Merc 8.1 MPI

[Tommy]

My cousin is looking at a 36' Clorox bottle powered by 8.1 MPIs with less than 100 hours, and he has asked for my input. I don't want to get off on a discussion of the Chlorox bottle boat; rather, I would appreciate your thoughts or experiences with this particular engine (375 HP). I assume "MPI" stands for "multi-processor injection", but I could be wrong about that. The boat would be nothing more than a "Howdy Boat" (different strokes for different folks), and would be used as a recreational cruiser/over-nighter on inland waters and sounds. Thanks,

Tommy

[STraenkle]

Tommy

Those are the same engines I just put in except mine are the HO version at 425 HP. I think my engine came from a Sea Ray, they had 250 hours on them when I got them. The owner of the Sea Ray wanted diesels due to the MPG and speed the 496's got for him. All I have read about these engines (and did a lot) they are good motors with reasonable fuel consumption for a Gas engine. Now if he was getting a Bert 31 with them.....

Scott

[BCBertie]

Tommy-

MPI is multi-point injection as opposed to throttle-body injection. GM originally used a throttle body shaped like a carb that they sat on top of a 2-bbl manifold and called the result fuel injection. The rest of the world considers it fuel injection only when the fuel is injected and controlled per cylinder. Eventually, GM agreed and started selling MPI as if they had invented something new.

Cheers!

John

[Capt Dick Dean]

From all my (ahem!) experience, the 36' with these engines are powered better than most. Most older boats in that lenght have 327's and they are pigs.

But maybe that idea comes from the fact that the 31 Bertrams had the go-go power to make them go. And better than most.

[Rocky]

MPI is muti PORT injection. Sorry, had to clarify!

[scot]

MPI is muti PORT injection. Sorry, had to clarify!

Ditto my understanding of MPI.

[Tommy]

Thanks guys, and yes, I remember now the P in MPI. When I pulled a Merc page up on-line, it referred to the 8.1 MPI as a "multi-processor" engine, so that threw me off. Sounds like the engine is a decent gas marine unit. Now, if I could just get my cousin of the Chlorox bottle.....

[bob lico]

but if you really want the "real thing" by gm then you go with tune port injection " now you really have injection in each port like corvette.cost all of 100bucks in a swap meet then go to the good old boys at bama speed for the injection computor used with with stock gm sensors over 15 %more power then muti port injection ten times the response .thottle body in terms of tune port injection is junk!!!!AL. SPEED also sells the big block manifold to accept the 350cubic corvette tune port.

[BCBertie]

MPI is muti PORT injection. Sorry, had to clarify!

Nope, MPI in a GM motor is "Multi-Point Injection" and Tommy is referring to GM engines. To anyone else in the world, it would be multi-port, but not to GM.

Try wikipedia...

Cheers!

John