BMW Rallying Forum

Hi folks,

So seeing as I don't know a whole lot about BMW's generally - other than what I've learnt from reading the excellent build threads on here - I thought I'd better start a thread about my compact rally car build. The car is to be used on gravel.

I posted on here before with a few questions around using a Z3, etc but in the end some sense prevailed (and for what I hope will make the build fairly straight-forward) I opted for a 323ti as the base.

I've built a few rally cars in the past (a Mk.2 and a couple of Pugs) but sorting the electrics/electronics on the compact is my main concern with this build. Anyway, the plan is to try to keep things as simple as possible!!!

The car is a late 323ti (i.e. Nov 1999) which - fingers crossed - should make the planned mods a bit more straight forward.

The car has OBDII and has the twin vanos M52TUB25 engine and ABS/ASC+T.

In general the plan is to fit a twin vanos 2.8L engine, a 2.8L Z3 automatic differential, a different gearbox (TBC) and I’ll keep the standard discs & callipers (front & back).

From what I’ve read on the internet the 2.8 engine swap should be fairly straight forward as the car is already wired for a 6 cylinder. As I understand it, I’ll need just the 2.8’s DME, EWS and ignition key and all the engine / DME / EWS / etc wiring connections are the same on the 2.8 and 2.5 so it should connect up to the existing looms without any modifications...

I’m hoping that the 2.8 automatic Z3 differential will bolt straight in as well and connect with the existing prop shaft and drive shafts. The reason for my choice of diff is that I believe that the 2.8 Z3 auto comes with a gear-type LSD (or torque biasing type diff) and a 4.1 cwp as standard which will do me fine for now.

I’m not sure what gearbox to use though. I’m wondering whether a 5 speed E36 M3 box would give me a close(ish) ratio box, be a straight swap on to the 2.8 and would I need to modify the prop shaft and clutch slave cylinders to make it all work.

Regards,
Nick

Brakes:

So the first item I want to tackle is the brakes and specifically getting rid of the ABS and associated ASC+T system.

Can any of the fine members of this forum give me any help here?

The 323ti has a 2 port master cylinder (and I think the 4 channel Teves Mk.4 ABS system - it has the white label ABS pump anyway).

I want to retain a servo assisted brake system c/w an OEM master cylinder and use a proportioning valve for the rear brakes. At this stage I don't really want to go for a bias adjustable pedal box.

From reading elsewhere on the internet - albeit applicable to an E36 saloon - I'm led to believe that if I strip out the ABS the DME will limit the engine revs to C. 5000 rpm. I've read that this issue can be overcome by running a jumper wire from the differential speed sensor signal input at the instrument cluster to the ABS speed sensor signal input on the DME loom. Is this right?

I'm unsure about whether it's a good idea to use the currently fitted original 2 port brake master cylinder and use Tee's to run brake lines out to the front and rear calipers. Can anyone give me some pointers on this and/or suggest a 3 port master cylinder and servo assembly that can be used with the standard brake pedal and bulkhead fitting arrangement?

The ASC+T is a fairly agricultural system in its operation. It basically relies on a throttle body with a butterfly which is fitted before the main throttle. An electric motor and cable assembly operates the butterfly on the ASC+T throttle body when the ABS wheel speed sensor detect slip. Can anyone please advise whether removing these parts will interfere with the DME and the engine operation?

I've read that when activated, the ABS/ASC+T signals as well as operating the ASC+T throttle body butterfly, can also interfere with the engine timing and/or spark to prevent slip, etc. Is this the case and any ideas on how to overcome these issues if true?

Thanks,
Nick

Easy enough to re-plumb the brakes,,,, front most port (H) does the rear brakes and rear /lower port (V) is the front brakes. That's what I did with my compact race car. I used a lever type brake limiter valve to restrict the rear brakes.

hi Nick
Welcome aboard, sounds like you have a good project with a rare donor .

Unfortunately I haven't got the knowledge of ews/dme to help in that department, its a lot easier on the older cars. There will be a fix I'm sure. The etk may help you see if theres a 3 port master cylinder available, a tee should be ok if there isn't one, that all you use on a bias box.

The 2.8 should plug and play if its out of another e36, you ought to use the matching gearbox as it has the correct torque rating, its the same as the 3.0 m3, also use the e36 2.8 saloon prop.
Gear ratios are all the same with a crap first but the top 4 similar to a ford 4 speed rocket. Therefore gear accordingly and effectively use it as a 4 speed using the top 4 gears.
You have an option to build a plate diff using an E30 lsd spool.
Luckily the 323ti` medium case back-end' has the correct shafts along with the better than normal trailing arms (wheel hubs and bearings differ to the more common 318ti's).

Keep us posted!
Regards
John

John and Gary,

Thanks for the info. I didn't know that about the 'boxes. Good to know.

Thanks,

So a small bit of progress made recently with the obligatory pic of the interior stripped out (mostly stripped out anyway).

Anyhow, I've run in to an issue regarding which roll cage.

I wanted to use the perfectly good looking Safety Devices B034 bolt-in cage (as used in the Compact Cup) since I could fit it myself quickly and get away without having to do too much surgery to the wiring harness and dash.

Anyhow, due to the ASN where I'm living at the moment (Middle East), I'll have to go down the weld-in cage route (bolt-ins aren't allowed ) which means a big jump in the amount of stripping out of the shell than originally envisaged.

