dyno numbers
12-19-2005, 07:20 PM
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Re: dyno numbers
well... point proven. lots of folklore and voodoo here. the dyno is a tool like anyother and the mathematics that allow the data correlation are well established and proven. everyone that says they have gone faster with slower motors is wrong. everyone that says that they ' tune by ear" is wrong. everyone that says that they can throw parts together in some haphazard fashion and end up with better motors than contientious and well skilled professionals is wrong. it is a romantic notion but simply not the truth.
a skilled and well trained professional will produce the correct motor for the correct application with the correct power band and the maximum reliability 99 times out of the 100 instances. the one random time that the homebuilder gets lucky is just that... luck and not even remotely repeatable. that was not my point in the beginning and is not now.
my point is and remains that the number of genuinely skilled engine builders that take the time and apply a true and genuine engineering approach to the design of a combination and package for a customer and then spend even more time on the development of that package in a ( again) a fundementaly and scientifically sound engineering manner are few and far between. for the most part it has been my experience with lots and lots of engine shops that their engineering and design is merely a matter of believing what the sales people are telling them about the parts they are buying.
it is also my experience that the dyno sheets that accompany these motors are mostly self serving fiction and seldom , if ever, represent what the truth of the matter is... and even at that it isn't that simple... again... my experience is in the cars and not boats but i can tell you that the same motor i built for road america or daytona was NOT the same motor that i built for sebring or mid ohio. if you are going to spend the entire race accelerating off slower corners then motor better have the cam advanced a couple degrees and have small high velocity ports as opposed to a motor thats going to daytona where the ports can be decidedly bigger and the sacrifice of 40 hp down low to make the same 40 up top is a MUCH better deal.... it is not only the AREA under the curve but the very shape of the curve itself.
i guess all i am saying is ( again) in the real world there are no magic beans and magic turbulators or magnetic fuel aligners that will make you 50 hp for free...and no easter bunny either. when someone tells you they are making 650 hp from a 454 on 87 octane fuel with a single four barrel just nod and keep your money in your pocket...
and then look for someone that will tell you the truth
a skilled and well trained professional will produce the correct motor for the correct application with the correct power band and the maximum reliability 99 times out of the 100 instances. the one random time that the homebuilder gets lucky is just that... luck and not even remotely repeatable. that was not my point in the beginning and is not now.
my point is and remains that the number of genuinely skilled engine builders that take the time and apply a true and genuine engineering approach to the design of a combination and package for a customer and then spend even more time on the development of that package in a ( again) a fundementaly and scientifically sound engineering manner are few and far between. for the most part it has been my experience with lots and lots of engine shops that their engineering and design is merely a matter of believing what the sales people are telling them about the parts they are buying.
it is also my experience that the dyno sheets that accompany these motors are mostly self serving fiction and seldom , if ever, represent what the truth of the matter is... and even at that it isn't that simple... again... my experience is in the cars and not boats but i can tell you that the same motor i built for road america or daytona was NOT the same motor that i built for sebring or mid ohio. if you are going to spend the entire race accelerating off slower corners then motor better have the cam advanced a couple degrees and have small high velocity ports as opposed to a motor thats going to daytona where the ports can be decidedly bigger and the sacrifice of 40 hp down low to make the same 40 up top is a MUCH better deal.... it is not only the AREA under the curve but the very shape of the curve itself.
i guess all i am saying is ( again) in the real world there are no magic beans and magic turbulators or magnetic fuel aligners that will make you 50 hp for free...and no easter bunny either. when someone tells you they are making 650 hp from a 454 on 87 octane fuel with a single four barrel just nod and keep your money in your pocket...
and then look for someone that will tell you the truth
12-19-2005, 07:22 PM
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Re: dyno numbers
If I may step in on this subject and ask a question about Dyno results and get some opinions from all of you who own and operate Dynos...
