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croat

irridium spark plugs

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When driving along on an open road in 2nd gear or above and i go full throttle, when the revs hit around the 5000+ mark the engine does not run as smoothly as before and begins to like missfire and the exhaust begins to backfire as if there is too much load or stress on the engine. Anyone know what this is? Some one said new irridium spark plugs would fix it? what are ur thoughts?

Thanks...

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id say that ur boost is at its highest and its blowing out the spark... try gapping ur plugs to .8 mm or getting irridiums and gapping them the same......worked for alot of us

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I just had this problem... replaced my spark plugs with copper ones gapped to .8 and its gone... still getting a lot of pops though but thats a different issue...

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try 0.8 gap. Also make sure all the intake hose clips are tight. I had one that wasn't done up fully and was leaking on boost. Terrible misfire and no power, which I guess was down to the induced overfuelling

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how regular do the copper plugs need to be replaced?

oh yeh.. whats the serial number for the copper plugs?

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copper plugs are easily good for over 20,000kms.

iridium/platinum is a waste of money in my opinion.

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The fancy iridium and platinum plugs are great for cars that are factory, and no forced induction. Greater service intervals and so forth.

For performance cars, standard plugs with the right gapping, and perhaps running a slightly colder plug does the trick.

A freind had a misfire just as he got on boost on his soarer, running 1 bar. While in the car you couldnt feel it or notice it, but on the dyno you could clearly see that was struggling at a particular point on the graph, and it was doing it almost all the time.

Gapped down to 0.8 and ran a colder plug, using standard NGKs, problem solved and t he car runs better. He has platinum plugs in there before, which were fairly new.

The iridium plug has a very small tip on the end of it, and its very fragile, expecially when exposed to the elements of high boost. Even a light detonation pulse with the front focused on the centre or starting out from the centre, could melt the tip or deform it in a way that the spark integrity is sacrificed.

9-10 second vl turbos run approiately speced standard NGKs with no problems.

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