question, when tuning on the dyno how do you pick a map as in the car will be under more load when driving down the road due to drag. The car doesnt have drag on the dyno.

 

the dyno doesnt have air blasting past it at 80 mph to cool it either.

j

 

That is why it is better to pretune the fuel on the road with a linear O2 sensor using 4th gear. Then on the dyno use 4th gear as it loads the engine more than 3rd, and do some timing adjustments.

But not all people have access to roads that allow speeds over 120mph safely. Then you only can use 4th on a dyno. Nothing is perfect.