AndrewG

Hi guys,
it is quite a while, from the time when I have had very hard times on autox. Luckily it only ended up with fender damage and broken bumper (hit tires).

So I will try to describe the issue. When running autoX or any other kind of high speed driving on the circuit, where you brake really late I can have big problem with braking. I would say it is best to say I have no brakes because that is how it feels like, or maybe slicks on the rain. Basically I hit the brake, ABS kicks is like crazy, If I hold the pedal to the floor it is really hard and ABS is pumping fast but there is no braking. Traction is definitelly available there but the car refuse to use it for some reason. It have nothing to do with temperature of the system or the tires. It is all different to normal situations where you activate ABS. I try to do treshold braking so I know very well how much grip the tires have. When situation like this happens it is really like sliding on the ice, but no real locking up of the brakes. If I realease a pedal and start braking again just lightly it is still there. I normaly try to repeat this again and again fast but it does not helping, so the only help is to hope that trans will be able to help with braking.... On autoX it is frustrating as you miss the gate because you have no grip to turn. What will happen if this happens in trafic ? I do not wanna know. So for that reason I need some advice, what to check. I tried to remove fuse of the ABS and braking was awesome. very solid feel and possitive feedback from the pedal, I knew exactly when the tires are locking etc.
My car is 94 NA8 with original brake system (10" brakes). I have very serious Carbone Lorraine brake pads, stainless brake lines and standard quality rotors OEM. I have Dunlop Direzza 03G tires, which I believe are not available in the US but those from Australia and the rest of the world know these tires as one of the best semislick on the market (different league to R888R A048 etc.)
Friend of mine just posted about same problem on local forum so I though it is not only me who have this issue so maybe there are more people with same problem ?
My though was also that the ABS unit is not correctly bleed. I use the method of bleed the system, start the car put it in the speed and brake while the car is in the air so ABS is activated. I do not feel that this is the problem with ABS as I think that in normal conditions (low temperatute in tires, low grip) the abs is working normally - kicking to the pedal but actually slowing down the car. And you also feel that the tires are sliding actually. Also this is not happening all the time. When the tires are hot and I manage to activate the abs because I overshoot the maximum grip available, the ABS is again working normally - you can actually hear tire squeeling, which is sign of really nicely set ABS). Before you tell me to remove ABS I do not want to do that. I like the feel of the no abs system, yes. But I do not like to spend 700€ on the tires every time I lock up the wheels. I will have to do this if there will be no help tho

Any ideas please ?

sshamrockk

I know you don't want to remove abs, but it's probably best. I don't have it in my 94 and I'v locked the tires plenty of times at autocross and on the street trying to avoid dumb people. Tires aren't ruined one bit.. Threshold braking will always be best for stopping, and when you do lock a wheel you hear and feel it instantly and release some pressure. Heck, even some of the top Miata guys at the autocross I run, lock up a wheel or two going into some of the quick turns, and they run full slicks. I doubt they junk a tire just because they lock it up for a second.

AndrewG

Well if you lock up lightened wheel (for example rear left while entering left hand corner under brakes) you do not ruin the tire that is for sure. But if you lock up the front tires under braking for the second there will be imediatelly flat spots on the tires which is not best if you want to be on the podium :-) I still hope that there will be some other tip about this, otherwise I will be removing the ABS and probably booster too, I just need to find some suitable dual master cylinder that will suit stock brakes.

BMWidmer

What pads from Carbone Lorraine?

sshamrockk

I don't think I'v ever locked a rear wheel up, I only ever lock the front, usually the right side and I don't have any weird wear or vibrations, sure flat spots aren't going to help with a podium finish, but neither is that paperweight they call abs I'v never driven a Miata with abs to the limit, so I can't say how well it works or doesn't, but if I had to guess the top cars aren't using it.

AndrewG

any tips guys ?

aidandj

iTrader: (5)

@codrus

My understanding is that the NA ABS systems is not the greatest.

I have an 01 ABS system and it works quite well.

curly

iTrader: (25)

I believe this is called ice mode, GTred had this same issue with his msm when he installed TSE's 11.75" bbk. Not sure if he ever solved it, but for what it's worth, next time I saw his car he had deleted the ABS....

codrus

I have an '01 ABS system in my 99, and while I haven't experienced "ice mode" where it takes away all of my braking as you described above, I do have some concerns about it. I've had some issues with my braking at the track, mainly that I brake too early and too much, overslowing the car for the corner. When I try to move my braking points forward I often end up blowing the corner by not slowing enough. I recently hired a driving coach to try to work on these issues, and after driving my car he was of the opinion that the ABS was part of the reason for it. He thinks that the ABS is getting fooled by the higher grip level of the R compound tires and the rapid rise in brake pressure of track braking and is taking some (not all) of my braking force away. This results in it not slowing as much as I'd expected, which leads to me pushing the pedal harder, which causes more ABS activity, etc.

His recommendation was either to disable the ABS (when I transplanted it into the car I installed a cutoff switch for the electronics power) or to think about converting it to a more motorsports-oriented system, such as that out of a BMW E46. The E46 one is another standalone ABS, 4-channel (vs 3 on the Miata), is known to play well in track environments, and I believe has also been cracked so that you can alter some of the parameters in case it's not quite right for the platform. I'm still in the process of investigating this option.

