Why don't I ever see dyno's?

[DAG]

This is my office chair when I browse the X. My 20mil stroked keyboard dyno's at 300HP

 

[kevbo]

We should dyno the pump first. Then we can make the engine match the load.

 

[Fro Diesel]

Also was thinking about billet gas caps and the like. Heavier, doesnt float, can corrode, annodizing can fade, but its better because it looks cool. Even if php put out the same exact dyno chart as xmetsl or dasa, people would still spend twice as much to get billet.

I like billet gas caps BC you can WELD a camera to them. Only reason I bought one. Thrillhill mount it should be called.

 

[Ratking]

I can make my dyno read whatever I want it to read. HP numbers are kind of irrelevant in any form of motor sports. Yes they are a great tuning tool but at the end of the day the true results show when the engine is put to its intended use, can't fudge those numbers.

What does that even mean? A proper calibrated dyno shows exactly how the motors perform, nothing more. How is HP and torque numbers irrelevant? Have non of you proper education with regard to physics 101?
Sorry boys, but this sounds more like a religion than facts to me. You just disregard torque and powerband and say that you know this better than a proven way of analyzing how a engine perform?

How can you say that a dyno plot with enough parameters does not cover how the engine will behave? You can tell how much torque the engine outputs for a given engine speed. I would love to get a good explanation(rational that is) why a dyno plot does not give a good picture about how an engine behave.

 

[Big Kahuna]

What does that even mean? A proper calibrated dyno shows exactly how the motors perform, nothing more. How is HP and torque numbers irrelevant? Have non of you proper education with regard to physics 101?
Sorry boys, but this sounds more like a religion than facts to me. You just disregard torque and powerband and say that you know this better than a proven way of analyzing how a engine perform?

How can you say that a dyno plot with enough parameters does not cover how the engine will behave? You can tell how much torque the engine outputs for a given engine speed. I would love to get a good explanation(rational that is) why a dyno plot does not give a good picture about how an engine behave.

If you have the wrong prop size, pump nozzle size, wrong pump size 140-144-148-155-160-162mm. If you have not optimized your driveline those DYNO numbers really do not mean squat. It is a baseline.

 

[Ratking]

If you have the wrong prop size, pump nozzle size, wrong pump size 140-144-148-155-160-162mm. If you have not optimized your driveline those DYNO numbers really do not mean squat. It is a baseline.

But that is another part of the driveline that needs to be taken in to account. That does not rule out that knowing how your engine perform is unnecessary? Let say that you have a brand x 1000cc motor giving y powerband on a dyno. The next engine builder provides another motor with the same plot trend but a starting point y+20hp. How can you say that this motor is not more capable? Maybe you need to change the pump configuration due to more aviable torque, but that does not make a dyno plot not useful when choosing an engine.

 

[thomps33]

A dyno will tell you what your engine is capable of. It is up to you find the right set-up to optimize that capability for its intended purpose. If you're shelling out $5000+ for an engine it would be nice to know what your getting. Having said that, I don't think the market is big enough to justify getting dyno results, you would have to run all the engines on the same type of dyno to get comparable results. The stand-up pwc is a niche market, and big dollar aftermarket engines are just a fraction of an already small market.

 

[masterblaster]

ratking,this has been going on forever,guys saying that dyno isnt worth doing because they cant match the load of dyno to pump.this changes pipe temp and fuel demand,on and on and on.almost all these guys have nothing to gain by a back to back dyno run on the same day with consumer motors like what is discussed here.There will be many losers and only one winner.

There are a select few that use dynos very effectively with motors and pipes for skis,most wont tell you that though.Sure a pipe developer would have to do water testing as well especially on a manual water injected pipe,but to not use a dyno? lol ok. How many dyno tuned and tested cars dont get road testing as well, kinda goes without saying imho

 

[Big Kahuna]

A dyno will tell you what your engine is capable of. It is up to you find the right set-up to optimize that capability for its intended purpose. If you're shelling out $5000+ for an engine it would be nice to know what your getting. Having said that, I don't think the market is big enough to justify getting dyno results, you would have to run all the engines on the same type of dyno to get comparable results. The stand-up pwc is a niche market, and big dollar aftermarket engines are just a fraction of an already small market.

