Real Time Thrust Tests with Complete Boats

Trust me I saw the video of that boat climbing the hill. It is nasty boat. Sounds awesome. If he has some really efficient heads that low timing may be best. My motor guy taught me the better the head the less timing a motor needs to run its best.

I just noticed the test had two variables. I know it is really hard to test with your own equipment (your own check book too). You have to beat the crap out of it and risk damage just to realize gains. It is a testament to how devoted the guys are that participated.
 
If you really want to see what each prop really does build a test stand with a wt motor that u can connect a dyno to and test each prop on that then u can turn any prop whatever rpm you want and you'll know what each prop will do you can take boat set up and everything else out jmo
 
Next Phase of Testing!

We are about to engage in the 3rd phase of testing. We will be focused on 2:38 vs 2:68 on same boat same prop, some testing on the poobought red sled with his new motor and a variety of prop changes with several boats.

Sensenich has volunteered to loan us a super wide for testing purposes and looks like we will have some RHR Sabers to test also. One other prop company may loan us a test prop as well. I know there has been some discussion with the second prop company. We appreciate these folks going out of their way to contribute with no guarantee whatsoever regarding the results.

Some changes since last test round:

-Poobought has replaced the 383 with a Waterthunder 6.2
-The 496 BBC Scorpion is now a Supercharged LSA with Stinger gear box (installation has just begun)
-The Jimmy White is about to have a 496 BBC with belt drive.


We will test the LSA with a 2:38 a Superwide, R and Saber. We will then use the same boat, motor, and props and test with a 2:68. I guess we will find out what ratio works better on this boat!

We have a lot of work ahead of us but when the motors are all installed we will be testing. Going to be a little while and we are open to suggestions for test day.
 
Motor swap is almost complete. Making up some water pipes tomorrow and exhaust on Saturday. With some luck a test drive on the Suwannee Sunday afternoon. So one motor swap down and one to go. And then back to some thrust testing.
 

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poobought said:
Motor swap is almost complete. Making up some water pipes tomorrow and exhaust on Saturday. With some luck a test drive on the Suwannee Sunday afternoon. So one motor swap down and one to go. And then back to some thrust testing.
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nice pic where do u have the braether line hooked to ?
 
JAMES said:
poobought said:
Motor swap is almost complete. Making up some water pipes tomorrow and exhaust on Saturday. With some luck a test drive on the Suwannee Sunday afternoon. So one motor swap down and one to go. And then back to some thrust testing.
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nice pic where do u have the braether line hooked to ?
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Thanks,and if your talking about the line coming from the gear box it's not hooked to nothing in the picture. Its just pushed down in the intake but with the cage on it is zip tied to it.
 
CarMotorBarge said:
Nice looking motor poobought. How many hours are on it? Is it brand new?
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No it's not new. It has fairly low hours but not sure exactly how much. I bought it from a good friend. He said it should be no more than 100.
 
Poobought isn't the only one with some new bling! LSA going on the Scorpion replacing the BBC.
 

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James I looked up the motor it was originally sold to Garrett in July of 08. So it's almost a 4 year old motor that has now been on three different hulls. Man I doubt a 4 year old 500HP motor can hang with several 600HP motors with dyno sheets and a bigger new supercharged LS motor.
 
poobought said:
fl cracker said:
cant hide money :lol:
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:lol: Well at least we know he had some but maybe not so much now.
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http://www.crateenginedepot.com/LSA-62L-SC-556-HP-Crate-Engine-19211708-P2385C2.aspx price isn't bad depending on how much extras you have to buy to get her running.
 
Yup. 25% reduction in pitch resulted in 7.99% increase in RPM and 6.05% increase in thrust. I enjoy looking for relationships in performance numbers.

What I get here is the relationship between decreasing pith by 25% and increasing thrust by 6.% its close to a 4:1 ratio, pith to thrust at this throttle setting. It is about 8% increase in RPM and thats about a 3:1 ratio. Fun stuff.
 
Update, Roxy and I finished up the motor swap today on my boat. We test drove it in my swamp and hay field and I'm thinking we will see a pretty big gain in thrust numbers. The motor run flawlessly and felt very strong. And believe it or not it even quieted my Rattletator down ALOT. Now on to getting Roxys New fire breathing Dragon installed.
 
It took awhile but I learned how to quiet them down on the EFI motors you can set them up where there is no clatter. We also used this to get Hamants 4 cyl cont to run smooth.
 
Dave, I was very suprised to hear how much the new motor smoothed out my box. It was misarable to drive before and now you can barely hear it. I guess the smoother cam in the motor really makes alot of difference. Its the smoothest carburated motor I've ever driven.
 
It is time for an update!

We have done a little more testing and a lot more work!

The 383 Scorpion boat now has a 6.2 Waterthunder, 2:68 rotator and 82" R. This is the same motor that was on the Jimmy White boat on the first round of testing. The main difference is the gear ratio and a more aggressive tune with the MSD ignition box. We did break one rule.........we changed 2 things before re testing.

The BBC Scorpion boat now has a Supercharged LSA motor from Marine Power. The HP rating is almost exactly the same as the BBC at 550. Ratio was 1.91 on the BBC. Changed to 2:38 on the LSA, tested and then changed to 2:68 and tested again. We also used 82" R blades then changed to 82" S blades. (Thank you to Sensenich for providing the S blades for testing purposes)

We also changed the BBC Scorpion from single rear driver, double up front to an air ride suspension with side by side driver and triple up front. Even though the air ride is much heavier the total boat weight dropped just over 300 lbs.

We have the test results for the changes above and just need to get them in a format to post.

We are also going to share some purely subjective "seat of the pants" opinions. Also will have some results of side by side holeshot performance by 3 of the test boats. That part is way more fun than trailer testing!

We are going fishing this weekend.......to much boat building and testing lately!
 
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