How much fasted should 75hp make it go?

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05-20-2005 | 04:02 PM
  #21  
Re: How much fasted should 75hp make it go?
Quote: Here's the link, sorry

http://www.go-fast.com/boat_speed_predictions.htm
That's incredible how accurate that is!!
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05-20-2005 | 04:04 PM
  #22  
Re: How much fasted should 75hp make it go?
Quote: Ron,
I totally agree. Even at this point 85 sounds good. I was readind an article in a Feb. issue of Powerboating mag. The article was on a Formula 380 Fastec hull, which formerly had 575's (not 525's) in it. It was rigged with the new 600 Merc's, and claimed a gain of between 4-6 mph. And that was with only 50 more hp. Does that sound right to you. I was going to bring the article home and scan it, then put it online here. Maybe Monday I'll do it.

Rick
Weren't the 525s outrunning the 575s?

Like I said, it depends on your starting point. If you have a 2500lb boat with 200 hp and you go to 275 hp you're gonna get a hell of a lot more than if you start with a 5000lb boat with 700 hp and go to 775 hp.
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05-20-2005 | 04:10 PM
  #23  
Re: How much fasted should 75hp make it go?
Quote: Ron,
I totally agree. Even at this point 85 sounds good. I was readind an article in a Feb. issue of Powerboating mag. The article was on a Formula 380 Fastec hull, which formerly had 575's (not 525's) in it. It was rigged with the new 600 Merc's, and claimed a gain of between 4-6 mph. And that was with only 50 more hp. Does that sound right to you. I was going to bring the article home and scan it, then put it online here. Maybe Monday I'll do it.

Rick
I rode on that fastek - no way it got 4-6 mph fsater. We only saw 78.X on GPS with 3 people and 1/2 tank of gas in Miami. It hit right about 5k rpm. Not impressive over the the 525s. I agree with the estimates that you will see 2mph over the 525, at best.

Let's see, that isn't $1000 for mph, more like over $10,000 per mph. Ouch
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05-20-2005 | 06:47 PM
  #24  
Re: How much fasted should 75hp make it go?
That Fastec Formula claimed a top speed of 83 !!! LOL
Anyway, if Merc hopes to sell these extremely expensive 600's that are only going to give you a mile or two an hour, they better think about upping the rev limiter to around 5600-5700 rpm, and turning the boost up alittle more then 6 lbs. You should see AT LEAST 4-5 mph. to justify spending that kind of money
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05-20-2005 | 07:20 PM
  #25  
Re: How much fasted should 75hp make it go?
FX, 4-5mph is like running half full of fuel verses full tank, or a solo run without the buddies. I would have to see 10mph for the money. What a shame.
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05-20-2005 | 09:42 PM
  #26  
Re: How much fasted should 75hp make it go?
This discussion comes at a very opportune time for me as well. Im ready to decide on the 525 or the 600SCi and quite frankly what Im hearings is forget the 600. It is a huge step for me to take $$$ wise to go with the 600 and there is certainly the WOW factor when you lift the hatch but WHERES THE BEEF!!!
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05-20-2005 | 10:34 PM
  #27  
Re: How much fasted should 75hp make it go?
Quote: This discussion comes at a very opportune time for me as well. Im ready to decide on the 525 or the 600SCi and quite frankly what Im hearings is forget the 600. It is a huge step for me to take $$$ wise to go with the 600 and there is certainly the WOW factor when you lift the hatch but WHERES THE BEEF!!!
At BURGER KING!
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05-21-2005 | 08:04 AM
  #28  
Re: How much fasted should 75hp make it go?
I hope Merc plans to do some more tweeking with these 600's to get a few more miles an hour out of them.
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05-21-2005 | 08:28 AM
  #29  
Re: How much fasted should 75hp make it go?
Another link to get the most out of a motor. Gear ratios and props.
http://www.go-fast.com/Prop_Slip_Calculator.htm
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05-21-2005 | 09:50 AM
  #30  
Re: How much fasted should 75hp make it go?
Quote: That's incredible how accurate that is!!

Craig is right on the money there.

I had a 350 carbed mag 270hp alpha on my boat 53mph gps
swapped it out with a 502 efi 415hp bravo
Gsp speeds of 71 was my Max
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