Fuel economy and trigger wheel offset
#1
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Fuel economy and trigger wheel offset
I have been getting poor fuel economy. Running NA, I have it tuned so that normal driving almost never gets richer than 14.7 and often is at 16:1. I use the diyautotune base spark map and have been running aggressive EGO correction. Still, I am getting about 10 - 20% fewer miles per gallon.
So looking through my msq to see what (if anything) could be causing this, i noticed that my spark settings are 55 +22.5. I must have done this because the stock ECU at 10* Base timing did not line up perfectly with a trigger offset of 77 or 78. Could this trigger offset be causing problems?
So looking through my msq to see what (if anything) could be causing this, i noticed that my spark settings are 55 +22.5. I must have done this because the stock ECU at 10* Base timing did not line up perfectly with a trigger offset of 77 or 78. Could this trigger offset be causing problems?
Last edited by akaryrye; 02-21-2009 at 04:04 AM. Reason: No replies, edited title.
#3
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The trigger offset is just an electronic version of twisting the CAS. Seems like you should have been able to get it right at 77 or 78, but if 55 +22.5 gets you at 10 degrees with "10" in the Fixed Angle box, then you should be good to go.
What does your spark map look like? Could it be that you're simply not running enough advance there?
What does your spark map look like? Could it be that you're simply not running enough advance there?
#4
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Ok, so its just as i thought ... makes no difference how I get to the correct trigger angle. Its not that it wasn't good enough with 77 or 78, just was better with 55 +22.5.
So here is the ignition advance table I have been running. It is the base map from the MSPNP. Also attatched is my msq which reflects changes i have made recently to the spark map in the idle and high vacuum areas.
So here is the ignition advance table I have been running. It is the base map from the MSPNP. Also attatched is my msq which reflects changes i have made recently to the spark map in the idle and high vacuum areas.
#5
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145 miles of 70% highway / 30% light canyon driving with very little wide open throttle got me 21mpg yesterday. Oh well, i guess it could be worse ... its just that on the OEM ecu I would have gotten more like 25mpg
#6
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what do your logs suggest? I think you can run more spark advance in the cruise cells too...not as much as mine of course, but a few degrees more.
Spark plays a huge role in fuel economy. I advanced on my stock 1.6 and scored roughly 5mpg in highway driving.
Spark plays a huge role in fuel economy. I advanced on my stock 1.6 and scored roughly 5mpg in highway driving.
#8
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I really should get a knock sensor and an egt to really get my map dialed in. I guess I am just a bit timid when it comes to tuning spark, but ill try adding a few degrees to that map above 2900 and below 75kpa
#12
I've got the same issue related to timing. Fuel economy sux nuts.
I've noticed that compared to the stock ecu, the car pulls hard as **** down low scootin' around town but up high (getting on the freeway) it seems to run out of breath. You notice this?
I've just been assuming it wont make a difference when my turbo goes on this weekend.
I've noticed that compared to the stock ecu, the car pulls hard as **** down low scootin' around town but up high (getting on the freeway) it seems to run out of breath. You notice this?
I've just been assuming it wont make a difference when my turbo goes on this weekend.
#14
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I have a feeling that my fuel economy is largely related to ignition timing, so I will have to play with it a bit. Oh an I forgot to mention, that I have 3.9 gears in the differential so that is 5% difference. That means that my trip was actually closer to 23mpg which is closer. I know that on the stock ecu though, i was getting 20mpg around town and 27mpg on the highway. I would like to get back to that.
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