Alpha One limits

[Eaglenva]

I have a Alpha drive and from what I understand it is limited to 300 hp and is that engine crank hp or prop hp? Is there no safety margin there or is that just a safe level and they usually break at a higher level?

Any guidance would be appreciated as I am in the decision stage of what hp to push for but dont want to destroy the drive by over powering it.

Thanks!
Todd

 

[supergenius74]

My buddy has a 21' centurion pad v-hull and runs a modified 350 chevy on it that dyno'd over 420 hp at the crank and turns 6500 RPM, boat hit 87 on GPS. He has ran an alpha drive on it for the past 4 yrs without any problems yet, he doesn't hammer it in hard turns or lots of trim, he doesn't hammer it for long periods of time and he changes the oil frequently. Just my experience.

 

[SneakyPete]

I had low 400hp thru mine last season, will be 500hp this season. Don't hammer it on hole shots, be very gentle getting it on plane. Most say once on plane you can put the hammer down, but I am gentle all the time with it when accelerating. A drive shower is a must, heat will kill it. I use the synthetic hi-po merc drive oil. Amsoil would probablly be great too. Don't air this drive out while jumping wakes, as re-entering the water on the throttle will kill it. Keep in mind that the gimbal is designed for 300hp, so a hydraulic steering is definately a good idea, and could prevent a fatal accident. Marine Machine makes a single ram setup, as does Imco. I will be going with the Imco ingle ram half setup. Prudence is the key when over-powering the drive. There is a guy on OSO putting 540hp to his and he says he is real hard on it, with no failures, but he starts the motor in gear. Shifting at other than low rpm is also hard on the drive. You may want to consider a cam that won't have a gnarly idle for the sake of the drive

 

[SneakyPete]

One more thing, the Imco system is about $400 cheaper. Also, their customer support was great when I called just to ask questions.

 

[JW]

All great advice for keeping the Alpha alive. For the record, the Mercury web site lists for warranty: 300 horsepower and 65 mph for the Alpha. Have fun, it's all about going too fast

 

[Eaglenva]

yeah, i knew what was recommended but thanks for the input as sooner or later i will be asking about something at leave that kind of stuff out.

I was just wondering if i pushed it to about 350 if that would be an issue. I figured 10% maybe but that would only be 330 hp... guessing the warranty is out on my 87 model so that should not be a problem - LOL ... already has the power steering and trim but the trim was acting up the last time i took it out so may be looking for parts on that when i get it running next month.

 

[SneakyPete]

I am not talking about power steering, by hydraulic steering I mean a big honkin stainless steel ram hanging off of the transom attatched to the bearing cap of the out drive. A guy on this board by the name of happy was nearly killed when the regular factory power steering failed on a boat he was testing. Consider an external hydraulic ram necessary above stock power levels, many won't go without it at stock power levels.

 

[firecatgreen]

I also ran 420+hp through a alpha for over 3 years never had any trouble No Holeshots used trim tabs alot tried to keep drive shaft stright ,400 SBC in a 1987 23ft Bow Winds Ultra1 great boat wish I still had it

 

[Eaglenva]

I will look into that Sneakypete - definite budget constraints this year. But also want to live to use it next year (grin). I have been considering trim tabs but again $$ is a limiting factor and the rebuild is gonna take the extra for this year. (Unless I put the money there instead of the tank and just look at it this year and use my paddleboat instead of my powerboat).

 

[dreamer]

I am running about 430hp through my alpha. I just don't beat on it. Easy strait starts, limit the trim, make sure its down on take offs. I have trim tabs and it makes a huge difference, with the porposing at mid range speeds. What are you running for a prop. Do you have stock exhaust??

 

[dreamer]

Eagle the trim might just be the limit adjustments.

 

[Eaglenva]

I am running about 430hp through my alpha. I just don't beat on it. Easy strait starts, limit the trim, make sure its down on take offs. I have trim tabs and it makes a huge difference, with the porposing at mid range speeds. What are you running for a prop. Do you have stock exhaust??

I am currently looking at having the hp at 300 - I have reg merc exhaust manifolds and risers at 4" in diameter. current prop is ss 21" - not sure where the new engine rpm will be and i have been told this prop needs to be replaced. considering 23" if engine will push it. reg 4bbl carb. orig engine was suppossed be a magnum 260hp.

 

[dreamer]

First thing you should do is change out that Merc exhaust, tons of weight there and bad performance. the stock motor in an 87 enforcer was a 454 right?

 

[Eaglenva]

the literature I have seen said the 260hp 5.7 was standard and the hull is rated up to 420hp officially. Largest block was the 454. the title on this one shows 260hp.

yeah, the exhause weights in at something like 150# right on her butt. all the lightweight headers, etc i have seen costs between 1500 & 2k. too many budget limits right now with the rebuild and exhaust and prop all in one season. also, if I was pushing a bravo drive and higher hp it would be more of a need.

this is our first "go fast" type boat so we are limiting our exposure until we see if this is what we really want. after the rebuild we should have about 10k in it. as to go fast boats, i know mine is a trike but is is the next logical step, last boat (19.5 four winns cuddy cabin) maxed out at 44 stock. so steppin up to CHECKMATE.

YEAH BABY!!! =)