Iridium Spark plugs

[timewind]

A friend o f mine who is working as an engine specialist for a racing team proposed to use Iridium Spark plugs instead of B7ECS for my Chimaera 500 and to take those Iridium Spark plugs one level colder then the B7ECS.

Has anyone experience with this or any comment why this could be a good or bad idea?

[Mark adams]

The NGK Iridium spark plugs should be good, and have a very long life. Personally I have had good results with the Platinum variety (PFR7B).

All the Iridium spark plugs I have seen have the smaller bodies, which are nicer to handle (especially on number 3 by the dipstick tube). If this is the case then you may want to fit new plug leads and suppressors, since the old rubber ones will have stretched to fit the old plugs. ACT supply Magnecor leads and boots which are ideal for this. Since the plugs cost more than the leads it seems like a good idea!

However I can't see any logic for going colder on the heat range, unless the car is on forced induction or very highly tuned (i.e. monster compression and wild camshaft). Due to the massive heat range on NGK plugs you will probably get away with it if there is very little town driving. Starting in really cold weather may be a little uneven too.

These plugs are used in the Jaguar XJR V8 (lovely motor) in the 5 heat range which is really hot. Apparently they stay there for nearly 100,000 miles!

[timewind]

Hi mark

Thanks for the comment. We deceided to stay on the same heat range (7) then with the others. This because as we looked at the old spark plugs we've seen that the engine runs a little bit on the lean side anyway.

[corin denton]

How much are they and are they a worthwhile upgrade for a standard 400 Chimaera?

[timewind]

They are around £ 17.-- each. Sounds expensive, but if you look at the longer life period (around 100k miles) I think it's well worth a thought.

I don't think there's something against using it with a Chimaera 400.

[corin denton]

Anyone know what the exact part no for the plug would be for a 96 400?

[xain]

Long life seems a bit daft when the plugs are supposed to be changed at each 6000 mile service anyway?

[timewind]

Well, it is definetly better for the servicebook to change normal spark plugs every 6000 miles but I'm not so sure what is better for the engine.

We have very good long life experience with other engines (such as dodge viper, mustang etc.)using iridium sparks.

But in the end, it's your own decision.