ITT: We discuss adding ABS to a car that didn't come with it..
 

I am probably adding ABS to the autocross car over the winter. It is a 92 chassis if that matters and did not come with abs. Hopefully someone who has btdt can offer some information and advise.

Is it worth the effort?

Which year donor Miata has the most effective ABS?

Is there an aftermarket alternative that provides value?

This thread. It's relevant to my interests.

I have done a tiny bit of light research regarding this. From what I can gather, using all Mazda parts, it would cost in the thousands from Mazda specialists for all used parts. I know off the top of my head that there are ABS specific axels. But that's about it.

The cheapest way is almost certainly to find a donor car and swap the bits over. I've pondered this myself, and I think you need:

- Front hubs with ABS rings
- Rear axles with ABS rings
- ABS sensors and wires
- ABS hydraulic unit (the big cube thingey)
- various hydraulic lines
- somewhere to remount the washer bottle (NB hydraulic unit goes where washer bottle sits in non-ABS cars)
- ABS computer (I think this is separate?)
- wiring harnesses
- ABS prop valve

I could see all that being a couple grand from Mazdacomp, but I doubt it's that much from a junkyard.

--Ian

The ABS computer is separate and only shares a few wires with the main ECU.

Here's what I posted on the pointy board a couple years ago.
http://forum.miata.net/vb/showthread.php?t=279977

Ideally, you use the 2001+ three channel ABS. That's what I've (mostly) swapped into my '90 XP car. Some of those things above aren't needed in an SM/XP build.

Things you absolutely will need.

1999+ ABS spindles (to mount the sensor to)
ABS front hubs
ABS axles
ABS rear uprights (to mount the sensor to)
Four ABS sensors
2001+ integrated ABS pump and ECU. There is no separate ECU for this system.
2001+ wiring harness plug to the Pump/ECU

That's all. You'll have to plumb and wire the system. If you can't find the schematics, I'll dig one up and send it to you. The plumbing is easy too. There are only two ports from the master cylinder to the pump, one front and one rear. From the pump there are three lines, front left, front right, and rear. The rear line feeds both rear tires. FWIW, I'm using it with dual master cylinders, no booster and a bias bar. Keith Tanner has a good post on M.net on different master cylinders, boosters and pedal effort.

http://forum.miata.net/vb/showthread.php?t=363284

Also, I was able to buy all the parts I needed above plus two more 2001+ pumps, a 2001+ ABS master cylinder and booster, the front hard lines, pump cradle mount, and spare front arms for around $200. There's no need to buy and part out a whole car for this stuff. The SpecMiata part suppliers have it sitting around because the race series can't use ABS.

You can also easily disable ABS so it will work with launch control.

Did anything ever come of this? Has anyone actually completed the 2001+ ABS swap on a NA chasis that came without ABS and actually had it work? Sorry to resurrect a year and a 1/4 old thread but this is VERY interesting to me and it seems was just left hanging.

Doing a swap right now, putting 01 ABS in a 99 non-ABS car. It's a prepared class autocross car so it won't necessarily be done in a stock-like manner :).

NA->NB shouldn't make any material difference; just don't try to mix-and-match the knuckles and (front) upper a-arms; the ball joints have different tapers (say people more knowledgable than I....)

-- Glenn

What about adding 2001+ 3 channel ABS to an NA chassis that already has ABS installed:
- What is shared in ABS hardware between the 3-channel and earlier models?
- Is it worthwhile to make the swap or is the gain negligible?

I like having a flat spot fail safe in place to protect my wallet, but don't enjoy the way ABS cuts is during rainy trackdays.

Different number of channels means different hard parts (lines); also (I'm told, will know for certain from my own experience in a week or so) the ABS pump & computer are integrated in the 01+ so you'd certainly have different wiring to sort out. Several other brake components vary between 01+ and earlier cars (master cylinde, booster, prop valve) but depending upon your needs you may or may not want to bother swapping all of that.

Everything at the wheels would be the same.