We (my engine builder and I) just finished dynoing my 325 hour HP500 carbed engine. Using an automotive header, it made 450 peak horsepower and 455 ft-lbs of torque at 5200 rpms. The torque number decreased steadily from 550 ft-lbs @ 2600 rpms down to 455 @5200. We will use this as a baseline up against the new builds. I have talked him into modifing his dyno set-up to allow us to test and tune the new motors using a wet marine exhaust. Can I compare the old to the new now? Or, should we run the new motor using the same set-up as the old motor?
I really want to run the new motors wet, so I can tune the carbs and have them broke in and ready to run in the spring. I already know what the boat ran before with the old motors. So can I take the difference between the new to calculate props and speed before I hit the water?
Sugestions please!!
Thanks,
Dave
We (my engine builder and I) just finished dynoing my 325 hour HP500 carbed engine. Using an automotive header, it made 450 peak horsepower and 455 ft-lbs of torque at 5200 rpms. The torque number decreased steadily from 550 ft-lbs @ 2600 rpms down to 455 @5200. We will use this as a baseline up against the new builds. I have talked him into modifing his dyno set-up to allow us to test and tune the new motors using a wet marine exhaust. Can I compare the old to the new now? Or, should we run the new motor using the same set-up as the old motor?
I really want to run the new motors wet, so I can tune the carbs and have them broke in and ready to run in the spring. I already know what the boat ran before with the old motors. So can I take the difference between the new to calculate props and speed before I hit the water?
Sugestions please!!
Thanks,
Dave
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12-19-2005, 07:37 PM
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Re: dyno numbers
apples to apples. if you really care you will re run the baselines in the configuration you are going to run the finished product... however the bottom line is always what are you trying to accomplish.... set a goal and a hard target and design your configuration around that.. regardless of what it is... decide at what rpm you will want to run and what fuel system you are going to drive it with... THAT will define the port sizes and cam profile... then decide what fuel is available and that will define your compression ratio... the rest is hard parts... and how long you want things to last....pistons with thick heavy rings will last a long time but make less power than thin rings... etc etc....
the first element is always to decide precisely what you want... then the configuration becomes almost self evident.
and the jetting is everything on a carburetted motor.... you will need to be prepared with all manner of jets , powervalves and the like when you get on the dyno... and step testing is what you are going to want to do as opposed to sweep testing.
if you are on your game youll set up the exhaust with exhaust gas temp sensors and jet that way... thats the only way you know whats really happening.
the first element is always to decide precisely what you want... then the configuration becomes almost self evident.
and the jetting is everything on a carburetted motor.... you will need to be prepared with all manner of jets , powervalves and the like when you get on the dyno... and step testing is what you are going to want to do as opposed to sweep testing.
if you are on your game youll set up the exhaust with exhaust gas temp sensors and jet that way... thats the only way you know whats really happening.
12-19-2005, 07:55 PM
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Re: dyno numbers
when my engine was dynoed , everything is on the engine as it would be in the bilge. only item not connected was the ps pump. all i may have to do is jet up 1 more size
when it is installed , but i should not have any problems(engine wise) and should live a good life on 87. i am satisfied with 1.04 hp per cube.
great thread...
when it is installed , but i should not have any problems(engine wise) and should live a good life on 87. i am satisfied with 1.04 hp per cube.
great thread...
12-19-2005, 08:04 PM
#25
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Re: dyno numbers
AXAPOWELL,
I am not a builder or dyno operator but common sense tells me that in order to compare old to new, you should use the same baseline configuration (i.e. setup). After that, go with the wet exhaust and observe the difference.
This thread has prompted me to read further into the world of dyno correction factors.
http://wahiduddin.net/calc/calc_cf.htm
As Smitty said, "It is the on Water Performance that tells the true story."
Russ
I am not a builder or dyno operator but common sense tells me that in order to compare old to new, you should use the same baseline configuration (i.e. setup). After that, go with the wet exhaust and observe the difference.
This thread has prompted me to read further into the world of dyno correction factors.
http://wahiduddin.net/calc/calc_cf.htm
As Smitty said, "It is the on Water Performance that tells the true story."
