Does anyone have Full HP and Torque Info on outboards over 150 HP

[hwsiii]

I am trying to learn a lot more about motors than I now know. I have good knowledge of propellers but my knowledge of motors is non existent. When I was a kid I rebuilt one, only because I didn't have the money to buy a new one, but what little knowledge I had then I have lost with time and age.

I have never really understood the relationships between HP and Torque with different loads from different props and now it seems I need to know this information to further my research on propellers. I have a halfway acceptable power curve for a 350 CI motor with 292 maximum HP at 4,800 RPM, but I need the actual HP and or Torque numbers from a 1,000 RPM up to the maximum rated RPM at 250 RPM sequences for a motor so I can verify the REALITY of what is happening with specific props on a specific motor at any RPM. If I can get these numbers then I can prove to myself exactly what is going on at any specific RPM with that motor.

I have spent a lot of time and effort in building some spread sheets to identify everything I want to know that is going on. I just need the curves to verify or NOT verify what I think is happening. Below is a picture of the 350 motor information that I am trying to use to know what is happening at any point in time. This not the complete spreadsheet as it is too wide to place here and still be able to read the numbers, so I had to cut it.



So if any of you have a complete RPM and Torque curve I would appreciate it very much.



H

 

[Silvertip]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

GM has HP and Torque curves for their marine engines in their Marine Engine web site.
Go here:

http://www.gm.com/experience/technology/gmpowertrain/engines/specialized/marine/marine_engines.jsp

Or to go directly to the 5.7L Vortec page go here:

http://www.gm.com/experience/technology/gmpowertrain/engines/specialized/marine/2010_5700_Marine.pdf

 

[hwsiii]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

Thank you very much Silvertip.


H

 

[Silvertip]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

Sorry about missing the "outboards" bit. Saw the 350 Chevy and away I went. I don't know if any of the outboard manufacturers publish their HP and torque curves for either two or four stroke engines.

 

[hwsiii]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

Hey that helped me Silvertip, I am using those in the meantime. LOL The only thing that matters is that you are willing to help. I don't are if the curves are 15 years old or not, I just need the data to run my analysis with. I am not trying to be current, I just need some for my project.


Thanks again,


H

 

[jevery]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

I don't know if any of the outboard manufacturers publish their HP and torque curves for either two or four stroke engines.

That data's as much a closely guarded secret as market share.

Have you run across this, Engine Output Calculator.xls, it seems to relate to what you're doing.

 

[hwsiii]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

J, no I haven't and thank you very much for the software.


H

 

[seahorse5]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

You have to understand how the torque is measured that you see in the graphs. What you want to do for comparisons would only be valid for WOT acceleration, not for running down the river.

The throttle is wide open throughout the measured rpm range when hooked to a dyno. When you are running a boat, lets say at 3500 rpm, you are only using partial throttle (high intake vacuum) compared to WOT at 3500 rpm in dyno testing. There is a world of difference in hp, torque, and fuel consumption from real life cruising to published dyno runs at various speeds.

There have been torque and hp charts published online from time to time. Evinrude published some in recent brochures comparing their motors to Yamaha's in the 150 and 225 ranges.

There are dyno tests that cover partial throttle rpms, and those are called 2nd order or 3rd order curves. I've never seen those published anywhere online. Those are engineering reports that never leave the R&D department.

 

[hwsiii]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

Seahorse, I thank you very much for the information on Evinrudes and I did find the charts for the Evinrude and the Yamaha, so that helps me a lot.

I also redid my Prop Power curve analysis and equations and I think that I have found a way to include the cruising torque analysis you talked about. What I did was take the REAL HP required from the prop and add another column for cruising Torque, multiplying the HP required for the prop at that particular RPM and then using the formula for Torque and adding that column under Motor Torque cruising.

Would you please go over my analysis and see if you think everything is right.


Torque HP chart

H

 

[RotaryRacer]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

hws,

I am intrigued by this project you are working on. It is similar to a lot of the analysis work I did when I was competing with my RX-7 (Rotary). Now that all of my recreational focus has shifted to the more family friendly boating, I have started to get curious about a lot of things. HP/Torque of a given motor under given conditions is one of them. I have also thought a lot about ways to make older 2-strokes more efficient.

So, what is this project you are working on. I assume it is related to props. However, after going through a lot of your recent posts, I haven't found anywhere that you describe what the goal of your research is.

