nitrous users please read!
 

I have a '90 GT with a mildly modified motor. The mods are listed in my sig. I am running a 150hp shot of nitrous. My question is about gapping the spark plugs. I have a Crane HI-6 ignition with a Crane PS-91 coil, which obviously puts out a more powerful spark then the stock Ford ignition. So I'd like to take advantage of that better spark. I only use my nitrous maybe once a month, if that...so I'd like to have a bigger gap than the .035 that running nitrous calls for. In a "perfect world" I'd like to run the gap at .035 on the juice and like .060 when just on motor. Is there a happy medium anywhere between those 2 numbers where I'd still be safe with the nitrous? Say like .045? Or do I have to change plugs everytime I want to use the nitrous? What are you street/strip nitrous users running your gaps at?

I ran mine at .045, but I'll drop that down to .040 for next season. I don't think there's a significant loss in hp with a thinner gap, why are you so concerned?

Just use two different sets of plugs. One gapped at .045 on motor then when you decide you want to use the nitrous you have your other plugs gapped at .035". I run an NGK or a Denso plug now gapped at .034". I also have an MSD 7AL3 box and other timers that take out timing when the nitrous comes in. But run those plugs like i suggested and you'll be fine.

nitrous users please read!
 

Umm...because I like to get the most out of my combination. Isn't that what we are all doing here? I just didn't want to drive around with my plugs gapped at .035 when I am driving my car only on motor about 90% of the time. I think with an aftermarket ignition like the Crane that I have, there probably is something to be gained by opening up the gap to take advantage of the more powerful spark, with burns the mixture better, which can make your motor run better. Every little bit helps, ya know? I think I'm just going to do what Eric4Nitrous said and buy another set of plugs to use with the nitrous. But if anyone else has something to add, please do!

Thanks guys-

Good luck with it. If you got anymore ?'s pm me.

nitrous users please read!
 

Thanks Eric. You'll probably hear from me in the future then.

Simi-

I wasn't aware there was that much of a performance loss with a smaller gap, didn't mean to come across wierd or anything. Maybe I should take a closer look at my gapping, just seems like a pita to change the plugs if I want to spray. How much performance loss are you losing with a gap of .035 on a motor run as opposed to an .050 gap?

You could lose alot actually. It all depends on the amount of motor work. A stock to mildly modified motor won't lose as much hp or as bad as a heavily built one would. Just play with the gap on the plugs and see what works for you.

I run NGK's on motor and juice gapped at .048 I think.. I would rather loose a plug then loose a piston... in other words to much gap on juice will foul the plug.. if it doesnt foul and just melts away at the electrode then surely the PISTON is gettin pretty dern HOT

Running too large of a gap with nitrous will not "foul" the plug... the increased cylinder pressure from, say, a 150hp shot like mentioned, will 'blow-out' the spark causing a miss, or in other words, a backfire. If you get lucky, you may get by with just a damaged air filter, or worse, a blown head gasket combined with damaged induction components (MAF meter, split inlet pipe, bent TB blade, grenaded intake, etc.)

I wouldn't suggest running any more than .035 w/ a 150hp shot, even with a 'hot' ignition system. That is how I would approach the situation... and do ;)

nitrous users please read!
 

Thanks for the info. ultraflo-
I guess I'm going to do what Eric4Nitrous said then and go with 2 different sets of plugs. Next time at the track I'll try to take some runs down the strip on motor only with both sets of differently gapped plugs...to see if there will be a small difference in times or mph.

Thanks guys-

Simi-

I run a 150 shot and the gap is at 40, I have read that by taking the electrode and cutting it down so that they are parrelel than u can opwn the gap and not worry about it melting. I havent tried thid myself but i will.

nitrous users please read!
 

What are you referring to when you say..."THEY are parallel"? Cutting down the electrode so that it is even with what?