2mpg gain from a muffler change

[SomeOldBlindMan]

Swapped the stock gigantic quiet-can in my Taco with a Magnaflow 4" round 18" long 2.25" I/O using stock plumbing.. installed between fill-up's on Tuesday.. increase on current tank was about 2MpG.. will see what difference made on full tank.

My ScanTool OBDLink also shows my Fuel Trims are now closer to zero.. they were hovering around -7 to -10 (combined). No noticeable loss of low-end torque.

Stays kinda quiet as long as I'm idling.

[Rob10_99]

Still have stock cats and resonators?

[Domman56]

Haha that's what i've been saying about huge ass factory truck mufflers all along

[Ryland]

I've noticed better mileage with a pin hole in my exhaust so it was louder, why? because I didn't hit the gas as hard or it would call attention to my car, the sound changed my driving and that improved my mileage.

[MadisonMPG]

Originally Posted by Ryland

I've noticed better mileage with a pin hole in my exhaust so it was louder, why? because I didn't hit the gas as hard or it would call attention to my car, the sound changed my driving and that improved my mileage.

Same way with my Geo, the exhaust fell off, forcing me to drive better.