I'd be curious to learn more about what you are working on.

 

[hwsiii]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

Rotary, I have a 1985 RX7 with with Lamborghini doors and TV, but it only has a 12A motor, and it is sitting in the carport right now. LOL

I am attempting to do prop analysis for boats in every mathematical way I can to try and analytically analyze all the components and try to find shortcuts to predict the performance that should be expected from a particular boat and motor setup with very limited information, usually just a WOT throttle RPM and speed, but I have a form that I ask people to fill out which does give me much more information. I just have to be careful trying to use too much linear math to arrive at the answers, I have already made that mistake.

My knowledge of motors is extremely low and I am trying to improve it, it helps me understand better when I can run scenarios and see what is going on with the numbers. That is why I am making these spreadsheets and then charting them out so I can visualize what is happening.

Hopefully this will help me understand motors better, and I also am reading a lot to help me as well. But as I am past 60 it takes longer to understand things now than it did, especially when I have preconceived ideas.



H

 

[RotaryRacer]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

I have to agree that it would be nice to choose the right prop for a given use right away. The old trial and error method of selecting the right prop can get expensive.

I have to think though that it will be nearly impossible to account for all the variables. I think of things like the cup of a prop or wether or not the hub is vented. Things like that add such small nuances to the way a prop performs that it will be hard to know for sure what prop is right.

I haven't quite followed how you are arriving at some of your assumptions or measurements....specifically how did you calculate the cruising torque required. The values seem reasonable and the graph seems to make sense, however, without seeing the math it is hard to know how you got the numbers.

To me it seems like you are going to need this sort of data for many different motor/hull combinations to ever get to the point that you can determine the right prop without trial and error.

I'm not sure if this project is for business or pleasure, but it seems like it may be worth some investment in test equipment to get real world numbers. Fuel flow numbers will be about as close to real time power requirements as you will get. On a sophisticated fuel injected motor it should only be taking enough fuel to create the power required for the given conditions/requirements. That combined with some additional data acquisition in which you can log throttle position, speed, trim angle, and acceleration should give you a clear understanding of what the motor wants and needs for a prop.

Recently I have been looking into the dynomite marine dyno that connects right to the prop shaft on an outboard or I/O. While they aren't cheap, a tool like it could be invaluable in learning about the power/torque a given motor can produce under given circumstances. I imagine testing a given hull/motor combo on the water and getting as much real world data on fuel flow etc. and then duplicating as much as possible with the dyno where can get actual torque/hp data.

I guess again not knowing the full circumstances you are working with it is hard to know if going to that much expense makes sense.

 

[hwsiii]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

Seahorse, I thank you very much for the information on Evinrudes and I did find the charts for the Evinrude and the Yamaha, so that helps me a lot.

I also redid my Prop Power curve analysis and equations and I think that I have found a way to include the cruising torque analysis you talked about. What I did was take the REAL HP required from the prop and add another column for cruising Torque, multiplying the HP required for the prop at that particular RPM and then using the formula for Torque and adding that column under Motor Torque cruising.

Would you please go over my analysis and see if you think everything is right.

Rotary, here is where I am getting my data.

1. From an Evinrude pamphlet that Seahorse5 led me to. It was the specs for a Yamaha 150, and I just scaled it to a 70 HP Yamaha, it is not exact, but hopefully it is representative of that motor.
2. Then entering the maximum HP produced at each RPM
3. Then I enter the maximum RPM the motor turned with that prop in my formula as well as the stated HP
4. My program automatically figures the HP required for any specific RPM with that prop, so I know the HP used The constant was formulated by Dave Gerr, a noted Naval Architect
5. For my Motor Torque Available I just multiply the available HP used by the standard Torque formula
6. For my cruising Torque I just use the Prop HP required by the prop and multiply by the standard Torque formula
7. For my Prop Torque used cruising I use the standard Torque formula but I use the actual Prop RPM instead of the motor RPM
8. True MPH from a GPS
9. The Prop Pitch of the prop, it is a Yamaha Painted Stainless 17" pitch
10. The Gear Ratio of the motor

The boat is a custom built Outboard Dory 18' and the MPH attained are from his numbers (These are numbers from a REAL boat and NOT a theoretical exercise) hopefully this makes it simpler



I hope that explains it for you, but if not let me know.

