[JABCAT]

Before the "who cares about mpg, it's a performance car..." comments, I care about mpg

I make the same 250 mi drive every Thursday evening & Monday morning, and have for the last year of owning the M2. It's basically flat, all highway and I set my auto cruise control at 84 mph for nearly the entire trip (minus 20 mi or so where cc is set at 87 mph)

Prior to the installation of the MAD intakes, Dinan x-pipe & MAD axle-back exhaust, I was averaging about 27.5 - 28.5 mpg on this trip consistently. I even hit a couple trips at 29.5. After my trip down on Monday mornings I would have enough fuel left over for my daily commute M-Thurs before filling up again on Thurs to head home.

After the installation of the intakes & exhaust I am now averaging 23-24 mpg on these long trips & have to fill up again on Tuesday afternoons instead of Thursdays.

Has anyone else paid attention to or seen a decrease in mpg after intake & exhaust additions?

[Dave07997S]

You're probably getting on the gas more to hear the intake in exhaust hence the lower miles per gallon

[Carefree]

Aftermarket intakes are money wasted unless you’re tuning.

IMO

[tylerdurdem]

Possibly due to colder weather now?

[JABCAT]

Originally Posted by Carefree

Aftermarket intakes are money wasted unless you’re tuning.

IMO

I understand they add little to no power increases unless paired with other significant modifications (same with exhausts). But that doesn't answer my question.

Re: " you're probably getting on it more to hear the exhaust",

I set my auto cruise control at 84 mph for nearly the entire trip (minus 20 mi or so where cc is set at 87 mph)

[JABCAT]

Originally Posted by tylerdurdem

Possibly due to colder weather now?

Temps are pretty consistent still in the 60s -70s.

[Carefree]

Originally Posted by JABCAT

I understand they add little to no power increases unless paired with other significant modifications (same with exhausts). But that doesn't answer my question.

Re: " you're probably getting on it more to hear the exhaust",

I set my auto cruise control at 84 mph for nearly the entire trip (minus 20 mi or so where cc is set at 87 mph)

It appears there’s a tradeoff between noise and efficiency which leads to a belief that BMW engineers know a little more than aftermarket hacks.

[JABCAT]

Originally Posted by Carefree

It appears there’s a tradeoff between noise and efficiency which leads to a belief that BMW engineers know a little more than aftermarket hacks.

Again, just a nonsense response that doesn't address the question. But thanks for your valuable contribution

[IanH]

My money is on the open intakes. A lot of effort goes into making sealed cold air intakes, removing for sound is fine if you understand the trade offs.

[Carefree]

Originally Posted by JABCAT

Again, just a nonsense response that doesn't address the question. But thanks for your valuable contribution

Perhaps to you but not to an educated designer experienced with intake dynamics.

[Carefree]

Originally Posted by IanH

My money is on the open intakes. A lot of effort goes into making sealed cold air intakes, removing for sound is fine if you understand the trade offs.

You’re right. Some people don’t understand the science but that’s fine. They drive Chevrolets.

[Dave07997S]

The exhaust isn't the culprit, my money in your case is the intake.

[BIGW0RM]

I had MST open intakes my G80 M3 and I got the same MPG around town as I did with stock intakes. I did feel that I lost a little low end grunt out of the hole though.

[mike@x-ph.com]

i always upgrade the intake on my cars, i have tried 4 different ones on my current G82, MPG has not changed compared to stock

[ZPD]

Did anything else change? Tires? tire pressure? oil viscosity? gas station? I can't think of why you would have that much of a delta from intake and exhaust. I was getting 30.5 mpg on a trip through Dallas once when I left my CC set to 82 mph. My only engine mod at the time was cat back exhaust. I haven't checked to see where I am at in quite a while.

[rons e92]

Has it gotten a lot colder in your area?

Adding Chinese FMICs and a drop in temps will add more dense air which requires more fuel to process at the same AFR. You'd notice this if you're driving 250 miles a day for sure, but on shorter trips it's difficult to tell because of the stop and go.

And before you try to say they're not from China:
https://www.instagram.com/reel/DB1sh...pnY3N6b3R1Ng==

Could have bought those intakes for less than $40!

The exhaust is 100% not the cause.

Edit: The only other thing I can think of is fuel. Have you gone to a new gas station? If you have something to monitor your AFRs and injector duty cycle, you might notice the car is spraying more fuel because it's lower quality or less octane. You'd see the AFRs trying to go down and the injector duty cycle going up, but you'd need to have had a baseline with a place you know has good fuel.

[Info@mad-us.com]

Originally Posted by Dave07997S

The exhaust isn't the culprit, my money in your case is the intake.

If the intakes had Mafs I would say that it's a possibility but they don't.

[Carefree]

Originally Posted by Dave07997S

The exhaust isn't the culprit, my money in your case is the intake.

High school chemistry and/or physics teaches us the relationship among pressure, volume, and temperature (pvt). A properly designed well intake system addresses all 3 resulting in what BMW engineers intended i.e. a balance of power and efficiency. It makes sense to those of us with a technical discipline.

Sticking an aftermarket cold air intake with paper filters in an open engine compartment is little more than eye candy. It, most certainly, alters the original aforementioned parameters. It’s not complicated.

If you’re heavily tuned, the Eventuri intake system is beneficial (allegedly).

[Info@mad-us.com]

Originally Posted by Carefree

High school chemistry and/or physics teaches us the relationship among pressure, volume, and temperature (pvt). A properly designed well intake system addresses all 3 resulting in what BMW engineers intended i.e. a balance of power and efficiency. It makes sense to those of us with a technical discipline.

Sticking an aftermarket cold air intake with paper filters in an open engine compartment is little more than eye candy. It, most certainly, alters the original aforementioned parameters. It’s not complicated.

If you’re heavily tuned, the Eventuri intake system is beneficial (allegedly).

Say what?

[Carefree]

Originally Posted by Info@mad-us.com

Say what?

Read it again slowly.

[Dave07997S]

Originally Posted by Info@mad-us.com

If the intakes had Mafs I would say that it's a possibility but they don't.

I was going to ask if we have Mass Air or speed density sensors. I have a lot to earn about the S58.

[Info@mad-us.com]

Originally Posted by Dave07997S

I was going to ask if we have Mass Air or speed density sensors. I have a lot to earn about the S58.

Nope nothing its straight tube that is unmetered into the turbo. This is why none of F body m3 /m2 intake maf issues that plagued the s55 (rough idle and cel's after steady cruising rpm happen on this platform.

Mpg drop isn't from the intake's.