Ok today I did some good ol' fashioned data acquisition by feel, touch, and thrill of acceleration. Heres what I got...
L27 peak hp @ 4800 rpm
L27 peak tq @ 3200 rpm
Now this is what I discovered while leaving the car in D...
At 40mph @ 5000-5200 rpm the trans shifts into 2nd, then at 80mph @ 5100-5200 rpm the trans shifts again into third.
Now this is what I discover by "manually" shifting the car through 1, 2, and D...
At 45mph @ 5400-5500 rpm the trans shifts into 2nd gear, at 85mph @ 5400-5500 rpm the trans shifts again into third.
When leaving the car in D I notice the speedo climb very uniformally. When manually shifting the shifter it appears that I'm getting alot more out of the gear, but boy is that engine reving like a mother!
When the trans shifts up a gear at WOT the rpm'* drop to roughly 3800-3900 rpms. Now keep mind the peak hp is @ 4800 and peak tq is @ 3200. So by allowing the engine to rev higher by manually shifting isn't there a waste of time by losing all the torque which is way down there at 3200 rpms? This is just my logic coming into play here.
I could see with a stock L27 manually shifting would be better for drag because lets face it, a stock L27 will run roughly 16.8 seconds @ 82-83 mph. So that way you don't waste time shifting into 3rd.
In conclusion, the only way to see the real effects of this are to do many runs at the strip and the help of a G-tech...*cough* MN meet* cough*.