Borla drop in muffler
 

FYI, just wanted to mention that a couple years ago I replaced my oem muffler with a borla in my Tacoma. The low gas light would turn on at roughly 250 miles which improved to approximately 300. That's a 50 mpg improvement per tank. Obviously, it was well worth the $200 investment. It also gave the engine a deeper more aggressive throaty sound. I would highly recommend this upgrade.

could a muffler alone really make a 50 mpg difference? I dont trust it

I think a tank is 17gal.

So Im guessing the OP meant to imply was 50miles per oh 15gal (when the light goes on) which equals about 3mpg improvement....

Still - at oh 17mpg - a 3mpg improvemnt is over 10%.

I dont believe that but its also not impossible IMHO.
(My guess is driving habit alone (aka right foot) can account for up to say 20% change)

They have done tests and have shown that driving habit alone can change your gas milage by 40%+.

My guess is that with the deeper/louder sound he was easier on the gas because he did not have to take it to red-line to have a nice sound.

Nah, my driving habits did not change. I rag the hell out of my truck btw. I am not trying to sell the borla product. Just trying to offer helpful advice. I am really impressed with the difference. I believe the muffler is a pro xs and it's a straight pipe design. I would love to do the same for my wife's 4runner but she wouldn't appreciate the louder deeper sound. And yes the difference is approximately 50 miles per tank. I've always been under the impression that pound for pound an upgraded exhaust will give you the best bang for your buck and it IS true in my case. Funny of you guys to make all these assumptions. In reality I honestly believe nothing changed except for more miles. ;c)

Well there wasnt enough detailed number info in the original post.

Please post up real numbers (filled tank, drove, filled tank, noted miles) the anecdote "roughly 250 is just an approximation.

That being said I have a Borla Cat back as well as a LC Header.. I still get 19/21mpg and thats with 31" tires, 2"lift, 4.56 gears....

I have 355K of gas logs to prove it.
Overall high was 24mpg
Low was like 9mpg (wheelin... btw GPH was about on target)

Oh - I have an hour meter too...

And Im and old fart - the Bora is too loud. I added a supertrap to the end to quiet it down some