Now at 60k miles, mileage isn't as good

VarmintCong · May 5, 2019

About to hit 60k on my 2017 Sport 6MT, and noticed my gas mileage has dropped. I used to get 42-44 mpg on highway trips, now around 40, and avg used to be 36-37 mpg, and now is 34 mpg or so. I also noticed my mileage computer is now underestimating by 2-3 mpg vs the fillup calculation. It used to be right on when the car was newer.

I mostly use Shell 93 octane.

Do these turbos need a cleaning like VW turbos or something?

Lazylahma · May 5, 2019

18 sport 6mt here, it sounds like you get exceptional gas mileage 36-37 is what I get on the highway 30-32 around town. Don’t drive too crazy but have a bit of fun here and there, i am on ktuner stage 1 map and always use bp 93

think3mm · May 5, 2019

VarmintCong said:
About to hit 60k on my 2017 Sport 6MT, and noticed my gas mileage has dropped. I used to get 42-44 mpg on highway trips, now around 40, and avg used to be 36-37 mpg, and now is 34 mpg or so. I also noticed my mileage computer is now underestimating by 2-3 mpg vs the fillup calculation. It used to be right on when the car was newer.

I mostly use Shell 93 octane.

Do these turbos need a cleaning like VW turbos or something?

Did you recently change air filter or other maintenance? Some things can make a couple MPG difference,

VarmintCong · May 5, 2019

think3mm said:
Did you recently change air filter or other maintenance? Some things can make a couple MPG difference,

Good thinking, i checked the air filter, it's pretty nasty, I'll change that, thanks!

turbo lover · May 5, 2019

How's the tire pressure?

VarmintCong · May 6, 2019

turbo lover said:
How's the tire pressure?

35 psi or so all around, that's where I have it normally.

BoostedSiCoupe · May 6, 2019

shit my si only gets 25-28 mpg regularly, hwy or city. always has since i bought it new.

VarmintCong · May 6, 2019

BoostedSiCoupe said:
shit my si only gets 25-28 mpg regularly, hwy or city. always has since i bought it new.

Is it modified? People talk about Si's getting 30-40 mpg.

BoostedSiCoupe · May 6, 2019

VarmintCong said:
Is it modified? People talk about Si's getting 30-40 mpg.

only a mishimoto intake. but even before the intake i had the same issue

VarmintCong · May 6, 2019

Multaq said:
Its most likely your filter lowering it if its that filthy

It was like a squirrel's nest in there, lol - probably restricting airflow. I rack up the miles so fast I probably skipped a few things.

BoostedSiCoupe · May 6, 2019

i do have a heavy foot, im surprised i havent blown myself to pieces.

VarmintCong · May 6, 2019

BoostedSiCoupe said:
only a mishimoto intake. but even before the intake i had the same issue

Lead shoes maybe?

I just drive for work so not many chances to fool around.

PhilF · May 6, 2019

VarmintCong said:
It was like a squirrel's nest in there, lol - probably restricting airflow. I rack up the miles so fast I probably skipped a few things.

Maybe a bit of overkill, I change both intake & cabin filters every 10k, the air quality here in Central Pennsylvania is so lousy with pollen, other allergens and just dirt, I'm usually surprised how dirty the cabin filter becomes, checked the intake filter last week at 7200mi, it's already pretty dark. So I change every 10k and then I don't have to monitor or worry about either of them, OEM filters usually cost me $30 & change. If I didn't do 10k, I'd change annually. Make up a small label for the airbox with the date & mileage.

VarmintCong · May 6, 2019

PhilF said:
Maybe a bit of overkill, I change both intake & cabin filters every 10k, the air quality here in Central Pennsylvania is so lousy with pollen, other allergens and just dirt, I'm usually surprised how dirty the cabin filter becomes, checked the intake filter last week at 7200mi, it's already pretty dark. So I change every 10k and then I don't have to monitor or worry about either of them, OEM filters usually cost me $30 & change. If I didn't do 10k, I'd change annually. Make up a small label for the airbox with the date & mileage.

Yeah, it's so easy to do, why not? I noticed the cover for the cabin filter was off and floating around behind the glove box, lol.

I use the cabin filter a lot, when stuck behind a truck spitting exhaust, I switch to recirculate. It wasn't working well recently, that should have been a clue!

Royal_Purple_Oil_Filter · May 6, 2019

... carbon buildup?

Now at 60k miles, mileage isn't as good

VarmintCong

Senior Member

Lazylahma

Senior Member

think3mm

Senior Member

VarmintCong

Senior Member

turbo lover

Senior Member

VarmintCong

Senior Member

BoostedSiCoupe

VarmintCong

Senior Member

BoostedSiCoupe

VarmintCong

Senior Member

BoostedSiCoupe

VarmintCong

Senior Member

PhilF

Senior Member

VarmintCong

Senior Member

Royal_Purple_Oil_Filter

Senior Member

Similar threads