Drop in MPG after K&N Dropin? - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

amaciose · 12-20-2013, 03:12 PM

I just installed my K&N drop-in filter and noticed my avg MPG drop from around 29 to 25. Has anyone else seen this happen, or would think it would?

I'll be making a 6 hour freeway drive soon for the holidays, so I'll be sure to check then (to hopefully cut out changes in driving style out of the equation).

Urmyson · 12-20-2013, 03:18 PM

I got an AFE filter and noticed the same thing. I went from 33 to 29, after a few tanks it went back up though.

cooldandani · 12-22-2013, 02:15 AM

yeah same thing happened to me, i went from 26mpg to 22.5 with k&n drop in but i do 99% city driving

humfrz · 12-22-2013, 02:35 AM

Quote:

Originally Posted by amaciose

I just installed my K&N drop-in filter and noticed my avg MPG drop from around 29 to 25. Has anyone else seen this happen, or would think it would?

I'll be making a 6 hour freeway drive soon for the holidays, so I'll be sure to check then (to hopefully cut out changes in driving style out of the equation).

Yes, please let us know the results.

humfrz

Hanni_0176 · 12-22-2013, 02:09 PM

My MPG dropped as well. I was at 29-ish before I installed mine, and it dropped down to 27-ish. Installed my K&N filter like 2-3 months ago I think?

It makes perfectly logical sense though. Upgrading the filter reduces air restriction, which means the car is able to intake more air. More air = more fuel = more power = less mpg.

For me, I only lost roughly 2 mpg, which wasn't/isn't noticeable. I do mostly city driving, with a little bit of highway driving here and there. I have a 6MT, and I tend to redline my car occasionally once the engine is fully warmed up (185 degree oil temps minimum).

reardrv · 12-22-2013, 05:34 PM

That's weird, I wouldn't think a high flow air filter would affect your mileage at all. I'd grab some MAF cleaner and give your MAF a few squirts. K&N's are usually significantly over oiled out of the box, you could have a dirty MAF because of this.

archer · 12-22-2013, 05:41 PM

Quote:

Originally Posted by reardrv

That's weird, I wouldn't think a high flow air filter would affect your mileage at all. I'd grab some MAF cleaner and give your MAF a few squirts. K&N's are usually significantly over oiled out of the box, you could have a dirty MAF because of this.

I put a intake on my miata and my Mazdaspeed3 and I actually gained mileage. About 2mpg in the miata and 4 in the speed3.

archer · 12-22-2013, 05:42 PM

The speed3 was a full intake but the miata was just a k@n filter.

amaciose · 12-22-2013, 06:58 PM

Also heard about resetting the ECU after installing new intakes. Would this be needed for a simple drop-in as well?

FR-S Matt · 12-22-2013, 07:59 PM

Quote:

Originally Posted by amaciose

Also heard about resetting the ECU after installing new intakes. Would this be needed for a simple drop-in as well?

Doesn't hurt. Let's the ECU learn the increased flow the filter provides.

dave77 · 12-23-2013, 03:55 AM

To reset the ECU you just unhook the battery for 60 seconds, is that right?

midnight23 · 12-23-2013, 04:16 AM

Sure it's not a heavier foot to feel more power or to try and hear the intake :P?

Robert95g · 12-27-2013, 02:51 AM

Ok how are all of you averaging this high of a number? Im lucky to average 22, but I do drive fairly aggressive and fast... a lot.

humfrz · 12-27-2013, 03:34 AM

Quote:

Originally Posted by Robert95g

Ok how are all of you averaging this high of a number? Im lucky to average 22, but I do drive fairly aggressive and fast... a lot.

Set your red light rpm indicator at 4,000 rpm ..... and you to can get 30 mpg.....

humfrz

12-20-2013, 03:12 PM	#1
amaciose Senior Member Join Date: Oct 2013 Drives: 2013 BRZ Limited Location: Tucson, AZ Posts: 266 Thanks: 224 Thanked 127 Times in 78 Posts Mentioned: 27 Post(s) Tagged: 0 Thread(s)	Drop in MPG after K&N Dropin? I just installed my K&N drop-in filter and noticed my avg MPG drop from around 29 to 25. Has anyone else seen this happen, or would think it would? I'll be making a 6 hour freeway drive soon for the holidays, so I'll be sure to check then (to hopefully cut out changes in driving style out of the equation).

