Spark Plugs for 10.5:1 Compression

[DJThom]

Good Day:

I'm looking for sparkplug recommendations for my Elan. It's 10.5:1 with cams one stage more advanced beyond the Sprint. What I have to date is as follows:

Bosch RO-482
Champion L105
NGK B5HS or BPR 7eS

Thanks
Darren

[worzel]

Hi

I've used BPR8Es type in my car for a couple of years. Mine is a sprint, unmodified and with the original unskimmed head and with all settings correct (yes they are correct) and with compressions of around 225psi.

These plugs work fine for me (but so do BPR7ES)- I don't drive at all hard.

John

[rgh0]

Darren

I would use as follows

NGK BP6ES for normal road use. For track use or very hard road use with continuous maximum revs use go one step colder to NGK BP7ES. For a full race engine on 12:1 compression go another step to BP8ES. The original Lotus recommendation of Champion N7Y was too cold in my opinion for normal road use and only suitable for sustained high revs use.

The suppliers of other brands can give the equivalents to these NGK heat ranges but in general I have found NGK's ( genuine ones) to be the best.

Rohan