Worse gas mileage than usual
 

Hey guys, got my GT86 about 4 months ago and just started checking the mileage because I felt that I was visiting the gas station a little too often.

I'm getting 8.8 km/litre combined which seems absurd. Everyone I've spoken to IRL gets at least 11-12km/litre.

My car is mostly stock with an aftermarket catback, so I have no idea why it is getting such bad mileage.

I've cleaned the MAFS and changed the engine oil.. Does anyone know what else to check or how to fix it?

I got a 74 Lincoln Mark IV that gets 10 MILES to the GALLON because MURICA. So you're fine. https://uploads.tapatalk-cdn.com/201...0d3646e87b.jpg

Sent from my SM-G975U using Tapatalk

What are your driving habits?
Checked tire pressure? Is it low?
How are you calculating mpg/kml?

This is driving like a normal person not going past 5000 rpm ever.
Tire pressure is 34 psi checked it last week.
Using the automatic calculator and also calculating litres/trip

Who tuned your car after the catback?

Sent from my SM-G975U using Tapatalk

So the car was imported to New Zealand from Japan, and has a japanese exhaust. There was a single owner before me who had the car for about 3 months before selling to a dealer. I bought the car and have only swapped out the wheels for forged wheels.

They wouldn't have imported with a tune right?

Yeah I would get it tuned just to be safe. You would be amazed what a guy and a few hours on a computer connected to a dyno can smooth out.

Sent from my SM-G975U using Tapatalk

Check for intake/vacuum leaks.

Also, if you have the means of data logging/monitoring, take a look at your fuel trims. This can tell you if it's running rich.

Disagree. Normal people wind it out at every opportunity.

By 'normal' I meant a typical non-86 driver. Only kept it under 5000 for the purposes of testing efficiecny ;)

You don't need a tune for a cat back.

I lose about 3mpg in the winter, but spring and summer see pretty decent numbers, even on wide/sticky summer tires. If this is bad (I don't know that math) then it definitely seems odd. Even with aggressive driving and bad traffic, any highway commuting puts me in the 30s. Even spirited back road driving returns in the 30s.

I'm thrilled with 17 mpg.

It helps to know what you have done with the car... and what tires you have on there.

Going with wider + stickier tires can plunge your gas mileage by 10-15%.