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marshallmosty

Ford Racing ABS Installation

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marshallmosty

Everyone,

I’m posting this to document the conversion of standard SN-95 ABS from my FOX Mustang over to the new “oh my God” Ford Racing ABS…

 

The first thing to consider is the location and mounting of the ABS unit itself. My SN95 ABS unit is/was in the passenger floorboard. Therefore, I already had all the lines (2 supply and 3 outlet) run around the car.

 

The stock HCU bracket could be easily manipulated to mount 2 points to the floorboard and I built a simple spacer to mount the third point. The mount has plenty of vibration isolation, so you can grab and shake the HCU in the mount. This gave me good feelings that vibration from the car during a race would not cause excessive issues with the HCU and ABS electronics.

 

The stock supply lines and outlet lines were “close enough” to just cut and flare for a simple union fitting. For the new lines going into the HCU, I just purchased AutoZone double flare 3/16 line. This was good for 2 of the 6 lines, but the other four required that line, but a M12 conversion nut to be purchased. You can also get these at AutoZone, etc. I also removed the rear prop valve, as the FR500 unit does that on it’s own. I did have to run a second rear line, as the S-197 system is a 4 channel and the SN95 is a 3 channel system. This consisted of just another few sections of 3/16 line running parallel to the original rear line.

 

If you want to flip flop back and forth between ABS/no ABS, install the prop valve in the rear supply line BEFORE the HCU. That would allow you to run wide open (no pressure drop) for ABS function, or reduce the pressure if the ABS is disabled. I chose not to do this, as I’m going to “set it and forget it”.

 

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The only harness you need to source from a junk yard is the ABS plug.

 

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Here is the plumbing layout for the HCU

 

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Here is the wiring diagram. For older cars, I just ignored the PCM portions.

 

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The brake position switch can be made from a 5 pole 30A relay.

 

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The speed sensor wire colors from the SN95 system match this diagram, so that is pretty nice…

 

 

I don’t have any pictures of the wheel speed sensor mounting, but it’s a simple redrill/tap for the new clocking on the S-197 sensors. The SN95 were just a magnet pole sticking out, so there was no orientation required. To drill/tap the rear caliper brackets, I found it easier to just remove the axles from the car and remove the caliper mounting plates from the axle and drill on a drill press.

 

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The front spindles on my car didn’t want to come off easily, so I drilled by hand on the car. Not the easiest, but worked fine.

 

All in all, I would put the installation difficulty at a 6 out of 10. Not super difficult, but time consuming to lay out in your head and then it’s just time… Having a welder, drill press, and overall shop tools was nice, but you could probably get away without them.

 

I’d say that since I had ABS on the car already, this entire conversion (not counting my time) was about $1100 in parts

 

$525 HCU

$50 ABS harness

$125 wheel speed sensors

$260 FR ABS Module

$25 Brake Fluid

$75 Brake Line and fittings

$25 Diff fluid and gasket

$15 5 pole relay with harness

 

 

The only thing I haven’t addressed at this point is the diagnostic port (Module Communications Network) section 14-2 on the diagram. I still need to do research on how to wire an OBDII port to these wires so I can trouble shoot the system.

 

 

 

Here is the parts list of what you will need to buy…

 

GT500 HCU

7R3Z-2C215-C

 

ABS Module

You want the "M-2353-A" sensor. The -A part is the FR500S module. The -B and -C are the same module for the new Boss cars, just with or without the bracket. I would guess the tune is for Pirelli slicks.

http://www.fordracingparts.com/parts/search.asp?q=2353

 

Wheel Speed Sensors

BRAB-290 (rear)

BRAB-291 (front)

http://www.autopartstomorrow.com/part_numbers/336251-rear-whl-abs-sensor

This is the cheapest place I could find and it was free shipping. They are Motorcraft parts.

These sensors plug into the stock SN95 plugs and are approximately the same length as the SN95 harnesses, so you shouldn't have to manipulate the body harness.

Edited by Guest

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UBR

I guess we know how you spent your Christmas break. Thanks for the write up.

 

I think we will stay with our non-ABS and bigger HP for now.It never rains in the Midwest anyway.

 

j

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marshallmosty

Jim,

I started the conversion around thanksgiving. The car is about 45 minutes from my house, so I have to plan my days to center around it (family, work, etc). It's been interesting. Not too hard, as I indicated, but just a bit of layout. Once I have more to share, I will add some more.

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Jay A.

Hi Marshal,

Now there are at least two of us with this system. I am anxious to see how you like it. I love mine and am going to keep it.

From the information I sent you from the same system I installed in my car two years ago I would just like to give credit to JEFF FEIT optimummotorsports.com. Jeff was the Ford Engineer that traveled with the Mustang Challenge series and helped develop this system. He found all the wiring and plumbing diagrams that I sent you as well as gave me a ton of advise.

 

Also I installed the brake switch as indicated in the wiring diagram. did you add this. Not sure if it is needed or not. It just seemed part of the system so I added it.

 

Good work!

