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Aluminum SBC Block? BuCrew Member help.


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41 minutes ago, Woodski said:

But we do have to keep our trusty drivers comfortable...particularly if the CFO, significant other, etc.

I have sat on a crate like that before.  It wasn't all that bad. 

Besides, it makes a great storage locker for the chicken you will cook for lunch! 

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  • 3 weeks later...

An interesting byproduct of the project, improved fuel economy.  Until giving it some thought, I expected the reverse due to more airflow from cam, larger jets and extra displacement or maybe no change at best.  FE has improved by .5 gph, and my theory is leaning towards reduced prop slip since I have had to adjust the PP cal down to dial in the proper speed, RPM drop has been between 75-100 RPM depending on speed / skier.  The obvious question is why, so I am thinking it is due to less weight making a difference even as there is a bit more whetted surface area since the water breaks a bit farther forward than previous due to slight forward CG movement so pitch angle has an effect on surface drag.  Prop is same as before so in order to propel boat to same speed as previous at a lower RPM, prop slip has to be less.  Moral of this story, weight matters and also kind of explains the high fuel consumption of the current crop of pretty heavy, high revving slalom boats on the market.

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Exactly.  The lighter boat will certainly reduce drag.  Even with the CG forward a bit, you have reduced total displacement.  That reduces wetted area, which reduces drag. 

I'm tickled at all the poor MPG comments about wake boats and big trucks.  Yes, you can gear the engine into its sweet spot for efficiency, but the power required to move a given rig a given speed doesn't change.  In your case, you made the rig lighter. 

Great work, by the way! 

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On 9/13/2019 at 11:32 AM, justgary said:

I have sat on a crate like that before.  It wasn't all that bad. 

Besides, it makes a great storage locker for the chicken you will cook for lunch! 

I drove a '77 Firebird with the interior gutted and nothing but a crate in it for about a month while in college.  The tough thing was taking turns at any sort of speed, the crate wanted to tip over so you were turning but holding onto the wheel and shifter to keep your balance.  Of course, dumping the clutch didn't make it any better either...

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1 hour ago, Michigan boarder said:

I drove a '77 Firebird with the interior gutted and nothing but a crate in it for about a month while in college.  The tough thing was taking turns at any sort of speed, the crate wanted to tip over so you were turning but holding onto the wheel and shifter to keep your balance.  Of course, dumping the clutch didn't make it any better either...

Those kind of experiences are what teach you about controlling some muscle groups differently from others.  I'm sure you are much more dexterous now.  Everyone should get to have that kind of fun!

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I have always thought it is amazing that the 50's to 80's era American gear head teenager actually made it to adulthood ... Not sure I see that automotive passion much anymore.

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56 minutes ago, Woodski said:

I have always thought it is amazing that the 50's to 80's era American gear head teenager actually made it to adulthood ... Not sure I see that automotive passion much anymore.

I think it's because everything is so integrated with digital controls that you need an engineering degree just to understand how it works.  You can't just change a cam anymore....

Oh, and for a long time now, auto makers have been slaves to mileage, so cars look like they were all designed in the same wind tunnel.  Hard to get excited about meh.

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22 hours ago, Woodski said:

An interesting byproduct of the project, improved fuel economy.  Until giving it some thought, I expected the reverse due to more airflow from cam, larger jets and extra displacement or maybe no change at best.  FE has improved by .5 gph, and my theory is leaning towards reduced prop slip since I have had to adjust the PP cal down to dial in the proper speed, RPM drop has been between 75-100 RPM depending on speed / skier.  The obvious question is why, so I am thinking it is due to less weight making a difference even as there is a bit more whetted surface area since the water breaks a bit farther forward than previous due to slight forward CG movement so pitch angle has an effect on surface drag.  Prop is same as before so in order to propel boat to same speed as previous at a lower RPM, prop slip has to be less.  Moral of this story, weight matters and also kind of explains the high fuel consumption of the current crop of pretty heavy, high revving slalom boats on the market.

More efficient, better burn. I look at the cars today making HP like our old big blocks. Like? no well beyond. Combination of all.   

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  • 6 months later...

Bumping a thread from last year.  How's that Aluminum 383 working out @Woodski

Any pics/videos of that thing in action?  Also, what'd you end up with for a prop and what are you hitting for MPH at WOT?  Your setup has to be the ultimate barefoot endurance race boat.

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@UWSkier - It's working well, although I ended up making a modified oil pan for it as the aluminum block holds more oil while running.  Prop right now is Acme 449 although thinking of going to a 425.  Have not really done the WOT thing yet, spent the hours on break in and slalom runs last year and did not accumulate enough hours to do an extended WOT run.  A quick blast I hit 5,300 and didn't really look at the speed but the speedos were over 50 at the time, it needs another round of fuel calibration work before some serious WOT runs.  It does have a ton of snap and it works really well for footing.  It accomplished the main objective of improving the slalom wake, skiers noticed that change.  No video so I'll have to work on that, as for sound you would hardly notice a difference from previous.  Thanks for asking:-)

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ahopkins22LSV
37 minutes ago, Woodski said:

@UWSkier - It's working well, although I ended up making a modified oil pan for it as the aluminum block holds more oil while running.  Prop right now is Acme 449 although thinking of going to a 425.  Have not really done the WOT thing yet, spent the hours on break in and slalom runs last year and did not accumulate enough hours to do an extended WOT run.  A quick blast I hit 5,300 and didn't really look at the speed but the speedos were over 50 at the time, it needs another round of fuel calibration work before some serious WOT runs.  It does have a ton of snap and it works really well for footing.  It accomplished the main objective of improving the slalom wake, skiers noticed that change.  No video so I'll have to work on that, as for sound you would hardly notice a difference from previous.  Thanks for asking:-)

Maybe a skier/engineer who has no previous experience should also review? ;)

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