esfishdoc
Well-known member
Will be right here as soon as I get back late this afternoon! 
Rev 4 report for F225 on 2520XL
- Thread starter esfishdoc
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DaleH
FOUNDER of Classic Parker Forum
OK rich ... that's 2 official teases now ...
Remember the 3-strike rule, once more and you're outta here
Remember the 3-strike rule, once more and you're outta here
esfishdoc
Well-known member
Prop: Rev 4 14 5/8 X 15
Purchased from Andy at SIM
Price…… about 500 dollars
Reason: Looking for prop nirvana…. There is no substitute for horsepower but there are ways to make what you have work more efficiently.
Props Used Before Rev 4:
1. Stock black stainless Yamaha 14 ½ X 19 pitch
2. Stilleto 14.24 X 17 (about 300 from Overtons)
To summarize, the stock prop only got a WOT of 5300…. Lugging the engine.
Switched over to the Stilleto which gave a proper WOT of 5800 to 6000 and better hole shot and acceleration… slightly less economy. My favorite cruising speed of 25 mph unfortunately came at about 4700 RPM light and close to 4900 loaded. Since I do some offshore runs of 50 to 60 miles I wasn’t happy with all those high rpm hours….. lugging vs. high rpms.
The Rev 4 was chosen from any number of good possibilities and suggestions. The 15 pitch was chosen by the rule of thumb that states if you want to keep the same WOT rpm going from a three blade to a four blade then go down in pitch.
So… what did I find today?
Bear in mind that conditions were not ideal for comparisons. Today we had a steady 18 mph wind from the South and there was a solid one to 1 ½ foot tight chop with white caps. Most of the run out to fish was into the wind and with a slack current and head sea and the ride back was with the wind and following sea but against a 2 mph current.
The boat had about 60 gallons of 87 octane and two adult souls on board.
From the very beginning it was obvious this prop was meant for this boat. I experienced acceleration that surprised me. It makes it crystal clear that the stock prop had too much pitch but a good “bite” and that the Stilleto allowed the engine to rev up and accelerate better but was slipping a lot.
Just yesterday I had the boat out with the Stilleto but flat calm and clocked a WOT of 6000 and 35 mph. On the same stretch today I clocked a WOT of 6000 at 35 mph…. and 2 miles per gallon…. But the conditions were much rougher and I had more tabs down. This tells me the Stilleto was slipping much more than the Rev 4.
For much of the ride out, the throttle stayed in one position with the tach at 4700 with speeds of 25 to 26 mph with fuel economy a solid 2.5 mph.
What does all this mean?
The prop is obviously a big improvement over the Stilleto. Even when comparing ideal Stilleto conditions to poor conditions for the Rev 4 there is an increase in fuel economy by .3 to .5 mpg. There is also an improvement in speed at cruising RPMs.
More testing in calm conditions are needed and hopefully will be done later this week.
On the downside I can’t help but think a REV 4 in 17 pitch is needed to complete the testing. I really won’t know until I get some time in flat water and some time offshore with 170 gallons of fuel and 4 adults.
I didn’t appreciate anything like bow lift or stern lift with this prop. Everything about the handling of the boat seemed about the same.
I’ve also learned from reading about prop slip and using online prop slip calculators that the 2520 in its various configurations with 225 to 250 hp singles is going to slip much more than the same motor on a bass boat or lighter smaller hulls. This is just the way it is. No one is going to get 10% with a 2520 and an F225 although the MV will be less than the XL which will be less than a DV.
More data is needed but overall things are looking up. On a flat calm day I think there is a possibility of seeing 3.0 mpg traveling light and trimmed just right. I think I might have a 25 to 26 mph cruise at 4500 to 4600. I think I might need to get my hands on a Rev 4 17 pitch prop to try out…..
No black drum were killed during this experiment and no tackle was lost. I did see a friend of mine fishing 100 yards from us catch a 25 lb black drum so I know they are there despite being a couple weeks early.
Richard
Purchased from Andy at SIM
Price…… about 500 dollars
Reason: Looking for prop nirvana…. There is no substitute for horsepower but there are ways to make what you have work more efficiently.
Props Used Before Rev 4:
1. Stock black stainless Yamaha 14 ½ X 19 pitch
2. Stilleto 14.24 X 17 (about 300 from Overtons)
To summarize, the stock prop only got a WOT of 5300…. Lugging the engine.
Switched over to the Stilleto which gave a proper WOT of 5800 to 6000 and better hole shot and acceleration… slightly less economy. My favorite cruising speed of 25 mph unfortunately came at about 4700 RPM light and close to 4900 loaded. Since I do some offshore runs of 50 to 60 miles I wasn’t happy with all those high rpm hours….. lugging vs. high rpms.
The Rev 4 was chosen from any number of good possibilities and suggestions. The 15 pitch was chosen by the rule of thumb that states if you want to keep the same WOT rpm going from a three blade to a four blade then go down in pitch.
So… what did I find today?
Bear in mind that conditions were not ideal for comparisons. Today we had a steady 18 mph wind from the South and there was a solid one to 1 ½ foot tight chop with white caps. Most of the run out to fish was into the wind and with a slack current and head sea and the ride back was with the wind and following sea but against a 2 mph current.
The boat had about 60 gallons of 87 octane and two adult souls on board.
From the very beginning it was obvious this prop was meant for this boat. I experienced acceleration that surprised me. It makes it crystal clear that the stock prop had too much pitch but a good “bite” and that the Stilleto allowed the engine to rev up and accelerate better but was slipping a lot.
Just yesterday I had the boat out with the Stilleto but flat calm and clocked a WOT of 6000 and 35 mph. On the same stretch today I clocked a WOT of 6000 at 35 mph…. and 2 miles per gallon…. But the conditions were much rougher and I had more tabs down. This tells me the Stilleto was slipping much more than the Rev 4.
