Splitfire spark plugs improved minibike performance.

[Kurtatron]

I think most people thought the splitfire plugs were snake oil, sales gimmick, and a waste of money.

I had never even heard of them. But since I got a minibike, I’ve followed YouTubers who modify minibikes. One such YouTuber tested the splitfire plugs.

The plugs were patented and made in America back in the 90s. The idea was that the split in the electrode allowed the flame to expand above the electrode, whereas normal spark plugs block upward expansion.

Black66 tested these plugs out in a 212 single cylinder engine, and got very noticeable acceleration and mild top speed increase compared to other spark plugs.

I bought some and installed in my minibike. For something where you’re trying to squeeze out as much performance as possible, these plugs are great.

These are no longer made, so they’re only available on eBay and third party sellers on Amazon.

A shame they never took off.

 

[zzyzzx]

I used them in a 1985 Ford Escort (1.6L fuel injected engine) and I thought they worked better. Better meaning I didn't feel compelled to clean them so often.

 

[wings&wheels]

"Took off" Mine sure did. Back in the day, I had a 1991 Turbo Capri that I improved w/ some Rod Millen Motorsports parts and a set of Splitfires. After about ~2K miles on my commute home, one of the plugs blew apart; the ceramic center section departed the center section and dented the hood from the inside. Spitfire wanted the plug back, well what I had left, and they eventually sent a check for the value of the plugs and bodywork.

There are other multi-prong and/or fine wire plugs I'd use before them. Cool that you are trying them though

 

[The_Eric]

"Took off" Mine sure did. Back in the day, I had a 1991 Turbo Capri that I improved w/ some Rod Millen Motorsports parts and a set of Splitfires. After about ~2K miles on my commute home, one of the plugs blew apart; the ceramic center section departed the center section and dented the hood from the inside. Spitfire wanted the plug back, well what I had left, and they eventually sent a check for the value of the plugs and bodywork.

There are other multi-prong and/or fine wire plugs I'd use before them. Cool that you are trying them though

That was pretty square of them to do.

 

[martinq]

You can easily modify a basic NGK plug using a small hand file (chainsaw round or triangle file) but the advantage of the sharp edges will not last, but that's not really that important in a short-life engine. A better and easier thing to do is use an NGK G-Power plug (single platinum) and close the gap to approx .015". I clamp the ground strap down on a 15 thou feeler and verify that a 20 thou will not fit, anywhere between 10-20 thou should be good.

The sharp tip of the platinum plug is very durable and reduces the voltage required to fire as does reducing the gap. Both of these will help magneto ignition engines start easier and run more reliably.

 

[chainblu]

I remember a few of my co-workers tying these in the early 90s. They all pretty much had the same reaction: They swore their car ran better than before, but after a while things returned to 'normal'. I always thought maybe they should try a new set of "regular" plugs and see if the result is similar.