This plea is aimed at Tephra, Gruppe-S, and any others who have been "inside" the various ECUs on an Evo X. If you could, somehow, devise a way to turn off the ABS without disabling the center ACD or the rear AYC, I would not only be grateful, but I'm prepared to show my gratitude in the form of hundreds (literally) of small green pieces of paper. And I doubt that I'm alone on this. Thanks.

 

I am not a tuner, but if you are looking for none abs set up for your GSR, you are better of with an aftermarket ECU bundle, or the RS set up.

The fact is your ECU reads the speed individually from the wheels via ABS ECU. There for you can not disable it, only mechanically, which will throw limp mode to your S-AWC and you wont able to change modes between tarmac -gravel -snow.

With the stock ecu we couldnt disable the ABS . Only of you have an RS ECU for your X either Japan or EU -AU etc. We didnt go to that route so i dont know how that will work with a rest of the GSR set up.
The way we did it, we removed the ABS pump ( mechanically ) from the ABS ECU. With that you immediatly put your AYC in a sort of limp mode. Which means it works some how, but it doesnt function properly as the AYC should. So from there doesnt matter which rear diff you will use. I have a revised IX diff set up for rally, but we still try to get a best solution for us , for the rear axels.

We ended up changing the whole ECU set up in the car. Like Engine ECU and ACD Ecu. Now works as it should.

Rob

ps:
probably the best way is what we did. Most of the guys either started with an RS or ended up like us and changed the whole ECU set up in the car.

 

Thanks, Rob. I have read everything (I could find) that you've posted on this, plus a lot more, especially from Eastern Europe and Scandanavia where, as you know, there are lots of Evo Xs being run on gravel and snow. I definitely do not want to lose the AYC and would like to keep the ABS for autocrossing and the drives home, as well as daily driving. This is why I was hoping that someone had gotten "inside" the relevant ECU to disable the ABS function while not putting either the AYC or ACD into limp mode and, maybe, keeping the single-wheel braking, as well. I have no idea how the ABS ECU works, but in a dream world we end up with a switch that simply stops the ABS ECU from doing anything when it predicts or detects any lock-up. Also in my dream world, this is all done in the existing ECUs. Worst case, I could see getting a new and programmable ACD ECU, so I could have a mode that locks as hard as Snow but also snaps open as fast as Tarmac, but that's not as important as turning off the ABS while keeping, at least, the center.

 

From what I can tell from having looked into this further, the ABS ECU is still part of the ABS unit, as has been true for many (if not all) generations of Evos. And, as said by Rob, the wheel-speed sensors are only directly connected to the ABS ECU, which not only uses the wheel-speed information, but also passes it to the other ECUs that deal with traction control, ASC, help for the AYC, and the ACD. This is why cutting power to the ABS ECU not only deletes the ABS, but also ends up disabling the ACD and AYC, leaving you with an open center and an open rear.

This implies that it's going to be very difficult to delete the ABS while keeping the stock ECUs. It really would require getting "inside" the ABS ECU and I can find no evidence that anyone has done this yet. For now, however, if anyone reading this has looked into all this, can you please verify the first paragraph above or tell me what I have wrong?

 

Is it possible that you could simulate the resistance of the ACD pump outputs on the ECU and still keep it active? I assume it might throw a fault code but it might solve your problem.

 

I had a similar idea, but for the opposite side of the system. My idea was to disable the valves in the ABS unit so that it would no longer be able to reduce line pressure (i.e., it would no longer be an ABS unit) and then, also, somehow fool the system into not throwing a code and, thereby, disabling the ACD. If I could disable only the valves that reduce line pressure without disabling the valves that raise line pressure, I'd still have the single-wheel braking functions if I wanted them. The trick, of course, is to disable the ABS valves without causing the entire system to shut down. Maybe this could be done in software. If not, I'm game for trying to figure out exactly which wires from the ABS ECU to the ABS unit activate the ABS valves and add switches to them. But, given how difficult this will be, I was hoping to do it by software or at least have an idea if doing this with throw a code and shut it all down.

But I'm happy to see that something like the above idea has occurred to someone else.

 

 

Reviving an old thread as this is the next thing I plan to tackle. My problem is that I have the SST trans so switching the ECU is not an option. I've got an evo IX rear diff and am just waiting on the LSD so AYC will be gone soon. I want to try to mechanically separate the abs by just rerouting the brake lines. Why won't that work? It seems like the simplest way but I'm probably missing something.

 

I started to plan that approach out last summer. I was even thinking of making it switchable. As long as you never fail to turn the ASC to off-off, so the ABS unit never tries to send pressure to a single wheel, I don't see a problem. In fact, given that many (if not all) RS models come with an ABS unit that's magically switched off, it seems feasible.

The $100k question is whether the ABS-ECU would somehow notice what you had done. It would be a huge drag if, after all that work, it ended up shutting off your SST or my ACD/AYC. I wimped out and didn't try it.

In any event, my plan was this: tap the lines going from the brake master cyl to the ABS unit. These side lines would rejoin the brake lines after the ABS unit (maybe after going through a new prop valve). These lines would have valves so that they could be shut off when ypu want the car to have ABS. When you don't want ABS, you open the valves on these lines that go around the ABS unit and close other valves that are on the original lines after the ABS unit. The reason for putting the valves on the original lines after the ABS unit was to allow the ABS unit to still "see" the pressure from applying the brakes (which might be necessary to keep it from noticing what you've done). Note that an A/B type switch could also be used, such that one of the lines would always be connected and both could never be connected.