To me it seems like you are going to need this sort of data for many different motor/hull combinations to ever get to the point that you can determine the right prop without trial and error.

I am NOT trying to find the BEST prop, only a BETTER prop for the people who come here looking for a better prop. Finding the BEST prop ALWAYS requires testing at least a FEW props

I guess again not knowing the full circumstances you are working with it is hard to know if going to that much expense makes sense.

I am just trying to use all of the data at my disposal to understand all of the variables involved to come up with better basic formulas for my analysis of picking a better prop for any particular boat and motor combination. And it is not worth buying that unit to test with, just to get the numbers more exact.


H

 

[RotaryRacer]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

I have a few questions...

- Are you using any dyno data that you can get or are you actually getting the data youself?

- It isn't clear to me how the hull is taken into account. A given engine on one hull may perform very differently on another hull. Significantly different prop pitches may be required.

- Are you entering the MPH info for a given prop with on the water results or is that somehow calculated?

This is all very interesting to me.

Thanks for the follow up...you answered some of my questions while I was typing this reply.

 

[Dhadley]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

Rotary, you are exactly correct. The hull design does indeed play a major role. Probably more so than horsepower. We also have to factor in intended use.

Case in point - we used a 15' Allison to drag race the V4 class. The rules did not allow any mods to porting etc. Anyway, we ran a V4 looper that turned 8200 rpm in a 1/4 mile. We know that torque and hp intersect at about 5250 and hp falls off dramatically after 5800 rpm. So at 8200 rpm the motor probably wasn't making 90 hp, probably less.

But once up and going there was very, very little of the hull in the water. So at higher rpm there was very little hull drag. Therefore spinning the prop faster made the boat go faster.

More food for thought about torque - we ran the V4 looper (140 hp) and sometimes ran a 140 crossflow. The looper ran 82 mph and the crossflow ran about 74. Same boat, same weight, same gearcase, same prop. The looper ran 82 at 8200 rpm, the cf ran 74 at 7400 rpm.

H - you have the attention of Seahorse5 - thats more valuable than you may know....

 

[hwsiii]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

Dale, thank you very much for the heads up on Seahorse5. Hopefully he will have a little time in the future to help me with my spreadsheets to ensure I am getting them right.
Roatry, I changed everything in the above example to a real boat, so hopefully that answers your questions.


H

 

[seahorse5]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

As was stated previously, most propping out of a boat is trial and error due to differences in prop designs, prop pitch measurements (guesses, actually), and boat hull efficiency. Good techs can narrow down a prop to use as a starting point, DHadley is an expert at that, but on the water testing with controlled variables is the only true way.

What you are trying to do is what has already been done many years ago using a formula. It is found in naval architecture books. I haven't used it and cannot even think of the originator's name at the moment, but it does take into account hull efficiency which you have to know or make an educated guess on.

Also due to motor tuning, design, etc. you cannot extrapolate from a larger motor to a much smaller one using a torque chart.

Some of your calculations may be lucky guesses, but there is no scientific methods to your procedures.

 

[hwsiii]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

I beg to differ with your statement seahorse5, and in my opinion I don?t believe you spent enough time to really look over the spreadsheet and see where my data came from and you didn?t even mention that I had referred to Dave Gerr as the naval architect?s constant I used to predict some of the numbers, you just said you had seen it before.

What you are trying to do is what has already been done many years ago using a formula. It is found in naval architecture books. I haven't used it and cannot even think of the originator's name at the moment, but it does take into account hull efficiency which you have to know or make an educated guess on.
Some of your calculations may be lucky guesses, but there is no scientific methods to your procedures.

To be termed scientific, a method of inquiry must be based on gathering observable, empirical and measurable evidence subject to specific principles of reasoning. A scientific method consists of the collection of data through observation and experimentation, and the formulation and testing of hypotheses.
Scientific researchers propose hypotheses as explanations of phenomena, and design experimental studies to test these hypotheses. These steps must be repeatable in order to dependably predict any future results. Theories that encompass wider domains of inquiry may bind many independently-derived hypotheses together in a coherent, supportive structure. This in turn may help form new hypotheses or place groups of hypotheses into context.

Also due to motor tuning, design, etc. you cannot extrapolate from a larger motor to a much smaller one using a torque chart.