And Boose Joose: I don't need ABS in the hope it will shorten braking distances; I can already threshold brake quite well. I'm trying to manage flatspotting, and larger & stickier tires makes flatspotting *worse*, not better. 1.6 vs 1.8 brakes is irrelevant; that just changes heat dissipation (which isn't a problem for autox, which is what I do), with 1.6 having worse heat dissipation. The size of the rotors or pad sweep area doesn't really affect flatspotting behavior, presuming you have taken steps to maintain appropriate front-to-rear brake bias (which I have).

The car in question already has 275 width A6s & 1.6L brakes. It stops... it just squares off a $200 tire (inside front one, often) every time that braking isn't in a straight line.

-- Glenn

ew abs

Well last night I picked up a 1996 ABS pump and ECU already paired with a RACE LOGIC traction control unit. So it looks like I'll be adding ABS to the car with the older parts. This was previously installed on a 400rwhp Track only that had been completely rewired and was removed as a unit. I'm in the market for some abs hubs, axles and NA Wheel speed sensors now.

Nice pick up. I am assuming you got it from Jeremy Schuster. I love shopping his spare parts bins too.

at the track i find ABS horrible, that being said what do you see as the advantage of going through the work to add this to your track car?

We have already had to ask mods to clean this thread up once because a newb questioned the rational...so I'm going to say this once.

1) This isn't for a road race car this is for an AutoCross car

2) You can find the perfect braking points on the track because you get to drive the same turn on the same track the same way 3 million times over 30 years...in Autocross we get to drive the course 3 times...and that's it. ABS will help overcome that.

3) 275/35/15 Hoosier A6's cost $1,200 a set and last 60-80 runs depending on the surface...one lock up of the brakes from taking a turn too hot and they could be a junked $1,200 set of tires

4) Traction control uses the ABS wheel speed sensors.

I haven't finished my XP build, but I have been party to updating E36 BMWs. There are standalone 3-channel and 4-channel ABS units before BMW integrated traction control into their ABS. We've had very good success with these units in E36s and Z3s. I'm expecting my Miata swap to go as well. I even thought about using the BMW 4-channel in my Miata.

And the 2001+ units do not have a separate ECU. The brain is built into the pump.

FWIW I am currently considering this for a track car after flat spotting a few expensive race tires over the last year. All it takes is a bumpy corner entry (the common factor from track to track IME) and the tire can easily be toasted.

OK so Modernbeat, you are talking about retrofitting a BMW ABS system from an E36 to a Miata? Interesting... go on please. Is the BMW ABS a superior system? Could it use the Miata ABS sensors and hub rings, or at least the hub rings? 4-channel might be cool, though all my flatspots have been on the front so a 3-channel would probably be fine. I assume the 4-channel would require installing another brake line to the rear.

I find the ABS in my 2000 Miata less susceptible to ice mode than my 97 M3.

Ice mode?

Give up because nothings going to help mode?

When you get on the brakes very hard and very quickly and a tire hits a bump (and skitters) it thinks you're on ice and so it applies the brakes very gently -- very weak stopping. You need to lift and brake again. Google "ABS ice mode".

Strange because Germans being the way they are, I'd expect that the BMW ABS computer would be more difficult to get into ice mode if it sees the external ambient temp sensor shows 70°F.

ABS makes it raw.. keep it off!

^^ Flatspot many Hoosiers in your V8 Miata while racing for contingency?

I'm guessing no.

I'm also guessing no...I'd like ABS on my 92 because of the same reasons listed above. I run my 13s and slicks on the track when it's cooler...and in sub 60 degree temps they work great (as does the car) ...problem is...they are easy to lock up at 100mph...

So I'd like it for that, for the fact I still autocross it and for the fact I street drive the car still.


I talked with Jason about the 01 ABS option once and it seemed like a good idea...but I'd probably need his help lol :)

I have the ABS components lined up from a 01+ Miata so I think I'll be installing it in the track car as soon as I get another car of mine taken care of.

