samluke

The car that I converted had the harness for the dash so the stock harness would plug in. Otherwise I would have had to make up an idiot light circuit.

I was using a TurboS rear end so I already had the hubs and sensors.

I switched to non TurboS front spindles and hubs with ABS.

Before i sent the 89 shell to the crusher, I sawzalled the pump mounting bracket off the car so I could re-use it. Even without that, the bracket is a simple fabrication. I have a spare pump to shell bracket.The ABS cars had a slightly different front wheel well panel to clear the pump. I simply re-worked the existing metal to clear the pump. I used a 1.5" hole saw (I think) for the factory harness to pass through.

I used the factory relay and fuse box arrangement. Again I had saved all the factory wire harness including the terminal into the fuse box. I cut into the power lead and ran it through a switch so I have a re-set capability on the fly.

The shell had the ABS holes already punched and plugged so I used the factory holes.

I kept all the factory ABS brake lines so it was an easy change over for me. I fabricated a bracket to mount the computer in the passenger side footwell.

My car looks identical to the factory. The only difference is the re-set on the fly capability.

What would I recommend?

The factory ABS harness is standalone from the rest of the vehiileharness with a couple of exceptions. The power cables from the battery all combine on the positive terminal. Power into the fuse block is the standard plugin like the rest, and the relay plug receiver in the fuse box has to be released. I would recomend trying to get a complete ABS harness from a breaker such as LART. It takes effort to remove it properly so its re-usable so most breakers would likely not help. If you can't get the complete harness you need at least the sections that connect to the pump, with the plug ( I have one of those) and the harness and plug to connect to the computer. If you plan to use the factory fuse block and relay you need the relay plug and wires from the fuse block. You will also need a red power cable and pin from a fuse block so you can run the power in. Again to get them out you have to take a plug out of the fuse block and then open up the plug (it all snaps a apart easily).

With those, you can make your own harness. The factory harness uses the pad sensor/ABS plugs, but you don't need them. You can run the harnesses all the way to each wheel and have a single harness to sensor connector. They are simple 2 pin with shield. Sensor cabling should be 2 conductor shielded.

If I were to make my own harness and the dash didn't have the fault light, I woul probably mount the re-set and light somehwre convenient.

APKhaos

Great minds think alike!
Somebody said all 88 models have ABS. Not so. I used an 88 chassis, which did not have ABS fitted, and did not have the ABS pump mounting bracket. There's a simpler way to rig an ABS reset switch:
The ABS harness relay wiring includes a free end which is the computer ground. Just add a switch between that line and ground, and you have an ABS reset.

samluke

I took pics of the 89 before I tore it apart. You can see the depression in the foot well to clear the pump, plus the bracket and the harness.

333pg333

Thanks very much guys for such complete write ups. Excellent documentation of what's involved. Pity we don't have areas in here for this good information to be lodged. I must admit to having a rethink about this process mainly based on the time involved and that it wouldn't be me doing it therefore it costs for labour. I may either just sell this '86 and buy a more modern car or there may be another option on the cards. I'm still interested if we couldn't implement a more sophisticated version from a more recent car. Any thoughts on this? As has been said, Tony G was looking at the Boxter as an upgrade. What would be the reasons why we couldn't use a number of other ABS units?

Olli Snellman

I suppose we can use ABS systems from various cars, if you can take most of the components. So if we can use newer models pump, brains, sensors etc. Most likely the hardest part are those rings ABS sensors read. Might be difficult to install them to a vechile they are not ment to be. This part can require some machine work. Also if ABS system is taken from a car which have OBD system, CAN/BUS etc. it will cause some difficulties as well.

333pg333

Just resurrecting this thread. I will shortly be at the point of having my old '89 car stripped. All the good parts will be going onto an '86.
The decision of swapping the ABS is still troubling me. My instincts are to have the swap done, but I know that this is a PITA job and
can take some time. As it's not me that's doing it, time = $$. I don't have a big budget at the moment but I feel like there won't be a better
time to do the swap as we will have the 86 car pretty much stripped down too. So this is one question I'm tossing back and forth. We've
sort of decided to look at it when we have the car stripped and make a decision then.

My second question is based on what a few people have said in this thread and others. That our ABS system is prone to cutting out on the track
and therefore we should mount an accessible re set switch. I've never noticed this happening with mine on the track btw and we hit / ride the gator
strips sufficiently enough to get air and crash back down on some corners and still no cutting out. However, it occurred to me that if the ABS cuts out
it sends a signal to a light on the dash doesn't it? That would tell you to re set it with a switch. So why can't an auto re set system be made?
Am I missing something here? I'm no electrical engineer, but I would think this could be implemented pretty easily, no?

Van

Well, at the very least, swap the control arms - then, at least, you have the sensors and hubs.

Personally, I think I'd do the swap - since you have the parts. It's just brake lines, the brain, and a bunch of wiring, right? As I see it, the time consuming part is going to be making brackets and studs to mount things (like the pump).

Maybe I'm missing something, too.

Also, FWIW, I've logged thousands of miles on the track in 10 years, and never had the ABS turn itself off... (Of course, now that I said that, I'm sure it'll die at the first event of the year!)

vette951s

There is another issue regarding time required for retrofitting, the punching holes in the body for routing a multitude of ABS wires and fluid lines.

