E30 M3’S

It`s inside the glovebox.Easy to get to - just a few screws to remove.

Edited by Darren M

Kev

It all depends on which clips are connected. There next to the ecu on the left. one blue and one black. there quite long thin connectors as well. both connected and should run on Ron 98 {optimax), blue only connected Ron 95 is ok.

Or you know somebody clever mapping your car on 98 AND 95 and you use the fuel quality wires to switch between the maps

Jonners, not the lead is the issue. The Oktan rating of the petrol. And of course if a catalytic converter is fitted than unleaded is a must, whatever Okan it is.
But I believe you're not unhappy with your "mistake"

Coasting,
you engine has a knock sensor fitted which senses the quality of fuel used and adapts the ignition accordingly. Our old bangers don't do this. So if you fill it up with lower Oktan petrol than mapped it goes BANG!

BTW that BP stuff is crap. It burns faster than I can fill the tank up! And smells funny.

Jonners wrote: another advantage of the later cars (i think) is that straightforward bog standard unleaded is ok whereas on earlier cars it's ok but with a power loss Uwe??

Nothing to do with earlier or newer cars. ALL M3's are running fine with unleaded, EXECPT the EVO2 which always should be run on 98 Oktan fuel because of the ignition timing. If you want to run the EVO2 on any fuel with less than 98Oktan you need to "switch" the ECU to the 95Oktan map. Or take your chances.......

another advantage of the later cars (i think) is that straightforward bog standard unleaded is ok

whereas on earlier cars it's ok but with a power loss

Uwe??

Kevin

Speak to Dave as he might have one as he builds his engines from what i've heard.

Nostrils wrote: Here are the difference of the lower housings... Airbox Difference and install

Ahhhh, then I already have the big collector box. The only issue with mine is that the previous owner thought it would flow loads more air by by drilling holes in the back of it........obviously, simple physics wasn't his strong point....

..because higher compression engines need higher octane fuel, with the advent of unleaded, there was no equivalent of 5 star around at the time. Therefore, BMW probably thought it would be a load less hassle (owners returning pinking cars..) just to build the evo sport with the l/c pistons. Also, remember the Evo concept of these cars was all about getting items homologated for racing. They already had the h/c pistons available from the evo2 so probably didn't need to build the evo sport with them, to allow them to be used for racing.

As for the power restrictions, none. The only limits were written into the Group A regs that allowed homologated items. (Anyone remember Audi getting stripped of their championship because they had used un-homolgated engines parts in their V8)

Roops