Quote:
Originally Posted by pair of jacks
. . . Like I said, boat just feels a little slugish unless you are at fairly high rpms. I tried to save some $ by going with 175 and since the year after I bought my boat SeaCraft starting selling the 21 with 150's on them as standard I expected the 175 to be fine. Always thought the 200 was more than I needed but it was probably the right fit. Like I said, overall very satisfied with engine but would be totally satisfied with a little more power.
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Sounds like what you really want is a little more mid-range torque for that relatively heavy 21, and that's why I recommended the big block 3.3L E-Tec, in either the 200 or 225 hp version, instead of the 2.6L motor. When any motor is tuned for max horsepower, the required port geometry (or cam on a 4-stroke) is generally different than it would be if the motor was tuned to maximize mid-range torque. I suspect the 200 hp version of the 2.6L small block motor is tuned for top end HP, so it might actually have a little less mid-range than the 175. Some very knowledgeable techs on the E-Tec owners forum have said that on the V-4 version of the 60 degree power head, the 115 hp motor actually has more mid-range torque than the 130 hp version of the same basic power head.
Gillie, that's a great comparison. I was frankly surprised to see the E-Tec beat the Zuke on MPG, but as you pointed out, the extra displacement of the Zuke probably doesn't help it's fuel consumption. I would suggest that there are a couple of other items that should be considered in that particular comparison:
The quoted weights are dry weights, which means no props or oil in the motor. Since the Zuke crankcase holds 8.5 qts of oil, that's another 15 lbs, so it's true weight for comparison to the E-Tec is 500 lbs! The 524 lb 3.3L motor is therefore a much closer match to the Zuke than 2.6L version in terms of weight! I would think the 21 could easily carry a 500 lb motor with it's 8' beam.
The fuel consumption of the 3.3L 200/225 HP E-Tec is probably closer to the Zuke, but one other difference on the E-Tec's is fairly significant . . . they run an extremely lean stratified charge mixture below about 1500-1800 rpm, so the fuel burn is less than any 4-stroke motor at low speed. BRP says the engine time-at-RPM data stored in the E-Tec computers show that most motors spend about 60% of total run time at low speed, and that's definitely true on my own motor. This means that even if their cruise fuel mileage is less than a comparable 4-stroke motor, the overall total fuel consumption is actually very close because of the significant differences in low speed fuel burn. Denny