What spark plugs do you run?

[Kev@carnoisseur]

I recently had my 89SE rolling roaded and it made 330bhp at the flywheel using denso iridium plugs. Last night after a fair bit of driving (hard) they have started to give up under load (happend to me before on another car and on inspection the tip of one of the plugs was missing! and they where two days old!!)

I remember reading a thread about the best plugs to use on the 4 cylinder esprits, but cant remember what ones they where?

Can any one suggest the best plugs to run?
Bearing in mind Im running 15psi and 330bhp.

Thanks.

Kev@carnoisseur

[superdave]

Kev,

A few people on this forum might tell you that you should be running the NGK standard plugs and that no other plug is acceptable.

I too tried Densos and they were great for a few months. Unfortunately they packed up due to the build up on the plug.
Denso Iridiums have a 0.4mm diameter core which is extremely thin. You could try NGK Iridiums which have a 0.6mm diamter core and they are also cheaper.
Iam running a cooler standard NGK plug at the mo.
Just a word of caution, on Densos, to go up a higher temperature range you choose an higher number but on NGK's you choose a lower number to get a higher temperature range.
Try www.spark-plug.co.uk they post FOC and have lots of very useful info on their site together with cross references.

Hope this helps.


Dave Walters

[kylie]

I have always been told to go by the Lotus bible in this case and run with NGK's all the way. The car runs very very well esp driving hard on the track.

[Kev@carnoisseur]

NGKs it is then. Sorry for being a pain but where can I get them from today and what number heat rating thing do I need?

[danny tattersall]

Kev,

The standard NGK plugs are bpr6ekn. As you are running more boost it may be beneficial to go for a cooler running plug. I think that you go for a lower number for the NGK plugs so you would need a 5. As for getting them, I did not find the standard plugs to be readily available in the UK (other than from Lotus or a specialist). As suggested in the earlier reply you could try sparkplugs.co.uk. I got mine through them and found the service and price to be very good. If you put the plug model into a search engine you will find very few UK sites that list them. If you go to a car accessory place they will not be stocked either and if they were to order some in they would want you to order several.

Good luck.

Danny

[NJGSX96]

danny tattersall said:

Kev, The standard NGK plugs are bpr6ekn. As you are running more boost it may be beneficial to go for a cooler running plug. I think that you go for a lower number for the NGK plugs so you would need a 5.

A colder plug goes higher in number so you would want a "7" if you want one range colder. Don't think it is necessary though. Roughly, figure one range colder for every 100HP past stock. Using 264/285HP as stock (as with overboost) you will not go one range colder until you upgrade the turbo and fuel system. The bpr6ekn will be fine.

I have a whole bunch of the NGK BPR6EKN plugs. If you want to pay for shipping from the USA, I will be more than happy to send you a set. $15USD plus shipping.