After talking with a friend of my I decided to do something about my air cleaner. I should have replaced it a long time ago but economically times are tough right now and my engine was still running so it doesn't need to be replaced. My friend said he just "hoovers" his after a while, so then I thought "well it couldn't hurt". Now I have read several places that have said that a new air cleaner (or cleaned out in my case) wont help MPG, but it will help acceleration.
Quote:
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Originally Posted by http://www.fueleconomy.gov/feg/maintain.shtml
A new study shows that replacing a clogged air filter on cars with fuel-injected, computer-controlled gasoline engines does not improve fuel economy but it can improve acceleration time by around 6 to 11 percent. |
I believe this conclusion is partially incorrect. It's true that newer FI vehicles will maintain a correct air/fuel ratio but if you still use a lot of throttle you wont get any MPG increase. The reason for the acceleration increase is that the engine can breathe easier which eliminates pumping losses. When you eliminate pumping losses you get more HP which means you can use less throttle to accelerate which means more MPG.
The method to my madness:
I took the top off of my stock air cleaner box. Pulled out the air cleaner. There was some loose dirt on it but it didn't look too bad other than being slightly yellowish. So I took out the shop vac and vacuumed it clean. I tossed it on top of the trashcan so I could start to pack up the shop vac. But then I noticed a lot of dirt around the air cleaner. -=light bulb=- Ok at this point I realized I needed to beat the dirt out of it so that's what I did. I kept beating it and vacuuming up the dirt until no more dirt came out. Then I put everything back together.
Now for the results:
Driving in to work I have struggled to get over 34 mpg (SGII) for the morning trip in. Bad days its around 30 and average days its 32-33. On good days its in the 35's. Lately I have been using the TPS sensor on my SGII, which I believe is the Throttle Position Sensor, to monitor how deep I have my right foot in it. What feels like a 1cm foot movement is 2 or 3 on the TPS. Prior to the cleaning I was at 16 or so to accelerate, sometimes as low as 15 on the TPS but never lower. I noticed at one point I was at 14 and accelerating still, and interestingly enough at 14TPS and 40mph my instant FE was over 40mpg and going up.
For the past week or so I have been able to consistently achieve 38 or better MPG every morning. Granted I rarely actually achieve the speed limit because it takes so long to accelerate up to the speed limit and I have a short drive, around 8.5 miles.
I hope this helps someone else out there who doesn't want to spend the money on a new air cleaner, especially when the current one is just fine.
