New Exhaust...Improved fuel economy?

[drchuck72]

Hey Guys,

Recently had an Eisenmann Race exhaust installed. Sounds fantastic. Couldn't be happier.

Weird thing though, the fuel mileage is at 11.8L/100 km (or 31.8 mpg). Previously, I was getting numbers in the 12.2 to 12.9 L/100km (or 30.7 to 29.1 mpg). Is it possible that the engine is running more efficiently with the freer flowing exhaust?

Thanks

DC

[J08M3]

is it possible you were even getting 29 mpg?

[1MOREMOD]

I noticed a very slight increase in mileage with my challenge xpipe but that quickly went in the tank with my tune. No one is getting 29 or 31 in these cars. Low 20s is about it if all freeway.

[884487]

12.2L per 100km is equal to 20 MPG (US)

[aberdeen]

less back pressure to a point will be more efficient and can increase mileage. Usually right after you put on exhaust your mpg's go down because you drive faster enjoying the new sound lol

[Grail05]

same here... after putting a 200 cel x pipe i am currently at 20-22mpg when i had my oem xpipe i was at 17-19 same driving style for the last 2 years...

[J08M3]

I had no difference when I had full system compared to stock.

[Bel-Tirid]

this is because of drone and more noice with the Eisenman. U control your foot, when u need to be quiter. In my case this is 60% of the driving. Im going under the drone level

[drchuck72]

Originally Posted by 884487

12.2L per 100km is equal to 20 MPG (US)

Right, I am getting around 32 KMper gallon. I forgot to convert to miles. My bad, I thought that number seemed a bit optimistic. Divide 32 by 1.6 and you get 20. Thank you sir. (you're the one on the left)

In any case, I am getting around 11.8 to 12L per 100km vs 12.9 or higher prior to putting on the exhaust. I open it up regularly ie. I don't drive more conservatively for 2 reasons. One, the drone is at its worst around 2K RPM. So, I try to get it over 2500RPM as quickly as possible. Second, the sound of the exhaust at WOT is addictive.

Bottom line, I love this exhaust.

[markjord]

Well the Eisenmann Race puts out its best noises below 5000 rpm. I just wonder if that encourages us to change up at lower engine speeds. So we're actually driving our M3s slower than before. Having said that I've not noticed better gas mileage with mine. I average about 21 to the UK gallon. Always have.

[GideonPops]

we didnt buy these fing cars for fuel conservation

[1MOREMOD]

but if it can be a beast and get decent mpg we arent gonna complain. we want it all dont we?

[e92Mjunky]

on the highway our DRB Motorsports exhaust seems to get a wee bit better than stock..but in the city it is hard to keep foot out of throttle so therefore city is worse..when you get an exhaust you like, you want to keep hearing it, unfortunately the downside is poor gas mileage

[drchuck72]

Originally Posted by GideonPops

we didnt buy these fing cars for fuel conservation

It certainly wasn't one of my primary concerns but as a daily driver, it does come into play.

[SRC]

Originally Posted by chriszeh

but if it can be a beast and get decent mpg we arent gonna complain. we want it all dont we?

+100, it is a performance based factor... anyone can make a big motor produce big power but how efficient is it? This car is very efficient compared to almost every other sport car on the planet. Advancing the state of this art is one of the reasons I read this forum. But all too often the knuckle draggers are the loudest posts…