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I've been working with Eric at OJ for a while now on a prop that will max out the performance on the 550hp boats. I and others have long said we are only at about 80-85% of what the 550s are capable of because to this point, we've been limited to the existing on the shelf avail props (15" max dia) from Acme. I want that last bit of performance/capability, less wear and tear on engine and tranny, sound reduction, better fuel economy etc. Tried to talk to Nautique engineers a couple times at shows and on here... they've not been interested in this.
My claim: We are basically stuck in 3rd-4th gear with how they are prop'd with the OEM Acme 15x14.25s(max dia then pitch traditional prop).
Bottom Line- Eric at OJ fab'd a trial 16x15 for me to test. Big improvement, And there is room for more improvement.
Specs: we are talking 550hp boats with the 1.48:1 trannys. Not the 2:1 trannys with 17" props, apples and oranges. I don't subscribe to the "Easy RPM" and "Hard RPM" theories. I assert that there is no situation where you are burning less gas at higher 3000rpm than at a lower rpms 2750rpm for example(huge brawl on here a few years back, shots out to you "easy and hard RPM" theorists!), regardless of speed or weight. Just stay with me for a moment. I also feel like the 550 GPH consumption is not linear in nature... go over ~3200rpms and it starts to guzzle fuel, blower spins louder(no hard data to support other than my credit card after 175hrs, and how easy the engine seems to run under 3000rpms). My boat is approx 5-600lbs heavier than a standard G23, with extra batteries, stereo and lead for your reference on the numbers below, full 100% tank of gas 2 on board. with the 16" prop, you still have 3-4" of clearance to the hull. OJ's 16" prop was much thicker, heavier and sturdier than the ACME, huge difference.
Results: The 16x15 accelerated faster and more evenly, absolutely no need to over-rev to achieve your desired speed when you go heavy to get going(save gas). You simply accelerate up to it and stay there, this increased 16" dia significantly reduces prop slip. It ran between 200-500rpms less for every given activity. 23mph no ballast was ~2900rpms(~300+ less rpm), 23mph full 2850lbs OEM ballast NCRS 0 was ~3250rpms(~3-400 less rpm). 0-23mph launch with full OEM ballast was ~6-7seconds(rough Iphone timing, max revs from 0-23). Top Speed no ballast was 41mph, achieved about 6 seconds at the max 5400rpms (same). This means we can still gain some pitch. Prop torque to the starboard side is much more pronounced. Awesome for us as we are 90% a goofy crew, made the wave better. For regular side, you will need more weight on port side and less on the starboard side to overcome the prop torque bias. The higher the RPMs the more pronounced the prop torque to the right.
Next stop: 16x16 test in ~2 weeks. I'll post up some pics later tonight.
My claim: We are basically stuck in 3rd-4th gear with how they are prop'd with the OEM Acme 15x14.25s(max dia then pitch traditional prop).
Bottom Line- Eric at OJ fab'd a trial 16x15 for me to test. Big improvement, And there is room for more improvement.
Specs: we are talking 550hp boats with the 1.48:1 trannys. Not the 2:1 trannys with 17" props, apples and oranges. I don't subscribe to the "Easy RPM" and "Hard RPM" theories. I assert that there is no situation where you are burning less gas at higher 3000rpm than at a lower rpms 2750rpm for example(huge brawl on here a few years back, shots out to you "easy and hard RPM" theorists!), regardless of speed or weight. Just stay with me for a moment. I also feel like the 550 GPH consumption is not linear in nature... go over ~3200rpms and it starts to guzzle fuel, blower spins louder(no hard data to support other than my credit card after 175hrs, and how easy the engine seems to run under 3000rpms). My boat is approx 5-600lbs heavier than a standard G23, with extra batteries, stereo and lead for your reference on the numbers below, full 100% tank of gas 2 on board. with the 16" prop, you still have 3-4" of clearance to the hull. OJ's 16" prop was much thicker, heavier and sturdier than the ACME, huge difference.
Results: The 16x15 accelerated faster and more evenly, absolutely no need to over-rev to achieve your desired speed when you go heavy to get going(save gas). You simply accelerate up to it and stay there, this increased 16" dia significantly reduces prop slip. It ran between 200-500rpms less for every given activity. 23mph no ballast was ~2900rpms(~300+ less rpm), 23mph full 2850lbs OEM ballast NCRS 0 was ~3250rpms(~3-400 less rpm). 0-23mph launch with full OEM ballast was ~6-7seconds(rough Iphone timing, max revs from 0-23). Top Speed no ballast was 41mph, achieved about 6 seconds at the max 5400rpms (same). This means we can still gain some pitch. Prop torque to the starboard side is much more pronounced. Awesome for us as we are 90% a goofy crew, made the wave better. For regular side, you will need more weight on port side and less on the starboard side to overcome the prop torque bias. The higher the RPMs the more pronounced the prop torque to the right.
Next stop: 16x16 test in ~2 weeks. I'll post up some pics later tonight.
I sold my wife on this boat partially because you don't need to add weight. haha.
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