I recently purchased a 2013 GT convertible with 50K miles on it. I am planning to change out the rear gears this week and after researching it on this and other sights observed that there is a lot of opinions on this subject but not much data. I will attempt to apply some data to the change out.
goals from the changeout are
-drop a few tenths on the 1/8th mile
-more fun as a daily driver
-no major change in the MPG. a little would be fine.
-no major change in highway noise
Pre-purchase mod's
- axle back flowmaster american thunder exhaust
- 255/35/20 wheels and tires
Post purchase mods
- Dyno Tune by JBA speed shop
- no CAI as I can not find one that is California smog legal.
Pre-Change out data
best 1/8 time = 8.6 (using sport mode- some spinning but hooked up pretty well) crappy track at the stadium here in San Diego.
gas mileage = 17 - 18 MPG. mixture of highway and roads. it always seems to fall in this range no matter how I drive it.
gear/rpm/speed on highway - i did this by setting the cruise control at the speed and then manually selecting the gear
3rd/3750/60 3rd/4250/70 3rd/4750/80
6th/1750/60 6th/2000/70 6th/2250/80
I am getting the new 3.73 gears installed on wednesday and will post the after data in a few weeks after a break in period on the new gears.
goals from the changeout are
-drop a few tenths on the 1/8th mile
-more fun as a daily driver
-no major change in the MPG. a little would be fine.
-no major change in highway noise
Pre-purchase mod's
- axle back flowmaster american thunder exhaust
- 255/35/20 wheels and tires
Post purchase mods
- Dyno Tune by JBA speed shop
- no CAI as I can not find one that is California smog legal.
Pre-Change out data
best 1/8 time = 8.6 (using sport mode- some spinning but hooked up pretty well) crappy track at the stadium here in San Diego.
gas mileage = 17 - 18 MPG. mixture of highway and roads. it always seems to fall in this range no matter how I drive it.
gear/rpm/speed on highway - i did this by setting the cruise control at the speed and then manually selecting the gear
3rd/3750/60 3rd/4250/70 3rd/4750/80
6th/1750/60 6th/2000/70 6th/2250/80
I am getting the new 3.73 gears installed on wednesday and will post the after data in a few weeks after a break in period on the new gears.