Guest tony78_280z Posted February 23, 2005 Share Posted February 23, 2005 David Vizard in the March issue of Popular Hot Rodding says that "The bottom line is that wide plug gaps (up to 60 thousandsths and sometimes more), top-of-the-line plug cables, and a powerful coil/ignition system can deliver extra lbs.ft. everywhere." 60 thousandsths sounds pretty wide to me, but It does kind-a make sense A more poweful spark could jump greater distance and get a better burn. Anyone with a powerful ignitions system wanna jump in with their $.02, and let me know what sytem they use and what you gap at. I got a 50k Volt Coild and am looking at a Multi Spark System. What brand of multi spark / ignition system do you recomend that I buy. I'm leaning towards the Jacobs Electronics because others have bragged that it is nearly bullet proof. Quote Link to comment Share on other sites More sharing options...
Guest Magnum Rockwilder Posted February 23, 2005 Share Posted February 23, 2005 On all my naturally aspirated SBC's, I've always gapped the plugs to .060 and used an MSD ignition. On nitrous motors, you have to gap down to keep from getting spark blowout. I usually gap in the .028-.032 range on a nitrous motor. Quote Link to comment Share on other sites More sharing options...
Thumper Posted February 23, 2005 Share Posted February 23, 2005 When I ran 13lbs of boost I had mine gapped to .05" Now that I am running 18lbs I lowered it to .045" to make sure I have good spark. I run a msd6al with blaster 2 coil. On my na sentra I run .06" with a msd6a and blaster ss coil, but had to go down to .035" when I ran a 100 shot. Hope this helps Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted February 23, 2005 Share Posted February 23, 2005 Maybe i'm the oddball here but i usually gap mine pretty big. Right now they are around .08 if i'm not mistaken.. I'll have to go double check one. -Ed Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted February 23, 2005 Share Posted February 23, 2005 You could also try side gapping the plugs. You trim off some of the ground and gap it to that. Old School trick. Quote Link to comment Share on other sites More sharing options...
Guest tony78_280z Posted February 23, 2005 Share Posted February 23, 2005 Nismo, what kinda ignition you got? You could also try side gapping the plugs. You trim off some of the ground and gap it to that. Old School trick.WTF are you talkin about? Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted February 23, 2005 Share Posted February 23, 2005 Ok, guys, here's what I know. The higher the cylinder pressure the more impedence there is and therefore the more energy it takes for a spark to jump the gap. You've already read where nitrous and turbo guys are lowering the gap when the spray or up the boost. I run alcohol and build race engines so I'm going to tell you what my experience is. If your running an HEI with a high output coil and the black module you can run as much as .050 gap with 9:1 motors, .025 is max with 12:1 or higher gas or alcohol. MSD's can tolerate more gap since there is more energy, but it depends on the model you are using and how many MJ of spark energy they have as to what they will tolerate for plug gap. The pro-stock guys have actually dyno'd engines varying spark plug gap and tuning the gap on a dyno to produce peak HP. 2 or 3HP means winning or loosing. There was an article sometime back about tuning at the dragstrip by changing spark plug gap and COILS, but I can't remember what it was published in. Vertex mags typically run .025 to .028 gap regardless on high compression engines or blown alcohol/gas. If not then they tend to misfire alot at low rpm's like around idle, which fouls the plugs and they never clear up. Since the mag makes more fire the higher you wind it the optimum would be a variable spark plug gap, but that's not possible. You can get away with .035 on low compression engines with a mag. Top fuel guys even run dual plugs and dual mag's, but I don't know what the gap is on those, and that's out of my league anyway, I'm more of a hillbilly homie. I run MSD7 series in both cars, gap at .035 on a 13:1 and 14:1 engines with the propower coil on the 14:1 and the HVC coil on the 13:1. Planning to run the new HVC2 coil on the 14:1 engine to see if it picks up any. If I had unlimited funds, which I don't, I'd run the MSD promag system for a cool $4,000.00 on both engines which would fire a gap almost as wide as the room. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted February 23, 2005 Share Posted February 23, 2005 If you have to side gap the plugs, then the plugs are too hot anyway, go to a cooler plug or a race plug. In the old days, we didn't have race plugs and the ground strap would get so hot that it would detonate the engine, so we'd cut the ground strap back to shorten the heat path and eliminate the hot metal strap in the cylinder. Quote Link to comment Share on other sites More sharing options...
Guest tony78_280z Posted February 24, 2005 Share Posted February 24, 2005 If your running an HEI with a high output coil and the black module you can run as much as .050 gap with 9:1 motors,K, I'm not into the whole engine building thing (yet hee hee) and I don't pretend to know what those compression numbers stand for. But what then was Mr.Vizard talking about. I dont want to discredit either you or he, but something is confusing me around here. A Guy with a stock motor, but a high output ignition system and running off a non-charged carb what would be the highest gap he should run. Quote Link to comment Share on other sites More sharing options...
2126 Posted February 24, 2005 Share Posted February 24, 2005 I'm running a 2800cc L6 (N42 with SU"s & headers) and the engine internally is stock (probably 8.3 to 8.5 compression ratio). My ignition setup is as follows...MSD Blaster coil, Mallory Unilite distributor (w/vac adv), Magnacore KV85 wires, and the ubiquitous NGK plugs (gapped at .040"). The thing runs like a top...from idle to max RPM. OK, you may ask what max RPM is! I don't push the L6 past...say 5500 RPM...being a relatively stock engine, theres not much more beyond 5500 rpm anyway. Side note: I always laugh when I see MSA's price for the Mallory Unilite...around $600.00, WOW!!! You can buy the same Unilite from Summit Racing for about $375.00...much much better price! Quote Link to comment Share on other sites More sharing options...
Nismo280zEd Posted March 5, 2005 Share Posted March 5, 2005 I run an allison coil, Bosch plugs, Magnecore wires, and 77 dizzy. Although the dizzy sucks @$$ -Ed Quote Link to comment Share on other sites More sharing options...
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