Do spark plugs really make a difference?

[curbed-them-silly]

Hello everyone. Looking for the next (reasonable) step in beefing up my One's performance, after a blufin upgrade where the buzz is starting to wear off.

I've had a look at the comments on induction kits and i'm not all too impressed, same with performance gains with an exhaust.

So, how about spark plugs? Do they make a difference in the performance/economy?

Any other upgrades you would recommend for my One other than a total engine rebuild? A turbo perhaps or a supercharger? . Seriously though....

Not looking to buy a 2nd hand cooper S as suggested by others as I couldn't live without the options I ticked when purchasing my One.

[s33gav]

spark plugs will make no difference to your performance. Or fuel economy as far as im aware.

just accept you have a slow car, it'll be cheaper ok that was a joke, sorry.

[cristo]

They make a huge difference. Took mine out and the car ran like ... well, it wouldn't
run at all. Made funny hissing sounds. At least I could measure the compression
with them out.

Seriously, changing worn out plugs for any new plugs can make a difference,
having an appropriate heat range makes a difference over the wrong one
(stock heat range is correct for the One),
I have NGK Iridiums on my Cooper, but to be honest, I doubt they get me more than
a fraction of a HP over the stock ones or a small fraction of a mile per gallon
over stock.

Bluefin is great on a One. I have one on my Cooper - much smaller increase than
you got, but same end result. Intake is worth only a couple HP, Exhaust is worth
only a couple to a few HP. Ported head and cam designed for a normally aspirated engine
like the One or Cooper matched to a sport manifold/cat would probably add at least
10 more HP, but would be expensive. If you add a turbo or charger, you'd probably have to
beef up the engine internals and lower the compression ratio.
Not sure if the 5 speed Getrag is up to that power, the 5 speed Midlands I have certainly isn't.

[Nath316]

plugs can make a difference but leads can as well

on a previous car I had HT comp leads and plugs and found that there wasnt a great difference but there was a difference

[s33gav]

Listen, if you're thinking of getting more hp out of your mini one, new spark plugs WILL NOT get you any more power.

[AprilWhine]

Neither plugs nor wires make a difference, as long as they are not worn out.

[Richard Crofts]

On my S I changed to irridium NGK upgraded plugs when I fitted a pulley and have noticed that my fuel economy is consistently better despite the power increase. i know yours is a ONE but the same should apply. other than a remap there is not a huge amount to be done on the Cooper to increase power other than a manifold and a change in the head. both are in theory bolt on changes and can make dramatic differences but the COoper /ONE gearbox does not like power above 140 bhp at all!

[DaFlake]

+1 with Richard.

I upgraded my plugs to a colder set after my pulley install only to see what the buzz was about. I had been running for about six months on stock plugs. After I installed the new plugs I noticed that my fuel economy went up, a side affect that I am very happy about.

As for modding a One, there is simply not a lot to be done without making some big changes.