Anyone finish this swap yet?
I have finally gathered all the parts.
Spindles, Knuckles, Hubs, Axles, wheel speed sensors, Pump, Computer, Brake Booster, Master Cylinder and lines.
All that coupled with a big lightweight brake kit from 949 should make my car WHOA as well as it GOES.
I hope to have it finished in time for the Toledo Pro Solo. Just doesn't look like there is time for Blythville.

I have a complete ABS system from an MSM donor car in my '90 track car. I used everything from the pedal set (MSM pedals add +5whp and look cool :loser: ) to the hubs. The hard lines fit perfectly with the slight exception of the rear line crossing the fuel lines at the passenger's feet. I mediated this with some rubber and zip ties to keep them from wearing on each other.

The ABS block needed to have some mounting points fabricated. I discuss it in and around post #53 here:
http://www.mazda-speed.com/forum2/in...,24668.45.html

My project was made easier by the fact that I was using the whole drivetrain and had the ABS hubs and sensors already. A pair of wires goes to each corner (yes, even though the rear is a single channel). The unit needs a heavy power source (30A), a medium one (20A) and a small one (~5 to 10A, probably much less current is drawn there). I have the little one on a toggle switch on the dash right next to my EBC toggle. I figure when the 'Zoom' switch goes up, the 'Woah' switch should go up too. :giggle:

It rained the first day at Laguna and I used the ABS - it worked as expected. My plan was to leave it off for dry conditions but I have found that the proportioning bias doesn't work correctly if it is off and braking from much over 100mph is a little hairy even in the dry. My current lack of aero in a ~250whp ~2100 pound car isn't helping. Flat-spotting insurance sounds like a great investment too even though I'm on $600 worth of NT-01s and not twice that of Ho Ho's...

Can you comment on lap times with the system on/off in various conditions? Are you running OEM brake pads and rotors? You said you have NT01s - what size are they?

I will write a few things which probably most of you know, but maybe didn't think of them all at the same time:
Static friction is higher than kinetic friction (in general) which means that a tire skidding (kinetic friction) has less grip than a tire on the limit of skidding; so if we can have the tires on the verge of slipping ALL THE TIME while braking (for that matter also while accelerating) it would reduce braking distance etc. all the good stuff.

With tires being ~hyperelastic materials things are not as straight forward as Coulomb friction, and they generate maximum grip when they're stretched slightly (when they're cornering this is the slip angle, when braking/accelerating it's called a slip ratio: read more here: http://en.wikipedia.org/wiki/Slip_ratio ).

So slip ratio around 20% is optimal (is this true about all tires - definitely not, just like optimal slip angle is not a constant for all tires). For the sake of argument, let's say 20% is ideal for all tires.

So how does the ABS work: it measures wheel rpm, it measure vehicle speed and it figures out what the slip is when the brakes are applied. You just keep you foot down and it "cycles" the pressure in the caliper lines so that the wheels stay around optimal slip (there's a lot more going on, but that's the essential part). Just from the essentials I can see a few things which may make factory ABS on a non-factory tire/wheel/rotor/brake pad combo non-ideal:
-maximum grip slip ratio may change
-if tire diameter changes wheel slip is not calculated correctly from wheel rpm
-changing ultimate tire friction coefficient has an effect on ABS system
-changing brake rotor inertial properties has an effect on ABS system
-change brake pad friction coefficient has an effect on ABS system

Now, I've corded a few R6s and know the feeling in my stomach every time I see/hear a tire lock up, but I feel that I'm paying for R6s in order to get the ultimate grip from them in every direction, so not being able to use them optimally with factory ABS would BRAKE my heart :giggle:

ABS comes with a "map" just as any other ECU, so if you're "map" is not tuned for your braking system it will not function at its best.

Am I a good enough driver to make a non-ABS car go around a track faster than the factory ABS... no idea :2cents:

Nik - very good at Need For Speed III Hot Pursuit

I have only had the car on track 4 days since I put it together. The brakes are OEM sports with XP10/8s. The Nittos are 225 15s. I'm not a good enough driver to comment on lap times but I am sure that at my skill level, I'm faster on ABS.

