It seemed there were a few persons doing this coversion, did anyone finish it?

It crossed my mind today so I did som investigation..
It seems the stand alone ABS without traction or DME interaction - Bosch ABS 5.3 - is actually just a 3-way ABS. It's only the 5.3 TC ABS that is 4-way.
So much for hoping to get a 4-way the easy way..

The regular 5.3 however seems super easy to retrofit and I suppose it's much faster then the old 944 ABS system even though it's still 3-way.

Found an excellent diagnose manual here:
http://www.europeantransmissions.com...abs5.3diag.pdf

 

Haven't heard anyone to done this. 5.3 should be more or less bolt on if you can find all necessary parts. Might need use of sensors as well from this system and most likely you need to have custom made toothed rings to be able to use with 951 hubs,. That's not a problem since you wll have cutom rings with your new billet hubs , so they can be fabricated

 

Sensors should be the same so it might even work without touching anything
Numbers of teeth would be good to match, but even with a different teeth number it should work the same. Don't know if the ABS adapts it's behavior depending on vehicle speed, if not it shouldn't matter!

 

BTW Olli I sent you an email yesterday, did you get it?

 

As you know, Tony G was looking at the Boxter setup but I don't believe he actually wound up doing this. He might be able to give you some insight though Duke. So are you saying that the Boxter one is still only 3 way though? I looked into the Bosch Race version but it would have taken something like $15k to buy it and have it installed. Lot of man hours sorting it out. You have to do a bit of prep work before you even buy it too.

 

After reading up on it today from 2 sources I'm certain the Boxster ABS that doesn't need to communicate with the DME is 3-way and not 4-way.
Seems it a bit odd though if the others looking into to it didn't discover it since I've only spent an hour on this so far.

Installation should be very straight forward in any car. 2 brake lines (front/rear) from the master cylinder to the ABS pump, then one line each to the front wheels and one common line to the rear.
The resistance of the Boxster sensors seem to have a nominal range of 1600-1800 Ohm versus the 944 sensors with circa 1000 Ohm, so the sensors might need to be changed.

 

Sure the Boxster (more modern) ABS is probably faster, but, in general, I've found the 944 turbo S system quite good. It comes on when I need it most - and that's it. Of course I only use the car on the track - so in a way I'm using the ABS in a "controlled environment", but it seems like a waste of money and effort to try and upgrade it (unless you're really trying to go for some kind of traction control system that works with a standalone engine management system...) Put that effort into a custom gearbox or something useful!

 

Yes.

 

It seems also the first generation 996 GT2 and GT3's use the 3-channel 5.3 ABS.
So perhaps it would be OK after all

 

Patrick, I recall you were investigating putting ABS into a earlier non-ABS 951, but decided against it as impractical. What actually made it so expensive? I would have thought the parts (944/951 ABS) would have been available and affordable... was retro fitting into a non ABS car trickier than first thought?

 

The ABS on the 944 is effectively a standalone system, and its easy to convert. The wiring harness is seperate from the main harness for the most part. I converted a late 86 manufactured car, it even had the plug for the gages, and holes in the chassis for the cables. The only thing that was missing was the bracket in the passenger fender well. I cut the one off my 89 and used that. All the brake piping converts over and the sensors are all easy to install.

I took the system off my 89, so I had absolutely everything I needed. It cost me nothing other than a few hours. The 944 system may not be the best by modern standards, but its more than adequate. I had ABS with cutout on my 89. On the new car I built, I tried it without the ABS. 1 event convinced me that it wasn't the way to go and converted it. I would never go back to non ABS. With the cutout switch, you can always run non ABS if desired, that's the way the Cup cars were configured.

 

...but the Motorsport one is so trick....

 

My initial hesitation was based on proposed hours to do the changeover but as Richard points out, perhaps that was a little misguided.
Then I was speaking to a Raceshop who suggested that running with stock ABS vs no ABS might be detrimental as the sensors are designed to cut in at an earlier % braking pressure rate than you can extract with good modulation on non ABS. Since flat spotting a number of tyres (including a 6 lap old brand new Hoosier R80 slick!!) I may still opt for the stock ABS before next season.

 

With my 89 I never had any ABS/tire issues other than cutout/fault when running over the alligators. That was easily fixed with a cutout/reset switch. Without ABS I trashed 12 tires before I figured out the car again.

I was warned beforehand that I would regret not putting the ABS on as soon as I trashed a set of Hoosiers. They were right and I soon learned an expensive lesson. So what if real men drive without ABS, its worth it just to save the tires, and if I want to run in non ABS mode I can turn the system off!

 

I will install abs in my non abs car.

Are there any pictures anywhere of abs attachment points under fender? I will need to fabricate them.