Why do i need a larger fuel pump for nos?

OrangeMustangGt

Founding Member
Mar 7, 2002
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Cape Cod, MA
what will happen because the regulator will keep teh fuel at the same psi, so what would the larger pump serve? Also, if i get a fuel pump as some people say, would i then be able to run the 125 shot with the zex kit or is that too much for stock motor. Also, what rpm is it safe to hit the nitrous at? i dont wanna blow anything, thanks!~
 
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GreenMustangGt said:
what will happen because the regulator will keep teh fuel at the same psi, so what would the larger pump serve? Also, if i get a fuel pump as some people say, would i then be able to run the 125 shot with the zex kit or is that too much for stock motor. Also, what rpm is it safe to hit the nitrous at? i dont wanna blow anything, thanks!~

Well most nitrous systems are designed for all other stock components on your car. I wouldn't recommend shooting over 100 hp shot, I don't care what fuel additions you put on it. I have 99K on my motor. I sprayed 100 hp shot for about a year and then the next year I bumped it to 125 hp shot. NX efi stage one kit. 6 months later my motor was being torn down. The number 3 piston was starting to get chewed up on the top and I blew a head gasket. Never had any problems from the 100 hp shot. Also the rods shown wear on the up and down areas where it was under quite a lot of stress. Now I'm rebuilding the motor and going with a supercharger. Also add fuel additives when ever you get a chance, to bump up the octane. Detonation is your enemy. Just throughing in my .02 and my experience. :nice:

I know a lot of people that will tell you that you can run 125 and 150 all day long. I'm going to disagree. You can run it every now and then, but don't do it very often. :)
 
Detonation is usually cause by a lean condition, or not enough fuel.

The regulator is vacuum controlled. WOT causes the regulator to pump up the psi to provide the proper amount of fuel to the injectors.

The Nitrous kit intervenes with this vacuum control, and when the nitrous is sprayed, it tells the regulator to pump at a much higher pressure to the injectors than the stock system ever did. This extra fuel is what gives the engine its power increase when you spray nitrous.

The stock pump is not designed for this kind of pressure since without nitrous, it never needed to pump at such a high pressure (and thus flow).

I'm sure there is a more accurate explanation, but this is the general idea.
 
when you hit the nitrous. it needs more fuel. the nitrous alone is nothing without being mixed with fuel. otherwise it will go WAY lean and couse too much heat. the larger fuel pump is needed to supply the fuel. this is true on wet or dry systems.
 
yes, "WAY lean" might be an understatement, haha. I'm with you Black70Fastback.

Nitrous = N2O, as in 2 Nitrogen and 1 Oxygen molecule. Alone, Nitrous is NON-flammable. With that Oxygen molecule, you are effectively adding a ton more burnable oxygen to the Air/Fuel Mixture.

To balance the A/F ratio back down to proper levels, more fuel is needed.

What time is it? I need to go to a bar. Head hurts.
 
ok, cool, is there any brand that you reccomend? cause ive found some 255's for say 100 and some for up to 200, just wondering what brands u reccomend, and, lol of course i plan future mods, thats what mustangs are for !