 

Jay

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marshallmosty

Jay,

I'd like to thank you as well for providing the stuff to me as well as the several hours of text and phone conversation on the topic. I'm sure I will have more questions before it is 100% developed for what I'm doing.

 

I "think" the brake switch wire that was used in the SN95 system serves the same function (hot under pedal application).

 

The car "should" be track worthy this weekend and I am planning on a track day Sunday the 15th to shake it down. The track I'm using is my "home track", so I can be pretty consistant and should be able to evaluate the braking performance once I get the new pads bedded in.

 

Look for an update on Monday the 16th...

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marshallmosty

Updated first post to list a picture of the 5-pole 30A relay required to make the brake switch work for the HCU. The brake switch/HCU circuit needs to be "on" when you are off the brakes, but once you power the brake light switch, it needs to interupt the signal to the HCU and turn it "off".

 

Thanks to Jay Andrew for the tech support and original diagram. The relay is in hand and will be installed Saturday. Hopefully I won't go out and lay more black marks...

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marshallmosty

Adjusted to include current market price of HCU and ABS module as well as 30A 5-pole relay.

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marshallmosty

Okay folks, I'm back from testing. The day was cold (55-60-deg), so there wasn't enough heat in the track to get the tires up to good temp, so no track records fell today. I was approx 2 seconds off my lap record, but my brother (CMC driver) was also off pace an equivalent amount, so I figure we were still at "qualifying" lap speed. The ABS system works as designed and here are my thoughts:

 

Initial bite:

Much more agressive than the SN95 unit. It felt like I was going to suck the fillings out of my teeth. Very nice.

 

Feel "in" the ABS:

This was very different from the SN95 unit. The car "hunted" around quite a bit, especially the rear two channels. After watching years of Continental Tire and Koni Challenge and seeing the cars be very twitchy under braking, I now understand what they are feeling.

 

Release:

Well, this is an area that you have to be careful with. If you aren't too deep into the ABS, it isn't too bad, but if you are heavy into the unit, the release is very abrubt and will upset the rear of the car (I looped it once under heaving braking to see what would happen). I think that a pad with a little softer release characteristics may help out.

 

Overall Impression

This will take a bit of time to "learn" the characteristics of the system. I'm not 100% convinced that it's a "class killer", however I will need to evaluate again in the rain. The local track I used (Motorsports Ranch - Cresson) is a HIGHLY polished ashphalt track that is down right "ice rink" in the rain, so I can figure out how it works under "extreme" conditions... more to come on that point.

 

All in all, I had approx a little over an hour of track time today so there is a bunch more that still needs to be worked out for me to utilize the system 100%. Also, this was my first time on track since early October, so I was shaking off the cobwebs a bit myself...

 

 

A note on my setup:

'89 Hatchback

316/332 HP/TQ

3100lbs

Splitter/Wing

StopTech ST40 13" with PFC01's (Front)

Stock GT Varga 1-piston with PFC97's (Rear)

425lb front coil overs

325lb rear coil overs

SN95 V6 front bar (endlinks almost completely loose)

No rear bar

Maximum Motorsports K-Member, Foward Offset FCA's (SN95 length)

Racecraft 2" drop spindles

Griggs Torque Arm/Panhard Bar

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johngeorge

How was the brake balance front-to-back? Do you set the brake bias at master? or does the ABS module have to be full pressure to work? We are toying with the idea of adding this ABS to our NASA 25hr Enduro FFR which runs 6piston wilwood front/4piston wilwood rear along with the CNC dual masters/balance bar setup.

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marshallmosty

John,

Brake balance was a little more rear than what I would typically prefer.

 

I use a stock Booster with 94-95 SN95 master cylinder (15/16" bore). There is no prop valve upstream of the unit and it regulates the rear line pressure (somehow). You will need to feed it full line pressure to work properly, however I don't know what would happen if you reduced the upstream line pressure with a prop valve.

 

According to others who have built this system around S-197 cars, it's very difficult to get the balance correct with a dual MC setup.

 

I think that trail braking will be more difficult on this system without some R&D time into brake pad compounds, especially when you release during trail braking (at least that was my feeling yesterday). However, with the track surface cold, there was no "bringing it back" when it started to go. The track was much tougher to drive than in warmer weather.

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johngeorge

How much do you feel the ABS through the pedal? wonder if this will be too much not using a booster (manual brakes for us)

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marshallmosty

John,

It's more feedback than the SN95 system, but not as much as most "street" systems (non-Ford). You feel it thoughout the car as the car starts to twitch/yaw. If your pedals are setup for manual brakes, you will probably will be fine with regards to pedal effort.

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Jay A.

Marshal,

I just found this video of my car from the first race after I had my ABS sorted out.Well mostly sorted out.

 

you can see some brief front wheel smoke at different places on the track. I was not even aware of this until I saw this video. My Data sample rate for wheel speed is only set at 10 times per second so it is hard to see very clearly what is going on but these moments of smoke are not from a lock up but about a 10mph reduction in speed for a fraction of a second. It probably has to do with the programming for a an ideal setting on a 1.5g tire and we are using a 1.2g tire.