Russ
12-19-2005, 10:00 PM
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Re: dyno numbers
Originally Posted by stevesxm
well... point proven. lots of folklore and voodoo here. the dyno is a tool like anyother and the mathematics that allow the data correlation are well established and proven. everyone that says they have gone faster with slower motors is wrong. everyone that says that they ' tune by ear" is wrong. everyone that says that they can throw parts together in some haphazard fashion and end up with better motors than contientious and well skilled professionals is wrong. it is a romantic notion but simply not the truth.
a skilled and well trained professional will produce the correct motor for the correct application with the correct power band and the maximum reliability 99 times out of the 100 instances. the one random time that the homebuilder gets lucky is just that... luck and not even remotely repeatable. that was not my point in the beginning and is not now.
my point is and remains that the number of genuinely skilled engine builders that take the time and apply a true and genuine engineering approach to the design of a combination and package for a customer and then spend even more time on the development of that package in a ( again) a fundementaly and scientifically sound engineering manner are few and far between. for the most part it has been my experience with lots and lots of engine shops that their engineering and design is merely a matter of believing what the sales people are telling them about the parts they are buying.
it is also my experience that the dyno sheets that accompany these motors are mostly self serving fiction and seldom , if ever, represent what the truth of the matter is... and even at that it isn't that simple... again... my experience is in the cars and not boats but i can tell you that the same motor i built for road america or daytona was NOT the same motor that i built for sebring or mid ohio. if you are going to spend the entire race accelerating off slower corners then motor better have the cam advanced a couple degrees and have small high velocity ports as opposed to a motor thats going to daytona where the ports can be decidedly bigger and the sacrifice of 40 hp down low to make the same 40 up top is a MUCH better deal.... it is not only the AREA under the curve but the very shape of the curve itself.
i guess all i am saying is ( again) in the real world there are no magic beans and magic turbulators or magnetic fuel aligners that will make you 50 hp for free...and no easter bunny either. when someone tells you they are making 650 hp from a 454 on 87 octane fuel with a single four barrel just nod and keep your money in your pocket...
and then look for someone that will tell you the truth
a skilled and well trained professional will produce the correct motor for the correct application with the correct power band and the maximum reliability 99 times out of the 100 instances. the one random time that the homebuilder gets lucky is just that... luck and not even remotely repeatable. that was not my point in the beginning and is not now.
my point is and remains that the number of genuinely skilled engine builders that take the time and apply a true and genuine engineering approach to the design of a combination and package for a customer and then spend even more time on the development of that package in a ( again) a fundementaly and scientifically sound engineering manner are few and far between. for the most part it has been my experience with lots and lots of engine shops that their engineering and design is merely a matter of believing what the sales people are telling them about the parts they are buying.
it is also my experience that the dyno sheets that accompany these motors are mostly self serving fiction and seldom , if ever, represent what the truth of the matter is... and even at that it isn't that simple... again... my experience is in the cars and not boats but i can tell you that the same motor i built for road america or daytona was NOT the same motor that i built for sebring or mid ohio. if you are going to spend the entire race accelerating off slower corners then motor better have the cam advanced a couple degrees and have small high velocity ports as opposed to a motor thats going to daytona where the ports can be decidedly bigger and the sacrifice of 40 hp down low to make the same 40 up top is a MUCH better deal.... it is not only the AREA under the curve but the very shape of the curve itself.
i guess all i am saying is ( again) in the real world there are no magic beans and magic turbulators or magnetic fuel aligners that will make you 50 hp for free...and no easter bunny either. when someone tells you they are making 650 hp from a 454 on 87 octane fuel with a single four barrel just nod and keep your money in your pocket...
and then look for someone that will tell you the truth
12-19-2005, 10:41 PM
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Re: dyno numbers
Originally Posted by stevesxm
well... point proven. lots of folklore and voodoo here. the dyno is a tool like anyother and the mathematics that allow the data correlation are well established and proven. everyone that says they have gone faster with slower motors is wrong. it is a romantic notion but simply not the truth.