So I'm about 75% of the way through with the ABS Addition. Here is what I have done so far.
1) Changed front Hubs, Upper control arms and ran the ABS sensors
2) Changed rear knuckles, axles and ran the ABS sensors
3) Mounted the ABS Pump
4) Ran all the ABS Hard Brake Lines
5) Converted my non ABS Maser Cylinder to an ABS Master Cylinder

So what I have left to do
1) Sort out the power sources for the ABS System
2) Sort our the ground sources for the ABS system
3) Route the signal to the ABS lamp on the dash
4) Mount the ABS Computer and RaceLogic Traction control unit

5) WIN

The best I can tell this setup will pay for it's self in one season of AX due to reduced tire wear.

I'm curious to find out if any of the other guys that started down this road have made any progress.

The ABS in my XP autocross car is working very well. A full year of $1600 Avons staying round. It's great!

-- Glenn

Tuba,
What year system did you source to put yours together. I don't have any experience with the earlier ones, but the NBB has all the brains and controllers in the ABS block so I didn't have a separate ABS computer to deal with. My ECU can't do traction control without adding more robust wheel speed sensors so I won't go down that road.

After the first few events, I stopped trying to drive the car with the ABS off. The rear bias just gets too hairy without a portioning valve. The valve is on my list to do as early as this season, but I need to get several other things sorted before I screw up brakes that are working fine otherwise. I want to do a shakedown day by the end of March to see how much I've screwed the car up this winter. :giggle:

As for the ABS in general, I do really like it. Not only does it keep me from flat spotting tires, but as a lower-end driver, I can practice threshold braking and know where I'm at based on the the pedal vibrating rather than a wheel locking up. Regularly engaging the ABS (i.e. using them on purpose instead of threshold braking) will thrash a set of pads in just a few sessions on a heavy road course. I know I'm improving as a driver when the lap times go down consistently AND the pad life increases over time.

Beyond the driving impressions, my pedal is rock hard - better than any of my other miatas and is very easy to modulate. I'm very happy with the upgrade.

I went with a 1997 unit. I was able to source a totaled car and get all the parts from it and already had a 1997 ABS Computer and harness that were pre-wired for the Traction Control. As for the traction control, what I am using is the unit from Race Logic. I'm glad to hear you guys have had success. I'm hopping it all works when I fire it up.

Some guys have reported issues bleeding the ABS system and there has been some discussion (probably m.net?) about a process that involves putting the car in the air and spinning different wheels to engage the ABS while you are bleeding. The dealer also has an interface specifically for the purpose of cycling the ABS block while bleeding to remove air. The chances of their lawyers letting them touch the brake system you installed from a wrecked car are somewhere between slim and none. :jerkit:

All that said, I bled mine traditionally and have a rock hard pedal. It was so hard in fact, that I was sure something was wrong when I finished bleeding. A very slow and cautious test drive - fine. A spirited test drive - fine. A cautious session at the track - great. A flatout session at the track - :party:...

Once I have it all set up and installed I am going to do an initial "bleed" with a power bleeder. Then a "traditional bleed" and then manually cycle the ABS pump while bleeding them. The procedure to manually cycle the pump is in the FSM.

And I'm sure a dealer would have a hay day if I brought my car in for service.

https://www.miataturbo.net/attachmen...ine=1359911002

Yeah, drive it down there, avoiding the attention of every LEO in town, and tell the sales guy you want to trade it on a minivan... :giggle: When he looks up book value and offers you $600 for trade, you'll have some hard decisions to make... :bowrofl:

Rotflmfbo

I purchased shocks for my 91 with out realizing I had abs.
The mechanic who installed them used zip ties to add the abs to the shocks.
They are oem shocks front of car.
Is there any way I can mount the abs unit ?
Thanks,
John

zip ties work fine for the rest of us

Are any of you guys running an adjustable prop valve? I have a 97 on race rate Fat Cats, I run a 205 street tire at autocross. I had been racing for years in other cars not equipped with ABS and I never had a locking issue but I found with the Miata it locked the fronts extremely easily causing very irritating flat spots. I managed to find a specialty vintage shop in PA that will shave used tires for $25, had to do that with a couple tires before I added the prop valve. My point is since I added the prop valve I have no issues braking hard and not locking the front tires. I run aggressive HP+ pads. Honestly I found the optimal balance with the valve fully opened, if I were to do it again I would just pull the stock prop valve and replace it with a union.