I was looking at the multi-point weld-in cage pics on the Custom Cages website and noticed that there is a bar transversing the a-pillars at the base of the windscreen with what looked like brackets to take the steering column welded to this bar.

If anyone has this cage fitted to their car can they let me know if the dash will go back as normal with the CC cage?

Regarding removing the loom, can anyone offer any tips / advice on tackling this job?

For those that have labelled the connectors, any recommendations on what to use for labels - ideally something that doesn't fall or rip off?


Thanks,

i cant really comment on the custom cage v's dash/heater etc but you are right to consider it. Faffing about re-inventing heater boxes and re-locating the fusebox will have a negative effect on build time
dymo labellers are ok for flat surfaces, but one night I labelled a load of wires by printing and folding the tape around the wire - the next day they were all in the foot well!
fortunately theres plenty of diagrams on hand > http://www.wedophones.com/Manuals/BMW/

Hi Nick

It soulds like you are going for a similar setup to my car. I will try and cover your questions in order.

EWS
Yes if you get the DME and EWS module from your donor engine with the matching key then what you are planning should work fine and the swap is not too difficult and commonly covered on the internet. I don't know all the ins and outs of the EWS system as I just cut the whole lot out but I believe it requires signals from the door locks and ignition key to demonstrate that the doors have been unlocked first (antitheft). It then sends a signal to the ECU to allow the engine to fire. Turn the engine off and lock the doors and the ECU switches back to the non start mode. So all of the other parts of the loom pay a part in it so becareful what you remove if you keep EWS operational.

Your other option is what I did and cut the whole lot out. I removed all of the door looms, EWS/ABS/ASC and have had no problems. Less is simple? I used Enda Ward of www.endtuning.com to remap my 328 ECU. As part of this he removed the EWS dependence from the DME. Prices are on his website but otherwise contact him as he is really helpful and you will find good reports on his work on this forum. He can sort the ABS/ASC issues as well I think. It is all fuctions within the DME program that can be over written. If you remove the EWS dependence then you can either remove the wiring or leave it in but you don't have to worry about it. Out of the EWS module comes a yellow/black (memory ?) wire that is the live feed for the starter motor. It runs through the harness plug to the seperate engine wiring loom. If you do remove the EWS just reconnect the yellow/black wire to the ignition barrel or a push button start to turn the engine over. As a note not all 328 DMEs are reprogrammable. The one that came with my donor wasn't but you can buy them on ebay for £40 - £50. Enda advised me which one to get, he sent me a list of part numbers to look for.

Gearbox
I will leave it for someone to correct me but the 328 gearbox is the exact same ZF gearbox as the M3 3.0. I don't think there is any reason to change it if you get your diff ratio right. Its 1:1 top and plenty strong enough. I am using the 328 box that came out of my donor and plenty of other people still use the 328 box however I have not yet had my car running with the wheels on the ground so can't comment any further.

Wiring loom labels
I just used masking tape and a marker pen. Worked fine and never came off. Double it back and create a loop in the wire before you tape it if neccessary.

Roll Cage Dash Bar
I don't have a custom cage but I have looked into this and I am 90% certain that any dash bar that runs above the steering column will foul the plastic ducting for the vents in the dash itself. I have gone for a similar setup and removed the plastic vents i.e. gutted the dash. As the CC cage is certified you cant really change it. Have you looked at the Harry Hockley cage kit as it doesn't have a dash bar? - http://hh-ms.com/parts_images/BMW001_CDS_cage.jpg.

Good luck with the build and keep the photos coming. Feel free to ask any further questions as well.

Rich

Hej there

I have a low budget compact 323ti i have been working and driving for about 2 years now.
I am slowly improving it when the cash is there

On ebay i found this ecu and i have had no problems with it regarding ABS AST. http://www.ebay.co.uk/sch/bmw-ecu-tunin ... pg=&_from=

The roolcage i have used is the FIA Homologated from
http://www.rallyshop.it/index.php?main_ ... s_id=14173
It is a bolt in ..

I have the 328/m3 gearbox with a 5,0 ratio and i havent had any trouble with it yet.

God luck with your projekt and just keep asking

Claus

Rich,
Thanks for the info re the EWS/DME/ABS / ASC+T etc. I've been reading your build thread with interest and will be following it closely.

I've read good reports about Enda on other build threads and will definitely be getting in touch with him in due course. As you mentioned, it's the dependencies across the various electrical systems that can cause issues - e.g. I didn't know about the central locking interface with the EWS!

At least now I can finish stripping out the loom and know that I have at least half a chance of getting the car going again one day!

Nick

Hi Claus,

Many thanks for your comments. EWS and ABS, etc delete via a modified DME definitely seems to be the way to go.

Did you get the 5.0 cwp out of another BMW or is it an aftermarket item?

I'd be interested in your thoughts on gravel suspension set-up's. The Scandinavians seem to have a knack for setting-up suspension for gravel!

Thanks,

Nick

Hej Nick

The 5,0 is a aftermarket, i tried the 4,1 it worked fine, but 5,0 is spot on with m3 gearbox

In the front i use the XYZ with tarmac springs and damper set too softest, the rear is Escort mk2 grp. 4
bilsteins and standard compact HD springs, works very fine for me and is at a nice price too

My next wish is bilstien for the front................

I use standard brakes with ferredo pads, works ok for me at the moment, iam 50 years old and braking earlier then a 20 years old

Claus