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I thought I would share this with my fellow members. This is my h2 on a dynojet 250i had a mile high location. What do you guys think of the a/f ratio? I was thinking of purchasing a pc for it and was not sure what the a/f ratio should be due to the bike being supercharged.
The dyno pull was done in fourth gear. At one point I had them dyno it in 6th gear and the highest out put was 236 hp.


Thoughts and comments welcome..




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I am assuming that this is for a stock bike with the ECU flash, correct? It looks like you raised your redline to 13,500 also. This flash did like mine and it is lean down low. See how it is 13+ below 8,000 rpm, I'm sure it stumbles and misfires a bit there. I think you would be happier with it in the low12's area. For a normal aspirated bike they probably do best in the 12.8 to 13.4 range, but supercharged want it richer, in the 11.5 to 12.1 area. I am not sure what would be best at your altitude, that is what the dyno is for. You can either send the ECU back and have it tweaked, or buy the PCV and be able to tweak it now and in the future as you make changes.


Honestly, these bikes are so new, that we are pretty much the guinea pigs for this as we make these early dyno runs. Take good notes so you can keep track of what works and what hurts it. Also, make one change at a time so you know what is helping. If you had done the ECU, a muffler and an air filter, you would not have had an idea of what was working or what was hurting. I have seen a lot of exhaust pipes that looked fancy, but didn't do much more than improve the sound, so always test before and after.
 

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I am assuming that this is for a stock bike with the ECU flash, correct? It looks like you raised your redline to 13,500 also. This flash did like mine and it is lean down low. See how it is 13+ below 8,000 rpm, I'm sure it stumbles and misfires a bit there. I think you would be happier with it in the low12's area. For a normal aspirated bike they probably do best in the 12.8 to 13.4 range, but supercharged want it richer, in the 11.5 to 12.1 area. I am not sure what would be best at your altitude, that is what the dyno is for. You can either send the ECU back and have it tweaked, or buy the PCV and be able to tweak it now and in the future as you make changes.


Honestly, these bikes are so new, that we are pretty much the guinea pigs for this as we make these early dyno runs. Take good notes so you can keep track of what works and what hurts it. Also, make one change at a time so you know what is helping. If you had done the ECU, a muffler and an air filter, you would not have had an idea of what was working or what was hurting. I have seen a lot of exhaust pipes that looked fancy, but didn't do much more than improve the sound, so always test before and after.
with Forced Induction at high altitude isn't there less drop off then with NA's, how much does that affect the desired a/f?

Curious, not as technical as most of you boys.
 

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If you think back in history, that was the reason planes were supercharged in WW2 and also why they used nitrous, to help offset the performance drop five miles above ground. You are correct about a lower drop at altitude with a supercharged engine. I have also heard that turbochargers are less affected than superchargers are. I have no idea what is correct though. I am also in the dark about the a/f differences. On a stock bike you would have the factory tune and the O2 sensor keeping you pretty straight. With a flashed ECU, the O2 is disabled, so you will see a different map in there. Someone with tuning experience in Denver or Albuquerque will be much more informative about the problems at altitude.
 
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