E30 Zone

I did a search and I know it's come up before, but I'm still a little confused.

I've got a 1990 318i which I just ordered service parts for (using the Genuine parts link on here). The plugs I got sent were something like NGK BPR6EQUP (they had that EQUP on the end, but the part number is in the car which is at the garage!), that have a quad-electrode end. The ones I took out were a mixture of single and double electrode!

Now I've put these new quad electrode plugs in, once the car's warmed up it idles higher than it did before - about 1200-1300rpm.

Are these the right plugs, or am I best just getting some normal single electrode ones?

Different types of plug have always confused me so this is nothing new!

Thanks.

as far as i am aware, the 4 electrode plugs last longer thats all...

OK, thanks. I think I'll just leave the new EQUP ones in.

2 valve per cylinder engines usualy work best with single electrode plugs.
The best test for ignition components is to run a car on LPG, and a converted E30 will make it clear that it doesn't like fancy plugs!

OK, thanks. I think I'll leave the 4-electrode ones in there for now, but when I get a moment I'll put either BPR6ES or BKR6EK in. I have no idea what the difference is, but I've seen people recommend both so I figure either is fine.

i was told by my motor factors that for the later low comp engines the plugs with the number 5 in were the ones not 6, as they burned hotter. i have these in my f reg with no problems yet. i know the colder engines are recomended in high comp engines as they burn colder and avoid detonation (pinking)

I had a look here:
http://www.ngkpartfinder.co.uk/

And it says that the E30 318 carb and injection should have BP5E, but only up to '88 (mine's 1990). It says that M40's made '88 to '90 shoukd have something called ZFR5F-11 and that the M42 and the E36 M40 should have BKR6EK!

Does anyone know what the best plugs are for LPG converted m20b20 engines? I have BPR6ES (i think) atm but they look fairly crusty...