MBRP to Super 10 Mpg Loss

HighCountry91 · January 18, 2017

I have a 2016 sierra 5.3 that had an Mbrp single exit cat back on it and I swapped the muffler out for a super 10. I could be crazy but it seems like my mpg went down after doing this? Anyone else have this problem with a super 10? Would disconnecting and reconnecting my battery help to relearn? Any help appreciated thanks!

namanc6 · January 18, 2017

Disconnecting my battery did wonders for me. Although, my issue wasn't because of an exhaust change. In my situation, I cleaned my k&n dry air flow filter and I reinstalled it. Unfortunately, it was still wet. I got water all over my mass air flow sensor. I sprayed cleaner on the sensor. Allowed it to dry and allowed the filter to dry overnight. My truck seemed to work fine but my mpg took a big hit. I couldn't break 17.5 on the highway. So, I disconnected the battery for about an hour after recleaning the sensor. Now I'm back up to averaging 22 highway at 70 mph.

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HighCountry91 · January 18, 2017

Perfect I will try disconnecting! I only have about 24000 on the truck would my filter be that dirty?

Crstfr · January 18, 2017

i wouldn't think after 24k... but wouldn't be a bad idea to check it anyways... .

Sierra 5.3 · January 18, 2017

Perfect I will try disconnecting! I only have about 24000 on the truck would my filter be that dirty?

I just checked mine at 15k and it looked perfect.

Silver ice 6.2 · January 18, 2017

I have a 2016 sierra 5.3 that had an Mbrp single exit cat back on it and I swapped the muffler out for a super 10. I could be crazy but it seems like my mpg went down after doing this? Anyone else have this problem with a super 10? Would disconnecting and reconnecting my battery help to relearn? Any help appreciated thanks!

Always heard that Flowmaster mufflers are more restrictive than the oem muffler.. (cfm)

wuznme · January 18, 2017

Always heard that Flowmaster mufflers are more restrictive than the oem muffler.. (cfm)

Don't tell them that on the phone...lmao..got into a convo on the phone about flow, dude got pissed and hung up.

Silver ice 6.2 · January 18, 2017

Don't tell them that on the phone...lmao..got into a convo on the phone about flow, dude got pissed and hung up.

I like acting like I have no clue when I go to muffler shop... then I start talking about cfm's and it gets quiet and tumble weeds pass by,

JRL1164 · January 21, 2017

Disconnecting my battery did wonders for me. Although, my issue wasn't because of an exhaust change. In my situation, I cleaned my k&n dry air flow filter and I reinstalled it. Unfortunately, it was still wet. I got water all over my mass air flow sensor. I sprayed cleaner on the sensor. Allowed it to dry and allowed the filter to dry overnight. My truck seemed to work fine but my mpg took a big hit. I couldn't break 17.5 on the highway. So, I disconnected the battery for about an hour after recleaning the sensor. Now I'm back up to averaging 22 highway at 70 mph.

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Did you disconnect both positive and negative or just one of them? My truck is doing the same after hollowing out my third cat.

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HighCountry91 · January 24, 2017

Only disconnected the negative, notice any difference with the 3rd cat hollowed?

JRL1164 · January 25, 2017

Only disconnected the negative, notice any difference with the 3rd cat hollowed?

Thanks did it over the weekend and my mileage is definitely back to normal. Possibly even gained some but still putting miles on it.

Difference as in sound or performance? Not that I can really tell. I was hoping for more volume for my Super 10 but still not loud enough for me. I'm debating now to do a 6" dump behind the rear axle. But there's a lot of conflicting talk over whether or not tips make a difference.

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HighCountry91 · January 25, 2017

Wonder if there's a louder muffler?

Luster · January 31, 2017

Wonder if there's a louder muffler?

I did a lot of research and I found the Flowmaster 10 to be the loudest muffler available. Recommended for 'Off-road use only'. Some states won't pass inspection with FM 10.