250 SHO Flash

[FSR1]

I recently had my ECU flashed and wanted to provide some decent feedback. Z521 ranger loaded heavy.

First piece of the puzzle that no one understands or can help with is high elevation. My home lake is at 5000 feet and the SHO sucks at elevation. I usually only put 10 gallons at time of fuel in the boat so I can get out of the hole. I also usually run 85 octane to keep it from bogging. Literally at elevation you have to feather the throttle to get out of the hole or it will bog real bad. Not quite as bad with 85 octane.

Old numbers by myself. 23p fxp prop. 3 inches BP. 1/4 tank fuel no livewells by myself. 9-10 second holeshot spin 5900 rpms at 65 mph. 2 guys no livewells 5800 at 63-64 mph, holeshot around 15 seconds. Air temps around 80. Hotter it got worse. Fill the livewells, 2 guys, and about 5600rpms, 61mph and hole shot was about 250 yards or 20 seconds or more and I had to raise the jp all the way.

Tried to run a fury 4 24p and was ok but with 2 guys and livewells it would not plane the boat. It would hit 2600rpms and bog.

After the flash same 23 fxp prop. By myself 3/4 tank of 87 octane, spin 6100rpm, at 68 mph, holeshot around 6 seconds. 2 people , 6000 rpms at 67 mph holeshot 8 seconds. Filled the livewells and still got 5900 rpms at 64 mph. Holeshot around 10 seconds.

These are real world improvement numbers. I saw a lot questions about actual before and after numbers. So there are mine with the same prop. I hope they continue as it gets hot outside. Haven't had a chance to try 85 octane or the fury 4 again yet.

Best part is no bogging. I can finally just stick it to the floor and go.

May not be the super numbers people are looking for but for 5000 feet it's a big improvement.

Thanks Wayne.

[jp10]

85 octane? I've never seen it, but I'm at sea level. What is Yamaha's minimum octane recommendation for that engine?

[FSR1]

Pretty sure it's 89 for sea level. Our octane goes 85,87,89. If I run the higher octane here it bogs. Wayne told me it's because the lower octane has more O2 in it. Made sense when I heard it put that way. Especially when the problem is oxygen starvation on the motor.

[bassmasterffej]

Flashed to a 300? Who did the flashing? How much $$$?

[FSR1]

Wayne at hydrotec. $650 plus shipping. Yes it was flashed to a 300. Wayne did a great job answering my questions and concerns about high elevation.

If you have questions or concerns call them first.

[bassmasterffej]

Thanks man...I'm going to holler at him.