Diyman25

Buddy call me in panic, say he almost died from ABS failed

I was like no way

I was on my way down there, ask him
Whats up
Yeah car have flat spot but it all drive fine!!!

And I drove for a lap without any issue

Then later today i saw this pic
I was like WTF WTF WTF

Back to the shop he bought it from
Detect a false on dsc button , so swap the switch

Did any one have similar experience????
I hope not

Shaozhou Zhang

I remember saw a post, maybe from MazdaManic, said that if the ABS fail on track something terrible would happen. I don’t quite remember it, but saw it somewhere.

TeamRX8

iTrader: (25)

It’s well discussed in this section

the ABS also provides EBD; electronic brake distribution, i.e. front/rear braking balance

No ABS = no EBD, without it the brake balance defaults to extreme front bias as a “safety” feature to prevent the rear brakes from locking up and spinning out. You just slam straight ahead with the front tires locked up into whatever’s in front of you instead.

it’s also why trying to bias front/rear brake pad compound, EBD will be working against and fighting to correct it

a bad ABS cable in the wheel well has also been known to cause this, you have to be careful to not let the heavy suspension pull on them when it’s disassembled, etc. Unbolting and/or disconnecting the cable/sensor out of the way is always best to do first. Been guilty of not doing it myself. If it loses a signal the whole thing defaults.
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Diyman25

some reply from RX8 cup series at AUS

I sum some most possible cause . wheelhub and brake light glove
=AZWm710rPXcha_Prt14f9Gz9RM8Yr2KxU9fpWYSRuI6p976dg _Iw9qeKAv3Gc_KS2j5sz0vKQouung_klxqPvqGjmdoop_4D7en iYZ7LShpdxyVcmt9ruqJA4ahLCwZJzNpbxpIr0C0LLbN2tRUGO GYkDad5wRHGsYhs7k16EfJlBGFzjg1FTkWn1p6jujnFAkY&__t n__=R]-R]RST Performance Racing
has been here, done that... our issues were due to a bad front hub resulting in the abs sensor failure. Only an issue on hard braking, gives you the rock solid brake pedal (like ice mode) but locks the front wheels.
It is also easy on a race car where wiring might be moved around a bit, the fog lights have the same connector as the abs sensor and they can be mixed up as they will reach if not routed correctly. Seems silly but it is easy to mess up.


Had an ABS problem at Morgan Park last year after dropping the rear of a ripple strip hard. Turned out both brake light globes had fallen out. One is fine but both break the ABS circuit and before anyone says it, no I'm not having you on. Tape your brake light globes in

Diyman25

very scary. i see many car have ABS failure ( ice mode) pedal hard full locking . cause many crash on track !!!!! thats why i am concern it because i have not see RX8 have this have problem but remember Z have this more. but after i ask in RX8 cup series . it is not un common. most of them are due to wheel bearing failure

thanks for reply, yeah it look very scary !!! will told the shop to double check with my friends car before head to track again

Mike D

Eric Meyer suggested treating the front hub as a wear item and change it once a season. The failure mode is to dangerous to mess around with.

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TeamRX8

iTrader: (25)

Got a good lesson on the above this past Sunday. Took Strokercharged’s former RX8 to the local SCCA autocross just to get a few runs in to restore my Motorsport membership status. Which it was also my very first time driving the car since taking possession of it several months ago.

First off, low-mid 500 whp in an RX8 is pretty awesome 😎 . Took it out for a quick run after getting it off the trailer to warm it up and then ran it though the gears on a long interstate ramp. Been a while since I’ve been behind the wheel with that kind of acceleration.

Unfortunately, at the event I was wailing away on first part of the course on the first run, flying into a pinched slowdown, barely touched the brakes, and the front tires immediately locked and likely flatspotted badly, but no slow down at all; full Farmer Jones mode plowing the field straight and true, lol. It didn’t help to have 225 real hard-rubber street tires on the front and 265 sticky “street legal” semi race tires on the rear. So apparently the ABS is disabled somehow, which I had no idea to expect for it, but probably should have recognized something was up.

Because the car has DSC, but it cranks up with and runs with the DSC Off symbol lit on the dash (don’t have to hold the button down). It also has the bone stock original suspension on it, which in total was impossible to go in fast or carry any speed in autocross type turns. Served the purpose of having timed results though. I didn’t even think about it before going out on the first run, just figured Stroker must have disabled traction control somehow since it was mostly a play/drag car for him.

Not sure if maybe the fuse is pulled or if the ABS module isn’t working, but at least I found out there rather than where solid objects and other vehicles could be smashed into. Hard to believe the RX8 braking system is that bad with a non-functioning ABS unit considering the opposite when it works, but a good lesson.
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RastaRx-8

glad to hear you are safe! it kinda sounds like the SAS is not working which is what resets the DSC off light and engages it (steering wheel turn trick) you could check the many fuses though obv... there is a 7.5 in the interior, 30 small fuse in the engine bay, both for dsc

Warrior777

iTrader: (11)

Wow, yea glad you are okay Team. Sounds scary.

