Motronic or Jetronic

[T-roy]

Hi guys,

Just wondering if there is anyone out there that can tell me any quick way of checking/identify if my E30 has Jetronic or Motronic,

IS there a certain ECU number or any identifing marks anywhere.i am 90% sure if is opnly Jetronic but as i am currently building a 2.7 stroker motor i was hoping i might get lucky and have something i can expand on.

If it is the Jetronic can anyone recomend a piggyback system
that will be compatible to the Jetronic all the systems i have checked seem to lead towards piggy backon the Motronic or stand alone systems.
Cheers.

[Ranchero]

I believe BMW revised the M20 from Jetronic to Motronic in 1987, so you should be able to work it out from the date of manufacture of your vehicle.

[Speedtouch]

Check out the Wiki guide, which clearly shows the differences:
http://www.e30zone.net/e30zonewiki/inde ... _Servicing

Most obvious is that Motronic has the distributor on the front end of the engine, driven directly off of the camshaft.

[T-roy]

yeah according to the Manufacture date i should have Jetronic but the prvious owner had done some work to the 2.3 motor and i thought (hoped) he did the right thing and uped the fuel system as well i checked the bosch number but after googling it there isnt really any info to let me know either way.

Cheers

[Speedtouch]

A 323i would originally have L-Jet. It can be converted, but it's not easy.

[T-roy]

mmmm looks like it is only Jetronic

What is involved with the change over is just the Engine loom and ECU ??? i am think aftermarket piggy back may be the go Any suggestions

[Speedtouch]

A 323i should have an ECU number of 0 280 001 308 (L-Jet).

Check out this recent thread on the topic:
http://www.e30zone.net/modules.php?name ... 78&start=0

[T-roy]

Thanks Speedtouch the articles certainly shed some light for me. Now i just have to decide what the better option is you know Bang for buck options.

Is it worthwhile just getting a decent piggy back sytem and wiring that in to the current Jetronic system? there are a few really good aftermarket set ups i am just not sure if they will run with the Jetronic system.

Just to give you some info on my little project

2.7 eta blockfully rebuilt min with o/s pistons bearing etc
I have a 731 head off my 323 that has had a fair bit of porting done to it so i am going to use that and keep the compression hopefully down around the 8.5:1
i am Looking at around a 280degree cam spring etc and a GT35 Turbo set up.

The only thing left to sort is the fuel / spark system so any guidance would be awesome.

I am a mechanic by trade and have done up lots of cars but this is my first BMW so i am flying a little blind on what they can and can't do.

Cheers Troy

[Speedtouch]

In your case, I would consider going for a standalone setup such as Megasquirt, etc., since they can be tailor made and specifically configured to suit the particular setup. See Flappysocks' site for more info:

www.diyefi.co.uk

Alternatively, Zoner Ant at A-Tech is reknowned for custom setups and 2.7 builds, and would be able to advise - try searching for one of his posts and dropping him an E-mail (he doesn't often read PMs).

I doubt that fitting a piggyback onto the aged analogue L-Jet system would yield any significant gains.

[T-roy]

Excellent thanks for the info i will see if i can track him down .

Cheers i will keep you posted on the progress and info once done

Thanks again all good info