2LS 2.92 diff to LT 3.27 diff question

[Javiergarcai]

I recently swapped my 2.92 carrier for the 3.27 carrier from a LT model and I’m a bit concerned because my car feels the same. The mph did not change locations in the rpm range in 1-6th gear. I assumed my mph shift points would change but did not. Does anyone know why both diff’s have the same shift points? I feel like I wasted my money to be in the same spot.

[ChibiBlackSheep]

Did you tune your car to adjust to the new gears?

[Javiergarcai]

No I know the speedo should be the same but it FEELS the same. like the motor revs the same as before, doesn’t go through the powerband faster than I thought. I’m getting it retuned Friday so i’ll See what my tuner says

[CamaroFred]

Originally Posted by Javiergarcai

No I know the speedo should be the same but it FEELS the same. like the motor revs the same as before, doesn’t go through the powerband faster than I thought. I’m getting it retuned Friday so i’ll See what my tuner says

The speedo uses the driveshaft speed to determine MPH and miles traveled.
Until you have the speedometer re-calibrated the speedometer and odometer will show higher speed/more distance than is true.
You gained ~12% increase in rear wheel torque, something you should be able to notice.
I don't know how Chevy tuned the trans and torque convertor for the difference, but it may be the convertor is locking sooner than it would on an LT that came with the 3.27. Your tuner may be able to change that.

[ChibiBlackSheep]

I would wait for the tune before you jump to conclusions, but also you might not feel too much of a difference off the line either, the v6s aren't that torquey until you get high into the RPM band anyway.