TeamRX8

iTrader: (25)

It wasn’t any big deal or any kind of safety issue since it was on an autocross course with plenty of runoff room, just smashed straight through some cones and such. Had it been at the track or on the street it could potentially be a critical situation not having been aware of it.

So I talked to him about it this morning about it. The car has the version 1 Adaptronic Select piggyback ecu. He said ever since he did the REW swap with it the ABS/DSC Off lights have been on. I can’t recall anyone having that problem before. Looks like I might have to dig into it at some point, but the plan is to eventually swap to the current Adaptronic PnP. So I may wait until then to mess with it since there are other mods planned then as well.

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RastaRx-8

cool im thinking maybe there is a can problem or SAS reading problem.. see if you can do an instrument cluster self test and check if its reading the can or has any issues. ive been using forscan to monitor and it will show codes for all the can stuff its nice for determining if something is working or not . will show you what ABS codes there are

if its piggyback it should be easy to figure out and still using the can system fine right? wish i could do an rew swap... i need one for my FD first

TeamRX8

iTrader: (25)

Thanks will look into that. Stroker only did drag stuff and said he never tried to brake in ABS mode since it was just drive there, make some runs, and drive home. So I don’t want any of this to come across on him as criticism or fault on him. I’ll get it figured out eventually, but ultimately prefer to reconfigure it to a non-DSC ABS module setup.
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John V

iTrader: (1)

Converting to non-DSC ABS is the right answer.

dallasreed

Had a similar situation happen many years ago on track resulting in a four way off

I scrapped the factory abs and run a dual master bias bar system without ABS. It is a bit race car but it does completely avoid any sort of electrical failure. I have this setup in both RX8 track cars and with some getting use to, dialing in and correct pad choice it works very well.

https://www.compbrake.com/product-ca...zda/mazda-rx8/

John V

iTrader: (1)

A setup like this will never brake as well as even the factory ABS system.

dallasreed

This is probably true for the vast majority.

Because the pedal pressure for lockup is immensely higher with this setup the spectrum of pedal pressure you can use for partial braking/trail braking I find easier and superior than the ABS system. If one can properly threshold brake I think that not much if anything is given up. But it is certainly not as easy as standing on the ABS for maximum stopping power. It also won't kill you when a wire or sensor fails so theres that.

My primary concern with the choice was safety.

I have knocked around the idea of messing with putting in a non dsc abs system in the car such that if it fails would revert to the bias set by the bias cage but haven't mustered up enough care to do so as I have found the bias bar good enough. Mostly to get that simple standing on the pedal for max force and making things easier in the wet.

John V

iTrader: (1)

It's true for anyone shy of a pro driver. Which none of us are.

TeamRX8

iTrader: (25)

not sure I’d go that far seeing as I haven’t actually driven on that particular system yet; which has interested me for a long time, particularly for track courses

John V

iTrader: (1)

Unless you give yourself four brake pedals and the ability to control each of them over every situation on track you're not beating the ABS system. Sorry.

TeamRX8

iTrader: (25)

In a dead straight slam maybe, but Dallas makes some good points. Which again, until I actually try it I’m not inclined to pretend to be an expert in comparing them directly, because I haven’t. Pretty sure neither have you, but then feel you’re free to speak for yourself.

John V

iTrader: (1)

I've driven plenty of dual-master bias bar setups, but never in an RX-8, so you're correct. The trait they all had in common was they required the driver to actively work to not lock up a wheel, and they don't work well over all weight transfer scenarios.

A good ABS system works over all weight transfer scenarios and requires no active management by the driver.

TeamRX8

iTrader: (25)

well I think some people lose sight of the fact that just because it’s not locking up a wheel doesn’t necessarily mean it’s outperforming a manual system

the RX8 system is pretty good, but it doesn’t always deliver in every single situation as Dallas stated. I’d like to have some control over the rear EBD software at times.

dallasreed

In an autox car I would stick with the factory abs.

In a track car I would rather have the bias bar set up primarily due to the failure mode of the rx8 abs. The bias bar also is easier to use / threshold brake as speed increases than at autox speed.

I own 2 rx8 with the factory abs and two with the bias bar setup. The two with abs are primarily used for autox while the two with the bias bar are primarily used for track.

I have ran the bias bar setup at autox many times and vice versa and the bias bar works fine with proper bias dialed in and being use to it. The rx8 abs does work very well when it works.

I have an Elise that is primarily used for autox and have the same bias deal in it and prefer it because the abs system in the Elise is hot garbage and loves to ice mode. For what it's worth Zust and glagolas car, now Jason West's, both ran/run a similar deal.

I do have the problem of if I get into someone else's car I am way too heavy on the brakes initially as I grow accustom to the high pedal effort to threshold brake on a bias bar setup without a booster.

John V

iTrader: (1)

Got to watch those Lotuses locking wheels entering corners in SSM competition at nats today. They didn't sell the bias barsetup very well

John V

iTrader: (1)

I was expecting these non-ABS cars to have some sort of advantage in braking zones versus the ABS cars based on what I was reading here. The SSM winning Miata (also won XP) was running a RX-8 non-DSC ABS system.