Say you buy a vehicle that's aftermarket supercharged and has a bunch of other power mods on it. How do you determine what heat range and gap you will need?
Newbie Spark Plug Range/Gap?
- Thread starter MDK210
- Start date
nobody?
All depends on the mods, but lets say your are pulling 8# of boost from a Kenne Bell on stock internals. Factory Gap is .054, start closing that gap otherwise you will start misfiring. You want the gap to be opened up as much as possible to produce the hottest and longest spark, but with the boost of a supercharger it is going to want to blow the flame out, which is why you need a smaller gap.
Heat range is important as well, a hotter plug will have more of a chance of accidentally firing (detonation) before the piston gets past TDC. Very bad. I would recommend going 1 if not 2 steps colder than the factory plug. Best of luck to you.
Heat range is important as well, a hotter plug will have more of a chance of accidentally firing (detonation) before the piston gets past TDC. Very bad. I would recommend going 1 if not 2 steps colder than the factory plug. Best of luck to you.
Unless you are running over 15psi, I'd run the Motorcraft AWSFA-22c or Autolite 764 copper plugs with a gap between .032 and .035.
I've been reading a lot about this topic at the NGK site which has really good unbiased info but never really understand how they even guessed which plug to even start with so this helped out a bit, thanks for that.
Last time my plugs were changed was about 1K ago and the guy that did owned a termi which was making some nice power and he advised me to get Autolite AR103's which I did and then he set the gap (which I don't know). I'm not running over 15psi so I guess my next question is what is the main difference between 103's and 764's? Thanks for the gap tip!
Last time my plugs were changed was about 1K ago and the guy that did owned a termi which was making some nice power and he advised me to get Autolite AR103's which I did and then he set the gap (which I don't know). I'm not running over 15psi so I guess my next question is what is the main difference between 103's and 764's? Thanks for the gap tip!
The 103's are one step colder then the 764's. Helps keep detonation away. I run the 103's in my car.
I'm due for a new set of plugs. I think I'm gonna get the Autolite AR103's gapped at .032-.035. I've been running the 764's, but I'm deathly afraid of detonation, being that my motor isn't forged.
Just out of curiosity: While the colder plugs help keep detonation away, is there any other drawback to using them?
Homer
Just out of curiosity: While the colder plugs help keep detonation away, is there any other drawback to using them?
Homer
If the tip of the spark plug is too hot it can cause pre-ignition leading to detonation/knocking and damage may occur.
If it is too cold, electrically conductive deposits may form on the insulator causing a loss of spark energy or the actual shorting-out of the spark current leading to a misfire.
If it is too cold, electrically conductive deposits may form on the insulator causing a loss of spark energy or the actual shorting-out of the spark current leading to a misfire.
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