what's EFI versus MPI ??

[squale]

Does anybody know what the difference here is and what is better and newer?

 

[arks]

Re: what's EFI versus MPI ??

EFI is "electronic fuel injection". With inboard boats, there are 2 types: throttlebody (TBI) and multiport, (MPI).<br /><br />The throttlebody is basically an injection unit placed on top of the intake manifold (similar to a carburator), while the multiport system actually injects atomized fuel directly into each combustion chamber. The MPI is much more expensive than the throttlebody, but they both work very well. I have a Mercruiser TBI.<br /><br />I'm no gearhead, so I'll leave any further description to others!

 

[squale]

Re: what's EFI versus MPI ??

what would you say is better? I am looking at the Mercury outboards. I see there is also a line called the Mariner outboards as well. What is the deal here? are they the same engines made by the same company? why two different names?<br /><br />and are the Optimax engines 4-stroke or 2-stroke? I thought they were 4-stroke but from reading more I can't tell..

 

[squale]

Re: what's EFI versus MPI ??

so arks.. you are saying that MPI is a form of EFI... so both of those types you explained are both forms of EFI right?

 

[arks]

Re: what's EFI versus MPI ??

Correct. I'm an I/O guy, but the "I" means Injection.

 

[ZmOz]

Re: what's EFI versus MPI ??

EFI = electronic fuel injection, a general term for any type of fuel injection. MPI is better and more fuel efficient, and TBI is cheaper. Both are much better than carbs.

 

[squale]

Re: what's EFI versus MPI ??

okay what do outboards have? and what is the best?<br /><br />also, how does this EFI differ in 2-stroke and 4-stroke?<br /><br />thanks

 

[JB]

Re: what's EFI versus MPI ??

Howdy NTBM.<br /><br />2 strokes have EFI, in which the fuel is injected into the air charge as it enters the crankcase, and DFI, where the fuel is injected directly into the cylinder. Both are computer controlled.<br /><br />EFI 4 stroke outboards use multi-point, computer controlled injection of fuel into the intake manifold, just like MPI cars and MPI I/Os.<br /><br />Technically, DFI is better for 2 strokes, but more expensive and heavier than EFI 2 strokes.<br /><br />EFI in 4 strokes is much superior to carburetion.

 

[squale]

Re: what's EFI versus MPI ??

what are the best MPI 4-stroke inboards and outboards?<br /><br />I need about 200 - 300hp to push a 25ft pontoon boat..

 

[roscoe]

Re: what's EFI versus MPI ??

I don't understand the need for sooo much hp on a pontoon. ??<br /><br />On a deck boat, maybe, but on a pontoon?<br />What am I missing?

 

[squale]

Re: what's EFI versus MPI ??

to waterski and stuff...