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-   -   Fuel system plan for conversion from carb to mpfi (https://www.offshoreonly.com/forums/general-q/367126-fuel-system-plan-conversion-carb-mpfi.html)

IHTFP 06-25-2020 10:40 AM

Fuel system plan for conversion from carb to mpfi
 
Hi,

This was posted in an earlier thread, but I am converting from carb to MPFI and have the following idea in my head for the fuel system. Please let me know your thoughts or criticism of the design. The mechanical pump is being used as a lift pump to avoid suction issues with the electric high pressure pump.

https://cimg1.ibsrv.net/gimg/www.off...ba03409f67.jpg

TomZ 06-25-2020 11:58 AM

I don't think you need the cooler. The loop back to the tank should keep it cool. And unless you have the tank really low, I do not think you would need the mechanical pump but that's me.

F-2 Speedy 06-25-2020 12:20 PM

typically fuel is cooled prier to going into the engine not on the back end, how much power are you trying to support in this application ?

Griff 06-25-2020 12:55 PM

I agree, should not need mech pump or cooler. Just mount elect pump low on a stringer.

IHTFP 06-25-2020 03:35 PM


Originally Posted by F-2 Speedy (Post 4745288)
typically fuel is cooled prier to going into the engine not on the back end, how much power are you trying to support in this application ?

The engine will be about 600HP. I know the Aeromotive is a little large for that power level ,but I really can’t find a USCG approved electric high pressure pump of a lower flow rate. I thought the fuel cooler would help keep the temp down from the excess fuel flow.

F-2 Speedy 06-25-2020 03:39 PM


Originally Posted by IHTFP (Post 4745317)
The engine will be about 600HP. I know the Aeromotive is a little large for that power level ,but I really can’t find a USCG approved electric high pressure pump of a lower flow rate. I thought the fuel cooler would help keep the temp down from the excess fuel flow.

Its good stuff made not far from me, Im running their stuff on my EFI Whipples..........you can return the excess fuel from the regulator to the filter head if you dont want to go all the way to the tank, this is how the Whipple kits are designed

AllDodge 06-25-2020 03:53 PM

Don't think the mechanical pump can supply all the fuel the Aeromotive will draw, it will turn into a restriction

Baja Rooster 06-25-2020 04:00 PM

Weldon pumps can lift as well as push and are USCG approved.

https://www.weldonracing.com/store/D...rine-p56797122

F-2 Speedy 06-25-2020 04:04 PM


Originally Posted by IHTFP (Post 4745273)
Hi,

This was posted in an earlier thread, but I am converting from carb to MPFI and have the following idea in my head for the fuel system. Please let me know your thoughts or criticism of the design. The mechanical pump is being used as a lift pump to avoid suction issues with the electric high pressure pump.

https://cimg1.ibsrv.net/gimg/www.off...ba03409f67.jpg

I see your fitting size is -6.....Id run -8 from the tank all the way through to support 600 hp and a -6 on the return side.........-6 is like 3/8 ID

AllDodge 06-25-2020 04:14 PM

I'm running Gen 2 cool fuel with 530HP (probably 500 at the prop) with stock Merc lines and return to tank


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