going through pads and rotors is high—and on the pad side particularly since I'm not willing to use the last 3/16" or so of pad due to heat transfer to the calipers, even with Ti backing plates. I've got pretty decent dedicated ducts up front, may look at improving them, but still.

http://www.rx8club.com/showthread.php?t=204813

If you guys are running 2.13s or so at VIR it all makes sense.

Bottomline: it's the speeds we'll see in the modded FD that's killing our brakes.

Yep and T1 cars are replacing rotors and pads after a weekend of racing. P cars came with REALLY good brakes that will last fairly well but there's no majic bullet for both tire and brake wear on a high HP car.

Pete the answer is in rotor size and thickness and pad size and thickness. Ducting helps some but if the brakes are too small and thin no amount of air will save em.

My RS has 15 inch brakes with MASSIVE pads both thick and long and I replaced the fronts after about 4 weekends or about the same as the FD with the GT kit bolted on. RS kit has decent cooling ducts and the FD has good cooling ducts.

I have not run the car at VIR, but we did 1.36's at Mid-Ohio this year, so maybe use that as your yardstick? That video was from a couple of years ago and was on Toyos, not Pirellis that we currently run. our time at RA on Hoosiers was in the 1:38's running relatively conservatively. Remember that we only have 225whp and run a rules mandated 17x8in rim and Pirelli DH compound slick. Originally we thought the slicks were going to overtax the brakes compared to the Hoosier or Toyo DOT's, but they seem a near perfect match.

Dependant on drover we can see 2930 with a full fuel load, so weight is about the same looks like.

There is also likely a difference in braking technique as well. Chip, JD, Jason, and Dan have all been extremely impressed with the car under braking and once they come to grip with the way they need to drive the car are able to put down extremely fast laps. If you happen to be in the area and the track is open you are welcome to take a few laps in one and see what you think.

Fritz,
I feel good about my decision to go with the 99 rear rotors. It was by far my cheapest date and I like the fact that they hold up well (according to you and Brent). I was just thinking that ST should offer the rears as an option under the circumstances. I will definitely be lightening my car this winter. Looking forward to some more schooling with "The Master"; as Brent would say. Cheers!:icon_tup:

Would love to try an RX8 race car. I've been on the track with a few and they look like loads of fun.

Technique is always a part of brake wear as most of us over brake but both me and Pete get threshold braking and go in with a balanced car at a decent speed of course we could do it better but who can't :) However I don't think his brake wear has much to do with technique it's basically going 160 mph and slowing to 50 that kills the brakes.

I brake just inside the 5 and if I reduced my speed to 140 I can brake inside the 3. Eric was probably braking at about the 2 at 125 or 130 and my car could do that with virtually no brake wear.

I've never been to RA but Brent who also has a TTS FD runs 33s there and will likely drop that to a 31 this coming year. Basically the typical track prepped FD is going a lot faster with much more tire which is what's tearing up the brakes. I'll get about 4 weekends out of my front pads and around 12 out of the rotors. However these are weekends going 3 or 400 miles.

Yep even the stock rears hold up well with 13 inch front brakes although going beyond the 13s could make the bias a challenge.

Look forward to hanging out some next year :icon_tup:

I'm running a custom Wilwood setup, built around a 12.9" x 1.25 GT 60 directional rotor. The added rotor mass with the thicker rotor allows the brakes to take the extra heat from the hard stops. I'm running 18-19 lbs of boost, which dyno'd at 459 rwhp. At the Edmonton Indy this year I was able to pull the car down from around 155-160 mph to 30 mph lap after lap without any noticeable fade. Many of the other cars (GTA style stock cars mostly) were having braking issues. I run a direct 3" duct into the rotor and Use the Willwood SL-6 caliper with the 1/2" thick brake pads. I managed two seasons on the pads before I changed them out due to the start of taper wear. In my mind, the stock rotors, regardless of year do not have enough mass to absorb the heat. Once you go above 400 rwhp you really need to step up to a much greater mass for the rotors to have any hope of longevity.

