soundwave

Tyler crokit sold me a 509 b&m 750 horse motor for my boat 25 outlaw 1999 what speed should I be looking at

Ebay Ed

fast enough that you need full hydraulic steering to be safe

Fenderjack

iTrader: (2)

Why the angry face??

John jr

Baja_man

At 750 you should be in the 82-85 range.

A.O. Razor

750 hp by which correction factor?

If SAE J607 as many smaller custom builders use 82-85 as Baja man said. If SAE J1349 like Merc, Ilmor, Volvo ect. uses 85-87.

And you will need full hydraulic steering and internal drive upgrades.

89notch

I have the same boat making similar power and have seen 79-86 depending on the GPS unit and lake conditions

A.O. Razor

Can you explain this? My gps units over the years have been VERY much the same. +/-1 mph. Garmin, Livorsi, sat nav, hand held ect. Are your gps units working right? Yes, load and water can deffinetly have a big impact, but your gps units should be more or less the same, mine has been. What is the highest reading on the gps that read 79 mph lowest and what is the lowest reading on the one that read 86 highest? Also, 7 mph is quite a huge difference imo.

Out There

GPS units won't vary much. Some read 10ths with digital display. Some may react quicker than others to speed changes. It takes time for GPS to calculate changes in speed.
The big variables are the conditions. Load in boat and water conditions. Easy 5-7 mph on some boats

89notch

Ive had my iPhone GPS read 81-82 while a friends Android read 78 at the same time. Ive also compared the iPhone to a handheld GPS unit and it was 2mph different. I'm hoping to fix this problem by wiring my livorsi GPS speedo to a garmin chart plotter nmea output. Now the 79-86 speed range was on completely different water conditions. I would say I consistently average 82mph

articfriends

iTrader: (1)

What kind of torque, what kind of lower, box etc?? I would say 77-82 mph without anything trick hanging on your transom, faster as you get dialed in, Tyler uses j 607 which is generous as far as correction factors go but so do most other shops. My 272 ran 76 with 502 blower motor off his dyno that made 650 hp/700 ft lbs of tq. Turned up boost further and saw 79, turned up boost even further and more timing and saw 82-83 back then with what we figured was 750 hp. When I made 945 hp my boat ran 92.8 light and 89 =/- when loaded down, I hear all kinds of "other" top speeds with less hp but haven't seen any 25's or 272's actually gps into the 90's without similar numbers. I installed a ext box and consistently ran slower, I installed a shorty drive and lost top end and boat became dangerous but my boat was well into the 90's at that point, Smitty