Tire pressure

[bullerman]

Box Stock with grooves tires. Ran heat race with 4lb inside and 6lb outside. Decided to go up on pressure to 61/2 lb inside and 8 1/2 lb outside. I slowed down almost 7 tenths of a second. I didn't change anything else. The kart seemed about the sewer but was just slower
Maybe it was me. I lost lap time a a little speed. I figured to would do better with a little more pressure.

 

[95 shaw]

If you are still a little bound, (another thread) this can make worse.
Increasing tire pressure makes contact patch smaller, but increases tire spring rate.
Stiffer spring gets the weight.
Ended up more dynamic rr which kept kart bound, or made worse.
Obviously, one overcame the other.

Play with tire pressures on the scales to see possible changes

 

[racing promotor]

Box Stock with grooves tires. Ran heat race with 4lb inside and 6lb outside. Decided to go up on pressure to 61/2 lb inside and 8 1/2 lb outside. I slowed down almost 7 tenths of a second. I didn't change anything else. The kart seemed about the sewer but was just slower
Maybe it was me. I lost lap time a a little speed. I figured to would do better with a little more pressure.

First off there's no reason for you to be running 2 lb split , plus track condition probably changed where you needed less air and you went up.