 

This was on an 18" RA-1 that was fairly fresh but was still from that 3 year old batch from 2007. I have Hawk DTC-70 Front with DTC-60 rear.

 

I did not have any moments when i felt that the car was coming around in trail braking and the rear brakes not releasing. However when i would over brake and trail too long this would happen. but that is driver error. I know this first race with the ABS working fairly well I was over braking. this is very easy to do with ABS. I know better now but am still learning.

 

I have never tired mine in the wet.

 

Jay

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marshallmosty

Jay,

For testing purposes, I went way too deep, too hard on purpose to see how it would "save my ass". That's where I found the funky wiggle, rear coming around on release, etc.

 

On the few "clean" practice laps at typical race pace, it behaved itself nicely.

 

I'll be at our first event in two weeks and will report back how it worked. This same event in '11 was a rain weekend, so we will see how it goes. My tires aren't the best specimens, as the rear tires have approx 25 heat cycles and were on the car for the start of 2011. The front tires only have 6 heat cycles...

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stevepoe

after running this for several years my thought is this is not worth the hp reduction for 2012 rules. I will be removing mine and taking the extra hp.

 

I have two sets of these that I will sell if someone is interested. I have wiring , brake lines and tone rings that will be removed along with wheel speed sensors.

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johngeorge
after running this for several years my thought is this is not worth the hp reduction for 2012 rules. I will be removing mine and taking the extra hp.

 

I have two sets of these that I will sell if someone is interested. I have wiring , brake lines and tone rings that will be removed along with wheel speed sensors.

 

Steve, I sent you a PM on this

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Racer91m

I would have stayed with the SN95 system and taken the .25 break...

 

I believe Leo Wanstreet has the hot setup in his car. His car has 03/04 Cobra ABS unit with manual brakes, but teh system is well designed and works really well. I got a chance to drive that car at Mid Ohio and I think it was faster than my car...

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marshallmosty

Dean,

If I find that it's not that great of a system, I can always put the SN95 system back in...

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marshallmosty

The FR ABS was "interesting" this last weekend. With StopTech's and GT stock rear calipers using PFC01 and PFC97 front/rear, there is WAY too much rear bias. Under trail braking, the back wanted to rotate VERY badly under release. I had to be very consious of my technique. I'm going to install an in-line bias adjuster BEFORE the HCU on the rear brake supply line. That "should" limit the line pressure and provide less rear "bite".

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Jay A.

Marshal,

you might try a different rear compound. Doesn't the 97 ramp up friction with temperature?

So at the end of the braking zone where you want more rear release the rear brakes are ramping up as your fronts are falling off. Exactly what you don't want as you are trailing off the brake.

So above 900F, which i am sure is the temp on your fronts at the end of the braking zone, the friction of the front pads is starting to decrease. This is the nature of all friction material as the binders or glue that holds it together starts to degrade above 900F. At the same time the rears are probably only around 600-700f which is probably the peek friction of the rear pads. If your are a PFC guy don't they have a compound 06 or something that has less friction than 01 but has a higher temperature range. That 97 is pretty old technology. I get lots of complaints on that compound like that.

Maybe Dean will chime in with PFC advise.

I know I had that problem of the rears over working with Hawk DTC70 front and rear but when I switched DTC60 on the rear the problem went away.

 

Jay

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stevepoe
Marshal,

you might try a different rear compound. Doesn't the 97 ramp up friction with temperature?

So at the end of the braking zone where you want more rear release the rear brakes are ramping up as your fronts are falling off. Exactly what you don't want as you are trailing off the brake.

So above 900F, which i am sure is the temp on your fronts at the end of the braking zone, the friction of the front pads is starting to decrease. This is the nature of all friction material as the binders or glue that holds it together starts to degrade above 900F. At the same time the rears are probably only around 600-700f which is probably the peek friction of the rear pads. If your are a PFC guy don't they have a compound 06 or something that has less friction than 01 but has a higher temperature range. That 97 is pretty old technology. I get lots of complaints on that compound like that.

Maybe Dean will chime in with PFC advise.

I know I had that problem of the rears over working with Hawk DTC70 front and rear but when I switched DTC60 on the rear the problem went away.

 

Jay

 

 

Everyone, This is why I buy my Brake pads from Jay....

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Ed M.

Me too my brotha!!!

 

Ed

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Patrick W.

Me three!!!

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redsnake08

Somebody mentioned using 03 04 cobra abs with manual brakes was a good setup... My question is then will the 03 modual work in my 97 cobra? Im using the stock harness still soo Can someone tell me what will I need and have to change to make this work? Also Ive ditched the hydroboost and have a tilton remote res setup in it now. Will these 2 systems work together?

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Mystic_Cobra
Somebody mentioned using 03 04 cobra abs with manual brakes was a good setup... My question is then will the 03 modual work in my 97 cobra? Im using the stock harness still soo Can someone tell me what will I need and have to change to make this work? Also Ive ditched the hydroboost and have a tilton remote res setup in it now. Will these 2 systems work together?

 

I'm interested in the answer to this as well. I have the stock ABS on my 96 Cobra and am considering a change.

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