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Old 08-28-2010, 04:24 AM   #1
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Default Tuning for gas milage

i really hope im not asking something thats already here, but, how would i go about tuning for better gas milage?
I use a AEM F/IC, and a AEM UEGO.
so really, is it as easy as going into the fuel maps and decreasing the fuel? out of boost the air/fuel ratios are in the 15's.
What would be the most lean air/fuel ratios i should go?
and is there any potential risks by doing this?
Any help is appreciated, or if anyone knows of a site or a post that i couldnt find, please tell me about it
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Old 08-28-2010, 12:37 PM   #2
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leaning the mix out will raise EGTs so make sure you have a good timing map (how you'll do it without an EGT gauge is anyone's guess). probably you'll be ok though.

some emissions info you should be aware of: 14.7 AFR is stoich for gas which means not only is it fully combusting the fuel, it is limiting the amount of other things produced (NOx, HC, CO, etc). So as you increase AFR beyond 15 or so, the combustion temp goes up and the excess air (Nitrogen + Oxygen mostly) gets turned into NOx.

NOx will end up in the atmosphere as smog and acid rain eventually, so bear that in mind next time you stay inside on a spare-the-air day or your paint goes to ****.

That said, some people run up to high 16s but the image below seems to suggest around 16.2 is best economy.

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Old 08-28-2010, 04:17 PM   #3
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Quote:
Originally Posted by y8s View Post
leaning the mix out will raise EGTs so make sure you have a good timing map (how you'll do it without an EGT gauge is anyone's guess). probably you'll be ok though.

some emissions info you should be aware of: 14.7 AFR is stoich for gas which means not only is it fully combusting the fuel, it is limiting the amount of other things produced (NOx, HC, CO, etc). So as you increase AFR beyond 15 or so, the combustion temp goes up and the excess air (Nitrogen + Oxygen mostly) gets turned into NOx.

NOx will end up in the atmosphere as smog and acid rain eventually, so bear that in mind next time you stay inside on a spare-the-air day or your paint goes to ****.

That said, some people run up to high 16s but the image below seems to suggest around 16.2 is best economy.

thank you, thats exactly what i was looking for, ill give it a try.
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Old 08-28-2010, 05:36 PM   #4
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I believe the Megamanual also says you can go as lean as you can get before the engine starts to stumble, buck and/or hesitate.
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Old 08-29-2010, 05:31 AM   #5
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Quote:
Originally Posted by y8s View Post
leaning the mix out will raise EGTs so make sure you have a good timing map
what would be the ideal timing map out of boost? right now its advanced 14 degrees i think. the previous owner set it. me = when it comes to this :(
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Old 08-29-2010, 08:55 AM   #6
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Uhhh, the AEM F/IC is a piggyback - the stock ECU handles everything out of boost... If you change anything when in closed loop, the ECU will adjust right back to where it wants it...
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Old 08-29-2010, 01:39 PM   #7
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Uhhh, the AEM F/IC is a piggyback - the stock ECU handles everything out of boost... If you change anything when in closed loop, the ECU will adjust right back to where it wants it...
no, the f/ic can do it, the shop i go to always installs them on the cars he turbos and he has done this before, i just dont want to pay him to do it.
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Old 08-29-2010, 03:39 PM   #8
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no, the f/ic can do it, the shop i go to always installs them on the cars he turbos and he has done this before, i just don't want to pay him to tell me that he did it.
Fixed that for you...
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Old 08-29-2010, 06:44 PM   #9
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Originally Posted by secretsquirrel View Post
Fixed that for you...
that works too lol, very true, but i have seen it programmed on his wifes g20, and i asked him about it, he told me what to do, i just didnt ask him about when he said to make sure you have a conservative timing map. he wasnt trying to get me to hire him, he is a friend.
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