Drops out of Vtec in 3rd gear.

Quade · Post by **Quade** » Tue Jun 30, 2009 7:38 am

Hi guys, This is my current tune and all I can say is that 1st and 2nd gear feels great but 3rd drops out of vtec and seems lazy. This tune is on a turbo H22A prelude with 9:1 mahle pistons and eagle rods. All other parts are stock. Boost is set to 12 psi but I find that when I change to 3rd gear the boost climbs to 15psi and seems to lose power hence fall out of vtec. All airfuel ratios are 12.5:1 in boost up to the 12psi column and I'm wondering if timing might be too conservative at around 4500rpm and 12-15psi which is where the map falls to in 3rd gear.

Another thing I'm wondering too is how do I know the AF Ratio at 15psi is correct? Do I have to turn up the boost to hit the 19psi column,tune, and then be satisfied that 15psi is correct?

Post by **Spunkster** » Tue Jun 30, 2009 9:43 am

Without a datalog showing the problem it is nearly impossible to speculate on what the problem might be. Has this been tuned on the dyno? Do you have a wideband to properly read the air fuel ratio?