It has been an AMAZING amount of work getting that little ABS light to turn on....then turn off.

VIDEO0023 - YouTube

ABS and Racelogic Traction Control are both now functional

I have and it is costly.

John just signed up on this forum and was going to PM you about ABS for my Miata. BUT I need 15 posts to PM. Ryan was going to put together some parts and bring them up to MSR Cresson. Could you please PM as I would like to get your thoughts.

Thanks

David T

John got your PM, however because I only have Two total Posts (counting this one) on this forum I cannot PM folks until I get 15 posts So I will post these icons, which have to be moderator approved and could not possible offend any one, to express my dissatisfaction with the 15 PM rule.

.:vash::brain::jerkit::fawk::td::cjerk::bsflag:

This is worst than flat spotting

I fought sponge pedal on my MSM I never could get the brakes to feel just right the car would stop fine but the pedal never felt right. I just did a break job in december and used a mighty vac kit to bleed the brakes, worked like a champ hard a rock hard pedal and only took 10 minutes.

Time to bring this back. Fuse box mounting, what fuse box bracket works with the 01+ abs bracket? I cant find the fuse box bracket in the mazda literature to see if its different between NB and NB abs. I'm probably just going to cut and splice the NA fuse box bracket.

Wiring, where do the damn wires go off the rear wheels? I cant find a hole in the chassis that the connector fits through because it obviously does somewhere with the rubber grommet built onto the wires. I'm using NA wheel speed sensor wiring. I'm considering just running it outside the frame rail.

The 03 ABS bracket bolted up and sat happily next to my 99 fusebox. IIRC, they both bolt to the chassis, there are no bolts that connect them directly.

I ran my rear wheel speed sensors along the PPF, because even if I had found a hole in the chassis (which didn't seem to be there), getting it through the passenger compartment and firewall seemed like it would be a PITA.

--Ian

I found the spot for the chassis. I figure I have to pull all the wiring along the sides up to do the fuel pump wiring and to move my ecu under the dash so its not going to be any more work. Here's the pictures that dont exist on the internet for posterity.

https://www.miataturbo.net/attachmen...ine=1387746238

https://www.miataturbo.net/attachmen...ine=1387746238

https://www.miataturbo.net/attachmen...ine=1387746238

https://www.miataturbo.net/attachmen...ine=1387746238

https://www.miataturbo.net/attachmen...ine=1387746238

https://www.miataturbo.net/attachmen...ine=1387746238

https://www.miataturbo.net/attachmen...ine=1387746238

https://www.miataturbo.net/attachmen...ine=1387746238

https://www.miataturbo.net/attachmen...ine=1387746238

And my cut and spliced bracket. I ended up cutting both brackets to make it work and I had to hammer the fuse box bracket a bit so I could fit the ratchet in to the bolt on the abs pump. I welded the two together because the fuse box bracket was really floppy once it was cut up.

https://www.miataturbo.net/attachmen...ine=1387746493

https://www.miataturbo.net/attachmen...ine=1387746493

https://www.miataturbo.net/attachmen...ine=1387746493

My solution was similar to Leafy but less elegant. I used the OEM ABS block bracket and cut a piece of aluminum angle to mount the fuse box to. The wires from each corner got new holes drilled in the tub with the OEM grommets from the donor.

Wiring. Fuses how did the rest of you handle this? I cant find any good ones in the stock box I already want to add a new fuse for the new fuel pump wiring so I am considering just adding a fuse block I have kicking around to the engine bay to run this. The pins for the ABS fuse in the fuse box arent populated and I have no idea where to get that weird connector besides cutting it out of some harness.

