ram jet 350 fuel system questions

[bsgreen]

I just bought a ram jet 350 for my truck and was trying to figure out the best setup for fuel lines, pumps, tanks ect. Does anyone know if you can run dual tanks with this motor? would I be better off with an inline or in tank pump?

 

[RootBreaker]

well i dont know anything about fuel injection... that aside.. i feel...
if you have an external fuel pump.. you should be able to run dual tanks...
i have dual tanks and would go 1 if need be.. dont remember last time i filled both with current gas prices!!!!!!!!!

 

[eagle mark]

If you run dual tanks you need dual returns and a dual switch that came in 1987 up trucks with dual tanks. Lots of plumbing...

If the truck it's going in is same as donor truck it'll all fit. But for RamJet you'll have to change out fuel pumps in each tank from TBI pumps to TPI pumps.

 

[bsgreen]

thanks the info! I guess I'll be looking through an LMC catalog for all of the parts out of an 87 shortbed. I know I'm gonna have to upgrade the rubber hose to handle 45 psi, but do I need to worry about the hard lines? Will the sending unit and pump from an 87 drop into an 85 tank?

 

[eagle mark]

No but you can get a 1987 tank sender fuel lines to and from TBI then just fit them to the MPFI feed and return. Still need TPI in tank pump in place of TBI intank pump.

 

[bsgreen]

Guess I'm gonna have to sell my MTS fuel tanks that I bought way to long ago to return. Thanks for the help Should get me going in the right direction.

 

[73k5blazer]

You'll be far better off with an in-tank pump. Many with this motor have expierenced dry spells with inline pumps and fry their pumps.
I put a ramjet 350 in my k5, I have an old-school hickey tank from the 70's, 40 gallon.
I installed this into it:

Check out post 78 here for more info
I had talked with several ramjet owners from other places, some in trucks, some in cars, all that tried the inline pump reported fuel starvation issues at some point.

 

[eagle mark]

There's a lot of cool in tank pumps to use, best one has a bucket on it for the slosh tank or baffles. Return line keeps the bucket full. They usually come from MPFI cars so plenty of fuel and pressure.

http://www.gearhead-efi.com/Fuel-Injection/showthread.php?354-EFI-Fuel-Pump-Upgrade

 

[Larry]

Bsgreen,

Definitely go with an in tank pump. I went through this as well on my ’78 with an 8.1L. I first started with a frame mounted WALBRO pump. What a noisy POS that constantly cavitated when warm. It just wasn’t a reliable pump situation I could live with as this truck goes all over the back country of the Southwest so I swapped on an ’87 TBI fuel tank, ’87 sending unit and an AC Delco EP241 (TPI) in tank pump. At that time the 8.1L was running a MEFI-4 ECM on speed density and low fuel pressure (43ish) like your RamJet has. I’ve since ditched the MEFI-4 ECM due to programming issues and moved to a P59 ECM running MAF like was intended for the 8.1L in a production vehicle. This also required a pump change due to the higher fuel pressure (63 psi) required for sequential EFI vs. the RamJet batch fire. Not sure if you are running dual fuel tanks or not but my point with this long story is I could not use the dual tank switch valve as the 5/16 return line that passes through it is too small and restrictive which caused the fuel pressure to run extremely high at the fuel rail even with the lower fuel pressure MEFI system. I even got a new Pollock dual tank switch valve thinking something was wrong with the original. Same deal, so I ended up mounting an electric diesel fuel transfer pump on the frame to move fuel from the RH tank to the LH tank. No lines are running through my dual tank switch valve but it is still connected electrically so I can read the fuel level in the storage tank. Kind of a PITA but it works and has worked well for the past 4 years.

 

[bsgreen]

Thanks for the info guys . I'm pretty sure I'm going to end up running the 87 tbi tank and lines with the in tank pump and put an inline pump between the passenger and driver tanks to move the fuel over when I need to.