crazy plans 4 wheel abs

[a_thomasmr23]

I'm just throwing this out there to what floats.

Could you add another abs pump for the back wheels and have it turn on/off with the pump for the fronts. Would this make a difference? Would this cause a poor control under ABS operation? Does the ABS on the e30s able to just pulse one wheel and not the other?

Open to all though minus it cost too much, this is concept only

[Fidhle007]

The stock E30 ABS pump is a simple, two-piston design, front and rear only. The only way to make the pump operate all four wheels individually would be to retrofit a newer pump/control unit and I'm sure that's a lot more hassle than it's worth. Most of us here have deleted the ABS already so UPGRADING the system isn't even in the picture.

[PiercedE30]

Actually, I plan on retrofitting 4 wheel ABS onto my car at some point. I would be using the E34 4-channel ABS pump and controlling it with the MegaSquirt GPIO (general purpose input/output) controller. They have already planned on using it as an ABS/traction control system with communication to the MS ECU handled via CANBUS. I haven't checked the status of the MS GPIO in a few months though.

[Fidhle007]

Well there you go! But to retrofit a complete E34 setup (brain and all,) would be much more difficult, no?

[a_thomasmr23]

so my impression that the abs pump is just controlling the front to wheel is incorrect then? I haven't heard anything about the MS traction features either normal i check out whats new every month. What year e34's is the 4 wheel system on

also it would be hard to add the wheel speed sensor to the back wheels, The system i'm talking about would be as simple as there is a pump for the back wheels that would activate when the pump for the front wheels came on

or is this off base

[DaveSmed]

Factory ABS in an e30 is a three channel system. Left front, Right front, and rear.

[StereoInstaller1]

Factory ABS in an e30 is a three channel system. Left front, Right front, and rear.

and why would anyone want more than that?

[jlevie]

and why would anyone want more than that?

Good point! In a racing environment a 4-channel system would be helpful, if the class rules allow that mod and you've done something to get more use out of the rear brakes. On the street there's always the option on dialing back to the point that you don't need a 4-channel system.

[erik325i]

Most of us here have deleted the ABS already so UPGRADING the system isn't even in the picture.

Some people have deleted the ABS (including me), but I wouldn't say most...

Erik

[Fidhle007]

Those of us who care... :-D

[JGood]

Those of us who care... :-D

I doubt there's very many people on this forum who are able to outperform the ABS system (consistently). Even if so, the risk of flat spotting a tire vs. the tiny bit of time saved by you outperforming the system and saving a tiny bit of weight is hardly worth it to *most* people.

If I ever touch the ABS system, it's going to be to upgrade to the Bosch Motorsport ABS M4

The only time I can think of where it may be an issue is autox'ing with 275+ v710's or A6's. With 225 V710's, at low speeds and full threshold braking, I had an issue once with the ABS engaging and not releasing even though the tire wasn't slipping. The deceleration rate was above what the computer allowed. It only happened on one course, one day, though.

[a_thomasmr23]

i didn't know about the 3 channel system that was what i was trying to get to so BMW beat me to the punch by about 20 years

wouldn't a 4 channel do a better job of keeping the rear wheel deacceling at the same rate that just a single line for both sides

[Fidhle007]

I doubt there's very many people on this forum who are able to outperform the ABS system (consistently). Even if so, the risk of flat spotting a tire vs. the tiny bit of time saved by you outperforming the system and saving a tiny bit of weight is hardly worth it to *most* people.

If I ever touch the ABS system, it's going to be to upgrade to the Bosch Motorsport ABS M4

The only time I can think of where it may be an issue is autox'ing with 275+ v710's or A6's. With 225 V710's, at low speeds and full threshold braking, I had an issue once with the ABS engaging and not releasing even though the tire wasn't slipping. The deceleration rate was above what the computer allowed. It only happened on one course, one day, though.

My pump was fucked so it was $1600 for a new one or $80 for a proportioning valve.

[jlevie]

wouldn't a 4 channel do a better job of keeping the rear wheel deacceling at the same rate that just a single line for both sides

It would if you do something to make the rear brakes more effective, like fiddling with the brake bias valve or switching to a dual master cylinder setup. In the stock configuration the rear brakes don't make a large contribution.

[JGood]

My pump was fucked so it was $1600 for a new one or $80 for a proportioning valve.

Or probably $30 for a used ABS pump that works great ;)