Mercruiser HP difference 5.0L MPI vs 5.7 L Carb

[delmarjr]

Why does a 5.0L MPI engine have 260 hp vs a 5.7L carburated engine has only 250 hp, and the 5.0L carb has only 220 hp and all three are rated hp at the prop? I thought there was no replacement for displacement. Does the 5.0L engine still use less fuel than the 5.7L engine? Is MPI superior in hp and efficiency? What are the pros and cons for each engine setup? Thanks.

 

[delmarjr]

Re: Mercruiser HP difference 5.0L MPI vs 5.7 L Carb

Also what about the 350 magnum MPI with 300hp? Is the 5.0L MPI really a 305 Magnum?

 

[John_S]

Re: Mercruiser HP difference 5.0L MPI vs 5.7 L Carb

The carb models use low-profile intakes with 2brl carbs. That limits the hp over the MPI. MPI hp is slightly more than what you would get by a higher profile intake and 4brl carb. There are maintainability and driveability benefits with MPI.

Depending on the boat/hull, the 5.7L carb may plane out quicker that the 5.0MPI. Launching and getting on plane, is where the displacement make the most difference. In top-speed the 5.0MPI would have the edge, but it would only be about 1-2mph.

 

[QC]

Re: Mercruiser HP difference 5.0L MPI vs 5.7 L Carb

Agree with John S. The other factor is marketing. You can charge more for 260 bhp than a 250 bhp and even more for MPI. You can charge even more still for a 300 combined with 5.7 Liters and MPI, so they make that even more attractive by keeping the 260 down in displacement. The Magnum thig is marketing too, and it might make some sense for them to call the 260 a 305 Mag and then they could charge maybe even more for that. . . Yeehaw.

 

[delmarjr]

Re: Mercruiser HP difference 5.0L MPI vs 5.7 L Carb

Are you saying that the 5.7L carb model has more torque and less hp than the 5.0L MPI? I have a 19 foot Stingray sporty cuddy cabin and you're saying it is probably a little slower getting on plane but probably has a 1-2mph greater top speed with the 5.0L MPI vs a 5.7L 4 bbl carb?

 

[John_S]

Re: Mercruiser HP difference 5.0L MPI vs 5.7 L Carb

Are you saying that the 5.7L carb model has more torque and less hp than the 5.0L MPI? I have a 19 foot Stingray sporty cuddy cabin and you're saying it is probably a little slower getting on plane but probably has a 1-2mph greater top speed with the 5.0L MPI vs a 5.7L 4 bbl carb?

The 5.7L will have more torque at lower rpms than the 5.0MPI.

The 5.7L is a 2brl carb, and yes the MPI would only be 1-2 mph faster (at most) with its 10hp advantage.

A 5.7L which has had an intake and 4brl carb upgrade done, would have 280hp at prop. It would out pull the 5.0L MPI and have higher wot speed.

and 350MPI will trump all the above.

 

[Bondo]

Re: Mercruiser HP difference 5.0L MPI vs 5.7 L Carb

Agree with John S. The other factor is marketing.

Ayuh,.....

I Agree completely with Both of you,.....

John's got the Mechanics of it,....
And,...
QC states the Reasons......