Is it necessary to add a fuel return and pressure regulator? I have a 600rwhp+ goal. I'm looking at the siemens deka 80lb injectors and the on3 twin 320lph fuel pump assembly. Truck as a '06 4.8
Thank you

 

You are at that threshold that you probably want to do a return-style fuel system, or spend a bunch of money on huge injectors.

 

What he said.

I ran the returnless system on my 2006 and went as fast as 11.00's around 120 mph (which was probably around 650 horsepower), but it was on the ragged edge fuel supply wise. I was running a meth kit mainly for the additional fuel needed.

It is a worthwhile upgrade and one that could help keep your motor alive.

 

I'm nowhere near that level yet but I went to return style anyway just to be safe. Plus it's already good to go for when summer rolls back around and I can start turning up the pressure without worrying about fuel starvation

 

I forgot to mention in the above post, the best my truck ever ran with the factory returnless system was 11.00's around 120 mph @ 4710 lbs. The setup was an intank 255 lph Walbro, factory lines split at the firewall to dual -6 AN lines to feed each rail. The front of the rails where connected to each other with the same -6 AN line. Injectors were 60 lbs/hr (rated at 43.5 psi). I had an Alkycontrol meth kit and used 100% VP fuel M1 methanol in the tank and had the kit turned up as high as it would go. HPTuners was showing IDC''s around 135% (which obviously isn't physically possible), which shows me that it was on the ragged edge. Also, if I remember right, the factory regulated 58 psi of fuel press was dropping drastically to around 40 psi during a full pass.

Just some fyi tech for the returnless guys out there.

 

What is the advantage of having the return style setup as opposed to returnless? Why do you need bigger injectors with a returnless system. I have an 01 so I know I have the return style for future plans.

 

The style of return isnt so much important but generally return style systems have the regulator near the engine and manifold pressured referenced and usually returnless systems have the regulator in the tank with no manifold referenced. The manifold reference is the important part. It allows fuel pressure to increase with boost. Without a referenced your injectors effectively gets smaller because there is less of a pressure differential across the injector (rail pressure on top stays the same but pressure on the tip of the injector goes up). To compensate for this, you need larger injectors.

 

Yeah, what he said.

It could also help if you are having issues with fuel temps/vapor lock.

 

Ah ok that makes sense. Thank you for explaining it. That'll help to know when I build a 370 for a blower.