Hello guys,

I have built a stroked BMW e36 M50B20 engine. The engine is an M50B20 with an M50B25 crankshaft, and changed conrods, which give the engine 2260ccm.

The stock comp ratio for this engine is 10.5:1 but is now 12.5:1.

I have a Miller Performance WAR Chip so i can program the ECU with my laptop. But i lack any experience with how to setup the mapping.

I use to paly with 2stroke carb bikes, and change jets, and look at spark plug color, i know for a fact this is same area, but i have never done this with a laptop, and i need more understanding of which way to direct my efforts with a high compression engine.

The engine i am working on, is my own personal BMW, and it has fired up, but at idle (which i have changed to 1000rpm) i am getting kocking, not constant, but sign that the engines is knocking. It revs fine, the problem is during idle. The ignition has been retarded at idle speed, and this didnt change a whole lot.

I am into fuel adjustment now, but i need help on which way to dial. More or less fuel?

Any experience would be great!

I think your engine needs more fuel.

You have increased the displacement and now the engine is pumping more air ....

May be you need to install a wideband o2 sensor in the exhaust pipe.

Thank you, that would make sense. I kept thinking that its compressing more, so more fuel more to comrpess, but i will turn up the fuel.

I have an AEM wideband O2 sensor :)

Here is a video of the engine running.

I upgraded to injectors from a 328i, but still have had do a lot of up adjusting on the jets to get to here.

The AEM says 14/15ish for the first few seconds, and then suddenly just red lines (needs more fuel!) Can this really be? :|

http://www.youtube.com/watch?v=In4kuMGwfyU

With that CR you have too use highest RON fuel.And ofc u have to give little bit more fuel for engine and adjust igniton little bit retarded to keep it away from detonation.And then you should be okay (Y) .WB gauge will help you a lot for adjusting maps (Y) .Keep it up

Thank you for the response.

I have been messing around with the engine today.

It seems my AEM air-fuel isnt working?

Today we did a compression test, to be sure its not a valve issue, and i am getting 185psi on all 6 cylinder (stock should be between 143 to 156) and since mine is high compression, this should be about right.

It seems the clicking noise is the intake valves not shutting soon enough, so i will try and advance the intake cam a tiny bit, and hopefully from here on, we should be golden to be pure ECU adjustment.

Do you think i need to retard the ignition, all across the map?

With that CR that compression is really well.But have you done cylinder leak test to be sure at rings or valves?For safe you should jeah set ignition few degrees advanceded i think.

Knocking problem solved! Was the MAF giving issues.

http://www.youtube.com/watch?v=NesN6DXhFCs

Now to map the damn thing!