Real Time Thrust Tests with Complete Boats

I know the feeling. But you might be surprised, I thought mine was going to be 3000 pounds but it wasnt. Our boats are setup similar except mine has a cast iron motor. Maybe one day we can get it on the trailer and see for sure.
 
Here is some good info the Waterthunder motor was brought to me because the new owner wanted us to fix an ignition problem with the MSD. So we took the motor and installed a 2.38 and ran it on our thrust tester. We set the RPM's to exactly the same they had it turning 5050RPMs on the trailer test. And made a few pulls then we set the pitch to turn 5,500RPM's. The only other change we made was for some reason someone removed the #5 chip and installed a number one chip in the MSD so we reinstalled the #5 chip. Here are the numbers going from 5050RPM's to 5500rpm's we picked up 286lbs of thrust can you imagine that 450RPM's picked up 286lbs of thrust. I can 5000RPM's is just below the sweet spot and the extra 500RPM's is where the motor and prop both start working.

So the next test we are installing a 2.68 and we will post the difference. I will tell the new owner how much more thrust he makes with the 2.68 over the 2.38 then the difference can be compared to the numbers they get with the 2.68 on the thrust trailer. I know it's going on a different boat so it will be interesting to see how changing the rigging will effect the forward thrust. I know when we raise a motor just an inch it changes the readings let alone how much thrust can be lost going downward instead of forward.

I had somebody say it's not much but they had to agree when the heard we bent a few trailers down and ruined them. Obviously a bunch of force was pushing down if you can bend a trailer.

PS just changing the chip dramatically improves the idle when you have more timing at idle the motors run smoother and tend to shake less.


PS PS The MSD problem was in the harness it looks like somebody didn't flip the cam sensor polarities when the MSD was installed.
 
Soon as i get my boat back together I plan to pull a little pitch out of the prop and get into that sweet spot as well. Should be fun. My thanks to all that have added to this project. like my by line says the company of men who seek the truth are much prefered to those that think they have it. My boats are works in progress. One change sparks three more. A guy told me at a knife show years ago that he owned Abraham Lincolns original axe. But it had three new heads and fourteen new handles since it was in his hands. I am starting to feel the same way about my boats.
 
anvil said:
Soon as i get my boat back together I plan to pull a little pitch out of the prop and get into that sweet spot as well. Should be fun. My thanks to all that have added to this project. like my by line says the company of men who seek the truth are much prefered to those that think they have it. My boats are works in progress. One change sparks three more. A guy told me at a knife show years ago that he owned Abraham Lincolns original axe. But it had three new heads and fourteen new handles since it was in his hands. I am starting to feel the same way about my boats.
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If you wasn't gettin' so damn old you wouldn't have to keep fixin' stuff. :)
 
thanks olf art got a clean bill of health from my doc yesterday said if i did not get killed i would live at least another half hour in good health. If dont quit making stupid mistakes in my other wise excellent driving skills the next guy can fix whats left after the wreck. Just about have lora talked into turning the prop i bought from you into a celling fan. Hoo ya.
 
You know, I never thought about using an ultralight prop for a ceiling fan ..... that would be cool. :thumbleft:
 
olf art if its the same one i used to test my mini. the guys i ride with said the same thing it looked like a ceiling fan.
 
Waterthunder said:
Here is some good info the Waterthunder motor was brought to me because the new owner wanted us to fix an ignition problem with the MSD. So we took the motor and installed a 2.38 and ran it on our thrust tester. We set the RPM's to exactly the same they had it turning 5050RPMs on the trailer test. And made a few pulls then we set the pitch to turn 5,500RPM's. The only other change we made was for some reason someone removed the #5 chip and installed a number one chip in the MSD so we reinstalled the #5 chip. Here are the numbers going from 5050RPM's to 5500rpm's we picked up 286lbs of thrust can you imagine that 450RPM's picked up 286lbs of thrust. I can 5000RPM's is just below the sweet spot and the extra 500RPM's is where the motor and prop both start working.

So the next test we are installing a 2.68 and we will post the difference. I will tell the new owner how much more thrust he makes with the 2.68 over the 2.38 then the difference can be compared to the numbers they get with the 2.68 on the thrust trailer. I know it's going on a different boat so it will be interesting to see how changing the rigging will effect the forward thrust. I know when we raise a motor just an inch it changes the readings let alone how much thrust can be lost going downward instead of forward.

I had somebody say it's not much but they had to agree when the heard we bent a few trailers down and ruined them. Obviously a bunch of force was pushing down if you can bend a trailer.

PS just changing the chip dramatically improves the idle when you have more timing at idle the motors run smoother and tend to shake less.


PS PS The MSD problem was in the harness it looks like somebody didn't flip the cam sensor polarities when the MSD was installed.
Click to expand...

