Recommended spark plugs on E85?

[ice445]

I’ll just put this here for anyone interested. I’m still processing it.

https://iopscience.iop.org/article/10.1088/1757-899X/160/1/012044/pdf

i. Smaller spark plug air gap width can produce good combustion with high injection pressure but
self-ignition might occurred and damages the engine.
ii. Higher spark plug gap width increases the chance of misfire. However, higher spark plug gap
will reduce the chance to ignite the fuel in low injection pressure.
iii. High injection pressure will make the flame front progression of the combustion more smoothly.

Seems about right to me. Large gap is better until it's not. Small gap is usually fine until it's not. Gap is just one aspect of a fine tuned system, that's why I just trust the engineers that made it.

I would be curious to see how port injection systems behave in the same test.

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[Pistol_91]

Stock.
If Boosted. .25 .28 .30. Whatever the flavor is for the day.

 

[GregO]

If Boosted. .25 .28 .30. Whatever the flavor is for the day

That is conventional wisdom but Roush SC package and Ford GT500 recommend the gap @ .037-.039”.
I’m still processing this, Roush & Ford are going the opposite air gap direction vs the other SC’er Mfg’s.

 

[K4fxd]

I’ll just put this here for anyone interested. I’m still processing it.

This makes sense. The larger air gaps light low pressure fuel better. The larger gaps started in the 1980's when we still used carbs and ran everything super lean. I think the reason to keep the large gaps is monkey see monkey do. It works so why mess with it.

Larger gaps also retard spark timing.

It's a can of worms. If you look at the trends in the linked paper it seems a .040 gap is best. This corresponds well with my starting gap around .03. After 60K miles the wear puts the gap around .04

I think I will start gapping at .035 from now on.

Thanks for the read.

 

[GregO]

This makes sense. The larger air gaps light low pressure fuel better. The larger gaps started in the 1980's when we still used carbs and ran everything super lean. I think the reason to keep the large gaps is monkey see monkey do. It works so why mess with it.

Larger gaps also retard spark timing.

It's a can of worms. If you look at the trends in the linked paper it seems a .040 gap is best. This corresponds well with my starting gap around .03. After 60K miles the wear puts the gap around .04

I think I will start gapping at .035 from now on.

Thanks for the read.

We did many GM HEI conversions so long ago, it was a wonderfully simple system and worked well, gone were the matchbook covers used to set point gaps….. most everyone stopped smoking anyways

 

[HKusp]

I’ll just put this here for anyone interested. I’m still processing it.

https://iopscience.iop.org/article/10.1088/1757-899X/160/1/012044/pdf

So I am already having an issue with the article in the introduction. It states "By the end of 2012, there are only 235.8 million tonnes of proved oil reserve in the world." Conveniently, that is exactly 50 years worth of oil reserves at the world average consumption since 2012. Bullshit.

 

[K4fxd]

It states "By the end of 2012, there are only 235.8 million tonnes of proved oil reserve in the world." Conveniently, that is exactly 50 years worth of oil reserves at the world average consumption since 2012. Bullshit.

Yea, I wondered about that too. If I recall correctly "they" thought we were going to run out of oil around 1960.

I do come from a fracking background and last I recall there was 3 or 400 years of known oil at the then current rate of increase in use.. 2012 or so.

 

[GregO]

So I am already having an issue with the article in the introduction. It states "By the end of 2012, there are only 235.8 million tonnes of proved oil reserve in the world." Conveniently, that is exactly 50 years worth of oil reserves at the world average consumption since 2012. Bullshit.

I imagine if oil exploration stopped in 2012 the reserve would be less today. But exploration continued and here we are a decade later.

Now about Roush and Ford gapping their SC’ed plugs @ .037”
What’s going on there vs. the others closing them up ?

 

[K4fxd]

Now about Roush and Ford gapping their SC’ed plugs @ .037”
What’s going on there vs. the others closing them up ?

Maybe the linked paper is correct and .04 gap is the best for high pressure fuel injection?

I guess we need to see if Roush gaps the gen 2 @ .037.

 

[GregO]

Maybe the linked paper is correct and .04 gap is the best for high pressure fuel injection?

I guess we need to see if Roush gaps the gen 2 @ .037.

I looked and found Roush Gen2 plug gap spec. @.037”
Interestingly NGK’s OEM spec GT500 plug comes factory gapped at .039”

Does anyone know if Ford is using low voltage Ionization to detect misfires ? How is Ford actually detecting misfires ?

 

[ice445]

I looked and found Roush Gen2 plug gap spec. @.037”
Interestingly NGK’s OEM spec GT500 plug comes factory gapped at .039”

Does anyone know if Ford is using low voltage Ionization to detect misfires ? How is Ford detecting misfires ?

Standard crank signal output speed variance as far as I know

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