1st to 3rd

RB supplied the fix. One of my original calipers was damaged. I noticed, and RB verified, the pad to caliper orientation is slightly different with the replacement calipers. Snow is flying here, so I have yet to drive on the new calipers. While I cannot verify the fix actually corrected the pad taper I witnessed, the change seems to be in the right direction.

This is consistent with my observations. I measured .01" taper after one track day.

If I read correctly, the taper you observed is consistent with the taper I had from pad to caliper misalignment. I wonder if it’s from flex or a dimensional issue.

Given your power and weight, the wear and temperature results are promising. Thanks for taking the time and reporting!

dclin

iTrader: (4)

Hyperion, I think you should have been the one to receive the free kit.

In either case, are there any other solutions to pad knock-back, other than springs? Is this an issue with flex in the knuckle/caliper mounting tabs, or lateral tolerance/play in the wheel bearings?

ptrhahn

iTrader: (9)

^^^^

It's likely a combo of things... flex in the hub carrier, play in bearings, floating rotors, vibration, etc. I remember Pettit used to do a center-lock hub conversion... I wonder how much that consisted of... new hub carrier? spindle?

Not that I'd want to buy two new sets of center-lock wheels at this point (though center-lock wheels WOULD be hot ****) , but it'd be interesting to ask them if the new parts helped.

Herblenny

iTrader: (13)

I don't know what happened to my previous post.. But anyhow,...

Plus One with you Rich!

When I opt for the $150 credit I also thought ONLY thing will be to grind the spindles and it will resolve any problems.. But now after reading thru some of the findings people are seeing, I'm getting little pissed about their lack of communication and efford to resolve some of the issues others are seeing..

Howard, Since you worked with them from the beginning, can you see what are the options we have to resolve some of these issues??

I'm not trying to be lazy, but I'm sure they (RB) doesn't want all of us calling them to find out whats going on.. I think better one or two of us call and find out if we need to just deal with it or take other measure to resolve the issues.

At this point, I think its pretty clear that not enough R&D and we took words from select few and invested on this kit. I hope all will be resolved in timely manner..

habu2

That is my understanding as well. No mention of caliper/pad/rotor alignment was made, only the spindle interference problem.

habu2

I also noticed they no longer have a sub-forum under Vendor and Group Buys ...

So is direct contact to Steve Woods our only means of communicating these problems back to RB? Is there a direct number for Steve or do we call RB at 973-335-0721 and ask for him?

habu2

Howard seems to have abandoned us as well. His last post to this thread was over two months ago (10/18).....

gracer7-rx7

iTrader: (16)

I usually just email swoods@racingbrake.com

He seems pretty good to work with and I can be a pain in the *** customer when a product or service doesn't meet my expectations.

Unlike Rich, I never had the pleasure of speaking with Warren.

Good luck and happy holidays all.

65Imp

iTrader: (8)

I'm in the same boat and I have their et500 pads to boot! Should we all individually get in contact with them? Or will they be sending out an e-mail? I have no problem with a little grinding, but the rest of these issues are unacceptable.

Herblenny

iTrader: (13)

I noticed that also.. And I'll be honest with you.. I highly trust Howard's words from the beginning and I have also told several people about this kit. I'm quite surprised that Howard hasn't got on and either confirm or defend these problems.. I really can't say if I'm disappointed or not as I haven't install the kit (still waiting on new hubs and engine) so, I can't give my 2 cents.. but what others have observed, its NOT looking good...

I think before we all individually send emails or phone calls.. I think we should PM Howard and see if he could help us. Maybe they are aware of the problems and working on a solution

Herblenny

iTrader: (13)

By the way, I was about to PM Howard and saw that he was looking at this thread.. So, I'll just wait

carx7

iTrader: (31)

I"m going to toss my name back out there to say that I too have the 1st gen kit and opted for the $150 rebate, and have yet to install any of it. I do have the updated lines, and they replaced a rotor hat that was damaged during shipping, and exchanged my green calipers.... BUT, when I took the rebate I thought it was ONLY b/c of some spindle grinding. These other issues concern me, and I don't even want to put the Et700's on for street driving.

I'm willing to wait for a "group" response rather than individually email bombing them, but sheesh.......

