Race Brakes
 

Looking for some sensible advice please.

89 NA has what I think is the original Goodwin Big Brake kit on the front (Willwood Calipers, 11" discs (need to check that size though)) and 1600 calipers on a large disc with a Flying Miata Adaptor.....

Running full race pads.

I may be just being silly but I find the pedal a little soft and it has a lot of travel under hard braking in track day/race situations.

I could just learn to accept it but it leaves me with a constant feeling of unease that they have faded / overheated etc....they don't overheat or fade but the do feel a bit like they have or are about too....15-20 minute sessions at competitive lap times.

They are great in that the modulation etc is easy and feel fine on the road.

But I think I would prefer are slightly harder feel and slightly less travel.....

Questions are,

- Should I just accept it, it is fine.
- this is common and you can do .xxxx to help.
- this isn't common and it is VERY expensive to change.....thsi is what you do xxx

When was the last time that you bled the brakes?
Did you bleed your brake fluid in the correct order?
Do you have the stock rubber lines or SS lines?

I had this problem too and it turned out to be my old gunky brake fluid which would start to boil after doing hard braking. Flush your brake fluid and bleed it in the RR,RL,FR,FL order..i believe that's the order.

As an additional upgrade you should replace your stock rubber lines with 949 racing SS lines.

Cheers but the car has full braided lines. Brake kit, suspension, engine came from one of our top, succesfull race cars (well in MX5's anyway), which was parted out mostly to me.

Bleeding might help but it feels pretty much the same as it did at the last track day when everything was fresh (fluid and bled).

Problem is I have approx 80-100 hp more now (via the engine swap) and the performance and feel is a bit more important than it was.....

It definitely sounds like boiling fluid though. If it feels fine when driving normal but gets soft when driving hard for a prolonged period of time i would think your issue is the brake fluid...especially if the car is still braking hard.

What fluid are u using?

You have a turbo car, why aren't you running TSE brakes? They are god.

Only thing left for you to do really is to add more rotor and pad for better heat capacity. Sell your old set up to help pay for the new one. Idk what 1600 brakes are unless you mean the stock 1.6l calipers? id suggest upgrading them to sport brakes or better if u go with the TSE front BBK. Properly ducting air to the caliper/rotor cant hurt either.

TSE BBK is on my to do list, cant wait to see what everyone is raving about.

I think the 1600 refers to stock rears with brackets for larger disks. What booster/master cylinder are you running? If it is the original '90, going to the 15/16th should help the pedal.

What are the weight difference between stock rotor and the 2 piece that TSE/FM has?

Carbon Ceramic brakes ;-) I wish

Imagine Angela Merkel dressed as Hildegard of the SS holding you in bandage, forcing you to modernize Nietzsche's Gay Science while her Germany Shepard laps boiling-hot Nutella off your balls (for your sins) ... every time you step on the pedal.

Significant improvement as well.

It's not "the 2 piece that TSE/FM has". Our 2-piece rotor is not shared with any other kit.

...I..I don't know what to say. You've brought tears to my eyes, thank you.

Did it out the pear in your birnbrot?

Hustler, sometimes I really do wish I could understand what you are saying.

Thanks for the replies.

Yes stock MC and booster on Goodwin big brake kit (willwood 4 pot) with 11.00" rotors and stock 1600 calipers on FM adaptor brackets to a 10.75" disc. Oh and they have TSE brake Prawns with 2.5" ducting from the front spoiler.

Despite Hustlers hustling of the TSE kit (I DO appreciate the advice :) and believe me would LOVE that kit!!) Going to the 15/16th MC is an upgrade for my current kit then...?

What is this likely to do...firmer pedal or less travel or both?

Kiwi, if you double tap the brakes is the 2nd hit of the pedal a lot firmer and with shorter travel? I mean, before you go to stop if you hit the brakes to the engagement point, let off then hit them again, is the pedal shorter? You could just be getting pad kickback because the rotors/hubs/spindles have some runout. Which is a much bigger issues on fixed rotor fixed caliper brakes than it is on brakes with floating rotors or calipers.

Both. Larger bore pushes more fluid (also makes it higher effort).

i had a similar issue on the brakes of my previous car, have you tried a different brake fluid. i know most people like motul or the blue stuff whos name escapes me right now or the wilwood stuff that comes with those kits. i had problems with the pedal feel changing as the brakes heated.

they werent fading, just the pedal would engage lower as laps went by and things heated up. i read up and saw that some of the porsche cup drivers had that issue (they called it comressability IIRC) and went to endless brake fluid or brembo lcf 600+. since that brembo stuff is not that expensive at ~$20 per 500ml i went with it. no more problems with the pedal compressing when hot after that and activating lower. i run it in my miata too with decent results. that siad, i am on stock brakes and running ~5 seconds under spec miata record and there is a huge difference in how stock brakes perform within a windows of a 2:04 (3 seconds under SM record) to a 2:02 (5 seconds under) at my track.

at 2:04, the stock brakes are being taxed, but ok, at 2:02 i didnt think i would make a few corners, not that i slowed down. i just had exceptionally high sphincter tone for a few corners.