-Trent

I have run my 93 rx7 since 1997 and have tried many combinations. Our track is super hard on brakes , ie. 220 kmh into a 1st gear corner! Here are some of my experiences.

The stock front brakes are too small for anything over 350 hp. My first upgrade was the brembo F40 kit (38/44mm) with 13 inch stillen rotors. These rotors were way overpriced and didn't even last very long. The pedal was low and needed a 929 mc. With the 929 mc I was still unhappy with the pedal feel and changed the pedal ratio by modifying the stock pedal to a 2.85 to 1. This gave a pretty firm pedal. The next step was i used the 94 supra turbo fr. rotor. It was cheap and 12.7 x1.2ish. I had to enlarge the center hole and had a machine shop make new mounts for the calipers. This was a great set up with the stock rears. I was still losing out to the Porsches and without good ducts the brakes were very hot.

I should have built good ducts.

Instead i found out the srt8 Chrysler has the same bolt pattern, center hole, and a good offset for the rx7. I had another set of mounts made for the calipers and ran these srt8 14x1.25 rotors with good results. And they are cheap! But....... Now the car would understeer in trail braking. Too much front bias. So I used all the left over supra front rotors and put them on the rear, cut them down to 1.1 , and used a c5 corvette caliper. The stock rr rx7 one is about 30mm, the corvette c5 rr is 45mm! Now i had pretty good balance. But now the pedal was less firm , but acceptable. This set up was great at 460 bhp with slicks. But in 2007 we installed a 700 hp 3 rotor. We were again heating up the brakes.

So i went all out with brembo's pro race stuff. 14x1.4 rotor as used in grand am, alum hats, and the monoblock brembo gtr caliper. I took these parts to a very talented race shop( nasport champions) and they said , You really don't need that much brake, you need 5 inch brake ducts! I really couldn't send the new brakes back so they made the hats, adapters, etc.

I made custom ducts that use every inch of the cente of the rotor and 4.5 inch ducts.

This has been a bulletproof set up until this year when we replaced the wiring harness for a race set up, and the stock abs with the s2000 system (twice the ecu speed, 4 wires to hook up.). It seems there are two limiting valves in the rx7 abs that handle the bias. All of a sudden I had way too much rear brake. Even with adjustable bias valve cranked it was not right. Unfortunately we found this out at a track with a mile long straight. And it seems the pedal was softer without these valves . So for this year I have added another in line bias valve and changed out the booster for a miata booster with 1/2 the boost. Now i have a very firm pedal and should have good balance again.

My advice on front calipers.

Most of the calipers on the market, especially the street ones, have a pad that has about 1/2 the meat of a dedicated race caliper. And I found the prices and availablity of compounds for race calipers to be cheaper. Twice as thick means twice the lifespan, and less heat transfer when new. That is a big savings. The gtr caliper I run uses the same pads as some nascar teams and they sell top line (pfc 01) pads with 90% pad left for about $75 on ebay! Sometimes 2 sets for $75!! Also these calipers are super stiff, and are made of a much better grade of aluminum. I have seen these on racecars for 7 years without a rebuild or a leak. I have seen a lot of leaks with wilwood and outlaw after 1 season.

My advice for a track car's front brakes:

You can get proper brembo/ pfc/ap/ alcon race calipers on ebay from nascar stores for about $1200 used. Get a machine shop to make some adaptors , and run the srt8 rotors ($110) or the supra tt rotor . Cheap pads, cheap rotors, and killer heat and stopping power. Ohh, and don't foget the 4.5 inch ducts!

wb

Walter,
Thanks for sharing your brake information/experience/progression. That is alot of valuable data in several different dimensions. The S2000 information is especially useful. I assume you are still using the stock RX7 pedal assembly w/ modified ratio and 929 MC?

