Nothing to hide - Ilmor opens the door on my 725/Indy buildup
#211
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Diamond Member #001
Joined: Oct 2000
Posts: 4,808
Likes: 5
From: Coastal North Carolina
Special thanks to JRapp, Noise Pollution, Jet Mech and 292Fastech07 for pitching in and making all the testing and changes go so smoothly. (So this is what it's like having a pit crew....) The GoPro video camera worked every run, but there is still so much spray from the exhausts that it's hard to tell much. I'm going to need a different rig to get the camera even lower.
Although it was a bit choppy to tell if there were any further improvements in the now-diminished hopping issues, there is no doubt that we are getting closer to "the setup". Although I couldn't feel any change with the new nosecone, taking the spacer out was worth about 7 or 8 mph. I was stuck in the high 70's back in June for JOTJ and now the boat consistently runs to 100 (and over) at will, with a best of 103+, and easily cruises in the mid-80's. The mid-range acceleration is back, too!
Ultimately, it still needs less pitch, as there is far less slip that we expected. I'll have to wait to review JRapps videos of the dash, but the best I recall was 103 mph at 5600, where I'm still giving up about 80 or 90 horsepower. I'm not sure if it will ever run the 112 that I had hoped, but I'm sure that we can get to 108+ with an inch or two less pitch. That'll work for 725 flywheel horspower in a 28' boat. I'll have to settle for 103 this year...
Thanks again, guys!
Although it was a bit choppy to tell if there were any further improvements in the now-diminished hopping issues, there is no doubt that we are getting closer to "the setup". Although I couldn't feel any change with the new nosecone, taking the spacer out was worth about 7 or 8 mph. I was stuck in the high 70's back in June for JOTJ and now the boat consistently runs to 100 (and over) at will, with a best of 103+, and easily cruises in the mid-80's. The mid-range acceleration is back, too!
Ultimately, it still needs less pitch, as there is far less slip that we expected. I'll have to wait to review JRapps videos of the dash, but the best I recall was 103 mph at 5600, where I'm still giving up about 80 or 90 horsepower. I'm not sure if it will ever run the 112 that I had hoped, but I'm sure that we can get to 108+ with an inch or two less pitch. That'll work for 725 flywheel horspower in a 28' boat. I'll have to settle for 103 this year...
Thanks again, guys!
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Retired! Boating full-time now.
Retired! Boating full-time now.
Last edited by C_Spray; 11-08-2010 at 06:31 AM.
#213
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Joined: Aug 2003
Posts: 2,975
Likes: 12
From: Charlotte, NC
I think you & I have both learned that with the type of attention to detail & planning that went into our retrofit projects fine tuning yields results a little bit at a time. Rarely are there any home runs just by going one direction or another but the combination of several small changes can be quite rewarding!
Good stuff! I look forward to continuing to learn from one another.
Good stuff! I look forward to continuing to learn from one another.





