Fuel injection option for Vortec

[QBhoy]

Just going by the figures produced. As mentioned, a 350 carb in its most powerful standard form is 260hp. The mpi is 300hp.
The efi is a different thing.

 

[QBhoy]

The AQ311 is a different beast. Crank, pistons and cam shafts are all different at least. Higher rpm band too over the standard aq271 350 and merc 5.7 350.

 

[H20Rat]

Just going by the figures produced. As mentioned, a 350 carb in its most powerful standard form is 260hp. The mpi is 300hp.
The efi is a different thing.

Just because I'm not overly familiar with mercury terminology, what is the system mercury calls EFI? I'm assuming it is single point/throttle body injection? Usually that would be called TBI, but I could see them throwing the generic EFI term on it since they all are technically EFI.

Also something to throw out, a good multipoint EFI will make better power in the right hands because of atomization. Liquid gasoline is bad, you need to break it into a mist, and EFI is far better at doing that than a carb. (more efficient fuel burn) Better atomization also means better cooling from the phase change, which means more power.

 

[thumpar]

Just because I'm not overly familiar with mercury terminology, what is the system mercury calls EFI? I'm assuming it is single point/throttle body injection? Usually that would be called TBI, but I could see them throwing the generic EFI term on it since they all are technically EFI.

Also something to throw out, a good multipoint EFI will make better power in the right hands because of atomization. Liquid gasoline is bad, you need to break it into a mist, and EFI is far better at doing that than a carb. (more efficient fuel burn) Better atomization also means better cooling from the phase change, which means more power.

Merc does use EFI for their TBI engines. It is a basic marine version of the GM system used on many vehicles in the 90’s.

 

[QBhoy]

Just because I'm not overly familiar with mercury terminology, what is the system mercury calls EFI? I'm assuming it is single point/throttle body injection? Usually that would be called TBI, but I could see them throwing the generic EFI term on it since they all are technically EFI.

Also something to throw out, a good multipoint EFI will make better power in the right hands because of atomization. Liquid gasoline is bad, you need to break it into a mist, and EFI is far better at doing that than a carb. (more efficient fuel burn) Better atomization also means better cooling from the phase change, which means more power.

Hi

you’re spot on. The efi is a single point throttle body injection and inlet manifold.
The mpi is a common fuel rail and individual injector to each cylinder.

 

[Scott Danforth]

TBI is Throttle Body Injection. A specific version of EFI - Electronic Fuel Injection. TBI is a glorified electric carburetor.

MPI is Multi-Point Injection and is a specific version of EFI and there are about 6 types of MPI that GM used over the years. This includes the infamous "fuel spider" version.... (dont get me started on the stupidity of pressurized plastic bits carrying fuel within an intake manifold)

we can all arm-chair this to death, however no one has convinced me that EFI in any form makes more power with a specific combustion mix. does it take care of drivability issues in differing climates, yes. however it wont make more power with a specific combustion mix ( given bore, stroke, compression ratio, piston style, cam/valve profile, spark curve and intake plenum volume).