I've been keeping an eye out on the higher end stuff that shows up at a greatly reduced price used on various sites and spoken to a few brake companies to get a few reccommendations. I want to stay informed so if/when I up the horsepower and need a brake upgrade, I'm in the loop enough to make an educated decision. My plan is the same as yours if that happens: Buy the calipers and rotor rings I want to run, and build a caliper bracket and rotor hat to adapt and fit the system. I've had a few racing buddies doing essentially the same thing as you have done with great success. One is running an Alcon setup from a NASCAR team with some huge rotors and some ridiculously thick pads that are really cheap.

One thing to caveat that you have eluded to: There are a good bit of calculations/math involved to build and size your brake system... as well as some unknowns, such as the restrictions in the mazda abs system. Or compensate other aspects of the system to balance other components. Luckily, with the dual master cylinder set up it should be easier to tune and balance the brake system by changing master cylinders to ensure I have the correct percentage difference between the front and rear. Once that's dialed in, you can go up and down in MC sizes to make the pedal more firm or less firm(which essentially gives more modulation, but you still have to take into account brake system compliance). From there, the balance bar provides I think 33% of proportioning adjustability(if memory serves me correctly) to fine tune variables such as track and weather conditions, etc...

WB,
Awesome info and thanks for sharing :icon_tup:

I also have the F40s and like you wasn't happy with replacement rotors from Brembo so I use Coleman Racing who make decent rotors for around 500 shipped and can still maintain the 2 piece setup which probably saves a pound or so.

I can live with the F40s but I'm still not completely happy with my pad and rotor life and the F40s are just a little bit front biased (13 inch rotor) which will always slow you down. I have a decent brake duct setup probably 3 inch pipes with 4 inch hose going to a tight backing plate but I'll bump the pipe size to 4 inch this winter.

I won't run more than 350 rwhp so I really don't have to sweat the brakes too much but I have a brake fixation :)

Again thanks for the great info it will come in handy when I swap to a different brake setup next year :icon_tup:

understandly so ;)

BTW, were you creepin at VIR on Monday? Saw a Red FD in one of Jon Felton's pictures that looked suspciously like you in the red 95 R2.

Where did you find the SRT8 Rotors that match FD hubs? Did you have to machine them at all?

2009 SRT8
http://brakeperformance.com/images/d...tors/63063.gif

1994 FD
http://brakeperformance.com/images/d...tors/45051.gif

Yep just go w/o them one time and from then on brakes will be your passion, obsession, fixation and constant worry :)

I wish that was me. I'm probably done for the year but might take the RS out for some fun on the Patriot course and F after T giving if the weather is good.

yes they bolt right on. The .6 mm center hole difference is not a big deal, thats .3top, .3 bottom, , the fit is good, especially when you factor in heat expansion. The larger bolt holes make up for the slightly larger bolt circle and they slip right on. No vibrations or issues. One note is some calipers may need trimming to fit a 14 inch rotor. What i liked about using the supra rotor ( which needs minor machining to fit) for many years is you could turn them down and put them on the back, saving a lot of money.

Just realized I misspelled you name Wouter. Sorry about that.

Happy New Year Folks! Just wanted to post the final upgrade and share with everyone. The final install ended up as follows:

a) Stoptech BBK (Race only version) It is biased for the 99 spec. rears
b) RZ (99 spec) rear brake rotors with RZ rear caliper brackets (rotors from Mazdaspeed-Thanks for the part numbers Brent)
c) 93' 929 Master Cylinder (re-manufactured; Ray Crowe hooked me up here)
d) Hawk DTC-70's - Front, Hawk DTC-60's - Rear
e)Pressure flushed the entire system with Motul 600 brake fluid

I am happy to report that the pedal is as "Stiff as a wedding Pecker"...I hope it has as much "Wow" as I think it will. I bet this pedal feels a lot like Petes'; "a freak of nature" as Fritz has said. Thanks to everyone for some outstanding tech input and experience based advise.