If your driving habits don't change the diameter of that length of pipe will have no effect on your fuel efficiency. It is quite a substantial increase in volume. I'm sure you can find a video with HD audio that gives you an idea. You don't really have a 3rd question.

 

On my second car with mid muffler delete and I have noticed no changes in MPG. Cold start is dramatically louder. I can't really speak on drone presence because I drive with my radio volume all the way up. If loudness is a concern this may not be the mod for you....I did this to my car for that reason and that reason only.

 

Swapped mids for dynomax mini bullets. No difference in MPG over 55k miles and 2 cars. Did it on my M6 T/A 392 and it sounded glorious. Did it again on my A8 1320 and its a winner once again. A little different because the auto sometimes keeps the revs lower than I would with the M6 but still wonderful. $140 all in is IMO >>> $1000 for a cat back exhaust. Cold starts definitely louder, no appreciable drone in either car.

IMO the mufflers remove a lot of the raspiness of the muffler delete. I also think it sounds better WITH the bullets vs without, but its very subjective. Everyone likes something different

 

Couldn't agree more. One of the best bang-for-your-buck mods out there.

 

California or not this is America make it loud. Loud pipes save lives.

 

9-10 in street mode?!

I was getting 9-10 with E85 and 940rwhp. Haha..

 

I wonder if you get better gas mileage with 93 vs 91?

Lowest I've seen is 10.7 and that's only if i drive in track suspension mode. Normally see 11-12 with mostly city driving.

 

I've searched through the forums and got some info but still have questions....

I daily drive this car in California so answers will be objective....

1) does this affect MPG.... I'm lucky to only drive 16 miles roundtrip to and from work.

2) In my state of regulating everything from guns, straws, and decibels...... How much louder is it if I don't hammer the gas? (eco mode)

3) I obviously knew what I was getting myself into...... MPG is a mild concern, Factory says 13mpg, i'm assuming thats ECO mode because i'm getting closer to 9-10 mpg in street mode mostly light footed. #3 question is really irrelevant besides asking if i lose more MPG.
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It doesn’t affect my gas mileage. My foot in it more just to hear it does though. ? It’s a good bit louder than stock & even in ECO. I get 15-16 mpg running at full power in custom setting, BUT I drive interstate to work.

 

There's an Eco mode???

J/K. I've seen the option literally have no idea of what it does.

 

Did mine last night sounds good

 

Without sounding dumb...when you do the mid muffler delete what is it replaced with? A straight pipe?

 

I ended up with the vibrants. Sounds deep and not raspy at all... No experience with just a mid muff delete or the mini bullets but I'm happy with my amazon purchases of vibrants... A pair for less than 100...... Awesome local work for $80. I'm happy. Deep and throaty, no rasp period. Cold starts much louder but didn't even wake up guests in my guest room at 5am on a Saturday morning after drinking. All I'm worried about. If it don't wake up someone sleeping behind a wall from the cold start, it's gotta be mild enough