MPG dropped after the ECU flash and DNA filter installed.

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MikeB

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2k miles after BT Moto ECU Flash and DNA filter installed, I noticed my mpg has dropped from 47 mpg to 38 mpg. Is this normal? What’s your mpg after the upgrade?
 
A 20% decrease in gas mileage sounds more like a different riding style than fuel/air mixture. Is it possible you're riding a bit more aggressive with the new tune?
 
MikeB said:
2k miles after BT Moto ECU Flash and DNA filter installed, I noticed my mpg has dropped from 47 mpg to 38 mpg. Is this normal? What’s your mpg after the upgrade?
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Averaging about 42mpg ...It goes down with greater revs. I am assuming you went with stage 2 DNA?
 
MikeB said:
Is a DNA air filter, I have stage 2 combo https://www.motodracing.com/dna-bmw-r-18-air-filter-stage-2-combo-2020-bm18cr20-s2-combo

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Ahhhh now I remember .. there was more talk about that in other threads ... I forgot ... sigh 🤪.

I have a few thoughts to your MPG change ... you are adding more air to the mixture by having a high-flow air filter (I am assuming that this is the idea behind that filter) in that case the ECU will add more fuel to the mixture in order to come back to the proper mix-ratio ... but that theory has a bit of a hole ... because your riding style hasn't changed and you are pumping the same amount of fuel mixture through your engine ... but then I thought, you did just have the ECU flashed and it may have gone into 'learning mode' which can have also an impact on fuel mileage.
I did something really stupid (I am good at that) a couple months back and had to factory reset my ECU .. which meant full-on learning mode and my gas mileage was horrible for the first 2 gas tanks .. then it started dialing back in.
IMO ... just run through a few tanks of gas and then see if it dials back in 😃 ... if not, revisit the subject 😉


EDIT: Thanks R18C!
 
My mileage is also around there (39mpg) after the Brentune flash and I almost never use sport mode or grab much throttle. I have fast bikes for riding fast and I use my R18 for leisurely rides, so my mileage is disappointing. It's 5 mpg below what I averaged on a Harley with a similar engine size.
 
None; but he wants fuel economy. My 2 cents worth. I wouldn’t know what my fuel economy is . When the tank is low, fill it up and ride. l have the DNA filter. Breathes better. That is all that matters.
 
kate_brett said:
None; but he wants fuel economy. My 2 cents worth. I wouldn’t know what my fuel economy is . When the tank is low, fill it up and ride. l have the DNA filter. Breathes better. That is all that matters.
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My frustration is that for a 4 gallon tank I'm having to stop more often than I expected to fill up. The people I ride with mostly go 150 - 160 miles between fill ups and my gas light comes on way before that. It's like I'm the chump rolling on a Sportster that has to get gas every 100 miles. Not that getting 45 mpg instead of 39 would fix that entirely, but it seems to be that gas mileage doesn't meet the expectations for some riders.

The good news is for me it doesn't seem to get much worse mileage when I ride harder than when I ride like a grandpa. On my other bikes the difference between flogging it and taking it easy is much more noticeable. Heck, on my Triumph last summer when I was at Sturgis and riding chill I got over 60 mpg out of two tanks in a row on my Triumph. When I ride that bike around town where the roads aren't clogged with geezer glides I average 48. That's a difference.
 
Ulrich said:
Ahhhh now I remember .. there was more talk about that in other threads ... I forgot ... sigh 🤪.

I have a few thoughts to your MPG change ... you are adding more air to the mixture by having a high-flow air filter (I am assuming that this is the idea behind that filter) in that case the ECU will add more fuel to the mixture in order to come back to the proper mix-ratio ... but that theory has a bit of a hole ... because your riding style hasn't changed and you are pumping the same amount of fuel mixture through your engine ... but then I thought, you did just have the ECU flashed and it may have gone into 'learning mode' which can have also an impact on fuel mileage.
I did something really stupid (I am good at that) a couple months back and had to factory reset my ECU .. which meant full-on learning mode and my gas mileage was horrible for the first 2 gas tanks .. then it started dialing back in.
IMO ... just run through a few tanks of gas and then see if it dials back in 😃 ... if not, revisit the subject 😉


EDIT: Thanks R18C!
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Thanks for the info.

I removed the DNA filter and put back the factory air filter and the air tunnel tube last night and fill up a full tank of gas this morning, reset all trips settings and drove to work. 50 miles later the display shown 40.3 mpg, I cannot tell any difference with performance wise. I’ll ride another 4 full tank and see how it goes.
 
I think (just guessing) that you have to give the ECU some time to adjust .. this is all new to me too. I am used to changing jets or the timing of the points and the results are instantaneous ... not so much with 4 O2, ping, this and that sensors and an ECU that tries to figure out what I want it to do ... hell for the most part I don't know what I want to do ... and more often than not my ideas may not be the best .. to put it mildly 😆
Hang in there ... don't over think it and (IMO) screw the gas mileage, you can play the numbers game to the n'th degree of stupidity ... it just ruins the fun .. just enjoy! 😁

Just my 2¢ ... 🙂
 
PistolPeteSTL said:
My frustration is that for a 4 gallon tank I'm having to stop more often than I expected to fill up. The people I ride with mostly go 150 - 160 miles between fill ups and my gas light comes on way before that. It's like I'm the chump rolling on a Sportster that has to get gas every 100 miles. Not that getting 45 mpg instead of 39 would fix that entirely, but it seems to be that gas mileage doesn't meet the expectations for some riders.

The good news is for me it doesn't seem to get much worse mileage when I ride harder than when I ride like a grandpa. On my other bikes the difference between flogging it and taking it easy is much more noticeable. Heck, on my Triumph last summer when I was at Sturgis and riding chill I got over 60 mpg out of two tanks in a row on my Triumph. When I ride that bike around town where the roads aren't clogged with geezer glides I average 48. That's a difference.
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I’ve done 40 miles with the light on and the tank still only took 14 litres. You should have no issue at all doing 150-160 miles between fill ups.
 
PistolPeteSTL said:
My frustration is that for a 4 gallon tank I'm having to stop more often than I expected to fill up. The people I ride with mostly go 150 - 160 miles between fill ups and my gas light comes on way before that. It's like I'm the chump rolling on a Sportster that has to get gas every 100 miles. Not that getting 45 mpg instead of 39 would fix that entirely, but it seems to be that gas mileage doesn't meet the expectations for some riders.

The good news is for me it doesn't seem to get much worse mileage when I ride harder than when I ride like a grandpa. On my other bikes the difference between flogging it and taking it easy is much more noticeable. Heck, on my Triumph last summer when I was at Sturgis and riding chill I got over 60 mpg out of two tanks in a row on my Triumph. When I ride that bike around town where the roads aren't clogged with geezer glides I average 48. That's a difference.
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My bike is still in it's stock configuration, with the exception of my exhaust system (J-&-H); I consistently get much better fuel economy than my buddies who all ride HD.

I've got through an entire ride on a single tank of fuel, where they are filling up halfway through the ride... We all meet up and top at the beginning of our rides at the same gas station.
 
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