Elevation changes and loss of power

big wake marty · July 21, 2009

I live in UT and boat mainly at Lake Powell which is at 3500 feet elevation. When I take my boat to the mountain lakes near Salt Lake at an elevation of 7500 feet, I get no power. I can barely get a wakeboarder up to 24 miles an hour and no way I can pull tubers. I always empty the ballast tankls at elevation and still get nothing. It's kind of embarrasing to have the 24 foot enzo with the loud exhaust system and the boat tops out at 25. All the little bayliners are flying right by me. What is going on?

Shadybrook Surfer · July 21, 2009

Well...

As you get higher in elevation, the air becomes thinner, thus creating (in theory) a lower compression ratio in the engine. I don't remember the exact ratio but expect to lose 3-5% per 1000' above sea level...

So a 330HP engine at sea level will only be like ~260 at 7500'

Bigcatpt · July 21, 2009

I live in UT and boat mainly at Lake Powell which is at 3500 feet elevation. When I take my boat to the mountain lakes near Salt Lake at an elevation of 7500 feet, I get no power. I can barely get a wakeboarder up to 24 miles an hour and no way I can pull tubers. I always empty the ballast tankls at elevation and still get nothing. It's kind of embarrasing to have the 24 foot enzo with the loud exhaust system and the boat tops out at 25. All the little bayliners are flying right by me. What is going on?

I brought my first boat from California sea level up to Utah. It was sickening how much power loss there was between sea level and 4600 feet. Now with this boat depending on what lake we run in (3600 at Lake Powell to 7600 at Strawberry) there is a HUGE difference in power both hole shot and top end. Most of the time I am running in Utah Lake which is about 4500 feet so I have the correct prop on it for that. It runs like a rocket at lake powell. If i was to spend any amount of time at higher elevation lakes around here (Deer Creek, Jordanelle, Strawberry, etc) I would prop down for a better hole shot.

Joe B · July 21, 2009

Prop down and Turbo UP! It's just a matter of time...

tgaugh · July 21, 2009

+1, prop down

duramat · July 21, 2009

BIG, WELCOME TO THE SITE!! :thumbsup: Another Utah boy here! What prop do you have on it currently? Im using a #537 for the higher Altitude. Levi, (D-90) on here on CC has an Enzo 24 and his prop is the same as well.

I didnt belive Bigcat at first, but there is a 300' elevation difference between Utah lake and Willard Bay! Sounds like you need to bring that Enzo up my way for an evening :yes

kgordon7378 · July 22, 2009

Living in Denver, the number one requirement for our boat was EFI. If you dont have it in the altitude, you will struggle as you need to rejet and adjust the carb. I would be surprised if you were not fuel injected. Thus the reason as others have stated is prop. Due to the loss of power, you cannot turn the same prop you do at sea level or lower elevations. I would contact your local prop shop or acme and give them the specs. Just to give you an idea my t-5 comp direct drive will hit the rev limiter with a 525 prop at sea level. In the altitude I am lucky within 500 rpm of the recommended range, not even close to the limiter. Yet I have plently of holeshot, thus no need to change for me.