e36 ABS Standalone w/dual master cylinders - reservoir question

[Bimmerman325i]

I don't recall if the ix uses the brake switch, but it does have it's own dedicated clutch switch. this is to detect engine braking on a slick surface (like ice). it then has a pin to communicate with the DME and open the ICV so the wheels don't lock up. Interesting, but not relevant to you probably. :p

what I really wonder is why you're not switching to the MK60 ABS/DSC system from the E46 M3? it actually works just fined standalone and is light years ahead of what the E30 and E36 have.. it can be programmed too, at a cost..

apologies for threadjack-- I've just done the Mk60 into my E36. I keep hearing people say the units are programmable but details are...scarce. What can be programmed on non CSL/ZCP unit?

On topic-- E36 3 channel for sure has wheel speeds at all four corners, but it just ties the rears together.

[Wh33lhop]

How many have you checked? :p

Yeah, 3 HYDRAULIC channel- but it still looks for lockup at the rear wheels separately...

So if one or the other rear is slipping, all it can do is reduce the hydraulic pressure
to both...

t

Exactly.

[nando]

All BMW 3-channel systems have speed sensors at each wheel, to my knowledge. Dammit nando you were my source on this!

I'm pretty sure they don't. RWD E30s only have 3 sensors, as far as I knew.

[TobyB]

Yeah, 3 HYDRAULIC channel- but it still looks for lockup at the rear wheels separately...

So if one or the other rear is slipping, all it can do is reduce the hydraulic pressure
to both...

t

[Wh33lhop]

it's actually still 3 a channel pump. but the ix has 4 wheel sensors plus the deceleration switch.

All BMW 3-channel systems have speed sensors at each wheel, to my knowledge. Dammit nando you were my source on this!

[nando]

it's really not. since it's a safety system, it always has to work. all it really needs is the 4 channel sensors and brake pressure senors for ABS to function. if you want DSC to function as well, it needs the DSC/yaw sensor. I don't believe the steering angle sensor is required for DSC. it doesn't need to communicate with the DME for ABS/DSC - that is only needed for ASC and you probably don't want that anyway!

it was a pretty common swap not too long ago. I don't know if it's still the bee's knees but you can still get the DSC pump & sensors pretty cheap. If you can get your hands on a CSL / Late M3 pump even better..

[catboy]

I guess I already had the bits for £30 ($50) and a few beers, and I was under the impression its a ball ache to make the mk60 standalone?
I have a standalone ecu and no dme in the car if that makes a difference? If its not a nightmare to do then I'm all ears..

[nando]

I don't recall if the ix uses the brake switch, but it does have it's own dedicated clutch switch. this is to detect engine braking on a slick surface (like ice). it then has a pin to communicate with the DME and open the ICV so the wheels don't lock up. Interesting, but not relevant to you probably. :p

what I really wonder is why you're not switching to the MK60 ABS/DSC system from the E46 M3? it actually works just fined standalone and is light years ahead of what the E30 and E36 have.. it can be programmed too, at a cost..

[catboy]

it's actually still 3 a channel pump. but the ix has 4 wheel sensors plus the deceleration switch.

The 3 line "euro m3" system has 4x wheel speed sensors too, just 3 outlets from the pump for fl / fr / rear (combined l&r)
It has a brake pedal switch too (brake lights basically) but cant remember if it uses the pedal posn. Sensor or not (think that might be the 4-line system only)

[djjerme]

Oh hell no TOBY!

PROTEST!!!

(just don't look too closely at the master cylinder setup in my car..)

[nando]

I would say it's likely. Both E36 and E30 use VR sensors, it may very well just bolt up or possibly (unlikely but I don't know for sure) even be the same unit. I don't know if the euro m3 units are different either, but people do e36 5-lug swaps and retain E30 ABS, so I would guess the reverse is possible quite easily.

Fun fact, the e30 iX has a 4 channel ABS, though not the M3. Don't know if it's any better with r-comps but I'd guess due to the all-weather nature of the iX, it's more adaptable to a broad range of conditions, so it's likely.

it's actually still 3 a channel pump. but the ix has 4 wheel sensors plus the deceleration switch.

[catboy]

I have a feeling the "abs only" (labelled ABS-ES on the ECU) 3 line system fitted pre-1995 was the same on the Euro M3 and 325i as their US equivalents, but i'm not 100% positive on this so you may need to do some research on realoem or similar to check part numbers - everywhere I've read about it its referred to as Euro M3 but unsure if its because US M3's has ABS+ASC or something as standard across the board?

Either way, what you need is a 3-line pump as below..



..which has 5 ports - 2x in from m/c (top left in photo) and 3x out (bottom in photo, for fl / fr / rear). You also need to know the german words for front, rear, left and right to plumb it in!
The correct ABS ecu looks like this..



..there is another version of this which looks exactly the same but doesn't have the cooling fins on the side - this is the same part number and works fine; not sure what its from (mabe an e38 or something?)
There's another "green label ECU" which looks like this..



..and that is no good! its for the 318 I think which has a different system and can not be remapped. It may also be the same one used in the e30? Im not sure..

