320i plug gaps?

[WaynE30]

Sorry it’s probably been asked a lot and I have looked but can’t find a definitive answer.

What should the plug gap be on ngk bpr6es?
And are these even the best plugs for my 1990 320i?

Thanks wayne

[reggid]

catted engine BOSCH W8LPR/W8LCR
non catted BOSCH W8DC
according to BMW.

i'd get the NGK equivalent as the plugs are better than Bosch (run cleaner with less deposits)

quick google suggests these are the equivalent NGK.

NGK ZGR5A for the catted (these have projected tip) same as the M20b25 8.8:1 (catted plugs) which work great
BP6ES/5ES seem to be the NGK equivalent both appear to be non projected non resistor. I would have though the BP5ES would be the correct heat range though.

BPR6ES is only what i'd use on a higher compression engine >9.5:1 that's going to be custom mapped.

[WaynE30]

Hi thanks for the reply
I went with bpr6es as e30 wiki suggested it.
Do you know what the gap should be ?

Cheers

[reggid]

its around like 0.7-0.8mm doesnt matter much, still runs fine at 0.9 or slighty more the stock ignition setup is pretty good

[WaynE30]

Great cheers

[TheWolfman]

Have a peep at this thread, might help also:

viewtopic.php?f=2&t=278876&p=2960557&hi ... p#p2960557

[WaynE30]

Thanks

[Lemon98]

catted engine BOSCH W8LPR/W8LCR
non catted BOSCH W8DC
according to BMW.

i'd get the NGK equivalent as the plugs are better than Bosch (run cleaner with less deposits)

quick google suggests these are the equivalent NGK.

NGK ZGR5A for the catted (these have projected tip) same as the M20b25 8.8:1 (catted plugs) which work great
BP6ES/5ES seem to be the NGK equivalent both appear to be non projected non resistor. I would have though the BP5ES would be the correct heat range though.


I've got some WR8LC's on order for my 320i which still has its cat but I haven't had the car for long so not sure if I'll be able to notice any difference.

Can't remember what is currently in the engine from when I checked their condition but I will post a reply updating that when I swap them in!

Also when you say that BMW recommend a different plug for non-catted engines I'm guessing you mean from factory right as if I eventually remove my cat I shouldn't have to change to a different plug should I? Like apart from back-pressure I'm not sure what else would change in the combustion chamber (unless back pressure keeps more/less exhaust gas in the cylinder and thus increasing/reducing the in-cylinder temps?)

[Lemon98]

Also I'm new to the forum so apologies if I replied to the comment wrong or could have made what part exactly was my reply and not the original post I was replying to

[Brianmoooore]

Also I'm new to the forum so apologies if I replied to the comment wrong or could have made what part exactly was my reply and not the original post I was replying to

Pardon?? You've lost me there!

The one type of plug you shouldn't run a M20 on is four electrode plugs. M20s don't seem to like these at all.

[reggid]

I've got some WR8LC's on order for my 320i which still has its cat but I haven't had the car for long so not sure if I'll be able to notice any difference.

Can't remember what is currently in the engine from when I checked their condition but I will post a reply updating that when I swap them in!

Also when you say that BMW recommend a different plug for non-catted engines I'm guessing you mean from factory right as if I eventually remove my cat I shouldn't have to change to a different plug should I? Like apart from back-pressure I'm not sure what else would change in the combustion chamber (unless back pressure keeps more/less exhaust gas in the cylinder and thus increasing/reducing the in-cylinder temps?)

The different heat range is due to the change in compression ratio. the non catted engines have a higher CR so need a colder plug at least for the M20b25 this is the case. i dont know much about the b20 and variants.