Spark plugs in hi-per applications

[mjoekingz28]

Hello. Do spark plugs pretty much always go the interval listedin the OM? I am wondering if you drive like a mad man or do track time do they need changing more often as with other similar parts.

Do you think by changing them midway (15k or 50k) on a track driven car thatyou will get better performance or better engine and emission life by keeping them fresh?





I guess, in other words, do they wear at a faster rate when you stay in the right pedal alot?

 

[Pontual]

It's an "on condition part". If you could compare performances between new and half life ...

 

[Gasbuggy]

No, they don't seem to. I would bet if anything the hard use keeps deposits off.

 

[PE400]

Are you using a std plug or HPX type? cut back angled ground could help.

 

[shanneba]

It seems to me that if you run at a higher rpm you might wear the plugs a little faster. Two stroke engines that fire every revolution have a higher plug gap wear rate than four stroke engines (unless they use a waste spark ignition that fires every revolution.)

You might get better performance if you adjust the gap and square up the edges of the ground electrode. Square edges reduce the voltage required to fire the plug. Don't try to square any of the fine wire center electrodes.

If you have added power through modifications you may need to reduce the gap slightly.
From NGK:
https://www.ngksparkplugs.com/about-ngk/...ew-set-of-plugs
Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005".


This is from NGK: NGK Spark plug gap wear
A worn spark plug not only wastes fuel but also strains the whole ignition system because the expanded gap (due to erosion) requires higher voltages.
Normal rates of gap growth are as follows:
Four-Stroke Engines: 0.01~0.02 mm/1,000 km (0.00063~0.000126 inches/1,000 miles)
Two-Stroke Engines: 0.02~0.04 mm/1,000 km (0.000126~0.00252 inches/1,000 miles)

I replace the plugs in my car at about half the suggested mileage when I track it. My plugs are four prong and the gap can't be adjusted.

 

[PandaBear]

If you run your engine harder you will wear it out sooner, that's for sure. However you will also keep them and the cylinders, intake valves, etc cleaner, so that the engine would run better even if your plugs are worn a bit more.

I personally would go grab a OBD scanner to check for misfiring and replace plugs based on the misfire rates.