--Ian

AndrewG

well I still believe that proportional valve will help with this at least a little. But for next season I think I will try one more race with ABS and then I will put my effort in teaching myself how to brake without ABS. TBH I like challenges like this so :-) Curly you are probably right with that Icemode, I believe that I know now how to name it will help in my way to find solution for fixing it. Thanks !

BTW I have CL RC5+ pads.

DeerHunter

Interesting. I had a similar experience with my MSM (with TSE's 11.75 front BBK and GLoc 12 pads) at MRLS last month. It was my first time at that track and my first high-speed outing with the MSM (our local track is much shorter and low-speed). Once I learned to ignore Turn 1 and power on through to T2, I was playing around with my braking point. For the most part, I was braking way too early, such that I was actually coasting to my turn-in point. I tried moving it up correspondingly and, the first time I did, I blew well past my turn-in marker (luckily, there's lots of run-off room and I stayed on the pavement).

After that, I erred well on the side of caution and braked conservatively for Turn 2. Now I'm wondering whether I ran out of talent or was tripped up by the ABS.

Still, the MSM ABS is light years better than the version in my '93.

Savington

iTrader: (31)

I quickly learned to disable the ABS in Acamas while on track. Bumpy sections under power immediately before a hard braking zone would result in a very firm pedal and zero decel rate (presumably ice mode). After experiencing that a couple of times, I pulled the fuse.

DeerHunter

Any issues with brake bias when you do that? Once the ABS in my '93 went out and even medium braking resulted in the rear tires locking before the fronts. Does EBD still work with the ABS disabled in the NB?

Mobius

iTrader: (2)

No, I can't see how it would. Whatever inherent bias physically exists is what you'd end up with.

I can't recall that I've had anything like Ice Mode happen with my '01 ABS. I've had this ABS brain for 10 years now and can't think of anything like what's been described. I'll occasionally get some feedback and feel the lighter inside front wheel activate a bit if I don't have the car settled and square, or sometimes when trail braking, but otherwise the brakes feel solid and effective. With R compounds I've always had the TSE 11.75 kit with Cobalts on the car.

Leafy

iTrader: (1)

I still havent run into ice mode on the MSM abs. And I've totalled a car due to ice mode before,

AndrewG

I am quite shocked to see all those comments about disabling ABS from "big names" as I read everywhere coments like "ABS is a good thing and I have never had an problem with it" and now when I asked about this everybody complains about it...kinda like when I bought shitty EBC yellow stuff pads few years back, they seemed perfect before I bought them and right after my purchase I read everywhere how shitty they are...and they were. Thank you guys for the tips, I will probably make som easy switch for ABS fuse to disable it from the cabin.

is there anybody who run no ABS with booster delete and could compare to braking with booster without ABS ? pedal effort is the thing that I am affraid of the most.I know pedal effort will be higher but how much ? ie. can it be still driven by a girlfriend ? (that is not a weightlifter lol )

crispyBYM

I've been having similar issues as well. Bedding in the brakes or hard stops on the street the brakes feel perfectly fine. On track I get the feeling of ABS vibration in the pedal way before I should judging by hard stops elsewhere and the car stops nowhere near as fast. ABS unit is an 02 system.

That being said I run HP+ at the moment and don't have a lot of track days in cars under my belt. Going to try better pads, more coaching, and bigger ***** before I rip apart the ABS unit!

Mobius

iTrader: (2)

One thing to consider is the ABS unit is not adjustable. I point this out not to be obvious, but that it is set up from Mazda for the street pads they provide, for the sport brake rotors they provide, on (at least for my nb2 system) 205/45R16 tires. Tyres for you southern hemisphere / EU peoples. The system is calibrated for those parameters. Lockup is encountered, line pressures are adjusted based on those parameters - so much rotor bite producing so much torque on the wheel producing so much grip adjustment to the pavement. So I think potentially what's happening with different people having different experiences is due to these varying combinations of tire grip and pad bite. If your ratio of pad grip to tire bite on your rotors is similar to what the unit is calibrated for, you don't see these issues. If however your ratio is different, maybe that's why some see ice mode and some don't.

I am tempted now that there is a slush of sodden leaves in my neighborhood to go try to activate ice mode for the first time. But I haven't yet filled the body holes from the tupperware mounting points, so I'm reluctant to get the car out.

Edit: if you are tracking with HP+ and not overheating the pads or otherwise experiencing brake fade, then either a) you are not pushing the car hard enough or b) the track in question is not hard on brakes. I say this not to be judgemental but simply as a datapoint from personal experience. A good friend is very (extremely) quick at autocross, but we would rib him for his track times at Portland International Raceway. He used HP+ with no issues. I tried HP+ once in my car at PIR, overheated them on the third lap. With even a stock power miata you should be able to overdrive HP+ pads unless the track is super easy on brakes.

sixshooter

iTrader: (12)

What compound you can get away with on the track depends a lot on the tires you use. Street tires pair well with hp+ on some tracks in a stock powered car. See some chumpcar setups for example.

Leveq

Yep, with 100whp they'll fade... Street-Race are ok tho, maybe a tad of fade on REALLY heavy braking zones after several laps (as in 160+ down to 60kph and such). They could do with some ducting, but even without they're fine. With more fast bits tho they'll probably struggle. If you have to drive on the street as well they're perfect. Assuming you can't be arsed to switch pads at the track which I am not.

Rear sometimes lol, guess it depends how hard you push and trailbrake haha. If you're locking the right side always then your axle weight is too far biased to the left... Lowering the right front or raising the left rear will help. Not too much obviously.