Quote:
Originally Posted by Taylor95
I have some data for the WAI vs. CAI debate.
I recently took a 1000 mile trip in a 2001 Outback. For the first 500 miles I had the factory CAI on. My average was 25 mpg. On the way back I removed the CAI and averaged 27.5 mpg. Typically the return trip should be less efficient because you are going up in elevation. I should add that removing the CAI also reduced drag. My average speed was similar both times (80+ mph most of the time). So the WAI definitely was good for efficiency.
|
As a fellow subie owner interested in improving efficiency, (I have two leggy wagons with normally aspirated sohc 2.5 liter engines in them and a wrx for fuelish fun) I am always interested in the mods that improve performance and fuel economy too because those are truly a win-win situation. Particularly since the NA subarus are so dang slow (compared to their turbo brothers). But having said all of that, I'm also quite happy to improve efficiency if it reduces operating expenses. So now to my questions:
When you took your trip was there a net gain or loss of altitude in either direction? I am sure the road wasnt dead flat. Case in point, when I go visit my lady friend who lives 2.5 hours from me, I always get better mileage going there than I get coming back because the terrain is more favorable in the going direction than on the return trip. I have done it enough and measured the results enough under different conditions that its a valid measurement.
If you were traveling east west on your trip and the return trip was going east, I could easily believe you got better mileage simply because you were traveling with the prevailing winds that grace our planet.
So if you could clarify the conditions under which you made your trip and verify elevation changes that you encountered that might explain the differences more than simply pulling the cold air horn off. But given that it is so simple to do, I am going to try it on my next road trip and see what happens.