Altitude adjustment

[caryt]

Just got my Carbtune and have tried to find the correct % adjustment for my alt. of 4500'. Best I could come up with is -15% or about 212 mmHG instead of 250mmHG at seal level. Does this sound correct?

Thanks, Cary

 

[Ignacio]

I think it's 3.5% for every 1,000 feet of altitude for normally aspirated engines. That's the figure on dyno adjustment I learned in school. That would make it 15.75%....or 211mm....so you're VERY close.

I'll be honest that I don't really check for inches of mercury as much as I make them consistent with each other.

 

[jimbemotumbo]

Just synched mine using the cylinder that gave the highest reading. I turned the screw for that cylinder all the way in, backed it out maybe half a turn, and confirmed it was as high as she'd go. Then just balanced the rest to that. I think it was around 215mm. BTW - I'm at 5800ft.

 

[caryt]

Thanks

Cary