Didn't see this coming

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WTERUNNER

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Ok so I'm prepared to eat crow here. Bought an AFE PRO DRY S filter to replace the stock air filter. Installed it after recently filling up with gas. Prior to the filter swap my truck was getting 21 to 22 mpg, or at least that's what the gauge reads. Now with the AFE filter I'm getting 19 mpg. Again not sure how accurate the gauge is. That's a 2 mpg DROP with just an air filter change.

To be fair I'm going off of assumptions here and will need to run this tank of gas down, put the stock air filter back in, and the track the mileage. If it goes back up then there is some seriously sensitive ECU tuning in our trucks.
 
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PitbullRescuer said:
We're you tracking it by dividing miles driven by halons required to refill? If not, you don't have any real baseline.
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No, just using what the gauge was showing. Also I had about 50 to 60 miles on the refill before I put the filter in. It's definitely not an accurate test, just something I noticed and the reduction occurred after the filter swap. I'm going to run this tank down to a 1/4 tank and then calculate the mileage with the AFE vs the stock filter. Going to need two tanks of gas to get an accurate comparison.
 
03_4x4Runner said:
Are you accelerating harder listening to the new noise from the intake?
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It's not an intake, just a drop in filter. Ever since I switched wheels and tires the truck has gotten over 20 mpg. The only variable that was changed was the filter hence my assumption. I need to do more accurate testing to confirm it.
 
guitarsail said:
I can't even get a decimal place higher than 17.2 on my brand new stock SR5...how the heck do you even get 20?
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How many miles are on your truck? My first tank of gas I got 17.8 but that is with the crap gas from the dealer. After that it's always gotten around 20 mpg and jumped to as high as 22 mpg when I switched to lighter wheels and tires.
 
WTERUNNER said:
How many miles are on your truck? My first tank of gas I got 17.8 but that is with the crap gas from the dealer. After that it's always gotten around 20 mpg and jumped to as high as 22 mpg when I switched to lighter wheels and tires.
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So first tank was 17.2. I switched to Duratrac tires at 100 miles or so, so midway through the first tank. I'm at 1700 miles now and still at exactly 17 to 17.2 Never seems to get any better or worse. Oh well I guess thats what the Diesel Jetta is for at 40mpg.
 
WTERUNNER said:
Ok so I'm prepared to eat crow here. Bought an AFE PRO DRY S filter to replace the stock air filter. Installed it after recently filling up with gas. Prior to the filter swap my truck was getting 21 to 22 mpg, or at least that's what the gauge reads. Now with the AFE filter I'm getting 19 mpg. Again not sure how accurate the gauge is. That's a 2 mpg DROP with just an air filter change.

To be fair I'm going off of assumptions here and will need to run this tank of gas down, put the stock air filter back in, and the track the mileage. If it goes back up then there is some seriously sensitive ECU tuning in our trucks.
Click to expand...

I put one in my truck at like 20k, zero difference in mileage. In fact I just washed it for the first time a week or so ago, 40k miles later.
 
guitarsail said:
So first tank was 17.2. I switched to Duratrac tires at 100 miles or so, so midway through the first tank. I'm at 1700 miles now and still at exactly 17 to 17.2 Never seems to get any better or worse. Oh well I guess thats what the Diesel Jetta is for at 40mpg.
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The Duratracs will affect your mileage. I'm on street touring tires now, Pirelli Scorpion Verde AS's to be exact. I have the stock wheels with BFG KO2's for off-road and winter use. I prob won't get much over 17 during the winter months once I swap wheels/tires.
 
guitarsail said:
So first tank was 17.2. I switched to Duratrac tires at 100 miles or so, so midway through the first tank. I'm at 1700 miles now and still at exactly 17 to 17.2 Never seems to get any better or worse. Oh well I guess thats what the Diesel Jetta is for at 40mpg.
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Have you reset the MPG gauge at all? If you don't it will be indicating your overall MPG for the 1700 miles. And the longer you go without resetting it the smaller the change it will make. I'm OCD enough I reset mine every fill up. It has varied from 12.6 - 21 over different tanks due to driving conditions. My overall average for the past year is around 17.5.
 
1400 miles - stock LE. Computer showing 19.0 - have not reset since new. Before today was showing 19.4 - drove 125 miles at 80 mph - 60 of that was with fairly strong headwind.
 
WTERUNNER said:
Ok so I'm prepared to eat crow here. Bought an AFE PRO DRY S filter to replace the stock air filter. Installed it after recently filling up with gas. Prior to the filter swap my truck was getting 21 to 22 mpg, or at least that's what the gauge reads. Now with the AFE filter I'm getting 19 mpg. Again not sure how accurate the gauge is. That's a 2 mpg DROP with just an air filter change.

To be fair I'm going off of assumptions here and will need to run this tank of gas down, put the stock air filter back in, and the track the mileage. If it goes back up then there is some seriously sensitive ECU tuning in our trucks.
Click to expand...

I had the exact same experience with a K&N drop in filter. Went from 20-21 mpg with a Toyota dry filter to 18-19 with the K&N. That was the only difference I noticed. I'm very observant of my fuel mileage and my average mpg so I know it wasn't a fluke bases on a single tank. I ran the K&N for a full 10k service interval and had consistent results. And yes, I know how to calculate average mpg and try to generally fill up at the same station and same pump to keep the baseline consistent. I do math for a living for Pete's sake! :dizzy:
 
guitarsail said:
I can't even get a decimal place higher than 17.2 on my brand new stock SR5...how the heck do you even get 20?
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My suspicion is a couple of things - 1) their city/highway driving mix is probably at least 20/80 and 2) the MPGs during the engine break-in period is usually not that great. I've read that it usually starts picking up around 10k miles or so.

I have a 2015 SR5 4x4 with 6k miles on it. My MPG over the first 4000 miles was around 17.5. I switched out to AT tires (stock size) and lighter wheels and it dropped a little bit to 17.3. However, I started getting obsessed with getting it higher and now I'm at 17.8ish. One thing that helped me a bunch is using cruise control at every opportunity I can. I've read that some people use sport mode in the city and marginally increased their MPGs, so maybe that works.
 
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I have aFe Pro Dry filters in my Camaro, Prius and RAV4 and in all three have noticed a SLIGHT increase in MPGs. In all three the engines seemed to run a little smoother after putting them in, especially in the RAV4 and the Prius. Prius engine is very noisy.

I am planning to put one in my 4Runner. My first 2 tanks have been 19.5 and 19.3 driving about 80% city.
 
you need to hand-calculate your MPG.

the MPG gauge isn't entirely accurate, even if you reset the MPG gauge with every fill-up. (mine typically under-reports by ~0.3 MPG.)
 
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