Timing vs MPG (Closed Loop)
I should have mentioned this is 93 octane fuel tests. Disregard the E85 number in my sig.
Also the best MPG timing I have above was done on the coldest day of all the other timing tests. So in all, temps get colder and MPG rises with lower timing.
Also the best MPG timing I have above was done on the coldest day of all the other timing tests. So in all, temps get colder and MPG rises with lower timing.
The way you are looking at mpg leaves a lot for variance.
Maybe consider doing something more scientific to better control the variables.
Say for example you used the following method:
Use a 10 mile stretch of road
log 2-Byte IPW and integrate the total fuel use then divided by distance traveled.
Test both directions on road multiple times to establish an average
Maintain a constant speed and/or engine load
Change map, lather, rinse, repeat
While more timing consuming and a waste of fuel, it will give you data that will be more representitive of engine efficiency and take out the driver in the equation.
Just changing from 70mph to 60mph average speed will probably change mpg by 2-3mpg. You may just be driving slightly different and not even realizing it. Or temperature changes could be the difference.
Maybe consider doing something more scientific to better control the variables.
Say for example you used the following method:
Use a 10 mile stretch of road
log 2-Byte IPW and integrate the total fuel use then divided by distance traveled.
Test both directions on road multiple times to establish an average
Maintain a constant speed and/or engine load
Change map, lather, rinse, repeat
While more timing consuming and a waste of fuel, it will give you data that will be more representitive of engine efficiency and take out the driver in the equation.
Just changing from 70mph to 60mph average speed will probably change mpg by 2-3mpg. You may just be driving slightly different and not even realizing it. Or temperature changes could be the difference.
EvoM Guru
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there is definitely an optimum timing for fuel economy. too much or too little reduces it. i think we'd have it nailed down much better if we had cruise control. one thing that would be helpful in comparing results is also including the rpm and load during cruise.
Ok scratch my results for now. .
This tank I used the 23.3 MPG tune from above and I only got 18.4 mpg all city driving.
This left me confused but I figured out what happened. With in my testing I have been using a newly built Shell gas station. However the ground is not level at this station, depending on which way you park, you will either be at an incline or decline. And I think this has been affecting my results somewhat.
Back to the drawing board for me. But if any one has great gas mileage and you are willing to share your low load timing tables, I would greatly appreciate it.
This tank I used the 23.3 MPG tune from above and I only got 18.4 mpg all city driving.
This left me confused but I figured out what happened. With in my testing I have been using a newly built Shell gas station. However the ground is not level at this station, depending on which way you park, you will either be at an incline or decline. And I think this has been affecting my results somewhat.
Back to the drawing board for me. But if any one has great gas mileage and you are willing to share your low load timing tables, I would greatly appreciate it.
Here's my timing map. As mentionned earlier, 21-24 mpg city and ~28 mpg highway. I'm also running 15.5 AFR in closed loop with my ZT-2's narrowband switchpoint.
Link to my fuelly profile:
http://www.fuelly.com/driver/raptord/lancer-evolution
Link to my fuelly profile:
http://www.fuelly.com/driver/raptord/lancer-evolution
^ I'd honestly think you'd do better than that man. Especially since you have that ability with the zietronix. I hit your best highway MPG almost every time I do a long distance drive, and I average 22mpg in the city. What size tires do you have and do you use EGR?
Maybe stock cams is working in my favour.
Maybe stock cams is working in my favour.
^ I'd honestly think you'd do better than that man. Especially since you have that ability with the zietronix. I hit your best highway MPG almost every time I do a long distance drive, and I average 22mpg in the city. What size tires do you have and do you use EGR?
Maybe stock cams is working in my favour.
Maybe stock cams is working in my favour.
I was expecting better with the lean closed loop too, I could do 28mpg when I was at 14.7 closed loop too. What I did notice though is that AFR fluctuates more when I'm using the ZT-2 output (normal since it's farther away than the stock o2), so I'm wondering if that fluctuation might have something to do with mileage not getting much better.
EDIT: yes I do have EGR and I'm running stock sized tires.
^ I'd honestly think you'd do better than that man. Especially since you have that ability with the zietronix. I hit your best highway MPG almost every time I do a long distance drive, and I average 22mpg in the city. What size tires do you have and do you use EGR?
Maybe stock cams is working in my favour.
Maybe stock cams is working in my favour.
I found the ZT2 narrow band switching to not work too well as the AFR fluctuates alot as mentioned. This appears to be due to the output signal. When I logged the O2 voltage, the factory NBO2 moved from 0 to 1 volt. The ZT2 seemed to be either 0 or 1 volt, no inbetween, so big flucations back and forth. The swings were so big that the car would go so lean that it stalls. I found it inaffective and dangerous. My car has no front NBO2, so my rear and WBO2 are at the same point in the exhaust.
I need to get back into this again. I've been concentrating on other aspects of the car.
I need to get back into this again. I've been concentrating on other aspects of the car.
Interesting. I considered the zietronix's customizable wb simulation to be the main advantage over a unit like my AEM. The AEM also does narrowband but only at 14.7. I also felt the fluctuations were too wild to use it for nb simulation.
@lazyfong: Plenty of maps in the timing thread. I wouldn't consider mine one of the better ones. Still needs work.
@lazyfong: Plenty of maps in the timing thread. I wouldn't consider mine one of the better ones. Still needs work.
Interesting. I considered the zietronix's customizable wb simulation to be the main advantage over a unit like my AEM. The AEM also does narrowband but only at 14.7. I also felt the fluctuations were too wild to use it for nb simulation.
@lazyfong: Plenty of maps in the timing thread. I wouldn't consider mine one of the better ones. Still needs work.
@lazyfong: Plenty of maps in the timing thread. I wouldn't consider mine one of the better ones. Still needs work.
I run 43-45* in cruise. Best of 22mpg on E85 hwy cruise.
I do not run EGT timing advance (zeroed out). I still have the actual EGR installed.
3-5* advance on average, went up 3mpg.
Regular closed loop stoich cruise.
One "problem" I have found is that once the plugs get some miles on them (wear) the car will start misfiring at cruise.
I was expecting better with the lean closed loop too, I could do 28mpg when I was at 14.7 closed loop too. What I did notice though is that AFR fluctuates more when I'm using the ZT-2 output (normal since it's farther away than the stock o2), so I'm wondering if that fluctuation might have something to do with mileage not getting much better.
I found this too over 4 months of using leaner burn at cruise. I ended up going back to normal 14.7 stoich at cruise and I got better mileage.
I honestly don't really care about mileage in the Evo but since I'm a tuner I like to fiddle with stuff.
I do not run EGT timing advance (zeroed out). I still have the actual EGR installed.
3-5* advance on average, went up 3mpg.
Regular closed loop stoich cruise.
One "problem" I have found is that once the plugs get some miles on them (wear) the car will start misfiring at cruise.
I was expecting better with the lean closed loop too, I could do 28mpg when I was at 14.7 closed loop too. What I did notice though is that AFR fluctuates more when I'm using the ZT-2 output (normal since it's farther away than the stock o2), so I'm wondering if that fluctuation might have something to do with mileage not getting much better.
I honestly don't really care about mileage in the Evo but since I'm a tuner I like to fiddle with stuff.
Last edited by razorlab; Sep 20, 2011 at 10:18 PM.