Spark Plug Question

[Swarzkopf]

The background:

I normally run Autoline #24 spark plugs- these are one heat range colder than stock for use with my Zex kit.

Because I don't own a fire jacket, don't plan on buying one soon, and would like some decent N/A times, I'm planning on running N/A at PRP the first weekend out there.

The question:

How much power am I giving up by running the Autlite 24s (gapped at .035), as compared to 25s (gapped at .052), the correct heat range plug and correct gap for my 5.0? Should I throw a set of properly gapped 25s back in for when I plan on running with no juice?

I know it's a pretty newbish question, but thanks for bearing with me.

 

[zZsKyZz]

I would also like to know.. I have the same situation and I'm wondering if I'm losing power... also, what if I go up a heat range to 26 plugs?!

 

[HISSIN50]

I have run colder plugs in N/A applications and never noticed a difference. Please note that this was on carbed stuff (dieseling in the summer time was a reason for swapping down). I have to say that my uneducated (I havent seen this stuff tested on a dyno, for instance) gut feeling is that the gap will have a LOT more to do with it than the heat range. I have new 24's sitting on the workbench waiting to go in myself (I run 0.050" gap - gives me room for gap erosion and a possibly weak coil, etc, since I removed the MSD).

I would open that gap up if losing the bottle. And if pulling plugs anyhow, might as well swap back to 25's (though I think 24's would do fine, esp since we get the ping thing).

That just gives an outline of MHO.

Good luck Shawn.

 

[Swarzkopf]

Thanks Hissin. Your feedback is always valued and appreciated.

Depending on how ambitious I'm feeling, I may make my first pass on the .035/24s and then switch to .052/25s and compared the MPH.

 

[SeventyMach1]

You can raise the gap on the 24's & still be fine.

That's how I run mine (except side-gapped & indexed) & there's no difference in running 25's (which I ran last & they were side-gapped & indexed as well). So pretty much, I kept the factors the same except one was a 24 .... one was a 25. No difference.