fuel pressure

[2fast4u2]

i would like to know how to find out wide open throttle fuel pressure? I need it for jet sizes for a wet 100 shot. can i just use a tire gauge and have a friend rev it up? I need to find the cheapest possible way and be accurate.

Thanks,
Andrew

 

[Don 95Vert]

What year car?

 

[2fast4u2]

2001 mustang gt 5 speed cold air intake and cat back

 

[Dope 97GT]

you can get the fitting that goes into the schrader valve on the fuel rail and get a cheap mechanical fuel pressure gauge that mounts on the top of the fuel rail for a total of like $30. I would suggest that especially if you run nitrous you want to be able to see what the fuel pressure is always

this is where mine is with the aarow

View attachment 403383

 

[Dope 97GT]

this is the part you need for the valve on the fuel rail part number i believe is 3280 i know it says that its for the electrical but i think i used it for the mechanical one.

http://www.autometer.com/cat_accessorieslist.aspx?pid=10

then find an autometer mechanical fuel pressure gauge with the water in it so its accurate with vibration and you should be good.

 

[LaserRed01GT]

The best was is to take a mechanical gauge and tape it to your windshield and go for a ride. You can also datalog your WOT fuel pressure. Sometimes the datalogs monitor the fuel pressure in KPA. Just mulitiply the KPA by 0.145 to get PSI.

My fuel presure at WOT without the N20 was right around 49-50 PSI. So at first I used the calculator and using 50 PSI, 1000 PSI bottle pressure, and a 57 N20 jet, the calculator suggested a 32 fuel jet. I tried a 32 fuel jet and it worked OK, but I noticed for some odd reason bank 1 was going a tad richer than bank 2. I tried a 31 fuel jet and made 17 RWHP more and I could feel the difference in the hit, and it balanced out the a/f on both sides.

The calculator should get your real close, but it wouldn't hurt to experiment a little with the fuel jets.

What size N20 jet do you plan on using? What brand kit will you be using?

 

['01 Steed]

Are you pulling fuel off the rail, or before it? The rail pressure wants to be 39.2 psi in stock form, and the computer will correct for this as demand increases and decreases. I believe you can bump that up in the tune.

 

[Stan Weiss]

First be save not sorry. Also start out rich and work down and not lean and work up. Do not know how it is done on EFI cars, but on stand cars fuel pressure is checked using a flow jet. If you are only using one fuel jet than that would be the size of the flow jet if you are using more than one fuel jet than you need to calculate the flow jet size. Also will you be using the N2O for the full run or have it come in during the run. I have seen when the solenoids open and the electrical system is not up to it a drop in fuel pressure which will cause a lean condition.