sparkplug woes..

[malloynx]

i'm having a problem with misfires over 20psi on my ITS 67MM turbo. i made 543rwhp @23.8psi with a very slight misfire over 5000rpms. plugswere gapped @.28 autolite 3923's

i installed a set of NGK iridiums BCPR6EIX. i think that is a 6 heat range for the NGK. plugs come gapped @.30 and the car ran great and cruise and idle. however over 15psi i was getting severe misfires. at 500rwhp the car was totally breaking up.

I installed a set of autolite 3923's again @.27gap and now i have a crappy idle but the car feels great under boost.

is there a plug out there that will be me the best of both worlds.

i'm trying to reach 600rwhp+

[mixmastermatt]

I would go two steps colder and try the .030 gap. Also check your AFR's when it breaks up, see if it is dropping a bit rich just before it hapens.

[malloynx]

yea, i was thinking the same thing. bigger gap, but a colder plug