Worse MPG with K&N drop ins?

zcar_dad · 07-29-2011, 01:03 PM

I have had the K&Ns since I bought the car new. My mileage has remained consitent since after the break-in period. I now have 9950 miles on the car. For highway driving I get 25-27 mpg depending on what my average speed is (between 55- 75 miles per hour). Around town it gets around 20-23 depending on average speed. When driven to work it gets more as more highway miles versus city streets are involved. The above includes having high flow cats and using Royal Purple motor oil.

4r3s · 07-29-2011, 02:34 PM

On my trip down to SC from MD last year I got 28mpg. Traffic was pretty light on that trip so I was able to use cruise control for rather lengthy periods of time. I've never been able to repeat that, car was completely stock at the time.

Methodical4u · 07-29-2011, 03:21 PM

Quote:

Originally Posted by zcar_dad

I have had the K&Ns since I bought the car new. My mileage has remained consitent since after the break-in period. I now have 9950 miles on the car. For highway driving I get 25-27 mpg depending on what my average speed is (between 55- 75 miles per hour). Around town it gets around 20-23 depending on average speed. When driven to work it gets more as more highway miles versus city streets are involved. The above includes having high flow cats and using Royal Purple motor oil.

Not to start any kind of oil war at all, but I would REALLY research that Royal Purple. It apparently breaks down really fast. Just some things i've read.

Methodical4u · 07-30-2011, 01:05 AM

I'm still curious how people lose MPG when they get an intake set-up... is it because the ECU is making the car run more rich and the car needs to be tuned?

Maila87 · 07-31-2011, 06:30 AM

More air with same A/F ratio means more fuel in injectors. The car feels more agile in low RPM (around 1000 rpm). Will wait few hundred kilometers and we'll see.

FYI: Using original 18" wheels and stock tires.

Methodical4u · 07-31-2011, 02:05 PM

Quote:

Originally Posted by Maila87

More air with same A/F ratio means more fuel in injectors. The car feels more agile in low RPM (around 1000 rpm). Will wait few hundred kilometers and we'll see.

FYI: Using original 18" wheels and stock tires.

odd as one of K&N's claims is that they get more gas mileage.

07-29-2011, 01:03 PM	#16 (permalink)
zcar_dad Base Member Join Date: May 2010 Location: Kansas City, MO Posts: 126 Drives: 2009 Nismo 370 #67 Rep Power: 16	I have had the K&Ns since I bought the car new. My mileage has remained consitent since after the break-in period. I now have 9950 miles on the car. For highway driving I get 25-27 mpg depending on what my average speed is (between 55- 75 miles per hour). Around town it gets around 20-23 depending on average speed. When driven to work it gets more as more highway miles versus city streets are involved. The above includes having high flow cats and using Royal Purple motor oil. __________________ 2009 Nismo 370Z #0067, Brillant Silver

07-31-2011, 06:30 AM	#20 (permalink)
Maila87 Base Member Join Date: Apr 2011 Location: Prague Age: 37 Posts: 138 Drives: 370Z Rep Power: 15	More air with same A/F ratio means more fuel in injectors. The car feels more agile in low RPM (around 1000 rpm). Will wait few hundred kilometers and we'll see. FYI: Using original 18" wheels and stock tires. __________________ -->2005-6 Nissan Micra 1,3i CVT 72PS Red MY 98 -->2006-8 Nissan Almera 1,5i N16 96PS Red -->2007-8 Skoda Fabia Combi 1,2HTP 3 cylinder 60PS Green -->2008-11 AUDI TT 2,0TFSI FWD S-tronic 200PS Red MY06 -->2011 Nissan 370Z manual White Pearl

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07-29-2011, 02:34 PM	#17 (permalink)
4r3s A True Z Fanatic Join Date: Dec 2009 Location: MD Posts: 2,077 Drives: Touring 370z Rep Power: 25	On my trip down to SC from MD last year I got 28mpg. Traffic was pretty light on that trip so I was able to use cruise control for rather lengthy periods of time. I've never been able to repeat that, car was completely stock at the time.

07-30-2011, 01:05 AM	#19 (permalink)
Methodical4u A True Z Fanatic Join Date: Jun 2011 Location: Maryland Posts: 1,393 Drives: 11 370 6mt pw w/sp Rep Power: 17	I'm still curious how people lose MPG when they get an intake set-up... is it because the ECU is making the car run more rich and the car needs to be tuned?