How much does "bad air" hurt your mph?

[Fred 86 GN]

Ran at a local track this Saturday and it was hot out. Mid 80's with high humidity. My GN was only running 105 to 106mph, which is about 2mph slower than when I ran it about three weeks before. Course the air was much better then -- mid 60's and low humidity.

How much does the heat and humidity affect your turbo regal?

 

[Roger]

I haven't made any track runs, but on the street, anything above 90* made the TR sluggish. The V4R raises that to about 98*.
Many of my buddies who run at the track tell me to expect big differences with air changes.
I think you've experienced the normal performance change expected with the air change.