12-22-2013, 02:09 PM	#5
Hanni_0176 Senior Member Join Date: Sep 2013 Drives: 2013 Scion FR-S 10 Series MT Location: Northeast Ohio Posts: 339 Thanks: 115 Thanked 231 Times in 106 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	My MPG dropped as well. I was at 29-ish before I installed mine, and it dropped down to 27-ish. Installed my K&N filter like 2-3 months ago I think? It makes perfectly logical sense though. Upgrading the filter reduces air restriction, which means the car is able to intake more air. More air = more fuel = more power = less mpg. For me, I only lost roughly 2 mpg, which wasn't/isn't noticeable. I do mostly city driving, with a little bit of highway driving here and there. I have a 6MT, and I tend to redline my car occasionally once the engine is fully warmed up (185 degree oil temps minimum). __________________ Mods: K&N Air Filter - Open Flash Tablet (Stage 1 v1.55) - more to come!

12-23-2013, 04:16 AM	#12
midnight23 dying bird under the hood Join Date: Mar 2013 Drives: 2013 SWP Limited BRZ Location: Disneyland, California Posts: 1,331 Thanks: 546 Thanked 451 Times in 295 Posts Mentioned: 34 Post(s) Tagged: 0 Thread(s)	Sure it's not a heavier foot to feel more power or to try and hear the intake :P? __________________ GReddy Turbo BRZ tuned by Evasive Motorsports Build Thread Instagram

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12-20-2013, 03:18 PM	#2
Urmyson Senior Member Join Date: Aug 2013 Drives: BRZ Location: FL Posts: 191 Thanks: 12 Thanked 45 Times in 28 Posts Mentioned: 5 Post(s) Tagged: 0 Thread(s)	I got an AFE filter and noticed the same thing. I went from 33 to 29, after a few tanks it went back up though.

12-22-2013, 02:15 AM	#3
cooldandani Senior Member Join Date: Oct 2013 Drives: Posts: 115 Thanks: 19 Thanked 13 Times in 10 Posts Mentioned: 1 Post(s) Tagged: 2 Thread(s)	yeah same thing happened to me, i went from 26mpg to 22.5 with k&n drop in but i do 99% city driving

12-22-2013, 05:34 PM	#6
reardrv Senior Member Join Date: Sep 2013 Drives: 2013 Subaru BRZ Location: NH Posts: 109 Thanks: 56 Thanked 40 Times in 27 Posts Mentioned: 1 Post(s) Tagged: 0 Thread(s)	That's weird, I wouldn't think a high flow air filter would affect your mileage at all. I'd grab some MAF cleaner and give your MAF a few squirts. K&N's are usually significantly over oiled out of the box, you could have a dirty MAF because of this.

12-22-2013, 05:42 PM	#8
archer Member Join Date: Dec 2013 Drives: 2001 jeep wrangler Location: california Posts: 38 Thanks: 1 Thanked 9 Times in 6 Posts Mentioned: 2 Post(s) Tagged: 0 Thread(s)	The speed3 was a full intake but the miata was just a k@n filter.

12-22-2013, 06:58 PM	#9
amaciose Senior Member Join Date: Oct 2013 Drives: 2013 BRZ Limited Location: Tucson, AZ Posts: 266 Thanks: 224 Thanked 127 Times in 78 Posts Mentioned: 27 Post(s) Tagged: 0 Thread(s)	Also heard about resetting the ECU after installing new intakes. Would this be needed for a simple drop-in as well?

12-23-2013, 03:55 AM	#11
dave77 Big Member Join Date: Nov 2013 Drives: 2014 FR-S Location: Los Angeles Posts: 284 Thanks: 216 Thanked 91 Times in 56 Posts Mentioned: 0 Post(s) Tagged: 0 Thread(s)	To reset the ECU you just unhook the battery for 60 seconds, is that right?

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