Dave,

What prop pitch did you use for the 5500 RPMs? Thanks.
 
I hate to state pitch angles because that will very from boat to boat depending on the rigging cage and seat package. We are making pulls with the 2.68 on it now and just like the other 100 times a 2.68 with a R blade has a sweet do all great spot at 5,400 engine RPM's the cruise is sweet and WOT is strong. Were gonna pull 6,000RPM's now and compare it to the sweet spot we will pick up a little but the cruise will fall way off. I'm sure the results will not merit turning more RPM's.

DSC_0347.JPG
 
Man come on now, don't jump in the middle of there test because you weren't on top. You never wanted to share info and that's fine but don't screw up their thread.
 
Give me a break data is data I just want people to see how turning 5,000RPM's is not a fair comparison to 5,500 let alone a 2.38 vs a 2.68. How could me ever posting anything effect their test. Anyway the owner of the motor thought he had a timing chain problem it turns out somebody just didn't install his MSD correctly so I fixed it for him.
 
good point Dave ... ya gotta hit the engines power curve to get the power .. a 600 hp engine at 6000 rpms is not 600 hp at 5000 rpms LOL even I know that one
 
ALl good JMO data is data, the cool thing is if you could put the complete boat on the trailer and see what changes with the rigging, heck nobody gave cntry crap for posting about his testing :D :D Be cool to have both kind of testing

Question if you have a 2.68 turn 5400 rpm = 2014 prop rpm
then you have 2.5 turn 5000 rpm = 2000 rpm

I know mine is a blower but would that not be the case for me why my boat liked the 2.5 better than 2.6??
 
Waterthunder said:
Here is some good info the Waterthunder motor was brought to me because the new owner wanted us to fix an ignition problem with the MSD. So we took the motor and installed a 2.38 and ran it on our thrust tester. We set the RPM's to exactly the same they had it turning 5050RPMs on the trailer test. And made a few pulls then we set the pitch to turn 5,500RPM's. The only other change we made was for some reason someone removed the #5 chip and installed a number one chip in the MSD so we reinstalled the #5 chip. Here are the numbers going from 5050RPM's to 5500rpm's we picked up 286lbs of thrust can you imagine that 450RPM's picked up 286lbs of thrust. I can 5000RPM's is just below the sweet spot and the extra 500RPM's is where the motor and prop both start working.

So the next test we are installing a 2.68 and we will post the difference. I will tell the new owner how much more thrust he makes with the 2.68 over the 2.38 then the difference can be compared to the numbers they get with the 2.68 on the thrust trailer. I know it's going on a different boat so it will be interesting to see how changing the rigging will effect the forward thrust. I know when we raise a motor just an inch it changes the readings let alone how much thrust can be lost going downward instead of forward.

I had somebody say it's not much but they had to agree when the heard we bent a few trailers down and ruined them. Obviously a bunch of force was pushing down if you can bend a trailer.

PS just changing the chip dramatically improves the idle when you have more timing at idle the motors run smoother and tend to shake less.


PS PS The MSD problem was in the harness it looks like somebody didn't flip the cam sensor polarities when the MSD was installed.
Click to expand...

We also tested at higher RPM. I believe it was 5400 or maybe 5450. (Don't have the data in front of me right now) We did see an improvement but no where near 286 lbs. We will be posting the numbers very soon for this boat and several others. I will also test with the various MSD tune chips in future tests. We may be able to educate MSD. (They recommended the #1 chip)
 
HuntingBigun said:
ALl good JMO data is data, the cool thing is if you could put the complete boat on the trailer and see what changes with the rigging, heck nobody gave cntry crap for posting about his testing :D :D Be cool to have both kind of testing

Question if you have a 2.68 turn 5400 rpm = 2014 prop rpm
then you have 2.5 turn 5000 rpm = 2000 rpm

I know mine is a blower but would that not be the case for me why my boat liked the 2.5 better than 2.6??
Click to expand...

Testing is good for the business regardless of the method if the results are not bias towards one product. If one product is proven to be superior in a given application so be it. It isnt bragging if you can do it.
 
We had to make changes to the pitch and the chip to make the big improvement. The little 500HP is right there with them 600HP motors and the 600 plus motors have dyno sheets!Were more then happy with the results and now the polarities were swapped on the MSD so the new owner should be happy with his motor. Didn't even charge him to fix work we didn't do.
 
so dave how much more thrust, on your machine, did the customers boat with the new 2.68 vs the old 2.38 turning 5500.
 
Greetings SA Fans ....

Here we go with our next series of Charts and Postings. This is but one example of several charts that will display how a single boat, tested under the same conditions, performs with different props, various configurations, with different pitch and rpm settings.

Additional charts may display the same prop on all boats tested, etc.... So much MORE to come !!!!
 

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