That is why I would do my research on the builder and what packages he has put together. PHP for example. When you follow Zack's advice and use all the components of his package you can get a damn good setup, if you dont, well, you may be chasing gremlins. Same with going with XScream, Run the package they recommend. I did this for the most part with my TLR setup. I deviated away from carb package but Todd knew it and gave me jetting specs. I also ran his carb combo for a while also. Dead on. Know what your getting if your spending that kind of money.

 

[masterblaster]

Warning this maybe long....


Dynos are awesome tools when comparing any modification to an engine. The one thing about freestyle watercraft engines is Peak HP isnt necessarily what were are concerned with. Rev rate and power at lower rpm is what needs to be considered. Not all engine dynos can consistently measure the rev rate or "time of test". Which is how fast the engine pulls through the set rpm parameters of the pull. A water brake dyno would be the most common because it is the cheapest way to put a load against an engine. However a water brake dyno doesnt normally apply the load consistent enough for a "time of test" measurement to mean anything. You would need either an inertia dyno or an eddy generator electric dyno. Now your getting more expesive. Even though these engines cost alot of money non of us engine builders are getting rich. They are expensive because manufacturing small quantities like this industry requires cost ALOT of money. So spending the 30k+(and i mean +) on the proper dyno to fully understand which engine suits our needs best would not make the best business sense.

Now to the part i may later regret. I have a dyno.........

That being said my dyno is a water brake dyno. The stand is homemade but the water brake and all the measuring components are by stuska. They are very well know for water brake dynos of all kinds. I use this dyno for racing engines of another platform. I have never even mounted a water craft engine to the stand(i could easily). I just hadnt before seen the need to do so for water craft as there are alot of variables that exist when the engine is in the water that even the very best dyno would not replicate.

IF AND ONLY if there was enough interest and a good amount of volunteers i would do a "dyno day" at one of the free rides. Best part of my dyno is its on wheels and could be moved anywhere. I have a small shop and needed this to be the case as i dont have the space to dedicate to just a dyno room. Volunteers would have to be willing to take full responsibility for any engines failures while on the dyno. I would bring a few engines to set as a bench mark and we could see who is king of the hill if we had enough volunteers....

Just food for thought

Chuck Palmucci
CPT Enterprise LLC
609 510 3062

bumping the best post in the thread

 

[Ratking]

ratking,this has been going on forever,guys saying that dyno isnt worth doing because they cant match the load of dyno to pump.this changes pipe temp and fuel demand,on and on and on.almost all these guys have nothing to gain by a back to back dyno run on the same day with consumer motors like what is discussed here.There will be many losers and only one winner.

There are a select few that use dynos very effectively with motors and pipes for skis,most wont tell you that though.Sure a pipe developer would have to do water testing as well especially on a manual water injected pipe,but to not use a dyno? lol ok. How many dyno tuned and tested cars dont get road testing as well, kinda goes without saying imho

Have you ever seen somebody mapping/finetune a car to program a ECU on a road? I just don't buy it, but you are free to do. Because someone with an agenda tells you something doesn't make it true. What power that the engine produces is not usable to a pump? Please give me data that proves that the pump does not load the engine somewhat linear with the rpm within the pumps range. I just don't follow the logic.

Giving a dyno plot for a motor everyone knows make great power will be useful for everyone. Whatever you say about pump load is nonsense. If you have a plot over a known setup/motor, then that is something to work towards, unrelated to how the pump may influence the end performance.

 

[masterblaster]

ditto...lol

 

[yamanube]

Saying pump load renders dyno horsepower irrelivant is like saying gear ratio and tire size render dyno numbers irrelevant. An engine builder should not release his HP numbers because he has no idea what kind of tires the customer will be using.

 

[Quinc]

So the guys that race jet boats with engines and pumps are also wasting there time with dyno tuning?

A better thing to look for would be thrust. That would measure the pump as well.

http://www.dynomitedynamometer.com/pwc-dyno/pwc-dyno.htm

 

[glennbbautomachine]

Saying pump load renders dyno horsepower irrelivant is like saying gear ratio and tire size render dyno numbers irrelevant. An engine builder should not release his HP numbers because he has no idea what kind of tires the customer will be using.

