Plug Gap

Paul1981610

Member
May 16, 2014
78
2
8
01 gt Saleen series one with intercooler smaller pulley 24lb injectors. No boost gauge yet. Having rich issues at WOT. presuming blow out. I am gapped at .035. Should I go smaller gap
 
  • Sponsors (?)


Supercharged applications require specific plugs with a different heat range (cooler) and tighter gaps. If my memory serves me correctly I ran NGK TR6's gapped @ .032 on my Supercharged 01 Cobra a number of years ago, it ran smooth as a stocker.
 
Last edited:
The greater the boost, the smaller the gap. Seeing that you are running a Saleen blower (probably the worst possible blower ever made), you are probably barely breaking 300rwhp. Your gap is not an issue. It is the tune that is running rich. Do you have a wideband?
 
Well I did t have this issue until I changed plugs. The tune never changed. And thanks for telling someone that their supercharger is terrible. I'm a low budget guy and proud I even have one. And no no gauges at this point
 
I do not think he meant anything toward you when he announced his opinion toward the charger on your car. But if the tune has not changed, and as we spoke before about this in your other thread, I would change out those Bosch plugs. I am telling you from experience, they are garbage when it comes to our applications. As they mentioned above, go to another plug, NKG or Autolite. The gap is smaller when it comes to chargers. The gap on yours should be .032, over time it will expand to about .035.
 
It's not just smoke blow out. It actually sputters or loads up at high boost. All the old plugs were sooty. Has to be spark blow out IMO. But that's why I'm here getting other opinions
 
Well re-gap them to .032 and also make sure your COP boots are in good condition. After time and heat exchanges continually the COP boots get hard and cut or rip very easily. So when you re-gap the plugs, look closely to each boot and if any are hard and and you suspect a tear or crack rip whatever you want to call it, replace them. They are cheap at any auto store, and I experienced stumbling on my Mark VIII last year and I had 2 boots cracked causing the spark to arch off the block. After fixing them, it purred like a kitten.
 
It's not just smoke blow out. It actually sputters or loads up at high boost. All the old plugs were sooty. Has to be spark blow out IMO. But that's why I'm here getting other opinions
You wouldn't be blowing spark blow out with that little blower. There are guys running twice the boost you are that aren't experiencing spark blow out.
 
How do you know it's going rich at WOT? Are you looking at it on a wideband? Contrary to most folks' intuition, spark blowout actually reads lean on a wideband. That's because the wideband is an oxygen sensor, and not a fuel sensor. Fuel not burning due to the spark blowout results in oxygen not being consumed, and thus a lean condition registered by the O2 sensor.

OP, buy a set of NGK TR6s. Last set I bought was only like $13 for the set. Gap to .030. If you still have problems, the spark plug isn't likely the issue.
 
As noted in my MAF thread that I realize I should have stuck with. Car was running good just a little low rpm (under 2k) stutter. Had gears installed came home cleaned MAF and installed speedo cal. Took it out and ran like crap in boost. Blowing black smoke and jerking. Thought I had screwed up MAF. bought a new pigtail and MAF. Still the same but not quite as bad. Realized since I am new to superchargers the plugs I had installed were garbage. Bosch platinum +4. Installed a week ago. So I pulled them and installed Autolite 103 gapped at .035. It is much better but still black smoking at high boost. My thought was with the Bosch multi tip and a dirty MAF it was fine. But now with a clean good reading MAF the Bosch just didn't work. Could I have messed up the ECM with the speedo cal. The ECM is flashed by Saleen.