hi guys I have a new engine in my gas eagle sgx..a.30cc monster with the new stainless large pipe from carlos at ccracing...my new prop from propworks is a 7318/2 -2040-LL ..my onboard tach says 17400 rpm my speed is way down about 62mph..the boat is faster with my old 2170 from andy...should I send it back or try different strut depths and angles on the sponsons ...right now I have .100 shim under the rear skis and the strut parallel to the bottom.....I know these boats are sensitive but don't know what to move to get it to be as fast as it was with my 26cc engine...74mph by the way
gas eagle with new 30cc CCracing monster
- Thread starter john bass
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Tim_Duggan
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What rpm did the tach register with the 2170?
pull the shim out???do you mean
the.100 shim that I use to set the strut height???? that would put me back to the stock as built strut height.....since the 7318/2 2040-LL prop has a larger diameter than the 2170 is that why I should raise the strut back to the standard height as in the build instruction?????I am told that andy browm sometimes helps out on these sights I hope he reads my letter...john out
the.100 shim that I use to set the strut height???? that would put me back to the stock as built strut height.....since the 7318/2 2040-LL prop has a larger diameter than the 2170 is that why I should raise the strut back to the standard height as in the build instruction?????I am told that andy browm sometimes helps out on these sights I hope he reads my letter...john out
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The issue here is horse power, not boat set up. Find out why your new, bigger motor is making less power than your old one.
BigChuck
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and prop..... You have said it yourself. You are down a 1000RPM and 10MPH. "SG'S" do not like a lot of prop,they do like RPM.
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Rene Danner
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A bigger motor does not always equal speed, My 26.4 is faster than my 28.5 in my rigger.Like they say RPM=speed..
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Whats your plug look like? Could be too rich / lean? Pipe length could be off causing you to be down on power.
Aside from that, where is the bottom of your strut in comparison to the rear ride pads? I know you said you have a .100" shim under the "skis" but that doesnt really tell me where the strut is. Is it the strut on the table while the shim is under the ride pads?
Brian
Aside from that, where is the bottom of your strut in comparison to the rear ride pads? I know you said you have a .100" shim under the "skis" but that doesnt really tell me where the strut is. Is it the strut on the table while the shim is under the ride pads?
Brian
the strut is on the set up board with a .010 shim under the nose to put the prop about a 1/4 degree down...the starting set up is to have the bottom of the strut level with the bottom of the skis with 1/4 degree down....this is where I started...also have the right sponson nose .060 higher than the left....the 2170 was fast with my 26cc engine...but the 18360 rpm is high for a 30cc motor....I did not have a tach when I had the 26cc engine so I don't know what the rpm was but the speed was radared at 73-74 mph...I am going to move the strut back up to the original starting point this weekend and start to make some better tests....these boats are way more sensitive than I ever thought they would be...it seems that I may need a prop that is between the two that I now have....2170..and ...7318/2...thanks for all the feedback guys this weekend should be a blast...
Tim_Duggan
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My thoughts would be find the right prop load for it first with the strut at the reccomended spot, then play with the strut. The prop characteristics will alter the handling, just as a strut adjustment can alter things. How much cup is in that 2170 - maybe it could use some more to load that big block a bit more......
If you dropped 1KRPM with that other prop and the speed dropped off as a result, it's not the right prop for the setup in it's current guise. You could raise the strut to cheat it in terms of load, but it's bound to not handle right or get the efficiency out of the prop.
If you dropped 1KRPM with that other prop and the speed dropped off as a result, it's not the right prop for the setup in it's current guise. You could raise the strut to cheat it in terms of load, but it's bound to not handle right or get the efficiency out of the prop.
Tony Jacuzzi
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what length are you running that monster pipe at ?
pipe length is 12 1/4 inch....from outer exhaust to center cone .....started at 12 1/2 and have moved both longer and shorter....right now I am at 12 1/4 ..it seems to like that length ......the new pipe is very easy to change length with...I like the design very much
Tony Jacuzzi
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I have that pipe on my gas rigger at about 12 3/4 from the face of the exhaust port, so I think we are very close
John, I could be wrong, but I believe it would have been a lot better for everyone on IW if U had given all the pertinent information regarding your gas boat and why U were posting asking for help.
1. The first day U brought your new boat to our pond the wind was blowing 16 to 20 mph right down the length of the lake and the water was very choppy which allowed your boat to run very loose on the water on the water without much drag.
2. The first few runs your boat was obtaining speeds in the lower 70's.
3. The highest speed was obtained after I adjusted the strut up about .80 thos because U were looking for more speed where the boat ran in the 74s.
4. The speed slowed down after I put the strut deeper in the water.
5. U left because U were in a hurry
6. After that day U or someone was driving your boat and wrecked it, I am not sure what all had to be repaired but U indicated U had sent it back to Andy to be repaired which was some time ago.
7. Last Sunday U showed up at the pond with absolutely no wind and the water was absolutely flat without a ripple, with your boat repaired and a new special CC prepared 30 engine and a much larger prop. I asked U if U had put on a setup board after it was returned from Andy, I would have liked to take the time to put on our setup board to make sure all the settings were correct however U were in a hurry so we just ran the boat as it was with the larger 7318 prop with a best speed in the 62 MPH range.
8. I then had U put a 80 thos shim under the front sponsons to loosen the boat up with out much change in the speed.
9. We then changed the prop to the 2170 and with out touching the strut which then ran in the 68"s pretty easy with the tach in the 18300 range.
10. I wanted to adjust the strut some and run the boat again but when I went to your car U were all loaded because U said U were in a hurry. I do not believe it will be very hard to get the boat running that 74 MPH again, the bigger problem I believe will be finding someone to drive it.
BTW, it was my radar gun being used for the testing and I was the one driving the boat during the testing runs.
JM2CW
dick
dwilfong
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Hay Dick I drove it at the last race.
You going to hook him up so I can have some fun with it at the next race. :lol: :lol:
I gave him a nice 2818 and it ran good at the last race cosidering the boom tube was cracked.
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HEY DICK YOU AND DAVID HAVE BEEN SUCH A BIG HELP TO ME WITH THIS EAGLE I JUST DO NOT KNOW HOW TO THANK YOU....I WILL BE AT THE LAKE SUNDAY EARLY.....AND SHOULD HAVE NO DISTRACTIONS....IT IS TIME FOR ME TO LEARN HOW TO DRIVE...HA...HA....DAVID I DONT KNOW HOW TO TELL YOU BUT JUST AS YOU GAVE ME TAT WONDERFULL 2818....I LET ONE OF MY RUNNING MATES TRY IT AND HIS RUDDER FAILED AND DESTROYED THW PROP...SO I ORDERED A NEW ONE FROM PROPWORKS...VERY EXPENSIVE AND THAT IS WHERE I AM NOW....SHOUD HAVE FOUNDD ANOTHER 2818....SEE YOU NEXT WEEK....JOHN OUT
