Thanks to my consistent and traffic free 100 mile round trip commute I have been able to do quite a bit of experimenting on an 06 Jetta I've got. I write my own tunes and thus have been able to incrementally change the stock program and record the results.
My test track is about 20 miles of 72 mph and then another 30 of 82 mph of mostly flat highways. The car is an 06 brm with a new timing belt and cam kit with currently 200k miles running rotella T 15w-40. 5 speed manual trans. All accelerating is always done at full throttle and cruise control is set once I'm up to speed. So theres the background on what I was doing.
So the first thing I did was EGR delete. Just simply deleted the EGR hyst maps in the ecu and unplugged the valve. My baseline result was 36-38 mpg.
Next up was changes to the injection timing maps. Stock for emissions they're completely stupid where there is several areas of injection after tdc and the whole map is generally not very agressive. So out of lazynesss I copied a cold engine temp map and replaced the hot temp map with it. This change brought me up to a consistent 39-41 mpg.
My most recent change was the n75 duty cycle. So in Europe they have the SDI NA 1.9 and it makes 103 ftlbs of torque at 1800-2400 rpm. And what this meant to me is that you can get atleast 103 ftlbs of smoke free torque from one of these motors without any boost at all. Stock the turbo is wound up all the time with cruise n75 duty cycles at 70-90%. All that having the vanes closed like that is doing is increasing the effectiveness of the EGR. So I made a handy excel spreadsheet that calculated the air fuel ratio of different boost values and found that the stock boost command gave an air fuel of up to 100:1 under light load. For reference the smoke limit is acceptable down to 18:1. Naturally aspirated the math said about 20mg/stroke of fuel is still above the smoke limit at 22:1 air fuel ratio. So I went back into the ecu and changed the target boost from 1000-3000 rpm down to a little above atmospheric for any injected quantity under 20 mg/stroke. Then I went into the n75 map and did a couple things. First I set idle vane position to wide open. I figured it's good to exercise the actuator and no reason to be running basically an exhaust brake at idle. Then I went into the below 20 mg area again and pulled 50% of the duty cycle out across the map. So now the duty is about 30-45% while cruising so the vanes are open about 70% assuming it's linear. Cruising down the road I'm making about 1-2 psi of boost where before it was 6-10 psi. And based in the last trips the boost map paid off in dividends.
Changing the vnt to be less restrictive brought me up to 44-46 mpg. By changing just the boost basically I was able to gain atleast 10% more fuel economy. No driving changes at all.
My test track is about 20 miles of 72 mph and then another 30 of 82 mph of mostly flat highways. The car is an 06 brm with a new timing belt and cam kit with currently 200k miles running rotella T 15w-40. 5 speed manual trans. All accelerating is always done at full throttle and cruise control is set once I'm up to speed. So theres the background on what I was doing.
So the first thing I did was EGR delete. Just simply deleted the EGR hyst maps in the ecu and unplugged the valve. My baseline result was 36-38 mpg.
Next up was changes to the injection timing maps. Stock for emissions they're completely stupid where there is several areas of injection after tdc and the whole map is generally not very agressive. So out of lazynesss I copied a cold engine temp map and replaced the hot temp map with it. This change brought me up to a consistent 39-41 mpg.
My most recent change was the n75 duty cycle. So in Europe they have the SDI NA 1.9 and it makes 103 ftlbs of torque at 1800-2400 rpm. And what this meant to me is that you can get atleast 103 ftlbs of smoke free torque from one of these motors without any boost at all. Stock the turbo is wound up all the time with cruise n75 duty cycles at 70-90%. All that having the vanes closed like that is doing is increasing the effectiveness of the EGR. So I made a handy excel spreadsheet that calculated the air fuel ratio of different boost values and found that the stock boost command gave an air fuel of up to 100:1 under light load. For reference the smoke limit is acceptable down to 18:1. Naturally aspirated the math said about 20mg/stroke of fuel is still above the smoke limit at 22:1 air fuel ratio. So I went back into the ecu and changed the target boost from 1000-3000 rpm down to a little above atmospheric for any injected quantity under 20 mg/stroke. Then I went into the n75 map and did a couple things. First I set idle vane position to wide open. I figured it's good to exercise the actuator and no reason to be running basically an exhaust brake at idle. Then I went into the below 20 mg area again and pulled 50% of the duty cycle out across the map. So now the duty is about 30-45% while cruising so the vanes are open about 70% assuming it's linear. Cruising down the road I'm making about 1-2 psi of boost where before it was 6-10 psi. And based in the last trips the boost map paid off in dividends.
Changing the vnt to be less restrictive brought me up to 44-46 mpg. By changing just the boost basically I was able to gain atleast 10% more fuel economy. No driving changes at all.