If you don't release torque over time how can you get the correct gear, tire dia, convertor flash etc. If dyno numbers aren't published it's a big guessing game that gets expensive to the customer. Or buying a complete package from an engine builder is fine but can be expensive. How do I know.....................I'm an engine builder lol.

 

[alberta guy]

Racing is a whole different cup of noodles. Dyno tuning is more about getting the best most USEABLE power curve and then getting the rest of the driveline to work with that. Peak hp doesn't mean anything if its an useable curve. Look a supercross. all of the riders always say that the 450s have enough power. All the motor testing it to make it more useable, smoother, and rider friendly.

Also for a freestlye setup, you could have a 701 and a 1200. Just for examples sake to 70hp and 7000rpm both motors have the identical rpm and power curves. But the 1200 peaks at 200hp at red line while the 701 starts to fall off after 7000rpm. If when doing a flip or spin the ski is out of the water when both motors hit 7000 rpm, The extra power of the 1200 is not doing a thing to actually help the ski flip because the pump is not in the water making thrust

 

[WB1994]

I believe the op and title are talking about dynos. Why are people arguing about pumps and thrust?

 

[jason184]

What does that even mean? A proper calibrated dyno shows exactly how the motors perform, nothing more. How is HP and torque numbers irrelevant? Have non of you proper education with regard to physics 101?
Sorry boys, but this sounds more like a religion than facts to me. You just disregard torque and powerband and say that you know this better than a proven way of analyzing how a engine perform?

How can you say that a dyno plot with enough parameters does not cover how the engine will behave? You can tell how much torque the engine outputs for a given engine speed. I would love to get a good explanation(rational that is) why a dyno plot does not give a good picture about how an engine behave.

I mean by changing the correction factors on the dyno program the HP numbers can be varied in many ways so comparing one guys dyno number to another guys dyno number is not necessarily accurate. Brand X can easily make their engine look like it makes more power on paper then Brand Y but in reality Brand X had their dyno set to inflate the numbers. I have seen it done many of times in the marine and automotive world.

Like I said a dyno is a great tuning tool for the builder to see which setup (porting, carbs, pipe, ignition, etc) makes the most power on their engine. It is still not the tell all tool though.

 

[yamanube]

I believe the op and title are talking about dynos. Why are people arguing about pumps and thrust?

There was a claim that there is a disconnect between dyno numbers and real world performance due to driveline variables and therefore dyno numbers are somewhat irrelevant.

 

[Schmidty721]

I mean by changing the correction factors on the dyno program the HP numbers can be varied in many ways so comparing one guys dyno number to another guys dyno number is not necessarily accurate. Brand X can easily make their engine look like it makes more power on paper then Brand Y but in reality Brand X had their dyno set to inflate the numbers. I have seen it done many of times in the marine and automotive world.

Like I said a dyno is a great tuning tool for the builder to see which setup (porting, carbs, pipe, ignition, etc) makes the most power on their engine. It is still not the tell all tool though.

^^ This is a very accurate post. I work for a company that has 5 motorcycle chassis dyno's and a number larger than that of engine dyno's and durability stands.

Just between our chassis dyno's of the same manufacture there are variances of a few % in power numbers. Between the two different manufactures we use there is 8-10% variance. I can assure you our load cells are calibrated correctly and the software is using all the same correction factors. Keep in mind these correlation test are done in the same location, on the same day, with the same operator on the same bike. Spreading those 5 dyno's over the country with different operators, different temp, baro, humidity data systems, etc is going to create an even larger spread in variance.

Dyno's are a very powerful development tool. Yes, they are wildly used in marketing efforts too, but you have to take all of those published power number's with a grain of salt.

Testing two strokes is hard enough. Trying to successfully use a dyno to develop and measure a torque pull on an engine that needs to go from just off idle to peak power in under what, 2 seconds?, for a free style application is almost impossible. And then the question of accurately heating the pipe, controlling to rate of engine rev, how soon and hard they dyno loads the engine etc all come into play.