Jetting effect on Fuel Pressure

Lets say the difference in FP between a 72 and going to a 52 I would think it would raise 1-1.5lb based off 0f 7.5lb is this in the ballpark.

Give a lot more information about the system and setup and I'll try and help.

whatbumper wrote:Give a lot more information about the system and setup and I'll try and help.

Just re-did the fuel system due to occasional prime issues so now the pump is on the down low. Step down box is used to make a non sreetable pump streetable 5-3/4lbs NA street duty, 7.5Lbs set on kill feeds both systems with a return, and a bypass. 2- stage X-plate with trash cans, thinking first stage 64N-52F wondering if I should lower the bypass 1-1.5 lbs or run it with 5-3/4 and leave the 7.5lbs for the second stage. SB Cleveland 260/550/108 ish 3500/4.11/10.5 ladderbar car street/strip.

FalconEh wrote:

whatbumper wrote:Give a lot more information about the system and setup and I'll try and help.

Just re-did the fuel system due to occasional prime issues so now the pump is on the down low. Step down box is used to make a non sreetable pump streetable 5-3/4lbs NA street duty, 7.5Lbs set on kill feeds both systems with a return, and a bypass. 2- stage X-plate with trash cans, thinking first stage 64N-52F wondering if I should lower the bypass 1-1.5 lbs or run it with 5-3/4 and leave the 7.5lbs for the second stage. SB Cleveland 260/550/108 ish 3500/4.11/10.5 ladderbar car street/strip.

Left out that Ideally I want to run the pump on kill and am looking for a better number for the fuel pressure 6-6.5 for both stages and jet the fuel side accordingly to compensate, the numbers are examples but this engine will not handle bigger Nos levels with the current configuration and I do not have enough data on the change to comfortably hit it with say 375 ring gaps are too tight for more that will be maximum.

Based on what the tune is you have posted it is a rich tune even at the lower pressure. raising the pressure is only going to make worse.. If you would like good clean tunes at the higher pressure it may be best to have the system flowed for the proper info.. SJ

Thanks Steve,
I do not want the higher pressures they were the spec'd ones I want 6-6.5 with the pump at full boogie and bypass the rest, jetting the fuel down too to get closer the manufacturers tunes were junk but the setup changed and I want a smaller tune, I might just use one stage 250-350.

I got ya. Sounds like a plan. If you have any further troubles please let us know if we can help you out.. Thanks, SJ

Dropped the FP to 6.25 changed the jets to 57-49 and pulled 8* I will give i a try and see how close it is, sounds clean from 3500 on a blip.