SoCal Jet Boats
Tech Talk => Jet Pumps => Topic started by: Ckaz21 on January 28, 2014, 03:29:31 PM
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I'm wondering is there is a way to roughly calculate your top speed? Last summer my stock 330hp 454 turned my A impeller 4,200 rpms at 54 mph. If I divided 54 by 42 I get 1.30. Now if I multiple that by 55 (estimating that my new engine will turn it 5,500) I get 72 or 72mph. Does this make sense? Or is there a better way to estimate top speed?
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Close enough.
Without getting into all the other factors like, pump condition, bottom of the boat, weight.....
Though I would say closer to 78 with an A impeller at 5,500 rpm.
That's just me though
-beerjet-
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I'm wondering is there is a way to roughly calculate your top speed? Last summer my stock 330hp 454 turned my A impeller 4,200 rpms at 54 mph. If I divided 54 by 42 I get 1.30. Now if I multiple that by 55 (estimating that my new engine will turn it 5,500) I get 72 or 72mph. Does this make sense? Or is there a better way to estimate top speed?
There is literally no multiplier on the planet to figure out the theoretical speed gains.
It is easier to calculate how much money it takes to make them faster.
I use "all of it" as that number.
There are, as beerjet states, hundreds of variables.
When just moving weight around in the boat changes speed either plus or minus, it a big time moving target.
I was told years ago that when you exceed 50 miles an hour, it took 100 HP for the next 10 miles an hour and 200 for the next 10 and so on. If you think about it, it almost works....
GT
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