Am in the process of getting VAFC tuned with a number of folks in DC area. I understand that there are pros/cons about dyno runs in either 3rd or 4th gear. Can you please enlighten me as to the difference between the two?

Thank you in advance.

 

Technically you want to be as close to a 1:1 gear ratio as possible. 3rd gear is closer, but 4th gear is somewhat the "standard" for dynoing. IMHO, you want to do what others have done before you...so that you can compare apples to apples. 90% of the dynos you'll find on the board are 4th gear dynos. From a performance stand-point, I saw a 20 HP drop when we dyno'd a test run in 3rd gear...see the lowest dyno line below. But, this was with the SC.