Avi

First I'd like to thank Exviper for his help with this subject and others concerning my S. I am looking for specific help on spark plug gap with comptech supercharger. If you have personal experience and or strong opinion please let me know as I am in the process of purchasing a supercharger with an aftercooler and the instruction say nothing about the spark plugs. Thanks Avi

AusS2000

0.035" (0.89mm) is good for forced induction.

jahwerx

I've researched... a little smaller - 0.028" with colder plugs is recommended for FI up to 20 psi.

I'm going to be running NGK BKR7E with a 7 psi turbo application

AusS2000

I just decreased mine to 0.028 because of misfiring. I'll let you know if it improves.

xviper

Aus, your setup is a bit more higher output and 0.028" might be the ticket for you, but for "out of the box" kits that have no other mods for more power, this gap might be too small, particularly if the car is not driven on the track, not driven hard in general and used for only the occassional foray into spirited driving. A gap this small may cause pre-mature fouling.
I've been running 0.034" for almost a year and it seems to work well for me. Mine was a bolt on and go.

wortham

on the subject, since xviper got me thinking about it, what are the consequences for running a bad gap?

i'm sitting at .035" with my IK-24's and FI, and went with that gap due to some research (specifically xviper).

xviper

Too big a gap and F.I. can "blow" the spark out at boost and high revs, causing a miss. Too small a gap and you get fouling pre-maturely and your plugs won't fire nor will they last too long.

Sideways

[QUOTE]Originally posted by xviper
Aus, your setup is a bit more higher output and 0.028" might be the ticket for you, but for "out of the box" kits that have no other mods for more power, this gap might be too small, particularly if the car is not driven on the track, not driven hard in general and used for only the occassional foray into spirited driving.

Hitman

I'm also running IK24s with my CT SC. Research from this forum suggests a smaller gap. However, this is the response from Comptech (2/25/04) when I asked them what the appropriate gap would be for these plugs with their SC kit:



I'm unable to call them during their business hours.

Avi

I had called Coptech 2 weeks ago about the IK24. they recommended to use the plugs as they are gaped .032. I had a SC installed couple of days ago and after getting input from all of you and especially from Dave (xviper) I instructed the installer to gap the plugs at .035. I am out of town, in few days I would be able to give my input. Thank you all for your help.