I have heard any 3 line pump will work fine, however I can not confirm this and as the parts are cheap and readily available it makes sense to get the "right parts" which are..

34521138219 - ECU
34511162291 - Pump

..there's also another pump which I think ends '94 which I know works too, however it doesn't show up in realOEM at all. This is a more common pump and much easier to find, which makes me think this is the original factory fit pump which was no serviced, and the '91 pump is the field service/replacement unit (hence rarer and harder to locate)

In terms of fitting it to other cars, this system of the "euro m3" pump and ecu can be run as a standalone and fitted to a multitude of other vehicles - I've found reference to people using this in e30's, e46's, even e90 touring cars in Europe, inplace of the very expensive bosch motorsport abs systems. I've also seen threads where people have fitted it to things like TVR's, Ultima's and Nobles and other high performance kit cars / production which didn't have factory ABS
The wiring information is in the early e36 electrical troubleshooting manuals, and basically it requires power/ground/ignition, wheel speed sensor inputs, and some additional wires if you want to connect it to the diagnostic connector, abs light on the dash, etc.. I can't comment on compatibility with e30's, but I think I read somewhere that the e30 has the same number of "teeth" on the wheel speed sensor rings as the e36, so it might be fine, or work with just a swap of the sensors..

The 4-line e36 and e46 system can be adapted, however I think there's much more interaction between ECU and DME so that's a more complicated to do and I'm not sure there's a massive benefit vs. a remapped 3-line system.. I also don't think the 4-line system can be remapped, however that's just based on me not finding anyone who can do it during my research

For 3-line remaps, I only know of one person who can do this and he's a) in the UK, and b) pretty damn hard to pin down as he's always busy doing more important things such as mapping race cars for (very) high level European motorsport teams! If anyone is serious about getting an ABS ecu remapped drop me a PM and we can discuss details - pay particular attention to the word SERIOUS, and be pre-warned its not cheap (although a lot cheaper than buying a gp-n ecu or a bosch motorsport system! )

hope some of that helps someone :)

ben

[Wh33lhop]

Not going to bother for this car, just curious about the mapping. With that said, can the 3-channel E36 system be adapted to fit an e30?

I would say it's likely. Both E36 and E30 use VR sensors, it may very well just bolt up or possibly (unlikely but I don't know for sure) even be the same unit. I don't know if the euro m3 units are different either, but people do e36 5-lug swaps and retain E30 ABS, so I would guess the reverse is possible quite easily.

Fun fact, the e30 iX has a 4 channel ABS, though not the M3. Don't know if it's any better with r-comps but I'd guess due to the all-weather nature of the iX, it's more adaptable to a broad range of conditions, so it's likely.

[Axxe]

FYI- early (through 95) E36s have 3-channel ABS, and late (96+) E36 have 4-channel so you will have to add another hard line and convert your chassis to 4-channel if you want to use late model ABS hardware in an early model E36. It's doable, just not a cake walk. Bimmerman325i I think just completed a 4-channel conversion to his 95 M3, so he can tell you more about it if you're serious about doing this.

Not going to bother for this car, just curious about the mapping. With that said, can the 3-channel E36 system be adapted to fit an e30?

[Wh33lhop]

awesome info thanks guys! So I guess over time if the pump is "refilling" the brake line between the pedal and the ABS unit, the ABS reservoir will empty into the brake reservoirs. Given the tiny amounts of fluid though, this is going to take a while, so practically I could get away with having independent reservoirs per m/c and a twin reservoir for the ABS.. I may look into joining the three together however I expect this to be more work than makes sense as my ABS pump is in the passenger footwell and my m/c's are in the engine bay infront of the driver..

I get what you're saying re: r-comps and high mu pads which is why I've specifically gone for the 3-line system from the euro m3 (im in Europe so was easy). I think this doesn't have "ice mode" or similar, and so shouldn't have a complete melt-down if you exceed its parameters! Also you can have the ecu remapped - mine is done with the gp-n / factory race car software which was designed specifically for slick tyres and sticky pads. im not 100% sure what this does, however I think it relies only on wheel speed and, the thresholds for slip ratio are reprogrammed as you mentioined

However its done, I've driven a couple of cars with this software and its night and day on track vs. standard. Its also nice to have as a safety net when its cold and damp first thing on an autumn track day! Looking forward to getting my car back in one piece so I can try it out.. :)

Yeah, if nothing else it's nice to know you're not going to flat spot your high dollar r-comps :) I don't know much about the euro M3 ABS, but it's sweet that you can get it remapped. I get frustrated with the stock primitive ABS and aggressive pads on the street, but on the bright side it's more motivation to stay out of ABS and brake smoothly.

How does one get this software onto their ABS ECU? What piece of hardware do you need to support it? This is for a 94 325iS, have 97m3 ABS pump available and 96 ABS ECU.

FYI- early (through 95) E36s have 3-channel ABS, and late (96+) E36 have 4-channel so you will have to add another hard line and convert your chassis to 4-channel if you want to use late model ABS hardware in an early model E36. It's doable, just not a cake walk. Bimmerman325i I think just completed a 4-channel conversion to his 95 M3, so he can tell you more about it if you're serious about doing this.