Poor MPG on 2011 FIT w/ Tanabe

[spike55_bmw]

I'm on my second tank of gas after installing a Tanabe T70143A Medallion Touring axle back. It took longer to line up the ramps to get the car up in the air than it did to do the change over. Used silicone grease on the rubber hangers and those slid right off the hanger on the car. Simple transfer over to the Tanabe. The gasket stay attached to the B-pipe and looked good. Used approx. 25 ft-lbs on the flange bolts.

Maybe because the exhaust tone is now pronounced versus the OEM muffler but the engine / transmission combo never settled and would seem to down shift and "hunt" all of the time.

MPG immediately went from my normal 32-33 down to 27 (dash & hand calculated). I'm not a spirited driver so I wasn't out burning up the road.

Part way through my second tank, the dash MPG jumped to 36-37 but eventually settled at my normal 32-33 (dash and hand calculated) due to city driving.

So, am I crazy or did the car have to learn the new exhaust or was it me? I still think the car shifts a lot now but maybe it did the same amount before but I couldn't hear it because of OEM muffle.

What do you think?

Don

[claymore]

I think you might have been driving a little different because of the "new" sound. Unless the muffler is plugged up with something there is no reason that it would lower gas mileage.

[spike55_bmw]

Maybe I am driving differently but I'd say slower and less extreme. I'll keep track.

[der Mond]

You will hear all kinds of things about it - search here and fitfreak for "Idle Learn Procedure" - One thing to try is disconnecting the battery for a half hour, then start the engine and let it stay at idle for 4 fan cycles. It's purported to allow the computer to integrate the new equipment. With a freash air intake, Megan muffler and good valve adjustment I'm pulling 2 mpg over stock.

[claymore]

Good thought.