more outdrive tradeoffs; big money = little return

[d1mbu1b]

Concensus seems to be:
Theres not much you can do with an Alpha at 500 horses...

So whats the biggest bang for your buck?
(with out transom modification and engine relocation)
basically bolt on options.

Here are three options for replacing a merc bravo/alpha that I found so far

A. Bravo to arneson conversion kit ~$16,000
B. IMCO Xtreme w/ standoff box and ext. hyd.steering ~$9,000
C. bravoXR with sportsmaster or IMCO lower ~$8,000

speedboat performance simulator shows a 5% (with Arneson) gain in speed over the sportsmaster lower. That tells me Arneson is out.

Straight Bravo lowers are the slowest out off all the options including alpha.
Bravo (XR) may not include hydraulic steering so the IMCO Xtreme package looks like a deal...

but for 9 grand plus labor you can buy 9 alphas...

What other options are there?
You would think there are a surplus of used offshore drives laying around somewhere.

If I'm going to spend the money on upgrading the outdrive I dont want to go slower.

Thoughts?

[yeller]

Why not just a Bravo. It'll easily handle 500hp. No need to go to an XR. Also, the XR will be slower than the Bravo

If I'm going to spend the money on upgrading the outdrive I dont want to go slower.
Because the alpha is a smaller drive, I'd think your going to loss some speed no matter which way you go...unless you go arneson. I'd also expect to see more than just a 5% increase from the arneson...but I'm no expert. If I remember correctly, GEOO picked up over 10% on his X18.

[mrfixxall]

Concensus seems to be:
Theres not much you can do with an Alpha at 500 horses...
So whats the biggest bang for your buck?
(with out transom modification and engine relocation)
basically bolt on options.
Here are three options for replacing a merc bravo/alpha that I found so far
A. Bravo to arneson conversion kit ~$16,000
B. IMCO Xtreme w/ standoff box and ext. hyd.steering ~$9,000
C. bravoXR with sportsmaster or IMCO lower ~$8,000
speedboat performance simulator shows a 5% (with Arneson) gain in speed over the sportsmaster lower. That tells me Arneson is out.
Straight Bravo lowers are the slowest out off all the options including alpha.
Bravo (XR) may not include hydraulic steering so the IMCO Xtreme package looks like a deal...
but for 9 grand plus labor you can buy 9 alphas...
What other options are there?
You would think there are a surplus of used offshore drives laying around somewhere.
If I'm going to spend the money on upgrading the outdrive I dont want to go slower.
Thoughts?

Volvo sx drive,stronger then what you have 5mph faster then merc..3900.00 for the drive 1500.00 for the gimble housing = 5400.00..

Me personally im probably going to go with a new volvo dpx on my x-18 over the winter. it should be interesting next summer,real interesting and mabe a little more power too...

[yeller]

.....If I remember correctly, GEOO picked up over 10% on his X18.
Opps...make that about 20%.

[d1mbu1b]

Volvo sx drive,stronger then what you have 5mph faster then merc...

Funny you say that.
I have a volvo SX cobra drive off my sunken chaparell 4 cyl.
I already own all the mounting HW with bell housing.
The hurricanes took it in 2004,,,sunk

How much transom work would be needed to convert merc to volvo drive?
Would the engine need to be moved?
Would it handle 500 horse w/ a gear change?
Does Volvo have 1.3 or so gears?

Thanks

BTW the 5% quote is not from me but that speedboat performance simulation webpage. I put in a basline config and changed the drive from bravo w/ sportmaster lower to ASD-6. So maybe you should just ignore my wild extrapolation.

[Tony]

Me personally im probably going to go with a new volvo dpx on my x-18 over the winter. it should be interesting next summer,real interesting and mabe a little more power too...

Great plan...I love the DPX on my 22' classic. This drive, remember, was put behind 600 hp engines...plus it has hydraulic steering built into the drive and all the way to the helm, duo-props for awesome holeshot/torque/bite, and a decent hydrodynamic profile.


:beer:

[mrfixxall]

Great plan...I love the DPX on my 22' classic. This drive, remember, was put behind 600 hp engines, plus it has power steering built into the drive, duo-props, and a decent hydrodynamic profile.
:beer:

When i said more power i ment,,,,,i removed my 100hp nos plate and im going to install a fogger kit 150-400 hp+: at the touch of a button:yes: I had problems hanging on the the wheel at 75 and still clinbing whth the old cable steering.so hopefully with the new mods and the help of hydrolic steering tiptoeing into the 80s wont be a problem, im still working out the price on the drive and the gimble housing..:beer:

[MOP]

4 cylinder ratio is different then the 8, you won't find props big enough.

[Cuda]

I must have missed it, what model boat is it?

[Donziweasel]

Bravo rated to 400 hp. Bravo X rated to 450. Bravo XR 600hp.

[yeller]

A Bravo will take 500 HP??
Why do say that? There are tons of people running 500+hp with a Bravo.

[Donziweasel]

Just Mercruisers ratings, not mine. :wink:

[pmreed]

Seems as though the Bravo 1 was derated a couple of years ago. My 22C with the 502/415+ is running through a Bravo 1. Don't know if Merc got more conservative or if something actually changed.

Phil

[yeller]

Well, I do know that they're not rated for 500hp, but you don't have to look far to find lots of people running that power with one reliably. I'm not concerned about the reliability of my 1X drive even though I'm pushing close to 600hp. I don't, however, hammer the throttle on start up and I'm cautious about getting too much air. Also, I admit the size of boat does make a difference. Of the 1/2 dozen people I know running over 500hp with a Bravo1, not one has exploded the drive. My cousin has 1500hrs on his drive...500+hrs at 525hp and the unit has never been apart. Alot of it comes down to driving style and maintenance. :)

EDIT: Sorry d1mbu1b for taking your thread off topic. :bonk:
I still vote Arneson :yes: It's only money. :wink:

[Donziweasel]

I agree, hell, there are people running 400 hp on alphas. Just how you drive them decides whether they will last or not.

[harbormaster]

Bravo 1 will hava long and glorious life if care for correctly.
1). Make sure it has a drive shower on it to cool it.
2). Throttle back when leaving the water. throttle back up smoothly upon reentry.
3). Eliminate the word "holeshot" from your vocabulary. Never slam the throttles forward from a dead standstill when leaving the local wateringhole.

[Tony]

3). Eliminate the word "holeshot" from your vocabulary. Never slam the throttles forward from a dead standstill when leaving the local wateringhole.


Oh, no...that was one of the BEST things about my old Ski Sporter with its 39 year old AQ200 and big 'ol prop! That boat would JUMP out of the water...it was way too cool, and obviously did not harm the outdrive. Of course...it is a Volvo! :)


:beer:

[d1mbu1b]

So to sum up this thread:
Is Volvo SX the way to go?

least expensive?
stronger (capable of performing hole shots at 500 HP)?
less drag than bravo?

If the answers are yes, then it sounds like a winner.

[Dredgeking]

A Bravo will take 500 HP??

I agree. The Bravo with 500 hp is a delicate balance with a boat that will be in and out of the water.