New member here looking for advice. My boat is an '04 Baja 245 with a 496 Mag. Back East it would run 64-69 on the speedo depending on water conditions, load, fuel, etc. The elevation was about 900'. I just brought the boat to Wyoming and am running it on a lake at about 6500'. Top speed with my wife, myself and about 20 gallons of fuel is about 60 on the speedo. What can I do to regain the lost mph? Any suggestions will be greatly appreciated.

Hi Oilfield

I boat in Colorado anywhere from 5000 to 8000 feet in altitude. To start with you need to drop your prop by about 2" in pitch from what you had at sea level. That will help you out of the hole but you won't see your top end improve unless you can add horsepower. A fair number of boats originally sold here will come with a "altitude" gear ratio such as 1.65 in the bravo 1. It's probably less expensive to play with or tweak propellers than a gear change. If you have a carburated motor you will need to re-jet the carb and possibly change the power valve. Depending on the motor, timing may need to be adjusted also.

If interested: I have a like new spare 1.65 bravo...I may be willing to swap since I now have a boat with 1.5's.

Add a blower.
I brought a boat to lake Tahoe once and had to go down 10 jet sizes front and back to get it to run ok. It was a 10.5-1 498 with a holley 850.

Your best bang for the buck, will be to upgrade the motor to a 496 MAG HO spec. with a new cam and ecmf or an HO. this will get you to a 425HP level from your current 375HP level and the extra 50 horses should get you where you want to be.

Ray @ Raylar

When I read your post I missed the part about the 496mag. sorry about that. I have the 496 mag ho in my 25' Nordic. I added the whipple supercharger kit. More than made up for the altitude.

Ufortunately there is no cheap way to get your speed/hp back
The air and compression is gone in the high country.
Your 375hp just became ~305hp and my 425hp is ~340hp (18.5% at 5000 feet)
If you are very disciplined a Whipple set at low boost (3lbs) would live a long time where you live now. At 5000 feet you are ~2.6 lbs in the hole to start with so by adding 3 lbs the engine hp would be revived and see virtually no more strain on the internals than you were seeing without boost at sea level.
Now when you drop to lower elevations is when you need to be very careful. I'm not so sure I can personally do that so I am leaning towards the Raylar packages with increased compression
This way when we run to Havasu or Mead I can still drive it like I stole it

If you have no plans of low elevation trips, Whipple it. Also if you do this consider going with an HO cam to go with the Whipple ECU flash for an HO. I will have two extras hanging around this winter.

Dave

Thanks for the replies and suggestions. Because of work, this is the 1st chance I've had to look them over. I guess the way to go would be with the Whipple. I really don't anticipate taking the boat to a lower elevation in the future, so that seems the best route. Would I still need to change out the prop? Right now I'm running a 23p Mirage and have not come close to the limiter. Hole shot and mid-range are still good, but no top end...very frustrating! Thanks again.

I would think that with the Whipple @ 3-3.5lbs you'll be at or just a tad better than you were at sea level.
Your existing setup should work fine but you will probabaly have to do a little prop tuning when your done.
Good Luck,
Dave

I think the Whipple is a good product. It will cost you money though. I installed the kit my self and am very pleased with the result. The kit is very well thought out, complete and provides you with a re-mapped ecm. The folks at whipple provided me with a smaller pulley so that I could run 5lbs of boost at 5000 feet. I'm not hard on the throttle. I realize the potential for breaking the engine. If that happens I'll make it better again. That goes with the territory. If you do the whipple you'll probably (most likely) still need to play with the prop. I went from a 24" bravo1 to a 30" bravo1. I think the Whipple Stage II- ecm reflash, new thermostat and premium gas - will give you back some of your horsepower but it will still be less than that at sea level.

Pat