nonojoe66

hey i just bought a nx wet kit for my 94 lt1 and i just checked my fuel pressure and it was reading between like 41 and 42 at wot and around the same at idle, this is all with the vacume line ON the fpr, is this good or should i look into a new pump?

Joe B

The ammount of fuel pressure you "need" for nitrous is completely dependent on the jet sizes your running........look in your book that the kit should have came with and see at what fuel pressure your jets and their advertised horsepower rating was figured at........or post your jet sizes............for example purposes only: if your jet sizes and their advertised horsepower rating was figured at 45LB's of fuel pressure....you (in your current situation) would either need to raise your fuel pressure to that area, OR slightly increase your nitrous kits fuel jet to a larger size to compansate for having less fuel pressure........and I can't tell from your post exactly how your checking your fuel pressure, but a very accurate way (if you diddn't already) is to hook up a manual gauge that you can see inside the car(even if you run it through the window and have a friend hold it), and make some full quarter mile passes to see exactly what the fuel pressure is doing under loads..........Joe

nonojoe66

well im not sure yet what jets to use, I havnt sprayed it yet i was just making sure that everythings good before i do, I have a NX shark nozzle so what jets do you think i should run with 41 psi for say a 50 shot to begin with? i think im just going to stick with a 50 shot till i get around to getting colder plugs. i checked it with a mechanical guage i stuck between the hood and cowl and taped to the windsheild lol

Joe B

Iv'e done the same thing in the past (taped the fuel gauge to the winshield ) when I had to: but nothing wrong with that since the info it gives you is way better than what many rely on by just pulling the vacuum line and having no idea whats happening under load in top gear ........Lowest I've ever went on nitrous HP with any engine was the 75 RWHP shot that I started out with on my current setup just for some initial testing and tuning and that was with a 40N/28F that NOS recomended with 43.5 PSI fuel pressure..... In my experience, this was a good safe (pretty rich) baseline jetting to start out with for any fuel pressure I used between 40-45PSI ..... for a 50 shot, Im sure some others with experience running that exact amount will chime in, rather than to strictly go off of one of the internet jet calculators which for me personally always came up WAY lean.......good luck with it...and get ready for the 50 shot to loose it's appeal in about a day, so get ready to jet up ......Joe