Exhaust ziptie affecting fuel economy?

[thiscarlife]

Hi!

I recently just cut off the ziptie on the exhaust flap of my 2015 lci 640i gran coupe. I remember before I did the ziptie I would get about 420-480 kilometres on a full tank (about 279 miles) which i was okay with. But ever since doing the ziptie, I only get about 250-300 kilometres on a full tank (about 180miles). I realised that the car has so many burbles and crackles when the exhaust valve is open, which to my understanding is fuel being dumped to the exhaust to get that popping sound. So my questions are:
1. Does putting a zip tie to keep the exhaust flaps always open make the fuel economy horrible? or is it just me?

2. Does your LCI 640i also have so much crackles and pops when the valves are open? (i.e sport mode)

Some notes:
- I live in the Sydney city area, I go through about 6-8 red lights every 3 miles constantly stopping and accelerating hence 279 miles on a full tank is very acceptable to me
- I drive very normally, especially considering city limits are at most about 40mph
- Car is completely stock, no tune, no jb4
- Could BMW possibly sold me a car with a hidden ecu tune that gives more exhaust popping effects from the previous owner? (I bought the car CPO)
-Current fuel average reading on-board computer is: 5km/L or about 20L/100km .........

I will update on total range after I go through my first tank without the zip tie.

Please let me know! I can't keep filling $100 tank every 180 miles....

[Walt White Coupe]

Exhaust ziptie affecting fuel economy? Absolutely not.

[bravo261]

That's a massive difference, if it holds up. Do us a huge favor and track it over a tank or two and post an empirical conclusion

I had zipties before going to an exhaust without flaps and still get about 320 miles in a 650, in deadly Los Angeles area rush hour traffic 5 days a week, so 180 miles can't be right. And thanks for converting to miles me...damn americans!

[BMPOWERED]

I also get poorer gas mileage with the zip ties...but that's because I can't help but to hit the throttle more and hear the lovely exhaust note!

[F06msportmia]

Originally Posted by BMPOWERED

I also get poorer gas mileage with the zip ties...but that's because I can't help but to hit the throttle more and hear the lovely exhaust note!

:

There is no way that zip tie mod increases gas consumption! No way No how!

How do you have a zip tie mod on a 640i those don't come with the exhaust flaps. I have a 640i and no flaps, unless you changed the exhaust to M or 650i.

[thiscarlife]

Originally Posted by bravo261

That's a massive difference, if it holds up. Do us a huge favor and track it over a tank or two and post an empirical conclusion

I had zipties before going to an exhaust without flaps and still get about 320 miles in a 650, in deadly Los Angeles area rush hour traffic 5 days a week, so 180 miles can't be right. And thanks for converting to miles me...damn americans!

I would love 320miles for a full tank, I would think that's even amazing for a 640 with only 3 litres and 6 cylinders Yes I am currently going through my first full tank without ziptie and will record 2 tanks without and then 2 tanks with and compare to update you all.

[thiscarlife]

Originally Posted by F06msportmia

:

There is no way that zip tie mod increases gas consumption! No way No how!

How do you have a zip tie mod on a 640i those don't come with the exhaust flaps. I have a 640i and no flaps, unless you changed the exhaust to M or 650i.

I do have an exhaust flap though... Here i've attached the undercarriage photo and you can clearly see the valve controller on the right exhaust pipe. Also interestingly, does everyone's 640i (LCI) have the same looking exhaust as mine? I find it very weird that the right side does not have a muffler.

Also note that this photo was when the car is completely stock (bought cpo) from bmw. Only thing changed about the exhaust is quad tips. (installed at the very end, not cutting of the vlave controller etc)

[thiscarlife]

Also I think it's worth adding I'm always using 98 octane fuel from the same brand everytime. (I think it's equivalent 94RON in US fuel rating)

[F06msportmia]

Originally Posted by thiscarlife

I do have an exhaust flap though... Here i've attached the undercarriage photo and you can clearly see the valve controller on the right exhaust pipe. Also interestingly, does everyone's 640i (LCI) have the same looking exhaust as mine? I find it very weird that the right side does not have a muffler.

Also note that this photo was when the car is completely stock (bought cpo) from bmw. Only thing changed about the exhaust is quad tips. (installed at the very end, not cutting of the vlave controller etc)

Wow, look at that... it has 1 muffler and the valve on the other side. I'm in the US not sure if that has anything to do with it. I have 2 mufflers 1 on each side.

Learned something new!

