I met up with Justin yesterday in Brunswick. We had a great time, and he did a fantastic job. Although I opted for a 'mild' (87 octane) tune, he spent a lot of time making certain it was just the way I wanted it. The 07 Tahoe trans coding is different (he said it was really 5 speed code), so it took him extra time to get it right. One issue he found involves how the Flex Fuel engines work. The '% of alcohol' is interpreted now - there is no alcohol sensor. When I added the CAI it skewed the calculations and the programming assumed it was due to the fuel - to compensate it 'tuned itself' for 20% ethanol. This didn't effect my in town mileage much, but it sure did my highway mileage. Prior to the CAI, I had one out of town trip and got 18 mpg (65-70 mph).
Since I've only had the truck a month, work from home and don't make a lot of trips I really only noticed the highway mileage drop in the last week. On the trip up I barely got 16.4 mpg, driving 70-75. On the way back, 20-17.8 mpg. I can't say for certain as there was a bad accident on I-4 and I idled my way through 10 miles of interstate for 45 minutes! I also stopped to see my daughter in Jax and fooled around a bit with a couple of other full size chevys intrigued with the Corsa...
Items done:
1. 87 octane tune
2. torque management adjusted (tricky as I opted to retain the Active Fuel Management). Still a smooth transition!
3. Speed limiter moved to 120.
4. Trans shifting adjusted to taste, part throttle and WOT.
5. 'Sport mode' enabled in Tow/Haul setting.
6. Alcohol % lowered back to 10%.
7. Sensitivity of O2 sensors adjusted down (Justin said they were a little too sensitive for the iron block 5.3).
8. Part throttle maps observed and adjusted.
I will always advocate for an in person tune if you can swing it. Its possible Justin could have spotted/interpreted my needs from a data dump and conversation. But to me the ability to discuss and tune on the fly is priceless.
Since I've only had the truck a month, work from home and don't make a lot of trips I really only noticed the highway mileage drop in the last week. On the trip up I barely got 16.4 mpg, driving 70-75. On the way back, 20-17.8 mpg. I can't say for certain as there was a bad accident on I-4 and I idled my way through 10 miles of interstate for 45 minutes! I also stopped to see my daughter in Jax and fooled around a bit with a couple of other full size chevys intrigued with the Corsa...
Items done:
1. 87 octane tune
2. torque management adjusted (tricky as I opted to retain the Active Fuel Management). Still a smooth transition!
3. Speed limiter moved to 120.
4. Trans shifting adjusted to taste, part throttle and WOT.
5. 'Sport mode' enabled in Tow/Haul setting.
6. Alcohol % lowered back to 10%.
7. Sensitivity of O2 sensors adjusted down (Justin said they were a little too sensitive for the iron block 5.3).
8. Part throttle maps observed and adjusted.
I will always advocate for an in person tune if you can swing it. Its possible Justin could have spotted/interpreted my needs from a data dump and conversation. But to me the ability to discuss and tune on the fly is priceless.
