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-   -   H12 ABS Swap (https://www.rx7club.com/3rd-generation-specific-1993-2002-16/h12-abs-swap-862605/)

hwnd 10-17-09 12:43 AM

From a 2001 FD3S.....

Here is a screen shot showing the part numbers of the wheel sensors
F146-43-70X (F.Right)
F146-43-73X (F.Left)

F146-43-71Y (R.Right)
F146-43-72Y (R.Left)

http://img269.imageshack.us/img269/8...pecsensors.gif


Here is a photo showing the ABS unit explosion

http://img391.imageshack.us/img391/1668/jspecabs.gif

cabaynes 10-17-09 04:08 AM

this thread keeps getting better and better...

you should definitely offer kits or a how-to. you're doing the community a great service!

hwnd 10-17-09 03:08 PM


Originally Posted by cabaynes (Post 9567335)
this thread keeps getting better and better...

you should definitely offer kits or a how-to. you're doing the community a great service!

I'm only interested in recovering the money I spent to get this far. Someone else can make the kits.

And for what it's worth - the ABS rings are the same.

Rxmfn7 10-17-09 06:08 PM

Ive been keeping an eye on this as well, I (as well as others Im sure) really appreciate the work you're doing trying to update/upgrade our cars. Ive been interested in doing this for a while and Im definitely going to be upgrading once you get it all figured out.

hwnd 10-17-09 09:50 PM

It's done... I know where to source the connectors (for the abs computer), wiring, etc...
I'm more so interested in a few people trying it out before saying claiming anything.

I've provided proof that the part numbers (wheel sensors, abs tooth ring, etc) are the same. The last thing I really need help with is for someone to pick up one of the pumps & computers and install it. There are 3 of us 3rotor guys with down cars who are doing the swap but our cars wont up up and running for a few months at the very least. Someone else needs to jump on aboard and pick up a pump & computer and install it! :-)

FDNewbie 10-18-09 09:01 AM

AWESOME bro. Simply AWESOME. You actually FINISHED what I started a loooong time ago. Have the parts sitting in a box somewhere, but never got around to making it happen.

I am still a bit away from having my car 100% up and running, but I'm def. gonna give this a shot. And if it works, I'd be happy to make the kits with you =-)

~Ramy
FDNewbie Imports

hwnd 10-18-09 11:39 AM


Originally Posted by FDNewbie (Post 9569001)
I'd be happy to make the kits with you


I'm not interested in making a kit, just want my initial investment back. Someone else can make kits. I'm not one to answer tech questions or sales.


In fact, one buddy gave a brief run-down of a stupid customer who wanted part numbers from one of their kits(i assume the customer wanted to build his own kit).. my reply to him was along these lines

p/n 001: Our Kit
p/n 002: Shipping Box
p/n 003: Shipping Label
p/n 004: Packing Material

I've just lacked "customer service" for a long time :-)

RotorMotor 10-18-09 11:25 PM


Originally Posted by hwnd (Post 9569171)
I'm not interested in making a kit, just want my initial investment back. Someone else can make kits. I'm not one to answer tech questions or sales.


In fact, one buddy gave a brief run-down of a stupid customer who wanted part numbers from one of their kits(i assume the customer wanted to build his own kit).. my reply to him was along these lines

p/n 001: Our Kit
p/n 002: Shipping Box
p/n 003: Shipping Label
p/n 004: Packing Material

I've just lacked "customer service" for a long time :-)

LOLZ! :lol:

KKMpunkrock2011 10-20-09 12:55 AM

I hate retarded people, your attitude is understood.

hwnd 10-20-09 05:08 PM

Took some photos today with the ABS computer mounted (used the newer brackets that accompanied the computer itself). Also did a really rough fitment of the ABS pump using the US bottom bracket and top JP bracket - it *could* but to do this, a few holes would be needed to keep it in place - at the very least you can get some idea of how the placement will look and the amount of room taken up by the ABS pump.

A note on the bracket... I wouldn't run it this way, personally I'm building a copy of the jspec bracket (only reversed) to fit our cars. it sits the ABS pump (height position wise) in between wiper motor and the engine harness wall grommet. This is ideal, very ideal.


http://img24.imageshack.us/img24/143/abs001.jpg

http://img26.imageshack.us/img26/1369/abs002.jpg

http://img202.imageshack.us/img202/8632/abs003.jpg

http://img24.imageshack.us/img24/4167/abs004.jpg

http://img202.imageshack.us/img202/6844/abs005.jpg

tt7hvn 10-20-09 05:37 PM

and on top of all that awesome braking you're going to have (you might as well check out the EVO brake kit thread) you have a damn 3 rotor in the thing

hwnd 10-20-09 07:13 PM


Originally Posted by tt7hvn (Post 9574183)
and on top of all that awesome braking you're going to have (you might as well check out the EVO brake kit thread) you have a damn 3 rotor in the thing

Sounds nice but I'm really interested in balanced braking - otherwise there are huge 6-pot brakes I've eyeballed a time or two but I really think no matter how big the brakes get - they need to be balanced.

