90 vs 115

[Realgun]

Dang it JB I wanted to answer this.<br /><br />Basically from what I can tell you will gain a bit of MPH due to the turn of a biger pitch prop.<br /><br />I have an 85 now and if I was to get a 115 I can gain pitch in prop size from a 15 to a 19. Same Diameter.<br /><br />Theoretically I can go 35 actual is 32 and thats about right as I get a 9% prop slip @WOT 5000 RPM.<br /><br />Real prop HP is actually about 65 here due to altutude and Force is a weak motor and HP is not measured at prop like it should have been. <br />In calculation the Speed with a 90 is 35 actual and 39 theoretical.<br />If I was able to get a 19 pitch prop to turn 5000 rpm I cam get to 43 mph Thoeretical is 47 mph.<br /><br />BTW this is @ 5000 Ft altitude for my speeds.<br /><br />A Verado is actually pretty interseting, you can take all the test boats to a very high lake and the Verado powered boat will run circles around the other boats. The Verado will not lose power due to altitude. To bad they don't make them in a 90-115 HP.

 

[LubeDude]

Re: 90 vs 115

I dont know what this is all about, but theory or what ever, a 15 HP difference isnt going to in real life get you almost a 10 MPH difference.<br /><br />Nope, not going to happen, not if both engines are set up correctly on the boat in question.<br /><br />JMHO.

 

[Ron G]

Re: 90 vs 115

I would think about 2-5 mph faster.But i would think it would get better gas milage.justmy 2c

 

[Realgun]

Re: 90 vs 115

Lube I ran off before I could finish the post the kids had to get to school read it again it might make more sense!<br />Actually it will make a ten mph differemce. thats why my father put the 65 out to pasture three weeks after buying the boat for an 85. Then as it was not fast enoguh on went the 115. Then to really make thing interesting it was a 135! These engines were all Mercs from 1977-1979. The dealer loved my Dad. <br /><br />I can tell you ther is a noticable difference by adding 20 Hp at a time. When the 115 was on the Boat my Brother though were were James Bond! <br />This was on a 17 Ft Mark Twain Trihull about the heaviest boat you could buy! The 135 was way too fast! Even the jet boats were afraid!<br /><br />I remeber the props, they started at 11 pitch and went to 25 at the top end.<br /><br />Oh Lube<br />115<br />-90<br />=25 JFYI

 

[JB]

Re: 90 vs 115

What part of (not engine topics) did you guys miss?<br /><br />Any reason you can't discuss this in the appropriate forum?