How much fasted should 75hp make it go?
SubscribeOldSchool
VIP Member
close
- Join DateDec 2001
- LocationCape Coral, Florida
- Posts:10,398
-
Likes:364
-
Liked:404 Times in 137 Posts
Quote:
http://www.go-fast.com/boat_speed_predictions.htm
That's incredible how accurate that is!!Originally Posted by FX10
Here's the link, sorryhttp://www.go-fast.com/boat_speed_predictions.htm
Quote:
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? Originally Posted by FX10
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
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.
Mentalpause
Registered
close
- Join DateNov 2000
- LocationIL...XLOTO
- Posts:3,949
-
Likes:259
-
Liked:93 Times in 57 Posts
Quote:
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. Originally Posted by FX10
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
Let's see, that isn't $1000 for mph, more like over $10,000 per mph. Ouch

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
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
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.
SUPERSTITIOUS
Registered
close
- Join DateMay 2001
- LocationCT
- Posts:2,064
-
Likes:211
-
Liked:136 Times in 65 Posts
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 $$$ wise to go with the 600 and there is certainly the WOW factor when you lift the hatch but WHERES THE BEEF!!!
Quote:
At BURGER KING! Originally Posted by OH-ZONE
This discussion comes at a very opportune time for me as well. Im ready to decide on the 525 or the 600SCi and quite frankly what Im hearings is forget the 600. It is a huge step for me to take $$$ wise to go with the 600 and there is certainly the WOW factor when you lift the hatch but WHERES THE BEEF!!!

I hope Merc plans to do some more tweeking with these 600's to get a few more miles an hour out of them.
Another link to get the most out of a motor. Gear ratios and props.
http://www.go-fast.com/Prop_Slip_Calculator.htm
http://www.go-fast.com/Prop_Slip_Calculator.htm
Quote:
Originally Posted by craig223
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
