BL: Does anyone have experience with using miata ABS in an RX7?

I would consider it not so much a "performance" upgrade, but reliability/safety modification that's easy on the wallet.

I saw someone had mentioned it, among other vehicles' Bosch ABS setups, so I started to look into it.

2001-2005 Miata ABS w/EBD

Pros:
o 3-channel
o same hydraulic inputs/outputs
o same number of teeth on the hub rings
o same resistance and voltage required from the wheel sensors.
o it's smaller and allegedly better.

Cons:
o adapt/bend hydraulic lines
o some wiring required
o ??computer programming not compatible with RX7 dynamics??

Additional considerations:
o use RX7 proportioning valve? the NA miata guys mess with a pre-pump proportioning valve even though it has EBD.

I don't know enough about ABS, or these specific models to say anything conclusive. Just researching.

Thought I'd ask because miata units are $40 with a pigtail, are newer, and have more to offer than the $150 used time-bombs for the 93 RX7.

 

This is a REALLY good idea. It's going to take someone to pioneer the trail and actually get in there and try it out.

I don't know much about the inner workings of the stock ABS - the system generally just works, so I've never needed to learn what all is involved with it. I imagine the ABS computer mainly just has inputs from the wheel speed sensors and outputs to the pump, the only other input I could think it could need is from the vehicle speed sensor, which is most likely compatible.

Would also be cool if the system saved some weight or space as well.

I may have to dig up the shop manual and look at the stock system, this is an interesting project!

Dale

 

At a glance: Wiring

All Miata required inputs are satisfied by the RX7 Harness.

Unaccounted for wires are below.

RX7
o Input (output?) from Alternator

Miata
o "Brake" light wire
o DLC diagnostic wire
o DLC/OBD2 diagnostic wire

 

So is the miata abs system the same as the 95 rx7 abs unit?

 

No

 

its still 3 channel? the 90's hondas are 4 channel and the harness is a standalone.

 

Is the 90s honda ABS compatible with RX7 wheel speed sensors?

 

I like the idea. Can I throw in another observation that may or may not matter:

The FD ECU is 8 bit. She's pretty antiquated.

Is the Miata ECU also 8 bit? Will the ABS module work if its out of a 16 bit Miata car? I know some things out of an RX8 will not swap as the RX8 uses a 32 bit ECU.

I'm not very up to date with this stuff, but I thought it might be something to consider.

Someone needs to look into it though. I'd be up for that swap if it's tried and works.

 

we did put a 16bit FD ecu into an 8 bit FD and it is a big upgrade. i'm a little surprised nobody offers an adaptor harness.

note the engine has an ecu, and the abs has an ecu

 

I appreciate your input so far, but the biggest reason to consider switching to the miata unit is the cost and age of the system. More so than the performance gains.

So I'd like to omit using expensive FD pumps, ecus, or any other vehicle's parts that require more than a few wires and some hydraulic adaptors.

I'll have to look up the miata ABS, but all of the inputs are "dumb" in that they are raw data/power that the ABS computer processes. The link between the ABS computer and pump is direct, since they are the same unit. I don't think the miata using an 8bit,16bit, or 32bit ecu will make a difference.

 

any success in getting this done?