For much of the ride out, the throttle stayed in one position with the tach at 4700 with speeds of 25 to 26 mph with fuel economy a solid 2.5 mph.
What does all this mean?
The prop is obviously a big improvement over the Stilleto. Even when comparing ideal Stilleto conditions to poor conditions for the Rev 4 there is an increase in fuel economy by .3 to .5 mpg. There is also an improvement in speed at cruising RPMs.
More testing in calm conditions are needed and hopefully will be done later this week.
On the downside I can’t help but think a REV 4 in 17 pitch is needed to complete the testing. I really won’t know until I get some time in flat water and some time offshore with 170 gallons of fuel and 4 adults.
I didn’t appreciate anything like bow lift or stern lift with this prop. Everything about the handling of the boat seemed about the same.
I’ve also learned from reading about prop slip and using online prop slip calculators that the 2520 in its various configurations with 225 to 250 hp singles is going to slip much more than the same motor on a bass boat or lighter smaller hulls. This is just the way it is. No one is going to get 10% with a 2520 and an F225 although the MV will be less than the XL which will be less than a DV.
More data is needed but overall things are looking up. On a flat calm day I think there is a possibility of seeing 3.0 mpg traveling light and trimmed just right. I think I might have a 25 to 26 mph cruise at 4500 to 4600. I think I might need to get my hands on a Rev 4 17 pitch prop to try out…..
No black drum were killed during this experiment and no tackle was lost. I did see a friend of mine fishing 100 yards from us catch a 25 lb black drum so I know they are there despite being a couple weeks early.
Richard
captbone
Well-known member
What was WOT with the Rev4?
I am a little confused on what RPM the Stilleto and the Rev4 gave you.
I think the 17 Rev4 will be exactly like your 19pitch Yamaha 3 blader in RPM but give better holeshot, cruise and speed.
I am a little confused on what RPM the Stilleto and the Rev4 gave you.
I think the 17 Rev4 will be exactly like your 19pitch Yamaha 3 blader in RPM but give better holeshot, cruise and speed.
esfishdoc
Well-known member
captbone":182b39km said:
WOT with the Rev 4 today was 6000 which was about the same as the Stilleto (I first reported 5800 for the Stilleto but just yesterday clocked a WOT of 6000 with the Stilleto on slick calm water)
I'll know more when seeing how it performs on calm water.
Outta Here
Well-known member
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Rev 4 props are designed to be direct replacement for 3 bladers. For example, if you reach max RPM's with your 3 blade 17 pitch, use a Rev 4 17 pitch also. Expect a 50 to 100 RPM drop with 4 blade.
IMO, biggest advantage of Rev 4 is tremendous "bite". If you do not raise motor to take advantage, you're shortchanging yourself, in terms of top speed and fuel milege.
IMO, biggest advantage of Rev 4 is tremendous "bite". If you do not raise motor to take advantage, you're shortchanging yourself, in terms of top speed and fuel milege.
PaulH / Emily S
Well-known member
On my new F250 on a 2520DV the slippage is well under control. Calculated as follows (15.75x15 SWSII, WOT = 6000RPM, 38 MPH, note F250 has 2:1 gear ratio) :
6000 RPM x (1 prop rpm/2 engine rpm) = 3000 PRPM
3000 PRPMx(15"/rev) = 45,000"/min
45,000"/min x (60min/hr) = 2,700,000 "/hr
2,700,000 "/hr x (1 ft / 12") = 225,000 ft / hr
225,000 ft/ hr x ( 1 ft/5280 miles) = 42.6 MPH
42.6 theoretical vs 38 MPH actual
6000 RPM x (1 prop rpm/2 engine rpm) = 3000 PRPM
3000 PRPMx(15"/rev) = 45,000"/min
45,000"/min x (60min/hr) = 2,700,000 "/hr
2,700,000 "/hr x (1 ft / 12") = 225,000 ft / hr
225,000 ft/ hr x ( 1 ft/5280 miles) = 42.6 MPH
42.6 theoretical vs 38 MPH actual
DaleH
FOUNDER of Classic Parker Forum
I get 12% slip for those numbers. To me, where the motor runs in the RPM range @ WOT is the number to shoot for, then MPG. IMHO, if people want MPH ... buy another brand boat !
!PaulH / Emily S
Well-known member
Dale - I think 12% is pretty good, and I'm thrilled with getting 2+ MPG under all loads to date.
I agree with you on all counts, prop to correct WOT RPM, and yes, Parkers are hard to push and not speed demons ......
I agree with you on all counts, prop to correct WOT RPM, and yes, Parkers are hard to push and not speed demons ......
BuddahB
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Your stock stainless prop was 14 1/2 x 19? I purchased my 25SE used but the prop on the boat was a Yamaha 15 1/4 x 17. I too tried getting more speed and efficiency out of mine going with the Stilleto, an Apollo with hub kit in pitches and diameters similar to the ones you posted, and after all that and now being the proud owner of a library of spare props I've come back to the 15 1/4 x 17 Yam which is the one the boat seems to run best with.
Is your boat a mod V like mine with a 16 degree deadrise?
Is your boat a mod V like mine with a 16 degree deadrise?
captbone
Well-known member
Put some of those spare props up for sale on this site and ebay. They might sell pretty good.
I assume you are swinging a SWII 17pitch instead of the black steel 17M on your 25SE?
I would say try an Enertia 18pitch or a Rev 4 in 17pitch would be the ticket for your hull.
I assume you are swinging a SWII 17pitch instead of the black steel 17M on your 25SE?
I would say try an Enertia 18pitch or a Rev 4 in 17pitch would be the ticket for your hull.
