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  • 3 Post By ar300johnson

Raise redline or Prop up?

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Old 07-08-2019, 12:28 PM
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Default Raise redline or Prop up?

Currently my engine redline is set at 5200, engine builder says its good for 6000, 6500 if i want to diminish longevity.
I run out of prop at redline. Hitting it is no problem. depending on water conditions load etc. speed is 78-82
No issue getting on plane at all. Matter of fact i take it easy as i know i am over powered the new XR drive.
I am running a labbed bravo 1 28P on a Nordic heat with a super charged 540. No stability problems runs great.
I was thinking testing a 30P and keeping my redline at 5200 or maybe 5500. I have a Holley HP system to manage it. I can program the new redline. Its done with a soft limiter.

What would you do?
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Old 07-08-2019, 02:42 PM
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There are benefits for each choice. Increasing pitch will be better for cruising and should be a little better for fuel economy. Longevity should be better at 3500 rpm vs 4000.

Keeping the smaller pitch will ensure that you should have a good hole shot even with a heavy load of fuel, lots of passengers. Hot weather wonít sap your performance.

I would decide if I wanted to have snappy performance available, regardless of load and or weather. If thatís the case, raise the limiter and use the horsepower you have paid for.

If you spend most of the time cruising and donít carry a max load, get a higher pitched prop. This will add engine life (unless you lug the motor) and be somewhat better on fuel.

Fuel economy obviously is not your biggest priority or you wouldnít have built a blown 540, so would I raise the limit and have fun.
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Old 07-08-2019, 10:36 PM
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Why not ask the builder at what RPM the engine should be run. at what RPM will the engine put out top HP and adjust it to that.
The guy that designed my cam told me where mine should be. ( 6400 )
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