I ordered the Fm 4 wheel kit, hustler promptly chastised me for not going with the TSE kit. idk, all 4 wheels for the same money sounded good at the time. i figure it will be hugely better than stock so ill not know the difference.

Just to confirm, brake does not pump up and it doesn't change (very little if any) as it gets hot.

Just that a long and soft'ish (but very standard feeling) pedal for road driving is not that confidence inspiring slowing down from 200km/h.

Absolutely no problem from 50-80km/h.

Just to confirm brake feel is very standard I just think a bit firmer and less travel would be a little less concerning at higher speeds. Probably me just being finicky.......or not enough experience.

Anyway, thank you for the suggestions, will also look at a different fluid.

Sounds like the 15/16th MC is the answer, Is this a direct bolt on?

It sounds like you have air in the master cylinder.

Either kit will give a big boost over stock, but the TSE kit will be cheaper to own over time and provide much better pedal feel. I think that's worth the extra money at the beginning :)

$32 rotors and they last longer than 8 weekends per year. My TSE baller brakes paid for themselves in 2 years. I don't even have spider cracks in them and they have 2+ years with the turbo, 6 days NA.

BTW, what is minimum thickness on these rotors? I don't know when to replace them.

Time to reverse bleed.

perhaps life will be easier if i just open an account in hustlers name, pour in my race car money and let him buy for me lol

I'd be surprised if it is air but will do yet another bleed...

In the meantime can you confirm that the 15/16th MC is a direct bolt in replacement?

Also, out of interest, you guys with track/race cars....do you have an oem feel to the pedal or you end up with a firmer pedal simply by changing to a Willwood BBK setup?

I appreciate the TSE kit improves feel but I am trying to clarify my current situation....

Our pedal feel is better than even the 11" Wilwood kits - the difference between stock and our 11.75s is significant.

The 15/16 Sport master/booster drops right into an NA chassis. You'll need to tweak some of the brake lines a little bit, but that's not difficult to do.

I have GSE BBK, bias valve, sport rears, sport master/booster and if I told you the brake pedal and balance felt as good as a 997 GT3RS, would you believe me? I ask because it felt better. I like a rock hard pedal, same pedal feel every time, every corner of every track,and more control.

Emilio drove the shit out of my car at Hallett,hopped out and said, "the brakes are great".

Make sure to get the 2001 lines with the master for minimal bending.

now you guys are just taunting me

LOL @ not listening to me.

Going to hijack this thread for my own benefit for a second.

I've got oe 99 brakes with carbotech xp8's all around. I quite like the braking performance but getting quite a bit of pad taper in front. Going to throw some xp10's on there to get me through the season and then put a bbk on to mitigate pad costs down the line.

That being said, I want to replace my master before hand. Will I be able to go to the sport master on my car with the oe 1.8 brakes for a while before going to the tse kit? Any potential downsides to running the brakes this way until the xp10's die?

TIA.

The pedal will be pretty touchy but you will adapt. On CT pads I expect the lower myoooooooooooooo to make the difference minimal. Now, on DTC-60 is would be pretty sketchy I think.

Thank you for the response it was very relevant to my interests. I've been a fan of dtc-60's on other past cars but I'm too much of a pussy to try them on my non abs equipped miata and street tires. Maybe one day when my skillz are mo bettah.

Don't be a woman.

I ran a bit on DTC-60 at the track this weekend, i could tell a difference in bite between them and the Hawk Blues I was used too with the 60's having substantially more initial bite. they were quieter when cold than the Blues as well.

My inferior Fm BBK turned up last night, i might install this weekend. Sadly i learned my xidas wont be here until april.

Shanem - intrigued to know what you think of the pedal feel on track when at speed when you do install them.

To the OP you don't mention what pads you are using. I once chased a spongy brake pedal half the day only to later find it was my cheap porterfields causing the problem. I switched to RS29 Pagids and the pedal became rock solid.

If you are not using any of the good known pads I would start there. Swapping to 15/16 sport MC and booster will reduce pedal travel and make the pedal firmer. good upgrade with any of the BBK's.

I'll let you know, i hope to install this weekend. it will be a while before i am back at the track though.

K24 - thats a good point. Phe previous owner of this race gear IS using a pad brand starting with P but I forget the name for the moment....you might be on to something....

A friend has just done (last night) the sport 15/16 MC and booster to great effect in his LS1 powered 90 NA. I REALLY Like that feel but he said he HAD to use the sport booster as the MC had a little extension out the back and it was incompatible with the NA booster.

Does anyone know if this is a resolvable issue or you HAVE to use the matching booster...

You resolve it by using the Sport booster. The booster swap is easy.

Yep, using Sport master/booster here in a '90. No issues other than a few reroutes of hard brake lines since I got an ABS master.

Thanks Savington and everyone else.

Parts are hard to come by here for those models, will scrounge ebay etc.

I got my Sport booster and master from Flyin' Miata for around $150 just for reference.

Thanks Z31, great advice. Will follow that up...

I'm pretty sure the LHD brake booster is different to the RHD one, it is different for the clutch anyway. Just a heads up!