Herblenny

iTrader: (13)

I just got a PM from Howard and he said that he will come on later on today to update us on his findings...

I think most of us on here are older, more mature crowd, and we all want this kit to work out for us.. That being said, I'm hoping these issues regarding this BBK will be resolved in a professional manner and not shouting match.

And as many you have said, I think group approach is better than "individual email bombings" as carx7 has suggested..

PS.. I also want to Thanks those of you who have spent your time testing and reporting the findings to us! One of these days if our path crosses, I'm taking you guys out for a beer.. even though I don't really drink

gracer7-rx7

iTrader: (16)

fwiw, RB sent out a group email to all of us that were waiting on the version 2 kit. They communicated regularly with us on the status of that.

Herblenny

iTrader: (13)

Version 2? So, people with Version 1 screwed??

hyperion

iTrader: (2)

I've reached out to a number of people from the automotive and racing industry on this one including the chief development engineer for a top Champcar team as well as an engineer involved in the new GT-R development. They have all said essentially the same thing: that knockback happens and it's always a matter of how severe it is. As Peter suggested it's caused by a number of factors, and some cars have it worse than others. After looking at a number of other cars that suffer from this issue (like the STi, for example) I'm pretty much convinced that it's a design issue of Mazda.

It's important to note that Stoptech puts knockback springs in their 'race only' kit for the FD, but does not do so for cars like the 'vette, 911, etc. The hubs and uprights on the Mazda just weren't designed to handle the lateral loads that you see when you remove a 225 series road tire and slap on a 285 series R-compound.

Next time you're at the track, try doing this: drive half a lap so that you hit each turn-in point without needing to brake. Just accelerate or coast so that you're at the apex speed just as you reach the corner. After a few corners find a straight and then push the brake pedal down. On my car the pedal will go about 50% of it's travel before any braking happens.

I may experiment with springs, but I'm worried that this is going to compromise the streetability of the car. So for now, I'm just learning to tap up. It's just like any other technique like heel-toe. And the rally guys do an even more aggressive version of 'tap up' to test surface conditions prior to a corner. I think it's a good skill to learn.

-ch

gracer7-rx7

iTrader: (16)

None of us here know, Phil. Don't jump to conclusions though.

All I'm really trying to say is don't rely upon second hand information and get in touch with RB if you want correct answers on the options available to you.

hyperion

iTrader: (2)

I'm away from my car for a few weeks, but when I get back I will definitely look into this. I was thinking flex because a piston/pad misalignment should have produced a taper on both the inboard and outboard pads. Since I saw taper only on the outboard my conclusion was flex because in the flex scenario the inboard half of the caliper can't rotate nearly as much as it's fixed to the spindle.

-ch

ptrhahn

iTrader: (9)

This is a good point Chris, and perhaps one deserving of it's own thread. I wonder if some of the RX7 shops that raced the FD professionally might have some intel on exactly WHERE in the whole mechanical equation the FD specifically suffers. Is it bearings? Is it uprights? I wonder if a modern CAD program, similar to what Saxyman used for his rear strut/harness bar could either create a reasonable stress/flex analysis of the FD hub carrier, or engineer one that doesn't flex?

jantore

Hyperion have u tried the Ferodo DS3000 pads?

I did run the DS2500 this year on my AP Racing front brakes and im verry happy with them. But im going to try the DS3000 this summer, and add 4 pot calipers to the rear breaks as well to get more breaking power in the rear.

But the pad wear and pad fading i would think would go away with some real racing padds.

Try the Ferodo DS3000 on Laguna Seca and i think u will see some diffrent results. That is if u can find pads that will fit the RB calipers.

Is there any issue with the rear kit from RB? i was thinking about ordering the rear kit for stock calipers. And add a 4 pot caliper from AP that will fit the RB rear disks.