As for faster with a slower motor, you apparently have never raced a dry slick dirt track or a green race track. HP is not the be-all and end-all of short track racing. A point that any Saturday night racer could make. If you really want to make time, get the setup book from a veteran. Chassis setup and driving is what it is all about.
Engine builders that cater to the racing crowd live and die on the reputation and reliability of their product. Dismissing the majority of them seems a little arrogant to say the least.
12-20-2005, 04:42 AM
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Re: dyno numbers
truth in all of that... and apologize for it. on re-read it is dismissive in a lot of respects and for someone like myself , new in a forum and marine environment in general is simply out of line. sorry about that. re the "slick track " comment , that does in fact illustrate exactly what i was trying to say... those conditions on that day would require exactly what you say they would... NOT nec bigger numbers. and you as that professional in that arena would know that and build the correct motor. thats what being a professional is.
as for the other.. for sure you can make big numbers ( legit) with supercharging and turbo charging thats pretty straight forward and becomes more of a structural exercise than anything else... normally aspirated, nominally configured is a different deal... and that discussion could take 1500 pages...
i started this, not as commentary against anyone . just as a reminder to those in the engine BUYING business that there is more to selecting your vendor than that nice 5 color web page with that impressive curve or that piece of paper straight from the word processor.
racing is different... " res ipsa loquita" ( if i remember my latin correctly) that means " it speaks for itself" in racing , the dyno sheets mean nothing... and the motor shops live and die on the true performance of their product. the motors either perfrom or they don't and the evidence is there immediatly for everyone to see...
in the recreational " hot rod" arena both boats and cars, it becomes more a matter of salesmanship rather than truth. that annoys me and i let it show through and apologize for that completely... hard as this may be to believe at this point was just trying to be helpful and unfortunately let my figers type without my brain being in gear all the way.
i go down to the marina on any given day and there is always some guy standing next to his boat thats been hauled out and the guys are just yanking one of the motors and the story always starts with " i JUST bought this from a shop in miami. SUPPOSED to be fresh rebuild and in four hours on the way to anguilla its started making this noise and then..... "
well... at anyrate... you are right and im wrong. will try to stick to factual issues from now on rather than philosophy
as for the other.. for sure you can make big numbers ( legit) with supercharging and turbo charging thats pretty straight forward and becomes more of a structural exercise than anything else... normally aspirated, nominally configured is a different deal... and that discussion could take 1500 pages...
i started this, not as commentary against anyone . just as a reminder to those in the engine BUYING business that there is more to selecting your vendor than that nice 5 color web page with that impressive curve or that piece of paper straight from the word processor.
racing is different... " res ipsa loquita" ( if i remember my latin correctly) that means " it speaks for itself" in racing , the dyno sheets mean nothing... and the motor shops live and die on the true performance of their product. the motors either perfrom or they don't and the evidence is there immediatly for everyone to see...
in the recreational " hot rod" arena both boats and cars, it becomes more a matter of salesmanship rather than truth. that annoys me and i let it show through and apologize for that completely... hard as this may be to believe at this point was just trying to be helpful and unfortunately let my figers type without my brain being in gear all the way.
i go down to the marina on any given day and there is always some guy standing next to his boat thats been hauled out and the guys are just yanking one of the motors and the story always starts with " i JUST bought this from a shop in miami. SUPPOSED to be fresh rebuild and in four hours on the way to anguilla its started making this noise and then..... "
well... at anyrate... you are right and im wrong. will try to stick to factual issues from now on rather than philosophy
Last edited by stevesxm; 12-20-2005 at 04:46 AM.
12-20-2005, 07:30 AM
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Re: dyno numbers
Steve, thanks for your thoughts and welcome to the forum.
Here are some more of mine.
BTW I am not an engine builder, I have used their services for years and have been around racing of many types for most of my life.
Building a hi-performance engine is for the most part a thankless task. From what I see the real money for an average shop is in re-manufacturing specialty type motors. Repetitive stuff etc.
