ford 460 only turns 4500rpm

« **Reply #50 on:** August 05, 2017, 10:50:45 AM »

Just to ensure the horse really is dead....

Quote from: mach1_557 on August 04, 2017, 09:00:04 PM

The chart references at what hp and rpm to change impeller material and that's it .

So why then does the curve not deviate when the stainless or mag bronze is recommended? Wouldn't if offset?

Quote from: mach1_557 on August 04, 2017, 09:00:04 PM

Any person with common sense can figure out that a heavier material will take more force to spin it and keep it spinning .

Won't take "more force", force is indicating torque, torque times speed is HP, it will take longer to get to the max rpm when heavier, but will take less force to sustain the max rpm. HP for HP and cut for cut, the top RPM will be theoretically identical.. The only disclaimer stated is that no two impellers are identical, so there could be a few RPM lost or gained here and there, but the tach in the dash probably wont indicate it...

If I'm wrong, you need to show me...

Meanwhile, I'm done.... And I'm not being a dick, just trying to educate, you challenged me to.....

GT

« **Reply #51 on:** August 05, 2017, 11:19:35 AM »

My 460 only turns 4500 hundred on a fresh pump. However, I'm pretty darn sure the engine came out of a car..
I
Just to chime in on the aluminum vs stainless impeller discussion: the difference in horsepower required by the change in mass moment of inertia, is negligible. Due to the geometry, one can assume it's a cylinder, which would scale the inertia by 3 ish times. However, my gut says the difference in horsepower required is less than a horse power, thus the difference in weight will never be noticed. There are other variables that have way greater influence.

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« **Reply #52 on:** August 05, 2017, 03:38:28 PM »

what impeller do you have?

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« **Reply #53 on:** August 05, 2017, 05:19:20 PM »

Quote from: GT Jets on August 05, 2017, 10:50:45 AM

Just to ensure the horse really is dead....

So why then does the curve not deviate when the stainless or mag bronze is recommended? Wouldn't if offset?

Won't take "more force", force is indicating torque, torque times speed is HP, it will take longer to get to the max rpm when heavier, but will take less force to sustain the max rpm. HP for HP and cut for cut, the top RPM will be theoretically identical.. The only disclaimer stated is that no two impellers are identical, so there could be a few RPM lost or gained here and there, but the tach in the dash probably wont indicate it...

If I'm wrong, you need to show me...

Meanwhile, I'm done.... And I'm not being a dick, just trying to educate, you challenged me to.....

GT

Here's the deal ,I've changed impellers at the river during the same day with the same boat the same engine and the pump setup within .002-.005 of the two different impellers and the stainless one spun 150 less rpm. The temperature was relatively the same because it was in February. So you telling me I'm wrong isn't going to change the data that came from changing the two impellers. Go ahead and pick it apart.

« **Reply #54 on:** August 05, 2017, 05:47:19 PM »

Quote from: mach1_557 on August 05, 2017, 05:19:20 PM

Here's the deal ,I've changed impellers at the river during the same day with the same boat the same engine and the pump setup within .002-.005 of the two different impellers and the stainless one spun 150 less rpm. The temperature was relatively the same because it was in February. So you telling me I'm wrong isn't going to change the data that came from changing the two impellers. Go ahead and pick it apart.

It had zero to do with the weight of the impeller........ Zero. I don't have to tell you you're wrong anymore, physics and my sharing an impeller chart should have shown you that.

If you changed impellers and the only thing different was the material (so you say) and you lost 150rpm, you simply had a different impeller, maybe the aluminum was cavitation burned and the SS was not.... I have changed HUNDREDS of impellers and I use an aluminum to get a baseline when going to a stainless because a stainless is a bitch to cut. They are normally SPOT ON.

I think I need to let you know that this is all I did for fifteen+ years....

GT

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driller41

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connorstexas

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mach1_557

Re: ford 460 only turns 4500rpm

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Re: ford 460 only turns 4500rpm