Black91n/a

It doesn't, turning faster gets you better milage becuase you're not slowing down for the corner, so you don't have to burn that extra bit of gas to get back up to speed, and it saves brake wear too. You might burn more in the corner due to the increased slip angle of the tires consuming more energy causing you to need to add power to maintain speed, but generally it should work out better in the end to go faster in the corners. Now I'm not saying speed up for the corners, just don't slow down more than you have to (leave a safety margin of course). Besides, it's more fun that way.

SpeedOfLife

iTrader: (16)

Hey, it's simply economical to use tools to get better mileage. If I'm seeing anywhere from 13 to 17 mpg (which I am) and that could be improved to 20-25 cruising, obviously better mileage at highway speeds, then I will get back the money I'd spend on a fuel controller and a wideband O2 sensor within a few months, not to mention the other awesome gains to be had with those things. If you have the ability and plan on having your '7 for a while I see no good reason to not do something like that to increase your fuel economy during reserved driving.

ericgrau

iTrader: (1)

The main reason you can't go closed loop all the time is because "closed loop" means feedback. There are no O2 sensor fuel maps, the ECU uses it to figure everything out on the fly. But if the conditions at the O2 sensor are different than what's at the throttle body b/c you just hit the gas, feedback is useless. I mean, let's say you're cruising gently and suddenly slam the pedal. The O2 sensor still thinks you don't need more fuel because it's looking at the last combustion cycle. If you relied on the O2 sensor you'd run lean and pop your engine. Thus you need the fuel maps to guestimate how much fuel you really need. So the ECU checks the throttle and decides whether or not closed loop is ok. That estimate isn't as accurate as an on-the-fly measurement, so you lose fuel economy.

That's where tuning comes in. You measure and adjust the stock maps accordingly; similar to the O2 sensor but you do it across the whole range of throttle/rpm. In this case the tuner takes the place of the O2 sensor. But at the same time the stock map is conservative for a reason. If conditions change and you don't re-adjust the maps, your engine goes pop. So don't go too far with the SAFC 2, be a bit conservative. It's not worth a few dollars at the pump only to have a blown engine.

Black91n/a

Another thing, be sure to check your tire pressures and maybe set them a little higher than normal. It might cause increased tire wear in the center, but it'll help your milage.