first off, i did a search and didnt find what i was lookin for so.... question here is.. dry kit or wet kit in my 89 iroc. And with a dry kit would it be a bolt on kit or would i need to modify my injectors and comuter to make up for the added nitrous? Or a wet kit? I can get a dry kit for cheap and would i put this in front or after the MAF?. i think im ordering the wet plate kit from NOS for it. Now when i run the 150 shot, should my fuel system be enough for it or do i need to run bigger injectors / fuel pump / colder plugs? Or my buddy has a dry Cold Fussion kit on his '02 ta that hes gonna sell for $300. Should i save the $100 and get his kit or spend the extra $100 and get the wet plate for it?? Thats for the info.. And what u think ill run with a 150 shot. Stock block and heads 350. Lingenfelter cam (500 lift about), ported plenum, SLP runners, hogged out Accel base, AFPR, Accel ingnition coil, headers w/ true duels, th350 w/ 2500 stall, 3.23 gears, underdrive pullies, no AC or emmisions anything?? what you guys think.

 

I'd go wet. Always. But that's just my opinion.
The stock fuel pump should be able to hold up to the 150, if it's working well. If not a walbro 255 intake is plenty. Retard the timing 2* for every 50hp. That's the very safe rule of thumb. One step colder on the plugs and make sure you don't spray under 3000rpms.

I don't think bigger injectors are required on a dry kit, but I don't like spiking the inj. that much anyway. You shouldn't have to modify anything in the computer on either kit.

AS far as what you will run, that's up to you. What do you run now? Take it to the track and find out.

 

2* retard, is that from stock timing (8* i think). Now i got it set to about 9-10*. So does that mean i cant spray out of the hole!?!?! lol. Why dont spray under 3000rpm?? So ill get a rpm switch and not spray it till 3000 until ?? 5500 rpm?? I was a N/A motor guy but im switching to the botle (cant beat the money to hp gain) so any words of advise is MUCH apprecated!!

 

BTW - welcome to the site, enjoy you stay.

Stock timing is 6* BTDC, but since you run 9-10 without detonation, then the -2* for every 50hp would be subtracted from 10 since that's what you're running.

For example, you run 10 w/o pinging, you spray 100hp (=4*) so your initial timing will be 6 instead of 10. Follow?

3000rpm - you can spray at less rpms, but it's not recommended. N2O has a constant flow from the bottle. So in 1 sec your getting x amount of n2o. Now, the motor is turning a lot slower at 2000rpms than 5000rpms. This means that the cylinder fills up w/ a lot more n2o at lower rpms than higher. Generating a lot more cylinder pressure and sometimes causing preignition, or blown head gaskets.

Plugs - don't use platinum plugs, ever. I would also suggest gapping the plug at 0.035 instead of .055 ~stock. By tightening up the gap it makes it easier for the plug to fire. Eliminating a misfire. Misfires are bad when spraying b/c the cylinder is filled w/ air, fuel, n2o and then nothing to burn it. On the next revolution of the motor some of that mixture is still in the hole, plus the additional mix of that revolution. Almost like doubling up the shot in that cylinder. When the plug fires that time, the a/f mix could be funky or the plug might just get washed out and not fire again, or it could just pop. In any case, it's not good.

 

Listen to his advice, ive seen a few motors, that the owners didnt listen to those simple suggestions, and they didnt just push out a head gasket, they had a new paperweight, and where shopping for a whole new longblock.

 

Timing and N2O are pretty much irrelevant, at lest in normal ranges. A 100, 150 or 200hp shot of N2O will not make an engine any more likely to detonate/ping, for example, NX doesn’t recommend any retard with their N2O kits.

The reason that some do recommend timing retard is exactly that, because timing is largely irrelevant when spraying. In most cases you can retard the timing 5* and you won’t see any measurable, repeatable difference in power. The reason to do it is if you are getting detonation, the initial pressure spike and BMEP is much bigger with spray then NA, and if you are getting detonation you’re MUCH more likely to break something (just about guaranteed).

So if you’re not getting detonation NA then you don’t really need to retard the timing with spray, and even if you are getting a little, the overly rich mixtures that most N2O companies jet for (around 6:1) will take care of minor issues.

The reason to retard is because it’s safer and won’t matter at the end of the track.

Not exactly (what you wrote is not exactly wrong, but it isn’t 100% answer what is happening either). HP is proportionate to the amount (rate) of air/fuel you can properly mix and get into the cylinder and burned. N2O just adds extra O2 so you can burn more fuel and make more power. All you’re doing is opening and closing a valve and forcing the N2O and fuel through a set size orifice (jet) at a set pressure, so it doesn’t make a difference, a 100hp hit of N2O is a 100hp hit at both 1500 and 6000rpm.

The reason why this matters is simple. Torque is what we can measure, HP is just a calculated value that represents how much work we can actually do with whatever is making the power:
HP = Torque * RPM / 5252
Or rewritten in a more useful format for us:
Torque = HP * 5252 / rpm

So that 100 hp increase at 6000rpm = 87 lb-ft increase
That 100 hp at 1500rpm = 350 lb-ft

Anyone want to guess what happens when you suddenly pound the bottom end of the motor that is barely spinning with 350 lb-ft more torque?

I’ll give you a hint, it involves carrying your engine home in a bucket.

naw, won’t happen… a misfire will just result in the N2O, air and fuel getting dumped out into the exhaust, where it will probably backfire but usually won’t do major damage.

Smaller gaps do typically prevent misfires, but you have to be careful there. Smaller gaps run hotter, so they are more likely to cause detonation. Also, when it comes down to it you’re using the voltage of the spark to fire the charge. The smaller the gap the lower the voltage the spark has. Surprisingly, some of the newer ignition boxes don’t like that and you could end up with a funky misfire from too small a gap. EX, crane swears that you need to start with a .045” gap with their high 6 boxes, even with power adders, bigger NA, and only cut down the gap if you’re having problems. You could also end up with a misfire from just too small a spark to start a proper flame kernel (though I’m not sure that that isn’t more theory then anything else, I’ve never seen that in a practical situation)