That should be a straight lifting strake  Southwind bottom...

Yes I believe it is. I think the Challenger was layed up heavier though not sure where I heard that over the years but I do know the hull was rated at 1000 pounds I don't believe many of the 18 were that heavy...

1977 Challenger

Looking at this 1978 artical in performance boats on Challenger, granted this test boat was a 454 and JG with a B, but the engine specs say max hp 325 at 4600 but further down it shows the calibrated tach hit 5050 and the dash tach hit 4900.

1977 Challenger

Those numbers jive almost perfectly with an impeller chart.... I'm just saying....


GT

Agreed. But it does seem to show a difference between engine specs and actual. And even at 5050 rpm top speed was only 61 62 mph

By the way thanks for schooling me here I am learning lol not trying to be combative lol

1977 Challenger

lol Gt


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lol Gt


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Dude this was not a pissing contest between myself an GT. Just questions and answers

1977 Challenger

Let me know if and when you get plans for San Antonio. Hopefully it will come back around to it's old glory soon.

1977 Challenger

Was actually thinking about heading down to Nacimiento to test the Southwind. Just cut the impeller down another step and want to see what it does....

Also have a Sea Doo to dial in....  (I know...LOL)

Nice I just like the fact San Antonio has shore camping for the motorhome. I am picking up a 95 SPX seadoo and trailer tomorrow to play around with

1977 Challenger

I have an XP and an SPX, a 650 and a 787. I'm in them virtually nothing (the XP under $300 and the SPX $150 with single trailers for each...).... We normally camp on the beach by the store at Naci... Been a while.

Nice I sent ya a pm so I am not thread jacking anymore lol

1977 Challenger

(Attachment Link)

Show me on this chart where a stainless turns a different RPM than an aluminum or a bronze.......

I'm all ears.......


GT

Man I hope my impeller doesn't explode. I'm at about 500 with an aluminum aggressor.


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Man I hope my impeller doesn't explode. I'm at about 500 with an aluminum aggressor.


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Loader? What RPM?

I doubt seriously you will have an issue. How old of an Aggressor?

Loader? What RPM?

I doubt seriously you will have an issue. How old of an Aggressor?

I'm not sure yet. Haven't had time to test the new motor. Maybe next week. It's an A/B cut which I think is equal to a berk A. I'm guessing it will be 52-5400. Has the sport intake grate.


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(Attachment Link)

Show me on this chart where a stainless turns a different RPM than an aluminum or a bronze.......

I'm all ears.......


GT

The chart references at what hp and rpm to change impeller material and that's it .   Any person with common sense can figure out that a heavier material will take more force to spin it and keep it spinning .

The chart references at what hp and rpm to change impeller material and that's it .   Any person with common sense can figure out that a heavier material will take more force to spin it and keep it spinning .

You are confusing "inertia" with "rotational force".

So what you're telling me, is that if I built a pump with a titanium impeller, impeller shaft and used an aluminum flywheel and no balancer but an aluminum hub, I'll pick up more RPM? Is that your argument?

It will rev quicker, but wont turn more RPM.... Fact.

Now I set forth the same challenge you did to me. What proof do you have that the material of the impeller changes the RPM cut for cut? And common sense wont fly.   

GT