Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

[mylesm260]

I'm cookin' up an idea for 350-400 HP @ about 7000 rpms. Would an alpha-1 MR hold up to this?

 

[Don S]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

300 hp, same as has been posted about a million times.

 

[JustJason]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

and that many rpm's is useless unless your building a racing hydro

 

[mylesm260]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

the motor I am thinking of has a very flat torque curve.


I'm toying with the idea of marineizing a toyota/lexus V8
They are basicly one of the toughest motors ever made, and they're cheap as hell because nobody needs them because they never ever die. People are putting 500,000 miles on the no problems. People are also turbo/supercharging them and they hold up great!

I have a friend with a C+C machine, I'm thinking about making adapter plates for the manifolds and run mercruiser 302 ford manifolds.

Then I could fab up my own bellhousing/rear motor mount. and drill the toyota flywheel to bolt up to the coupler.

This is just an idea on paper right now.

So what happens when people run 454's on alpha-1's? how do they fail?


Most marine motors that make more than 300 HP would most likely do it with torque and displacement. I plan on doing it with RPMS

HP = torque / 5252

350 HP on a 454 would be at like 4000(ish) rpms so that would be 460 ft/lbs

The motor I'm thinking about using would be 350-400 HP @ 7000 RPMS so that would only take 262 - 300 ft/lbs of torque

Basicly the trade off would be less twisting force, but a lot higher RPM (VS a chevvy big block)

 

[Uraijit]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

If you want more than 300 HP, get a bravo drive.

 

[JustJason]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

doesn't matter if you can spin your engine to 20K.....
and your engine makes 1000's of horsepower.....
It needs to be geared down to slow down prop rotation....
because..... and just in case ya didn't know.....
props stop working at a certain rpm.
when you spin a prop to fast, because of the pressure differential of water between the leading and trailing faces of the prop, water instantly boils and turns to steam.
Not only wrecking your prop, but props don't work especially well trying to push a boat, when the only thing the prop can bite into is steam.

so like i said... that many rpms is useless

 

[stinger222]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

I agree, you can't spin the prop that fast. Your idea would have already been implemented by Merc's engineers years ago if it would work. I do take issue with those who think the the Alpha will break if you exceed 300 hp. I have a High hp/tq 383 which is beyond 300hp and have had no problems with my alpha for 13 years. I also have a buddy with a 454 and an Alpha, again no problems. Of course if you have a choice, go Bravo, but an Alpha will hold up better than 300 hp. just don't punch it out of the hole.

 

[Uraijit]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

I agree, you can't spin the prop that fast. Your idea would have already been implemented by Merc's engineers years ago if it would work. I do take issue with those who think the the Alpha will break if you exceed 300 hp. I have a High hp/tq 383 which is beyond 300hp and have had no problems with my alpha for 13 years. I also have a buddy with a 454 and an Alpha, again no problems. Of course if you have a choice, go Bravo, but an Alpha will hold up better than 300 hp. just don't punch it out of the hole.

If you have two components that cannot work together to maximum power, you have a mismatched system.

You can put a 1000HP engine into a Ford Fiesta as long as you "don't punch it too hard".

Ford would never dream of offering a 1000HP Fiesta, because that engine wouldn't be "compatible" with that vehicle.

A +300 engine, and an Alpha drive are not suited to each other. Can you bolt them together, and get away with it, so long as you don't use the engine's full power? Yeah, but what's the point?

If you can't utilize the full power of a component with another, that's the epitome of non-compatibility within the system.

 

[erikgreen]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

You guys need to think outside the box a little

What if he got some custom gearing done, so he had a 4:1 gear ratio? He could run a really big prop

Or, he could skip the alpha entirely and just run the motor to an airplane prop, for an airboat.

What kind of gearing do jet pumps have? Is it 1:1?

His idea may have some merit if the engine's he's talking about are much cheaper than GM V-8s, and can be marinized

Erik

 

[mkast]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

So what happens when people run 454's on alpha-1's? how do they fail?

SeaRay talked Mercruiser into installing 454/Alpha1 into fairly heavy boats.
When the hulls are on plane, the sterndrive is out of the cooling water. Drive lube overheats, breaks down, drive blows.
Since then, drive showers and syn. drive lube has helped.

 

[Uraijit]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

You guys need to think outside the box a little

What if he got some custom gearing done, so he had a 4:1 gear ratio? He could run a really big prop

Or, he could skip the alpha entirely and just run the motor to an airplane prop, for an airboat.

What kind of gearing do jet pumps have? Is it 1:1?

His idea may have some merit if the engine's he's talking about are much cheaper than GM V-8s, and can be marinized

Erik

Nobody's saying that the engine can't be put in his boat, but his question was whether or not he should use an engine over 300HP with an Alpha...

 

[stinger222]

Re: Anyone know the HP and RPM limits of an ALPHA-1 MR drive?

If you have two components that cannot work together to maximum power, you have a mismatched system.

You can put a 1000HP engine into a Ford Fiesta as long as you "don't punch it too hard".

Ford would never dream of offering a 1000HP Fiesta, because that engine wouldn't be "compatible" with that vehicle.

A +300 engine, and an Alpha drive are not suited to each other. Can you bolt them together, and get away with it, so long as you don't use the engine's full power? Yeah, but what's the point?

If you can't utilize the full power of a component with another, that's the epitome of non-compatibility within the system.

I hear what you are saying, but i would argue that the systems are not as wildly mismatched as you suggest. While I don't floor it out of the hole, I do have many poker runs under my belt and until I had my 2 kids, drove the sh*& out of 383 alpha, many times with 5 passengers. No breakage on my drive. I see many guys on here who have 19-24 ft boats with alpha drives and they want to upgrade their stock motor and guys are so quick to tell them the 300hp limit of an Alpha, and to "go get a Bravo", well that is not an easy swap to do for the avg non mechanic boater, nor is it cheap. Would I put a 500hp 502 behind an alpha, no, but a warmed over SB 300-400hp should be no issue.