M104-AMG 10-20-09 08:21 PM


Originally Posted by hwnd (Post 9560710)
Good question.. Here is what Mazda said about the 2000 GF-FD3S:

Four-channel, four-sensor ABS - This is the best scheme. There is a speed sensor on all four wheels and a separate valve for all four wheels. With this setup, the controller monitors each wheel individually to make sure it is achieving maximum braking force without locking the wheel(s).

Three-channel, three-sensor ABS - This scheme, commonly found on pickup trucks with four-wheel ABS, has a speed sensor and a valve for each of the front wheels, with one valve and one sensor for both rear wheels. The speed sensor for the rear wheels is located in the rear axle. This system provides individual control of the front wheels, so they can both achieve maximum braking force. The rear wheels, however, are monitored together; they both have to start to lock up before the ABS will activate on the rear. With this system, it is possible that one of the rear wheels will lock during a stop, reducing brake effectiveness.

In other words, you can drive/corner the car harder without spinning out because the ABS computer able to pay attention to each wheel.

My understanding is that this 4-channel system is ABS, not a "stability" system.
If so, then going to this 4-channel ABS system does NOT allow you to drive/corner harder without spinning.

It does allow you to engage ABS and the rear wheels will be independently pulsed so each rear wheel remains at maximum traction.

My understanding of something like an Autologic traction control system, is you only need to install/read wheel speed sensors on the two rear wheels since a 3-channel ABS system doesn't have sensors on the two rear wheels.

Regarding bleeding the ABS system, if it's anything like the Mercedes ABS systems, a power bleeder at 30-psi is all that is needed.

:-) neil

hwnd 10-20-09 08:32 PM


Originally Posted by M104-AMG (Post 9574529)
My understanding is that this 4-channel system is ABS, not a "stability" system.
If so, then going to this 4-channel ABS system does NOT allow you to drive/corner harder without spinning.

It does allow you to engage ABS and the rear wheels will be independently pulsed so each rear wheel remains at maximum traction.

My understanding of something like an Autologic traction control system, is you only need to install/read wheel speed sensors on the two rear wheels since a 3-channel ABS system doesn't have sensors on the two rear wheels.

Regarding bleeding the ABS system, if it's anything like the Mercedes ABS systems, a power bleeder at 30-psi is all that is needed.

:-) neil


I mean by that is it gives the ability to brake harder & later in turn taking a corner at faster speed & braking later.

hwnd 10-23-09 04:50 PM

Alright Guys... I've got a good deal of PM's on the swap and info on how to do it, etc..

Here are the parts needed for the swap:
a) ABS Pump & Computer
b) Computer Connector (off the shelf Bosch connector)
c) 3 * 20awg wire about 7' long
d) Pump mounting bracket

a) ABS Pump & Computer
I bought 6 total from various places (I got four from an auto wrecking yard in Japan). I bought another one from ebay.com.au (which came with wheel sensors). So these can be picked up here and there. Expect to pay for the parts. I've not seen them "cheap" by any means.

b) Computer Connector (off the shelf Bosch connector)
http://www.bosch-connectors.com
p/n: 1928402198 / 88way connector

c) 3 * 20awg wire about 7' long
...

d) Pump mounting bracket
You can use the stock US ABS bracket (lower half) and build your own plate to mount to the JSpec pump or something. My view on this is it'll sit too high.

The JSpec bracket is a nice one to copy so for those interested - I'll send photos of what they look like or maybe you can figure it out on your own (say if you're going to mount the ABS unit where your HVAC use to be!) :)


Some thoughts on the swap:
there is only a 3 wire difference from the 3channel vs. the 4 channel;
you can cut(or as i prefer 'de-pin')the old connector and install the new Bosch connector, run three additional wires and you're done. I've managed to note the wheel sensor wiring, pump wiring, power wiring & even the diagnostics port wiring.

I've got nothing to offer in terms of the hard lines - there have been a few posts to websites with "better than good" quality brake lines with tool rental,etc.

I have not completed the installation myself - I've only managed to figure out the correct part numbers & wiring issues. I've toyed with mounting the pump and I've discovered (for me at least) i'd rather copy the JSpec bracket. Who knows how long it'll be before I get around to getting under the car and run brake lines myself - I'm hoping by then a few guys will have done the swap and can report on how their brake-line install went. this is one of those swaps where it can get costly pretty fast so I think if a few of us join up and tackle the swap from different ends that we can keep coats down on this.


I've had a handful of questions asking about one of the units I've got stateside..
still have some left but I can't promise you a direct bolt-on type of swap but surely will help along the way - i'm in it too. :icon_tup:

Julian 10-23-09 05:37 PM


Originally Posted by M104-AMG (Post 9574529)
My understanding of something like an Autologic traction control system, is you only need to install/read wheel speed sensors on the two rear wheels since a 3-channel ABS system doesn't have sensors on the two rear wheels.