My Rothman Turbo Cup car has a power cycle switch for the ABS system which I tend to use about once every three track weekends. I takes about a second or two pause to reset the ABS system - a quick flick of the power switch does not reset my system. The original Rothman Turbo Cup contestants were issued a factory bulletin for the installation of the power switch, mine was mounted on the radio delete panel on the center console. It beats having to turn off and on the key in the ignition switch while on the track - an event I used to do on my old Turbo S street/track car!!

John

Oddjob

I had a bad wheel sensor that would fault out quite often when hitting bumps, so I needed the reset. After replacing that sensor, the ABS has been pretty fault proof on the track car.

The stiffer the car, the more likely it will fault. A stock Turbo S will probably seldom have a problem, but the track cars with solid bushings, 600+ lb/in , 18" wheels w/ 30 series race rubber can fault the ABS when hitting rumble strips on occasion.

I wired an unused rear wiper switch in the center console as my ABS reset/shutoff. Cut the power wire to the ABS relay to work (this cuts power to the brain and pump). FYI cutting power to just the ABS brain does not reset the system.

If you want an auto reset, Im sure it could be done with some trinkets from Radio Shack.

333pg333

Well I have pretty much that setup you describe Jim, springs, bushings, wheels/tyres yet I've never had it cut out.
Makes you think why Porsche didn't create an auto reset especially as John above has described that this was a common enough phenom that the factory sent out a bulletin re the Rothmans cars?

samluke

Having a re-set switch is just plain good insurance. There is no downside and its no effort to install it. If you never have to use it then that's fantastic.

I ran for a few years without a reset. I am very abusive with my car, I run hard on the aligator strips/rumble strips. If it faults out, you have a very erratic braking system. On track you cannot reset unless you power off. I used to key off to re-set, which is not recomended. I had another fault occur in one race by keying off, and never did find what had happened, and lost power ever since. That was my learning experienece.

I had a buddy drive another friends S2 in an Enduro. It glitched out, he had no reset, and didn't consider it an issue. He ended up hitting another car in a hairpin turn. Two cars damaged, and some very upset owners. He avoided a 13/13 as it was judged a mechanical. Its not worth the risk for a couple of wires and a switch.

ABS is a very easy but very time consuming install "IF" you remove everything carefully from your 89. Make sure you keep the bulkhead fittings on the firewall, you will need them. Cut the ABS bracket off your 89. Take all the brake lines off, you don;t necessariy need them all but its best to have them. Mark things and take photo's.

gt37vgt

if it was auto reset it would effectively have no faults . so if there was a real fault with the system you wouldn't know until you you were trying to out brake a a GT3 and come unstuck in a big way .

Oddjob

Patrick,

From your in car camera footage you posted in your thread on the racing page, my initial thoughts were 1) its a very smooth well maintained track surface. 2) didnt look like a real high speed, heavy braking track.

So, those factors contribute to you not hitting the ABS often and will also be a factor in reducing ABS faults.

I dont recall faulting my ABS during last season. But it has happened on occasion. If you want to take the position that its not necessary, I wont argue with you and I will not say that a reset switch is absolutely required. But I have had to use it even with fully functioning sensors and pump. And compared to the work and effort required to swap ABS into another car, installing a shutoff/reset switch is very little work. So I see little reason not to.

And thinking about it, I have a little concern about an auto-reset switch. It may mask a fault and continuously reset the system w/o making you aware of the problem. Although I think the dash warning light would at least flash or flicker as the system was auto-resetting.


All the 87+ cups came w/ an ABS reset/shutoff switch. Partly to be able to manually reset a fault, and also to give drivers the ability to run with the ABS shutoff if they chose to. At the time, ABS was very new, and not fully tested in racing applications. So they had this manual shut off available if the system didnt really work well in racing conditions, or if the drivers preferred to drive w/o it.


I have a copy of a document sent from Jochen Freund of Porsche Motorsport Weissach to Tom Seabolt, the operations mgr (under Al Holbert) of Porsche Motorsport North America, dated 21 MAY 87. The letter is a response by Porsche Motorsport to questions about the US Escort/Club Sports imported for racing in the SCCA Escort Endurance Championship by Porsche Motorsport North America. I do not have the list of questions that were asked, but can infer from the answers that several of the questions were related to the ABS system.

Here are a couple paragraphs from the letter. I will type it as written to include spelling and translation errors (they are kind of funny).

333pg333

Thanks again Richard for your time to detail all this. Much appreciated.

Well yes in effect I guess you're right Adam, but if the 'fault' is symptomatic of racing then if it auto resets vs me hitting a switch, what's the difference? I guess it might be possible to log the events still and check it out later?


Jim, thanks for that transcript. Great to see something so authentic!
Yes on that track it's pretty smooth and we hardly hit the strips at all. Being that this is my 'home' track for now I agree that's in this regard it's pretty reassuring. We used to use another track (Oran Park) which involved a lot more kerb jumping and even then there was no time that the ABS failed. It's hard to hear but we actually get a bit of air and come down on the 3rd last turn before the straight. Oh, and I don't recommend using a splitter without fixing stays...
http://www.youtube.com/watch?v=TJcQW_KDYNk

Olli Snellman

Simple answer to this. Our cars are over 20 years old. System used is the first gen Bosch.