Boost and spark plugs

[FatXJ]

Sorry, the ignition system IS REQUIRED for a fuel motor....it IS possible that overheating in the combustion chamber can cause the engine to diesel...that does frequently happen.....but most of the engine explosions occur BECAUSE the ignition on one or more cylinders failed...the cylinder then hydraulics from the massive fuel load and something has to give.:explosion And the actual hp a fuel motor makes is an estimate anyway...no dyno will handle one...and it won't run under boost long enough to get a pull.

"Spark plug electrodes are totally consumed during a pass. After 1/2 way, the engine is dieseling from compression-plus the glow of exhaust valves at 1400 degrees F. The engine can only be shut down by cutting off it's fuel flow."

from http://www.wediditforlove.com/techtalk6.html

 

[badron]

Yes, it need the spark to run right. Lean burns are common at the strip and they often pay for it in parts. But in 1972 yes that's 1972 I say a record setting run. With the magneto top half draging under the rail. Believe it or not.

 

[Flash]

A Y ba well, humm could, wow!!!!!

thanks for for link!!!:cheers:

 

[XJtoy]

OK...the OLD FART speaks....Often times the misled and uninformed think that "hot" or "cold" has something to do with the "power" or "heat" of the spark.....NOT SO....spark plugs (more properly called igniters) are made in "heat ranges" ....to understand how this works, one must know how a plug works....first the obvious....an electrical spark jumps the gap between the center electrode and the side (or ground) electrode....If the temperature of the electrodes and the ceramic insulator are too cool....fuel deposits will accumulate and the plug will short...(no spark).....if the temperature of the electrodes and the ceramic insulator are too hot....they will erode away or just melt....the construction difference between a "hot" or "cold" plug has to do with the LENGHT of the INSULATOR....long, deep insulators have a long heat path to the head (where the heat is dissapated)....short, shallow insulators have a shorter heat path....the easier it is for the plug to cool, the lower the operating temperature at a given combustion temperature.

The trick is to pick a plug that runs at the proper temp for YOUR application. Generally speaking, the higher the engine output, the higher the combustion temperature MUST be (because heat is the driving force) the colder the plug needed while under "boost" ....but if the engine spends most of the time off boost and short periods on boost, it may very well be possible that a stock range plug will do....I run stock plugs in my ET bike....it's only on juice for 3 seconds...if I make a full pass at 100%....i change 'em down two notches to avoid preignition and the resultant...KABOOM!!!

I couldn't have said it any better. I need to save this so every time somebody asks me this question I can have them read this.

 

[XJtoy]

I've boosted about 20 hondas, and the colder plugs are honestly just a tuning bandaid.

If you're running good engine management, and know what you're doing stock plugs gapped down work fine. stock gaps were .044" on those, and I would take them down to anywhere from .028" to .022"

If you're running a basic fuel controller type setup, you could use colder plugs to make it work

Well if that the case then we put band aide on all of the cars around here. I run around with just about every high horsepower Honda in KC I have tuned on some well over 700hp and we all run colder plugs. I have run just about every kind of plug in my 460hp daily driver and it all comes down to the good old NGK bkr7e. I have tried gaping stock plugs down to .022 and it still cuts out I swap to the bkr7e that are two ranges colder at .026 and it stops cutting out and if 460 to the ground and 25mpg is a bad tune then I’m down. I’m not saying stock plugs wont work I just don’t see any need to do it when I can just run a colder plug make lots of reliable power and get on with living.