[thiscarlife]

Originally Posted by F06msportmia

Wow, look at that... it has 1 muffler and the valve on the other side. I'm in the US not sure if that has anything to do with it. I have 2 mufflers 1 on each side.

Learned something new!

Could you clarify whether your car is an LCI as well? I think I read somewhere that only LCI 6er has the electronic valve controller from factory.

[F06msportmia]

Originally Posted by thiscarlife

Could you clarify whether your car is an LCI as well? I think I read somewhere that only LCI 6er has the electronic valve controller from factory.

Maybe that's it, mine is a late model 2014. Still strange, I think it may have to do with country spec.

[siegester]

Originally Posted by thiscarlife

I do have an exhaust flap though... Here i've attached the undercarriage photo and you can clearly see the valve controller on the right exhaust pipe. Also interestingly, does everyone's 640i (LCI) have the same looking exhaust as mine? I find it very weird that the right side does not have a muffler.

Also note that this photo was when the car is completely stock (bought cpo) from bmw. Only thing changed about the exhaust is quad tips. (installed at the very end, not cutting of the vlave controller etc)

Your exhaust has been modified. Look at the heat shielding around the area where the muffler should be. Also notice how each bend is welded instead of mandrel bent like the rest of the exhaust, and that straight through resonator/race muffler is not something I've seen OEM before.

It does appear that the 640i does come with an exhaust flap on the right, but yours has been modified presumably for more noise when the flap is open, but same level of noise with it closed.

OEM muffler (see the diagram)
https://parts.bmwmonterey.com/p/BMW_...308643636.html

[Malik550]

Looks like someone deleted one muffler and added a resonator in its place. First time I've ever seen some mod half their exhaust system.

[thiscarlife]

Originally Posted by cjof2003

Your exhaust has been modified. Look at the heat shielding around the area where the muffler should be. Also notice how each bend is welded instead of mandrel bent like the rest of the exhaust, and that straight through resonator/race muffler is not something I've seen OEM before.

It does appear that the 640i does come with an exhaust flap on the right, but yours has been modified presumably for more noise when the flap is open, but same level of noise with it closed.

OEM muffler (see the diagram)
https://parts.bmwmonterey.com/p/BMW_...308643636.html

Hi! Thanks for the information and link to the part. The exhaust definitely came like this when I bought it CPO from BMW May 2017. The first time I put the car on a lift, I definitely doubt that the exhaust was stock. Do you think that this might be a big effect on my gas consumption? Also, if it is, is it something that I can bring up to BMW? I'm not sure whether they could sell me a CPO car that is not stock without letting me know about it? Now I am also wondering whether the previous owner had done something to the ecu that makes fuel consumption very poor.

[thiscarlife]

Can anybody with a 2015+ (LCI) 640i please please please take a photo of their stock exhaust system? I just want to know whether you all have 2 mufflers and what it looks like.

[Malik550]

Well lookie here, I found a pic and you are correct, this appears to be the stock set up, I've never seen this before.

[thiscarlife]

Originally Posted by Malik550

Well lookie here, I found a pic and you are correct, this appears to be the stock set up, I've never seen this before.

Wow!!! Thank you!! you don't understand the relief I'm having right now

[thiscarlife]

Weird though, I did a check on the oem parts website. Even for the euro spec right hand drive cars still have both mufflers.

[thiscarlife]

I've decided to give up on gas consumption and will be removing that center resonator for an xpipe.
All jokes aside, now that we've established it's a stock setup, any ideas why the ziptie is affecting gas consumption so much?

[upstate650]

Originally Posted by thiscarlife

I've decided to give up on gas consumption and will be removing that center resonator for an xpipe.
All jokes aside, now that we've established it's a stock setup, any ideas why the ziptie is affecting gas consumption so much?

It has NOT been established it is a stock setup - I sincerely doubt that it is. But to answer your question, no, removing the zip tie isn't going to effect your fuel economy.

[Walt White Coupe]

Based on this parts catalog what you have is not a "stock" system. Under "exhaust system rear" you should have two similar mufflers one right and one left.

http://bmwfans.info/parts-catalog/F0...xhaust_system/

[Malik550]

Originally Posted by Walt White Coupe

Based on this parts catalog what you have is not a "stock" system. Under "exhaust system rear" you should have two similar mufflers one right and one left.

http://bmwfans.info/parts-catalog/F0...xhaust_system/

Well it's odd that there is another car out there with the exact same setup. Who would do such a thing and why? Why delete just one muffler? What could be the possible benefit from That?