3.23 to 3.73 Gear Change Question
#1
03-17-2011, 07:16 PM
3.23 to 3.73 Gear Change Question
Hi,
I am new to hopping up the newer 'computer cars' and I hope that this question doesn't sound stupid. I have a 1994 Z28 that has factory PosiTrac with a 3.23 gear ratio. I am changing the ring/pinion to a 3.73 along with all new bearings, seals etc. My question is will I have to have my computer re-programed afterward to show the correct speed or for any other reason that I may not yet be aware of. The following week we are adding long tube headers and true duals with CAI. The car has the EGR removed and has no cats. The previous owner (CNCMAN) had the ECM redone for the EGR and cat removal. I have a spare ECM that I can send in to have re-programed while I still drive. I LOVE this car and want to get the best performance I can from it and any and all hints, tips or advice will be greatly appreciated.
Thanks for your help !
William
I am new to hopping up the newer 'computer cars' and I hope that this question doesn't sound stupid. I have a 1994 Z28 that has factory PosiTrac with a 3.23 gear ratio. I am changing the ring/pinion to a 3.73 along with all new bearings, seals etc. My question is will I have to have my computer re-programed afterward to show the correct speed or for any other reason that I may not yet be aware of. The following week we are adding long tube headers and true duals with CAI. The car has the EGR removed and has no cats. The previous owner (CNCMAN) had the ECM redone for the EGR and cat removal. I have a spare ECM that I can send in to have re-programed while I still drive. I LOVE this car and want to get the best performance I can from it and any and all hints, tips or advice will be greatly appreciated.
Thanks for your help !
William
#2
03-17-2011, 07:20 PM
Have the ECM redone was just so that it wouldn't need to run off the data coming from the sensor behind the cat and the sensor for the egr. You will need to tune for the gears but that's something you can have done at a local parts store. As for headers you don't need to tune but to get the Max it's worth it.
#3
03-17-2011, 07:58 PM
what would there be to program in the comp? even if it has abs, the tone rings (its part of the sensor to u car noobs) are part of the brake rotor..
or even in the sensor is located on the pumpkin, and tone ring on the ring gear it still should be fine, but might freak out cuz it will be rotating way faster..
your car will just rev higher and get worse gas milage
but will be much much more jumpy and torquey
or even in the sensor is located on the pumpkin, and tone ring on the ring gear it still should be fine, but might freak out cuz it will be rotating way faster..
your car will just rev higher and get worse gas milage
but will be much much more jumpy and torquey
#4
03-17-2011, 08:19 PM
what would there be to program in the comp? even if it has abs, the tone rings (its part of the sensor to u car noobs) are part of the brake rotor..
or even in the sensor is located on the pumpkin, and tone ring on the ring gear it still should be fine, but might freak out cuz it will be rotating way faster..
your car will just rev higher and get worse gas milage
but will be much much more jumpy and torquey
or even in the sensor is located on the pumpkin, and tone ring on the ring gear it still should be fine, but might freak out cuz it will be rotating way faster..
your car will just rev higher and get worse gas milage
but will be much much more jumpy and torquey
I didn't know if the speedometer would be reading correctly or not. Isn't it run by a speed sensor or is it a cable?
#6
03-18-2011, 06:49 AM
Thanks for the answer. I wonder if the local GM dealer can re-program the ECM for the new gears or will I have to send it off somewhere?
#7
03-18-2011, 07:30 AM
Ya gm can. All they do is plug a computer in, select the new gear ratio and then take your money.
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