View Full Version : Horsepower and elevation
03-26-2008, 02:21 PM
I've been looking for my first 94-95 Prostar 205 and have found several standard engines but not many corvette engines. The reason why I'm looking for the corvette engine has been more horsepower and the ability to go a little faster for barefooting.
What I like to know is anyone's experience with the standard engine at higher elevations? The boat will maily be used anywhere from 4,000 ft to 8,000 ft. Also, how important would the powerslot transmission be? I don't even know if they were available or not. Would it be worth exchanging the transmission? costs?
Basically, I've found a few standard, 285 Hp boats and is it worth really trying to find one with the corvette engine in it.
03-26-2008, 02:25 PM
I would hold out, and get the one you really want. It makes for a PIA to try to take what you don't like, and make it into what you want. I wish I had got the powerslot in mine, but the price to switch it over is pretty high from what I understand.
03-27-2008, 12:49 AM
I have been skiing behind mastercrafts in Colorado my whole life. Here is my experience, we have never had any power issues for normal skiing and some basic barefooting
My Boat: 1984 S&S with 351 W with Power slot
- The guy I purchased the boat from was a big barefooter. On my test drive I watched him do a deep water, tumble turn, and a dock start. He was selling the boat because it was not fast enough for backwards tricks.
Dads Boat: 1986 Tri Star 190 with 351 W no slot
- many deep water starts have been performed with this boat, no advanced tricks. We have had multiple adult skiers up at once.
Moms Boat: 1993 Pro Star 205 with 351 W no slot
- again, many deep starts but nothing advanced. None of my boats had the power yours will have if you go with a 94. The Fuel injection added good power
03-29-2008, 10:52 AM
Thanks for some real world experiences. I've been looking almost every day on the net for the past 3 months trying to find the right one. I remember my dad taking the 79' Cobalt to Yellowstone lake with a 260hp engine. After prop changes, we could barely get the thing to plane. I think the max speed was around 25 mpg. Lesson learned that elevation can play a major roll in the performance :)
03-29-2008, 11:09 AM
At 8K ft above sea level, you will loose approx. 30% of rated hp. The fuel injected engine may sense atmospheric pressure when first started, so they may adjust the A/F ration for altitude. I'm not 100% sure that the boat engines do this, but I know the cars do so therefore I suspect that the boat engines would measure something at start to adjust.
At any rate, hold out for the FI if you plan to vary the operational altitude. It is your best bet.
The ECM checks baro when the key is turned on. It adjusts the fuel accordingly, based on their high altitude testing. Make sure the calibration is the most recent version.