Regards
Jan-Tore

Howard Coleman

iTrader: (6)

i had planned a more lengthy post but we are switching over, finally, from dial up to a satellite setup and my net time was limited yesterday and unfortunately today. mix in the holiday madness. normalcy may return next wednesday.

based on Hyperion's track observations and other recent comments i pulled my ET700s and did some measuring.

i received the initial RB pieces in mid April. Warren indicated they were primarily for dimensional usage. we worked thru a number of issues together over a period of time. my car was not ready for the road until june 11.

during that period an immediate issue was rotor to upright clearance. i posted this on the thread and sent Warren pics. i chose to grab a file and see just how much needed to be removed. i shared this w Warren and said it was his call as to whether people would be asked to do a modest bit of work or whether the rotor latitudinal location should be changed.

once on the road in June after some miles i didn't like the wear location on the rotors. it was too far outboard. i spoke w Warren, sent him pics. after further miles it became obvious that something was wrong. i pulled the pads and measured the location of the piston imprint on the backing plates. i found they were off the center towards the outside.

i spoke w Warren and he said that the calipers were just beta and it would be fixed on the production items.

i received a set of calipers on july 17. they had stainless steel pistons as i had requested. the pistons were relocated. they also produced a better wear location.

i logged 2000 miles on a combination of the two caliper sets and the original rotors.

observations:

at no time after spending 5 minutes a side w a file have i had any noise from the rotor/upright... so anyone concerned about this bit of work should not worry. Warren apparently chose to move the rotor out a touch so no filing necessary but it isn't a big deal.

i measured my ET700s that i have more than a thousand miles on... they measured out as i expected. there is no leading trailing wear difference. there is a touch of inner/outer difference.

rather than caliper flex (which of course could be a factor) i suspect a modest amount of remaining piston to pad misalignment is the culprit.



i spent a couple hours yesterday measuring things and have not yet located my sheet but will find it and add the numbers later. the point is on my calipers the pistons are still located too much outboard. they are closer to centered than the picture indicates because the backing plate pad gap is 2 hundreths of an inch wider at the inner face of the pad. as i recall i think the pistons on my calipers are off center by about .06.

caveat:
my calipers may or may not be similar to yours.
perhaps there is a reason for the offset. i am not a brake engineer. Warren is.
my wear pattern is near excellent. (note following picture)

as to the entire caliper being situated properly w re to the rotor.... mine looks good. no need for spacers.



i remain optimistic the the RB system will deliver. going thru the development on anything requires patience, resolve and work.

we have something special here. it does not surprise me that Hyperion logged excellent temperatures. the 1.26 inch front rotor is better than you think. Warren shared w me the results of a top of the line testing lab relating to his rotors v the competition, and when i say "competition" i am not talking street crap. unfortunately i cannot share the particulars but i will tell you his rotor material has no equal. i have the actual study from the lab.

i am looking forward to the snow melting, hopefully March, and getting out on the track. i did not invest the effort and resources into the totality of my FD, which has been 7 years building, to drive around the street. i share everyone's frustration w the process and do apologise for not fulfilling part of my job in 07. thanks to all that did get out ontrack and carried the ball.

08 is almost upon us and we have the opportunity to end up w an outstanding system.

howard coleman

1st to 3rd

RB does not recommend using Ferrado 2500 or Carbotech XP10 pads with their rotors. http://www.racingbrake.com/v/main/pa...g.asp?full=yes
As I stated before, the RB caliper uses the same pad as the AP caliper commonly used on the FD.

The issues have been limited to the front kit. The rear kit seems to work great

Howard, correct me if I’m wrong, but your pad to rotor alignment looks as bad as mine without the spacers. Comparing your picture to the ones I posted here: https://www.rx7club.com/showpost.php...postcount=1202
It looks like your rotors do not have the rust ring cut into them, which was causing a lip to wear into my pads.


I will measure the caliper piston imprint on the pad backing plate as shown in the picture. Howard & Hyperion, could you do the same? I’d like to compare results.

habu2

Thanks to Howard for posting. I'd like to see this thread as a means of feedback comparison rather than RB bashing.

And thanks to Hyperion & 1st to 3rd for posting their results. This is the kind of info we need to make this kit live up to it's potential.

cabaynes

iTrader: (4)

If only we had threads like this elsewhere on this forum, with actual research and technical understanding... oh what a day that would be

*makes a Christmas wish*

ptrhahn

iTrader: (9)

^^^

No kidding... instead we've got 1,000 post on the relative merits of twill vs. plain weave carbon fiber liscence plate frames.