Exhaust muffler design/placement vs mpg
 

I was shopping for exhausts and decided to go with the nameless axle back and downpipe combo. I've recently come across some people saying due to the muffler design it decreases the aerodynamics of the car and possibly reduces the fuel efficiency.

Does anyone have any before and after mpg data from installing exhaust systems like the nameless one that drastically change the placement and size of the muffler.

Does anyone have any before and after mpg data from installing exhaust systems that more closely match the Oem muffler size and placement like Perrin's design.

Those are the 2 exhausts I'm debating between.



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I bet the mpg went down because you want to hear te exhaust so you gotta floor it an redline

I'm sure that plays a factor.

I hadn't really even considered the exhaust design may change the air flow under the car enough to effect the drag coefficient and fuel efficiency. Was just checking out a thread when trying to research the exhaust systems and saw someone comment on seeing a 6% decrease in fuel efficiency and they speculated it may have something to do with the change in exhaust design effecting the stock rear diffuser.

Just trying to see if anyone else has seen an efficiency drop and how it compares to designs that are closer to stock.

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The guys at Nameless are pretty nice guys. I'm sure they could design a diffuser if you asked.

The first picture you posted from Perrin is just their slip-on exhaust tips for the OEM exhaust. You can see the OEM muffler did not change in the before/after picture.

Didn't realize that. I'll remove it.

I'm not trying to knock nameless, they have a great reputation for making quality stuff. That's why I was leaning towards them. Just trying to see if anyone else has seen a mpg drop after the install or if it's a fluke.

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There was talk about this in the aerodynamics thread.

There may be some changes with muffler setup, which seems to be why Borla added the diffuser. And I think someone mentioned this to Nameless and they may be looking into it.

Thanks for the info. Anyway you can post a link to that thread, not sure where to look. - found it

May have to call nameless and hopefully postpone my order until the diffuser thing is worked out to cut down on shipping cost.

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