Since my installation was replacing an existing ABS system with a newer system. I just copied the original fuse box/ABS mount. Fabricated some 3/16" steel into two 90* ears and welded them to the new bracket. Drilled and taped for 6mm studs. Basically just copied the old bracket layout. Hyde's solution is probably easier and quicker. I still have to unplug the wiper connector to open the fuse box lid.

I don't know how much of this would apply to an NA, but for putting the 2003 ABS unit into my 99 I needed 3 fuses:

10 amp for the electronics. In the 99, this was shared with the airbags from the factory, so I just piggybacked off it (fusebox under the dash) and ran a wire out through the firewall over to the ABS box.

20 amp for the ABS solenoids. The 99 fusebox is in two pieces, with an internal wiring harness that connects them. My non-ABS car came with a vacant socket for a 20 amp fuse, a wire connected to it inside that internal harness, but no pins in the connector that went between that internal harness and the main harness. I tapped off this internal wire and ran a wire out to the ABS unit right next to it.

"fusible link" for the ABS pump. The amperage is unspecified here, I measured spikes of around 50-60 amps when testing it. The top of the fusebox had the bus bar for this, but there were no contacts or wire in the internal harness connector for it. I dremelled off part of the internal harness connector and hacked up a female spade-lug connector to fit in its place, then ran a heavy gauge wire outside of the box and used female spade-lugs to connect to a 50 amp maxi-fuse and wrapped it in electrical tape. It's ugly, but it works. One of these days I'm going to replace it with a fuse holder of some kind.

--Ian

Why do you only have 3 of the hard lines hooked up? Or is that just an in-progress shot?

--Ian

In progress, I don't have the MC/booster installed. I am going to add a prop valve inside the cabin. Haven't fully thought out the routing.

Is there any reason I shouldn't mount the ABS pump in the pass. floorboard? I don't really have room for it in the stock location in the engine bay, and I already have the fire bottle and cool suit cooler keeping me from reinstalling a pass. seat.

The only downside I see is having to make new hardlines from scratch and safely route them through the firewall.

Making new hardlines is the only downfall I can think of. Having cheap as shit lines that just fit perfectly is pretty nice, like really nice.

Mine is in and works perfectly. I really dont see why people stress over it being hard, it was pretty pretty fucking easy. Do remember the power wire in the diagram that says switch power, really needs to go to switched power, or else it draws over 2 amps with the car off, and thats bad, lol.

I’m not excited about making new hardlines, but if it lets me mount the 10lb pump almost 2ft lower and also lets me keep my current intake setup (and the ability to play with this sweet new Raetech SIR), it’s definitely worth it.

What was your process for bleeding brakes? I’ve read that bleeding is a pain with ABS but I haven’t really looked into why. I’m wondering if making the ABS pump the lowest point in the system (instead of close to the highest) will help the bleeding process.

Bleed, till no air. Drive a bit. Bleed till no air, drive a bit, bleed till no air, figure its got to be good now, go race, mushy pedal, bleed until no air. And I'm on that last step now. Sunday I'll know if I still have a mush pedal. HOPEFULLY it wont be that bad ever again, since my abs pump spent a good amount of time out of a car and spilled brake fluid all over the box it was shipped to me in. I know there was still fluid in it though because I bled all the super blue out of the car the first time with type 200, and I keep getting blue brake fluid when I start bleeding, so I'm assuming my abs block was used in a car with superblue before it was wrecked.

I haven't solved the mushy-pedal-after-abs-swap problem yet, and I've put about 2 gallons of brake fluid through the car after a half-dozen different bleed-then-go-out-and-engage-the-ABS sessions. It's at the point where I'm hooking it up to the diag ports in an OEM fashion and trying to find someone with the Mazda factory ABS service tool to see if they can bleed it properly with a factory procedure.

The other minor issue with mounting the ABS hydraulic unit in footwell would be fabricating the bracketry for it. OEM it's not hard-mounted to the chassis, rather there's a two-piece bracket with rubber isolators installed. I dunno if that's just for NVH reasons or if the ABS unit needs protection from the engine vibrations.

--Ian