Not all 3-channel systems have only 3 sensors. Our Rx-7's have the 4 wheel sensors for lock up dectetion but only brake control of both rear wheels together.

Julian 10-23-09 05:47 PM


Originally Posted by hwnd (Post 9580835)

b) Computer Connector (off the shelf Bosch connector)
http://www.bosch-connectors.com
p/n: 1928402198 / 88way connector

c) 3 * 20awg wire about 7' long

Are we to assume that the three extra wires go between the computer and pump, and two new connectors for both Pump and Computer?

Is the pump lighter than the 93 - 94 pump like the 95 unit was or heavier?

Julian 10-23-09 09:26 PM

Has anybody confirmed that the Proportioning ByPass Valve is the same or at least the same specs

i.e.

origin:0,0
A-A':570 psi , rear 530-610 psi
B-B': 850 psi, rear 626-739 psi

Julian 10-23-09 10:08 PM


Originally Posted by hwnd (Post 9564832)
Wheel sensors measured in resistance

rear: 1.6ohm
front: 1.04ohm

I have other sets I could test but for the moment this is what I've decided to post up.

I don't see if you looked into this more this but USM cars sensors have specs 0.8 to 1.2 kohms front and rear. Front fits but rear is a big differance

hwnd 10-24-09 12:19 AM

6 Attachment(s)

Originally Posted by Julian (Post 9581382)
I don't see if you looked into this more this but USM cars sensors have specs 0.8 to 1.2 kohms front and rear. Front fits but rear is a big differance

Thanks for pointing that out.. Having read that post caused me to go back and double check the part numbers for the wheel sensors.

I made a mistake
The wheel sensor part numbers ARE different.

As you can see they're off (FD01 vs. F1). I'm surprised I didn't notice that mistake.

I've included screen shots showing the part numbers as they are - no more mistakes!

hwnd 10-24-09 12:22 AM

Now does this mean the sensors function differently? no

Since the ABS unit is flashable - I *may* look into the idea of flashing the cpu's (abs computer has two cpu's on board) and adjust for the us-wheel sensors. but i think its far more important to see if they actually function differently.

I do have two sets of wheel sensors (both sets came from '01+ model fd's).

hwnd 10-24-09 01:37 AM

Let's now give up just yet... I'm noticing that the 16bit ECU went back a lot further than anyone may have thought. I'm seeing the 16bit ECU part number on H7 model FD's (starting with vin: FD3S-407533 / Type-RS).

I'll dig around a little more and see if wheel sensors were interchanged or not.

hwnd 10-24-09 02:52 AM

H7 & H10 w/ 16bit ECU

Front Wheel Sensors
FD04-43-70XC
FD04-43-73XD

Rear Wheel Sensors
FD04-43-71YC
FD04-43-72YC


US Wheel sensors from a '94

Front Wheel Sensors
FD05-43-70XB
FD05-43-73XC

Rear Wheel Sensors
FD04-43-71YC
FD04-43-72YC

I think we're just fine on the wheel sensors folks. I say this only because the "99 spec" ECU was used in the '97 model cars with those FD04 wheel sensors - and thats really where it counts - the sensors are wired to the ECU and nothing else. Seems the wheel sensors where interchanged with this ABS Computer. My sensors might show different resistance-readings for many reasons (bad meter, bad wire, who knows) or they might be right on. Perhaps resistance isn't an issue with the ABS Computer? I'm not sure. Either way, I'm still running 'em.

Narukas 10-24-09 05:02 AM

2 Attachment(s)
Very nice write up!
I am currently working FD3S-4xxx Type-RS RHD-LHD conversion :)

I can tell that it has same 314mm RZ or 99 spec RS-RZ brakes, brake booster, ABS sensors.
But still it is 3-way, ABS pump is slightly different and overall got only one brake line to rear end.
ABS sensors look same. I am concerned regarding ABS sensor wheels. Will try to measure gaps to see if there was any difference between 94 USDM - 8 bit, 97JDM - 16 bit respectively.

My plans were to make it work with 94 USDM ABS cpu, but now getting excited of making it 4-way as it is allready 16bit.

hwnd 10-24-09 06:12 AM


Originally Posted by Narukas (Post 9581865)
Very nice write up!
I am currently working FD3S-4xxx Type-RS RHD-LHD conversion :)

I can tell that it has same 314mm RZ or 99 spec RS-RZ brakes, brake booster, ABS sensors.
But still it is 3-way, ABS pump is slightly different and overall got only one brake line to rear end.
ABS sensors look same. I am concerned regarding ABS sensor wheels. Will try to measure gaps to see if there was any difference between 94 USDM - 8 bit, 97JDM - 16 bit respectively.

My plans were to make it work with 94 USDM ABS cpu, but now getting excited of making it 4-way as it is allready 16bit.

Awesome! If your VIN is equal to or greater than FD3S-407553 then you've got the updated 16bit ECU in there (good chance anyhow). As far as upgrading you're only lacking the brake lines and pump itself.

mind checking the vin and computer for me?


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