E30 M3 S62 Build - Loads of queries about 4x4 drivtrains

[nando]

damn you suck. :p I looked for one forever, but people want way too much for them if they do pop up.

PWM = pulse width modulation. basically a varied voltage pulse (or ground) that would increase or decrease the lockup based on the duty cycle.

it may actually be on/off, but I doubt it. I wouldn't mind getting my hands on one to bench test with..

[Turk]

Lol. If u can let me know what to try I will be happily trial it on a bench. I can post pics of plugs etc once I gave. If you can tell me a bit more about the the actual electronics I will need to rig up I can take it to the guys at work tomorrow and see if they are as good as they say they are :D

Im guessing a couple of wires paralleled into the abs sensors into a microprocessor or chip, then a modulated output, triggering a relay then into the Tcase?

Is there anywhere we can find the actual electrical diagram for these?

Would there be any negative effect if we had the tease permanently locked?

[The Dark Side of Will]

I think an E34 t-case would be relatively easy to control. All you really need is to calculate the % difference in wheel speed between the front and rear (probably an average of the 2 pairs of ABS sensors), and then output a PWM dutycycle to the transfercase to lock the coupling until the %slip falls below your threshold.

How does the T-case control box operate? Does it communicate with the ABS over the bus or piggy-back on the wheel speed sensors?

Working the original E34 system into the E30, if feasible, is going to be a lot easier than reprogramming a megasquirt or ardruino to run the T-case...

The next step will be finding appropriate cv joints for the prop Tcase end and front diff end.

If I use an X5 front diff, will this already have limited slip or does that require electric-tronics too?

I'm expecting to use E30 or E34 outers with E53 inners and custom axle shafts (Moser or similar to produce).

The production X5 diff is open. No electronics, no limited slip.
The Quaife for a Z3 4 cylinder supposedly fits, but will need to be disassembled so that the gears can be turned around for it to work in the front end application.

[nando]

I think the ABS computer pretty much controls the entire thing

I don't think there's anything particularily awesome about the E34's electronics, though.

[The Dark Side of Will]

Does the E34 ETM cover the 525iX?

[Turk]

I'm just downloading the e34 bentley manual to see if theres anything in that.

Edit - download failed :(

basic:

http://tis.spaghetticoder.org/s/view.pl?2/04/88

[The Dark Side of Will]

The US Bentley doesn't cover the iX... Is there a different one for the UK?

[Turk]

No I believe the uk one is the same. It's not in mine either but then again I did download it as a torrent.

Where else could this info be hiding?

[Turk]

Try these links. Taking ages to load on the iPhone.

http://www.armchair.mb.ca/~dave/BMW/e34/

[ZM Blue Devil]

Nice project and love the user name!

[Turk]

Cheers. I am turkish so I can get away with it. Been my nickname since uni.

[nando]

you need an older copy of the ETM and TIS. BMW has removed a lot of stuff from them..

[Turk]

So picked the e34 ix gearbox up tonight. That thing is F***ing heavy!!!!!!!!

But to my surprise the only connector I can see on it is a 2 pin plug!

I have had the following response re the e34ix gearboxes on the e30Zone.net

"The E34 system exists in 2 generations with a major difference:

Generation 1 has separate control unit which control electromagnetic semi-wet multiplate disk clutch in centre and electrohydraulic wet rear differential. It recieves ABS wheel sensors data signals from special, modified ABS unit. Front differential open. In production from april 1991 up to september 1993.

Generation 2 has ABS/ASC+T unit which controls semi-wet electromagnetic multiplate disk clutch in centre and an open differential rear through rear wheels brakes (ABD). It also controls throttle. Front differential open. In production from October 1993 up to end of production."

Where do I start bench testing this bad boy???

[nando]

try applying power to the wires. see if it locks. since it probably wasn't meant to run at full duty, don't do it for long. I'd start at a lower voltage like 5v.

2 wires is expected. It should vary the lockup by changing a voltage pulse to the electromagnetic clutch. 100% duty = full lock, 0% duty = full open, etc.

[Turk]

Cant be that easy :0 surely?

+ to one - to the other? or ground the box and + to both?