FASS DDRP lift pump and aftermarket injectors
 

Whats the largest injectors I could use if I have the aftermarket FAA DDRP lift pump without starving the pump? I'm planning to add 4" exhaust and the Edge juice programmer.

My first post, lots of good info here....thanks

What are your fuel pressures currently? Idle, Cruising, and WOT? You don't want to go below 10psi in any of those situations. I'm pretty sure you can get away with 100HP's with a DDRP.

17-20 psi idle. 16-18 running and never lower than 14 WOT even when the filter is getting dirty. So if I wanted more than 100hp, I should upgrade the pump is what your telling me?

Can I assume if the injectors are asking for more fuel than the pump can supply, I'll see the dramatic drop in fuel pressure?

I appreciate the help

Yep, if you inject more fuel, more fuel needs to be supplied. Pressure is a measure of the resistance to flow. Less resistance, same flow, less pressure.

I'm betting you could get away with 150's, maybe more.

With a DDRP I wouldnt go much over 40hp injectors with a juice with attitude. And speaking from experience I would be very careful at that. The DDRP is like a 70gph pump so bigger injectors and tuning isnt friendly to what that pump can flow. Not saying that it wont work but be careful if you try it

I just installed a ddrp on my 99 and when i started the truck it only had 6psi on idle. contacted fass and the told me to take the pump plate off and stretch the spring. Has any one else had to do this. It made a difference and the told me they would send me a new spring and ball.