Stock ignition + Nitrous ??

[skiwesser]

I'm spraying 100 shot and it's backfiring on hard shifts, #2 plug stays wet with oil all other plugs look good I guess the oil ring on #2 is shot but all have good compression.
I've had problems with it backfiring off the spray but a new plug usually fixes it, it does it almost everytime on the spray but it pulls hard and never misses a beat just "BANG"......."BANG".
I don't want to go to strip like this but I will if I have to, I figure a bottom end re-build is the only solution but wondering if a MSD 6 would mabye light it, I,m almost sure fuel is loading up in header at high RPM's and exploding when I let the clutch out? sound right to you guys??
P.S. timing at 10* W/93 octane autolite 24's at .035 gap,
fuel is there with 190 lph in tank and wet system

I can't remember how big of a shot you are running? What RPMs are you shifting at? Hopefully you're not shifting at the same RPMs as you do when running on just motor? You should shift a few hundered RPMs lower when on the juice. My mods are in my sig. I have a shift light that comes in real handy when drag racing, especially when using nitrous. I have a 5800 shift pill in the light when on motor. I put a lower, 5600 rpm pill in when using the nitrous. It seems to help out. It's been my experience with my dry shot that the nitrous works best from about 3500 - 5500 rpms. When you get up around 6000+ you can risk engine damamge from back firing, over revving, etc. My guess is that your back firing is coming from valve float. Maybe you're revving it out too high on the juice? A better ignition would definitely benefit you though. I run a Crane HI-6 ignition with a Crane PS91 coil. The NOS techline said I could keep my stock spark plug gap of .054, even with the nitrous, being that I have an aftermarket ignition. As for what's wrong with your #2 cylinder...your sig states that you have 155K miles on that beast. It's probably getting tired. Especially since you're squeezing it now.

[skiwesser]

I'm gonna go ahead and get the crane hi-6 too.
I use stock tach and have been shifting at 5400-5600 both on gas & off
just put nitrous on last week, should i shift lower than 5400?

No, shifting at 5400 is fine.

[Dark_5.0]

Originally Posted by skiwesser

I'm gonna go ahead and get the crane hi-6 too.
I use stock tach and have been shifting at 5400-5600 both on gas & off
just put nitrous on last week, should i shift lower than 5400?

The Crane HI-6 sux ass. I had the Crane HI-6 Ignition box and coil and had nothing but problems from the 1st day to the last day. (2 months) I literaly pulled that piece of crap out of my car and beat it to death with a hammer.

If I would have been spraying when using the Crane box I would have went B00M!

Sorry to hear that. What kind of problems did you have? I've had 0 problems with two different Crane HI-6 ignition boxes in two different Mustangs. Yours must have been assembled on a Friday...

[Dark_5.0]

Originally Posted by Simi Stang

Sorry to hear that. What kind of problems did you have? I've had 0 problems with two different Crane HI-6 ignition boxes in two different Mustangs. Yours must have been assembled on a Friday...

Yeah maybe it was. First I beat the hell out of the ignition box with a hammer and kept using the coil and shortly after the coil went out

My car wouldnt rev past 5500 rpm so with the box.

You should have called Crane. They probably would have replaced it with a new one as long as it wasn't real old. From my experience with Crane, their customer service is pretty decent.

[skiwesser]

ignition box seems to work okay, but still backfiring.
Gonna try new ford wires and a new cap and rotor?

[pearlgt40 306]

need more plug gap man...35 is puss.

[skiwesser]

Do you think?
I figured less gap would be less likly to foul out, easier to for spark to fire?
Am I wrong?

Definitely. As I stated earlier in this thread, I run the Crane Fireball ignition & PS-91 coil. The N.O.S. techline said that I can run the gap between .050 & .055, which is basically the stock gap, being that I have an aftermarket ignition. If you just had the stock ignition, then closing the gap down to .035-.040 would be wise. The more powerful ignition allows you to open up the gap some.

[skiwesser]

But I am trying to stop #2 plug from oil fouling ,which is causing the backfire, so you're saying still open the gap up?

Oh yeah...I forgot about that #2 cylinder you were having problems with. Have you figured out why that #2 cylinder keeps fouling? Maybe you could just keep that one cylinder's gap a little lower...like .040-.045. I really don't have much experience with the whole fouling plugs thing. The fouling I'm sure is linked to the wear & tear on your high mileage motor. Someone else is going to have to chime in here. If I were you, I'd call the N.O.S. techline & explain your problem. They'll probably tell you not to juice a motor with a plug that fouls though. Good luck. Sorry I couldn't be of more help.

[Hozer 88GTConv]

If you really know/think you have a busted oil ring, I'd back off and fix it.
I lived with a bad broken oil ring on number 5 for over a year and kept telling myself that it might have been something else (bad intake seal, valve seals, guides, yatta..) I can't tell you how many plugs I changed and those stupid anti-foulers are a waste.

A bad ring will foul your plug right away, cause fuel to dump into the cylinder, and burn in the exhaust.
If I had to do it all over again, I would have just dropped the pan, pulled number 5 rod/piston out, re-ringed it and stuffed it back in the hole.
good luck...