Worse MPG with K&N drop ins?
 

Since have installed K&N drop ins and ECU has been reseted. Z is getting worse MPG. The drop down is on highway from around 26 to 22 MPG.

Is this unusual, or have to get used to?
Guess, that it could be caused by ECU putting more fuel to keep A/F ratio.

that doesn't make much sense. The better filter causes less restriction and should get better mileage.

Are you actually measuring your gas mileage, or are you just going by the info center?

The info center will be accurate regarding the change. It's not like he swapped out fuel injectors.

You had 26 MPG :eek: When I put my K&N filters I went from 20 MPG to 22 MPG. IMO that 26 MPG is way high for a Z. I believe the number you are seeing right now is what you are supposed to have.

When I added the HPS tube it went up to 23.7 MPG

mine is just over 20 with aftermarket filter. i thought 26 mpg on these things was impossible

It is on specific route. I'm not info center ;) but really curious.

No, injectors are still same. Just switched from original filters to K&N. And yes, I guessed, that MPG should be same at least :mad:

Another ECU reset should help. Engine is new with 2200 miles done, so it should be getting better. :iagree:

Any suggestions?
With previous filters I done 40 MPG once in midnight cruising at 50-60 MPH.

switch back to your original filters (without ECU reset) and see if the mpg changes.

if mpg stays the same even with your original filters, it could be that the ECU is keeping a/f on the rich side for safety while it relearns (just a guess).

My thoughts are.... who cares what the mileage is? It's a fire-breathing VQ, not a Firefly.

i say dont start counting gas millage until you 10k miles...... mine varied so much in those first 10

It was first thing, what I thought about.
HPS tubes are ordered, so we'll see if it make some difference.

VQ are grass eating beast, but sometimes you have to cruise and in this situations I check MPG :driving:

VQ's are not herbavors!

I have installed K&N drop-ins on several vehicles and I have always seen a very small increase in my fuel mileage. Generally, I would get about 1-2MPG better.

whats gas milage?

I averaged 25.6 on my second tank of gas and that was around town, highway, stop and go traffic, etc. It's very possible to get these cars to get good mileage. Add in some AMSoil SSO 0-30 and free flowing exhaust, intake, etc and 2 mpg should be the very minimum gains you see.

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.

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.

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.

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?

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.