I definitely agree wholeheartedly that extrapolations like that are not correct, but I am sorry I didn?t have the HP curves for that motor, so I did the best I could. LOL

David Gerr is a renowned Naval Architect that has written many books, including The Propeller Handbook, and is recognized as an authority on propellers. This formula is directly from his book.

George Crouch is also a renowned Naval Architect that was a Dean of the renowned Webb Institute of Naval Architecture. His formula has been used by Naval Architects for over 60 years, so it has been tested many times over the years. Mercury Marine also uses Crouch?s formula for their prop picker at their website, and that is good enough for me. In fact they use a lot of Kenny?s numbers for their projections with Crouch.

The following numbers come from Evinrudes 2007 E-Tec Brochure and their performance reports and I cite both browser locations directly below here.

The boat is an Angler 204 FX with an Evinrude Etec 150 HP motor.

http://www.evinrude.com/NR/rdonlyre...93C7-DB18667AD407/0/2007_EvinrudeBrochure.pdf


http://www.evinrude.com/NR/rdonlyres/F4AB6628-0C3E-4134-8B50-3C7B0E4F9215/0/PE403.pdf

1. The HP curve you so graciously gave me the information on so I could find it, I want to thank you once again for your help in this.

2. Tachometer RPM

3. Propeller RPM

4. Taken directly from the Etec brochure

5. Prop thrust using the standard Prop Thrust Formula

6. Motor Torque available at this RPM and HP

7. Boat Weight, this is directly from Evinrude?s performance report

8. Theoretical Speed from the standard formula

9. Knots Speed from the standard speed for conversion from MPH

10. Real MPH, these numbers come directly from the performance report

11. Tach RPM, just there so it is close to the other end of the spreadsheet

12. Pitch, this is the prop pitch that was used for this boat

13. Gear Ratio, this is the gear Ratio for the Etec 150 used on this boat

A & B. This is David Gerr?s constants for deriving HP used by a specific prop on a specific boat

C. This is the HP derived from using Gerr?s constants

D. This is George Crouch?s formula for finding the HP attained from a specific speed on a boat, after calculating his constant from the weight and speed of the boat

E. Excess HP available is calculated from Motor output HP available at WOT and subtracting the Prop HP Required cruising

F. Motor Torque used cruising is figured from the Prop HP required cruising and the standard Torque formula

G. Prop Torque used cruising, is calculated using the motor torque used cruising and the gear ratio of the motor

H. This is for my uses only

Crouch and Gerr chart analysis of consensus

If you would please show me where I am not using scientific methods in my spreadsheet, I would be very pleased to know this, because I definitely think everything in it is scientific.

Although I have found in the past that I am NEVER wrong, UNLESS I am breathing. LOL



H

 

[seahorse5]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

Yep, it was Crouch's name that I couldn't remember.

 

[4JawChuck]

Re: Does anyone have Full HP and Torque Info on outboards over 150 HP

I have read all the posts in this thread and there seems to be some confusion about motor ratings.

First off all that matters is torque, HP is a mathematical function of rpm and torque and really doesn't tell you anything other than it makes a certain amount of torque at a specific rpm. To add to the confusion the point of maximum torque production does not occur at the point of maximum HP.

Since this project is not delineated in the thread it is impossible to determine what it is your trying to achieve.

Is it maximum fuel economy at cruise rpm?

Is it maximum acceleration?

Is it maximum speed with specific pitch props?

In general a propeller is a variable load on the motor that changes efficiency at speed, really what you need to know are the load/efficiency of the different props as it relates to their advertised pitch. Add different gear case ratios to the equation+propeller blade count=you can never find the answer without testing props.

A torque output device is the same no matter what name is on the hood, they all do the same thing but with different multiplication factors created by their gear case ratios and torque curve. Before any study can be done to relate props to motor ratings you need to test the props to find out how their shape relates to drag and efficiency at specific rpm. In summary what you really need to know is not the torque curve of the output device but the nature and relationship of the load to rpm which is strictly a function of propeller design. You will never be able to graph or understand how to answer any of the above questions without knowing prop data.

I think the question should be;

"Does anyone have any rpm/drag/efficiency data for the various blade count/designs/mfg's of specific propellers so I can relate hull weight/factor to a certain design/mfg of propeller."

Engine output is the easy part, it can easily be estimated especially since all outboards do not use complicated tune pipes which can significantly skew the torque curve at specific rpms. Propeller design factors far outweigh any particular motor output specification and gear case ratio relationship.