2 Fuel Pressure Regulators

[flatlineracing.ca]

Hi There,

We are setting up to run nitrous on our Pro Mod bike. We've recently relocated the tank from the backbone to underneath the rider. We have the proper seats in the carbs to run pressured fuel vs gravity feed for this type of setup. The fuel pump that we have is a Holley Blue. I need to run about 4.5 psi to the carbs, and 7 or so to the NOS. (Right?) Carbs are Lectron 48's with Power Jets, NOS system is a NX Express Pro Mod setup. I was planning on running two fuel pressure regulators - 1 for each pressure. My question is do I set up the regulators off a T after the pump, or in a series? (Assuming all my other assumptions are correct) I should also mention I was planning on using -6AN fittings and hose.

Thanks for your input.
-Blake

[Marion Ford]

Tee the regulators and put a small bypass on both

[flatlineracing.ca]

Would running a return line from the regulator back to the tank satisfy that? I have piece of fuel rail that has fittings feeding each carb, so i could easily mount the regulator on either side of it. Which side would be more consistent/accurate?
Thanks for the info. and input.

[Marion Ford]

before or after the carbs it wont matter. I am assuming you are talking about the old holley style dead head regulators. I have seen some be fine and others creep to the pump pressure. To avoid this and make things accurate, install a line with a restriction(.010 or so) back to the tank. You can use a nitrous jet with a 1/4 line. Just enough to relieve the dead head pressure but not enough to compromise the overall fuel flow needed when everything is on and full throttle.

[flatlineracing.ca]

Thanks for all your help. I appreciate it!

[tcjr]

dont think those lectrons will take 4.5 psi you may have to get a low pressure reg. I run two on my busa.

[Bikerphil]

I'd be interested in where you get the special seats and needles for the lectrons. I run mine off one of those small NOS pumps that come in the bike kits, they give 4.5psi very reliably but standard trons won't take it. I use a malpassi reg to drop it to 1.5psi and that keeps them from flooding.
I could loose the reg completely if i could get the parts.

Check the holley blue for consistent pressure, i got one with a view to using it, but it never made it past my test rig, i found it a complete pig to prime and it would give a different pressure every-time i switched it on.

[Marion Ford]

If you have the standard needle/seat and are using that 4.5 pump and also have NO other things on the fuel system then just run a common line to the carbs and a return with a restriction back to the tank(after you carbs). The restriction size will regulate the pressure to the carbs and keep a constant flow of fuel avalible. Used to do this with the lectrons with the ATAK chassis where the tank was in the bottom of the chassis.