It is rare that an engine builder is given free rein to produce exactly what he wants to build except at the very top end of the market. There are always financial/time or other considerations.
Lets say that he has come up with a very reliable 600hp NA package which he can produce time after time. The customer takes the motor, puts it in his boat/car with his cooling/oil/fuel system and the motor fails because one of these items that was adequate for their old power is now inadequate. The engine builder often gets bad mouthed.
If you search this forum re oil coolers/ oil lines/ fuel pumps/ fuel regulators/ ignition timing. You will see what I mean.
There is indeed much more to selecting an engine builder than reading their sales pitch as you say. There are undoubtedly people that use sub-standard components, produce dyno sheets that are optimistic etc.
I think that in this day and age, the smart approach to buying a package performance motor is to research the builders in the various forums. Run a BBB report and go from there.
Had I started here when I moved up from a jet boat to an offshore type boat I would have saved a bunch of money. Same horsepower but a world of difference in the demands placed on the motor even at 4K rpm.
PS You may not be aware, but some of the people that have responded to this thread (not me) and added their anecdotes are an invaluable source of information and experience.
Here are some more of mine.
BTW I am not an engine builder, I have used their services for years and have been around racing of many types for most of my life.
Building a hi-performance engine is for the most part a thankless task. From what I see the real money for an average shop is in re-manufacturing specialty type motors. Repetitive stuff etc.
It is rare that an engine builder is given free rein to produce exactly what he wants to build except at the very top end of the market. There are always financial/time or other considerations.
Lets say that he has come up with a very reliable 600hp NA package which he can produce time after time. The customer takes the motor, puts it in his boat/car with his cooling/oil/fuel system and the motor fails because one of these items that was adequate for their old power is now inadequate. The engine builder often gets bad mouthed.
If you search this forum re oil coolers/ oil lines/ fuel pumps/ fuel regulators/ ignition timing. You will see what I mean.
There is indeed much more to selecting an engine builder than reading their sales pitch as you say. There are undoubtedly people that use sub-standard components, produce dyno sheets that are optimistic etc.
I think that in this day and age, the smart approach to buying a package performance motor is to research the builders in the various forums. Run a BBB report and go from there.
Had I started here when I moved up from a jet boat to an offshore type boat I would have saved a bunch of money. Same horsepower but a world of difference in the demands placed on the motor even at 4K rpm.
PS You may not be aware, but some of the people that have responded to this thread (not me) and added their anecdotes are an invaluable source of information and experience.
Last edited by Wobble; 12-20-2005 at 07:45 AM. Reason: typos, duh
12-20-2005, 08:12 AM
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Re: dyno numbers
Originally Posted by stevesxm
my point is and remains that the number of genuinely skilled engine builders that take the time and apply a true and genuine engineering approach to the design of a combination and package for a customer and then spend even more time on the development of that package in a ( again) a fundementaly and scientifically sound engineering manner are few and far between. for the most part it has been my experience with lots and lots of engine shops that their engineering and design is merely a matter of believing what the sales people are telling them about the parts they are buying.
I think in life we find this with almost any profession. The home builder with the fancy trucks and big ads in the paper may cut corners and use inferior products but because of the "show" he is considered good. Where as the guy driving a 1998 Dodge with 200K miles is a very skilled builder and refuses to use sub par material and low cost subs.
You bring out some good points about our industry and I agree the problem is if we combine the years you have been doing it, I have been doing it, Smitty's been doing it, and some others we still don't have enough experience to change human nature; we like new flashy stuff for the most part.
Salesman, I resemble that remark. My take on my profession. I am a problem solver. A customer calls with a need/problem. It is my job to solve his problem. Simple. It is not my job to sell him something that may increase the problem. By doing the first you keep customers, by doing the later they will look for other resources. When I got into sales in '95 in this industry a fellow by the name of Len Sabatine of Sabatine Automotive in Easton, PA was my first sale. Len to this day still buys from me and I am with my 4th company in this industry. It's all about problem solving.
Welcome to the board!!
Chris
