Timing vs MPG (Closed Loop)
#1
Timing vs MPG (Closed Loop)
Previous results were not accurate due to gas station not being level.
Evo: 93* fuel , HTA Green // OEM block & Head
New results: (I'll be doing 2 tests for each timing map)
Round 1
(Loads: 0-120 copied from user Raptord)
Test 1: City Driving only: 21.2 MPG
Test 2: City Driving only: 18.0 MPG (Replaced the muffler section to factory muffler, which is less restrictive off boost than previous dynomax valve muffler)
Round 2
Test 1: City Driving only: 23.9 MPG
Test 2: 19.4 MPG
Test 3: 19.4 MPG
Round 3
Test 1: 21.6 MPG
Test 2: 19.4 MPG
Test 3: 26.9 MPG (50% highway)
Test 4:
Evo: 93* fuel , HTA Green // OEM block & Head
New results: (I'll be doing 2 tests for each timing map)
Round 1
(Loads: 0-120 copied from user Raptord)
Test 1: City Driving only: 21.2 MPG
Test 2: City Driving only: 18.0 MPG (Replaced the muffler section to factory muffler, which is less restrictive off boost than previous dynomax valve muffler)
Round 2
Test 1: City Driving only: 23.9 MPG
Test 2: 19.4 MPG
Test 3: 19.4 MPG
Round 3
Test 1: 21.6 MPG
Test 2: 19.4 MPG
Test 3: 26.9 MPG (50% highway)
Test 4:
Last edited by BluEVOIX; Oct 31, 2011 at 09:37 PM.
#2
And also, I have tried different driving techniques in the past. Everything from shifting at 1,500 rpms , 1700 rpms, 2000 rpms etc... Also I even tested light throttle acceleration vs quick short accelerations.
Just including this info to avoid the usual "stay off boost" or "granny drive" your car comments.
Just including this info to avoid the usual "stay off boost" or "granny drive" your car comments.
#5
Ok now that Im looking at it with my computer and not my phone its obvious now it was erased with paint. Im tweaking my fuel map in the cruise area to see if it will help with mpg. After that I will try to tweak timing. I have always gotten around 17mpg in the summer months with no highway driving. I can get around 20mpg on the highway. Would be nice to have better mpg but if it doesnt work out Im not to concerned.
#6
I run timing similar to the 2nd last graph and get 28mpg. On 94oct though.
One reason I keep EGR is because I believe it helps with mileage. Otherwise I'd force the car into open loop sooner and lean it out at cruise.
One reason I keep EGR is because I believe it helps with mileage. Otherwise I'd force the car into open loop sooner and lean it out at cruise.
#7
i upped my 9 from 22 to 24 mpg highway by going from ~33* at 70mph cruise to 37. it allows me to basically stay out of boost constantly on the highway, i can even easily pass people in 5th without getting out of vacuum.
im not sure why your seeing better results at lower timing tho...
im not sure why your seeing better results at lower timing tho...
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#8
Ok now that Im looking at it with my computer and not my phone its obvious now it was erased with paint. Im tweaking my fuel map in the cruise area to see if it will help with mpg. After that I will try to tweak timing. I have always gotten around 17mpg in the summer months with no highway driving. I can get around 20mpg on the highway. Would be nice to have better mpg but if it doesnt work out Im not to concerned.
Would you mind posting your timing chart? Although you have EGR I'm still curious on how it looks exactly.
i upped my 9 from 22 to 24 mpg highway by going from ~33* at 70mph cruise to 37. it allows me to basically stay out of boost constantly on the highway, i can even easily pass people in 5th without getting out of vacuum.
im not sure why your seeing better results at lower timing tho...
im not sure why your seeing better results at lower timing tho...
It could also be a possibility that EGR running cars benefit from higher timing and EGR disabled cars benefit with less timing?
#12
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.
#15
Heres my timing:
I also scaled my MAF extremely tight. The mid LTFT is -0.18. I found leaving it a bit negative tends to make the cruise AFR a little bit leaner even in closed loop.
For city driving I think the trick really is in the launch from stop lights. I don't have my AFR gauge displaying (only use the logging cable) but I think if you adjust your driving style so that your AFR doesn't need to go rich to keep the engine from stalling then you might get better gas mileage.
EDIT: Also when EGR is activated another 8* is added between 3000 and 3500.
I also scaled my MAF extremely tight. The mid LTFT is -0.18. I found leaving it a bit negative tends to make the cruise AFR a little bit leaner even in closed loop.
For city driving I think the trick really is in the launch from stop lights. I don't have my AFR gauge displaying (only use the logging cable) but I think if you adjust your driving style so that your AFR doesn't need to go rich to keep the engine from stalling then you might get better gas mileage.
EDIT: Also when EGR is activated another 8* is added between 3000 and 3500.
Last edited by deeman101; Sep 19, 2011 at 01:43 PM.