Can spark plug gap change hp?
Thread Starter
Pro
Joined: Jun 2001
Posts: 683
Likes: 0
From: Calgary
Can spark plug gap change hp?
When I had my engine dynoed, I didn't check the gap on the plugs. It completely slipped my mind. As a result, My engine was dynoed with 0.027 gap spark plugs. The plugs are NGK's version of the Champion RC12YC. I am running a MSD pro billet tach drive distributor, with a 6 al box. I have since gapped the plugs to 0.045" as per MSD recommendations. Does anyone think this will affect power levels?
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Re: Can spark plug gap change hp? (74vetteman)
Jacobs Electronics and many others have run tests on this very issue and, yes, wider gaps do allow more power production up to a certain point.
To successfully run wider gaps, the other ignition components have to be up top snuff or you'll get misfire. It takes more spark energy to jump the wider gap, but once the jump is made a larger kernel results giving a more complete burn.
Hope this helps.
Jake
To successfully run wider gaps, the other ignition components have to be up top snuff or you'll get misfire. It takes more spark energy to jump the wider gap, but once the jump is made a larger kernel results giving a more complete burn.
Hope this helps.
Jake
Safety Car
Joined: Feb 1999
Posts: 3,631
Likes: 14
From: Fountain Hills AZ
Re: Can spark plug gap change hp? (74vetteman)
In addition to what Jake posted: Before electronic ignitions, it was common practice to reduce gaps for high rpm use. The shorter burn times and higher cylinder pressures associated with higher rpms favor a smaller gap when all else is equal. With a modern ignition though, .045, or maybe even wider in some cases, is practical and should give better performance overall. If you retest with no other changes than the wider gap, I'd expect to see increased power in the low/mid range but less of an increase at peak.
Le Mans Master
Joined: Jan 2000
Posts: 8,721
Likes: 108
From: Canada
Re: Can spark plug gap change hp? (Vetterodder)
Need some advice guys, I have just rebuilt my small block with some hd. mods. Which spark plugs should I be using, will be using points for the next month or so them will move to an electronic setup. And advice on the gap as well. As always much appreciated.
