Re: Real world difference between Mercruiser 5.7 and 5.7 MPI
Hi, Im looking to buy a 21 foot bowrider family ski boat. Ive found a well priced centremount with the 270HP carburetor 5.7 Mercruiser motor. I know the MPI version is normally around 315HP. Has anyone had any experience with both versions? Does the extra HP make a big difference in the real world or is it only at the very topend? Is there a big difference between the two in fuel economy and reliabilty? I imagine the carby would be alot cheaper to fix if any problems occur. Is it worth spending extra to buy the MPI version for family sking / tubing and the odd barefoot?
Cheers.
It sounds like you are comparing crankshaft hp not at the prop. Need to know what year/serial numbers. Big difference between a 5.7 4brl (standard head) (250hp@prop) and a current 350 MAG MPI (vortec heads) (300hp@prop).
In general, the MPI will require less repairs, but will probably have to take to shop when it does. MPI will be more fuel efficient, and in the case of the two motors I stated, 50hp is a noticeable differance that will get a 3-7 mph at top speed, depending on hull.
PS:OK I see you are talking about MIE engines not MCM. Your hp are probably correct, and that type boat probably would tend to be on the lower side of the speed improvement.
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