What FP with wet n2o kit?

[Marlboro_Man]

So what should i set my fuel pressure to? It is a "WET" kit. I have read anywhere from 40 to 50 psi but that was not mustang specific. If it helps I will be starting with a 50 shot and then working my way up to a 100 shot.

I have everything hooked up except a msd window switch, FP safety switch, micro switch, and relay. Once I have these things I will be ready to spray.

I was wanting to do some testing so I hooked up a button to the fuel sylenoid and then turned the fuel pressure to 48 psi vacuum line off. I took it for a drive and hit the button at 3k rpm's @ WOT to simulate spraying. I watched my fp gauge. It instantly dropped to like 30 psi for only a split second and then it went right up to 48 and stayed there. Is this normal for it to drop for less than 1 second and then jump back to where it should be?


I posted this in the "power adders" forum as well but since there isn't very much traffic in there i thought i would post it here as well.

:SNSign:

 

[N8Miller]

I cant comment on the slight drop in FP, but mine went right up when i had it. as for your fuel pump, a 190 or 255 will do the trick!

 

[Marlboro_Man]

I cant comment on the slight drop in FP, but mine went right up when i had it. as for your fuel pump, a 190 or 255 will do the trick!

It already has a 255 in it. I was asking what should i set the Fuel Pressure at?

 

[N8Miller]

It already has a 255 in it. I was asking what should i set the Fuel Pressure at?

my bad, i read it wrong. you should just be running your normal FP for when your not on the bottle, but when you hit the button, it should nearly double.

 

[Rick 91GT]

Set it for what ever the kit tells you to, the jets are sized based on the FP and different brands use different pressures.

 

[Marlboro_Man]

my bad, i read it wrong. you should just be running your normal FP for when your not on the bottle, but when you hit the button, it should nearly double.

So i should run it at 40 psi (WOT) like normal and when i hit the button your saying it should jump to 70-80 psi? Hows that?

 

[Marlboro_Man]

Set it for what ever the kit tells you to, the jets are sized based on the FP and different brands use different pressures.

Well there wasn't any instuctions with the kit because it was second hand.

However on the coldfusion website their jet calculator lets you choose what fuel pressure you want to run and it will tell you what size fuel jet to use. It does say that "most efi systems use 38-45 psi" .

 

[N8Miller]

So i should run it at 40 psi (WOT) like normal and when i hit the button your saying it should jump to 70-80 psi? Hows that?

from what i understand, yes.

 

[Marlboro_Man]

from what i understand, yes.

I'm not knocking what your saying (typing lol) and i really apreciate the help. However i have never heard of this and it doesn't seem to make sense to me how the fuel pressure would rise above what the fuel pressure regulator is set at. Can you explain? or can anyone else confirm this?

 

[Marlboro_Man]

ttt

 

[Marlboro_Man]

ttt

 

[Marlboro_Man]

ttt

 

[Curse]

I believe N8Miller is thinking about a dry kit, which uses some nitrous to increase fuel pressure in order to get the proper mixture.

Rick gave you your answer. I would call customer service and see what they say. Your fuel pressure will determine what fuel jets to use. My kit had different jets for different pressures. At 40 psi for a 75 shot my fuel jet size would be 24, at 50 psi the fuel jet would be 22. Your kit might be different. Good luck.

 

[352Ford2]

only dry kits kick up your fuel pressure, what is the make and modle of your kit? you can get jet cards on the compnays website usaly. One thing to note, most online jet calcs are usaly not optimiesed for the higher fuel pressures of FI.

this one is pretty good:

http://www.phasechangeracing.com/nitrous/N2OCalc.N2OCalc.html

Keep in mind NOS is well known for having very conservitive tunes.
it is usaly a good idea to flow them, if you are woried about it.