2.7 stroker question.

[M6luvva]

I have 323i with the dreaded L-jetronic, and am seriously considering a stroker conversion with an ETA bottom end. Assuming I can source a decent donor block/pistons, beyond the usual filters, seals and gaskets that'd be required for reassembly, what else would I need? Wondering about intake etc. Frankly I'd be happy to keep the L- jet just to minimise complexity.
Opinions on a postcard please! Chris.

[e30mreg318i]

you will find info on building a 2.7 on the e30 wiki, many options and ways of doing it. But it wont be the easiest to convert. If you have a 323i then could you buy a cheap late 320i and convert that?

[daimlerman]

Easy option is 325i inlet/injectors and convert to the later motronic ECU/engine management whilst you have the thing in bits.At a guess,you will also need the later type of water pump to get clearance around the cam end mounted h/t cap.

But as you say,your real problem will be finding a usable crank!
The other option here is to go the Alpina route and search Euroland Ebay for an M21 diesel crank....

[M6luvva]

Thanks for your input. I did consult the wiki, and the impression I got is that I could retain the L-jet, my 731 head would match perfectly to the ETA block with some matching to the 325i intake manifold and the 325i throttle body to get some more air flow. I really was hoping to keep it as simple as that - would that fly? I really don't want to tune it to the umpteenth degree, I just figured out that bang for the buck this is the cheapest way to more torque. I was going to stick with the standard 323i cam and just refresh the top end as you would with any rebuild. I know the fuel economy is poor with L-jet and the tunability is negligible but I wanted a stealth look where it looks standard as is effectively a 'sleeper'! MPG less relevant as the car is seldom driven. Hope that makes sense....

[daimlerman]

My knowledge of L-jet is limited to bin it and use the later system!

You will need to arrange for the injectors to issue more fuel at different times,the way I did this was to swap the chip in my later Motronic ECU,can you make similar changes to the earlier L-jet?

I'm using an ex 323 cam in my 2.7 ATM,it gives a power range from about 2000rpm and still pulls well right upto the red line.I started with a 325 cam,this pulled so well from around 1500rpm that dropping a gear to overtake was un-nessesary,but it was all done by 5000rpm.

Bit like skinning a cat,there's no 'right' or 'wrong' way to build on of these engines,it's choosing the correct spec to suit your needs/driving style that counts.

Regarding fuel consumption;
325 cam averaged 35/36mpg,with a 'best ever' of 38mpg
323 cam,I struggle to get 31/32mpg,best was 33mpg over a 4 day trip up the west coast of Scotlandshire this May.

[E30_Aza]

I have an eta bottom end here if you fancy it?

[M6luvva]

Appreciate the offer, just wondering why one couldn't use the ETA bottom end with 731 head, 325i manifold/throttle body and retain the L-jet. I just want affirmation that this'd run with decent driveability, mainly from someone who's done it!

[gromgsxr]

If you have an engine that is 400cc bigger it would have different requirements in the fuel side eg more fuel to mix with the extra air. The older l-jet I would assume would be less tuneable than the later motronic management.

[maggspower]

The first line of your opening post contains the phrase "the dredded L-jetronic", yet you seem to want to keep it?

If you want more torque put an m20b25 in there. If you actually want a 2.7 then do it properly. If you keep the L-jet, the car will never run right it will think its still running a 2.3l. It will under fuel and the ignition timing will be wrong too, and that is bad for the engine. Just upgrade to motronic 1.3, dont worry it will be "stealth" enough.

You can build it using the entire ETA bottom end, this will mean your m20b23 head will go straight on to it. Then you need to fuel it (motronic 1.3 please). You will have problems finding a good bottom end that doesnt need rebuilding. Although you have been offered one above, and I think I saw sweep had an entire engine for sale.

Or you can aquire an m20b25, and use the pistons, head, ancillarys, and motronic gubbins, and build a propper one, using the crank and rods from a ETA. There is substantial work required doing it this way.

The bottom line is, building engines for performance gain is rarely a cheap hobby, and when it is conducted as so the results a often disappointing, and short lived.

[AardHawk]

The cheapest and simplest mod is to take the 731 head, exhaust manifold and inlet manifold from your M20b23 and plunk it onto the unmolested eta bottom end. Open up the inlet manifold throttle body flange to accept an M20B25 throttle body, then fit Motronic 1.3 together with its bits and bobs. You can get all this up and running in a weekend with a bit of proper prior planning. You can then fart about with it to your hearts content, knowing that you have a car that actually runs.

By the way, there is nothing wrong with L-jet. Its one great advantage is that it allows you to play with ignition timing and advance/retard without having to reprogram the ECU.

[AardHawk]

The cheapest and simplest mod is to take the 731 head, exhaust manifold and inlet manifold from your M20b23 and plunk it onto the unmolested eta bottom end. Open up the inlet manifold throttle body flange to accept an M20B25 throttle body, then fit Motronic 1.3 together with its bits and bobs. You can get all this up and running in a weekend with a bit of proper prior planning. You can then fart about with it to your hearts content, knowing that you have a car that actually runs.

By the way, there is nothing wrong with L-jet. Its one great advantage is that it allows you to play with ignition timing and advance/retard without having to reprogram the ECU.