Shift Points?

This not a street tire or stock tune question. At now four different tracks I have trapped 97-99 mph with the highest gain between the 1/8th and the 1/4 mile being 20.65 mph. It seems to me my car should gain 20-21 mph. But it doesn't seem to matter how fast I run in the 1/8th mile, I still end up with 98-99 trap speed.

I am under the impression that an E30 tuned car should trap around 103 mph, it shouldn't matter if I do the 1/8 at 78, 79 or 80 mph the car should always the same gain.

My car even heat soaked should run 100 mph trap all day.

Shifting at 6,000 seems to work but so does shifting 1-2 at 6000, the rest 5500.

I launch between 4500-4800 depending on track conditions.

This past Wed was best DA to date. My ET were all personal best, but trap remained the same; I'm sure the car would have run 101-103 after being cooled for over an hour but I missed 4th but still went [email protected] mph.

Just trying to see if my car is making the power it should as removing weight is max around 1-1.5 mph increase for all the seats + spare/tool/jack.

Thanks