04-03-2012, 08:34 PM
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#181 (permalink)
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herp derp Apprentice
Join Date: Oct 2008
Location: Lawrence, KS
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i was confused too doax, just gotta buy into his logic to see the explanation....
Quote:
Originally Posted by mja1
...Measured target AFR will be 5-15% over the actual, meaning you'll be running slightly lean. If this lean event is not enough for the ECM to add enough fuel to noticeably effect long term fuel trims, you'll net slightly better mpg...
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and i think the 'if' will be over in about 2 seconds
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Today
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Other popular topics in this forum...
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04-03-2012, 11:31 PM
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#182 (permalink)
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EcoModding Lurker
Join Date: Mar 2012
Location: Houston
Posts: 46
truck - '06 Chevrolet Silverado WT 90 day: 22.65 mpg (US)
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Quote:
Originally Posted by 2000mc
i was confused too doax, just gotta buy into his logic to see the explanation....
and i think the 'if' will be over in about 2 seconds
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guys, I apologize about my poor explanation of things, let me make it in the simplest terms I can.
The frequency at the MAF is the same with or without the CAI. The ECM uses this frequency to force a commanded AFR at the O2 sensors.
The MAF will read the same frequency in hertz as before, but with a slightly larger volume of air. The O2 sensor will force a slightly lean condition (*vs a measured/actual AFR*) from what is being commanded by the ECM (unless a large enough volume of air is sensed by the MAP to force engine into open loop and/or change fuel trims, and a number of other factors), if you read it off a tuning device it will say the O2 sensor is what it should be at '14.7' lets say. But this isn't the actual its just being commanded by the ECM. That reading, if you put a wideband in the same exhaust will read a slightly higher AFR than *what the computer is telling the O2 sensors*.
If the ECM/car has stock widebands in the system, like a stock forced induction car, this will be prevented, also if there is no MAF on the car. If you don't believe me then go try it yourself, the MAF frequency should be tuned for the increased air volume of the CAI, when this is done then yes all the warm air vs cold air thermo engine theory that has been talked about becomes true.
...the actual measured AFR will be 5-10% (or on extremely large engines as much as 15%) leaner than what the ECM is commanding.
Last edited by mja1; 04-03-2012 at 11:47 PM..
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04-04-2012, 12:39 AM
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#183 (permalink)
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herp derp Apprentice
Join Date: Oct 2008
Location: Lawrence, KS
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Quote:
Originally Posted by mja1
The MAF will read the same frequency in hertz as before, but with a slightly larger volume of air.
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are you assuming a larger volume of air due to a CAI? or have some other method of measuring the volume of air?
under what conditions is the MAF reading the same? at idle, cruising at a steady speed, WOT?
i wouldn't expect to see a difference in from the MAF readings until you are at or very near WOT, because untill then the volume of air going past the MAF will be governed by how far the throttle is opened or the IAC.
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04-04-2012, 03:42 PM
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#184 (permalink)
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This is the year
Join Date: Apr 2010
Location: Columbus, OH
Posts: 36
Bug - '06 Volkswagen Beetle TDI PKG1 90 day: 37.04 mpg (US) F-350 - '11 Ford F-350 Lariat 90 day: 16.23 mpg (US)
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I have a hard time believing a narrow band O2 sensor won't be able capture the AFR variation at steady state driving (economy/stoichiometric driving). Sure a wideband may give accurate numbers at cold start up/idle or WOT, but both are closed loop operations. Wideband O2's have wider voltage ranges to detect wider AFR ranges.
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05-26-2012, 06:44 PM
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#185 (permalink)
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EcoModding Lurker
Join Date: May 2012
Location: Vancouver, WA
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broken link
The link for the Civic VX Lean Burn info is broken, the original site appears to be no longer registered. I did find an archived copy at the Internet Archive at archive dot org, if you copy and paste the URL from the article into that site it will pull up the original site that is down. Someone might want to permanently link it somewhere. Unfortunately, none of the pictures were archived; only the text of the article, with the exception of one of the photos of the ECU pinout.
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09-21-2012, 11:36 PM
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#186 (permalink)
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Corporate imperialist
Join Date: Jul 2011
Location: NewMexico (USA)
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There are more like 80 mods on the wiki now, not counting the disproven ones.
__________________
1984 chevy suburban, custom made 6.5L diesel turbocharged with a Garrett T76 and Holset HE351VE, 22:1 compression 13psi of intercooled boost.
1989 firebird mostly stock. Aside from the 6-speed manual trans, corvette gen 5 front brakes, 1LE drive shaft, 4th Gen disc brake fbody rear end.
2011 leaf SL, white, portable 240v CHAdeMO, trailer hitch, new batt as of 2014.
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02-12-2013, 03:29 PM
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#187 (permalink)
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Master EcoModder
Join Date: Aug 2011
Location: Warren, MI
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Just found a typo...
Quote:
Of all aero mods, a full boat tail will probably have the single largest effect on reducing fuel consumption, though it is obviously more difficult to construct (and will result in more heads turned than anything other mod!).
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Should be "any".
Now, it might be difficult but I was wondering if we might order them by effectiveness, money and skill. Could we lump money and skill together, then plot them on a graph with links to the different mods? That would be an easier way for newbies to overview possible mods.
Also, kill switches are much more effective than the listing suggests. Even my boat tail had nothing on some hardcore P&EOC. A 10% (4mpg) difference.
__________________
He gave me a dollar. A blood-soaked dollar.
I cannot get the spot out but it's okay; It still works in the store
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06-12-2013, 06:06 PM
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#188 (permalink)
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EcoModding Lurker
Join Date: Mar 2011
Location: New Jersey
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What is the real MPG gain by changing to all synth, motor oil, trans, diff, bearings?
I have to get almost all of this done as routine upkeep on my 1997 Mercedes E300D.
I know it's on the list, but really. Has anyone done a before and after?
If it's on the forum already I couldn't find it. Point me in the right direction.
Thank you.
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07-30-2013, 12:31 PM
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#189 (permalink)
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Master EcoModder
Join Date: Dec 2012
Location: ff
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Need add GPS
I learned that one last weekend ended up 23 miles out of way with 1 simple misturn then couldnt correct later due to no knowledge of location or area.
Its simple but true savings.
Also brake pad return springs they dont work on every car infact possibly only 1/3 but for old hydro brakes that just piston straight in and out they do help to lessen parasitic brake drag.
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03-20-2014, 03:38 AM
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#190 (permalink)
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EcoModding Apprentice
Join Date: May 2011
Location: Oregon
Posts: 106
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Motorcycle mod
In case this hasn't been suggested yet:
Eliminate stock mirrors and put Bug Eyes on your helmet:
BUG EYES Rear View Helmet Mirrors
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