In My Twilight
 

Hey guys, I recently picked up a 1994 Baja 22' Twilight Cruiser with a factory 454 Magnum mated to a Bravo 1 (1.50 ratio), with thru hull exhaust and trim tabs . Bought it from the original owner and was pleasantly surprised to see the engine hour meter is only at 164. She starts and runs nice but I am only getting about 58mph WOT spinning a Mirage three blade 21 pitch. We boat at 5000 ft elevation, but it still seems like this is a 65mph boat. There is very little information out there on this model. Does anyone know about this hull, and or have any intel they can spare? I would love to know more about the boat.

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https://cimg0.ibsrv.net/gimg/www.off...2ce5b7e40e.jpg

Its not gonna run 65 at 5000 feet. Every 1000' is about a 3% loss of hp which means you are making about 300hp.
What is rpm at WOT???

Thanks for the reply Griff. I knew the elevation was a factor, but have never seen a real approximation like the 3% loss you brought up. Rpm at WOT is 4900-5100 depending on conditions, etc...

Prior Internet searches identified that the boat is around 3200 lbs. My guess is with the current Merc power she is more like 3400. I have also seen Internet claims that she is either a 22 or 23 degree deadrise at the transome. The original owner passed away and his wife sold the boat, but she did not know if or where any of the original documentation was.

I think you're getting all it has at 58, Id think maybe low 60's at sea level

Not gonna run 65 unless its a 454Mag. We had one years ago with the 310 Carb 454 and I remember speeds around what you are saying 58-60mph. I had a 310hp 232 and it ran 58-62 as well. My current 252 Islander is a 310 hp and I only get about 52-55 loaded. 58 GPS best Ive seen low fuel, light chop and just me in it.
Mine came with a 23P 3 blade Mirage which is best for top speed but I mostly run a 21p Rev 4 esp when its loaded and sometimes a 23p Rev 4 with light load. The four blades plane and handle a little better but I lose a few MPH top end. Best Ive ever seen playing with all those props was 60 on the speedo.

What are you turning for RPM? You might be able to pick up a few MPH with a 23P. I would of thought thats what that boat came with because all mine came with 23P with the 310HP.

You need more hp. Open your wallet! :D

Yeah, it always gets back to the $$$. Maybe headers along with a better intake? It's already a magnum so the cam should be good to go.

58mph is better than I would expect of that model and elevation.

Boats suffer at higher elevation way more than a car would with it constantly under load and no wheels to help roll.

I hear ya CTRB, and it is a magnum. I have two of the 21 pitch so I was going to have one modified and balanced to a 23. I think that should get me 2-3 mph. After that it's going to get expensive with possibly adding headers and a better intake. Do you happen to know where I could find more info on this boat? Factory info.

I hear ya BR, and appreciate the feedback. This is the fourth boat I have owned at this elevation, and I got almost the same speed from larger, heavier, boats that were running a standard 7.4. I was expecting the magnum to push this little hull just a bit faster is all.