BMW M3 Forum (E90 E92)

BMW Garage BMW Meets Register Search Today's Posts Mark Forums Read


Go Back   M3Post - BMW M3 Forum > E90/E92 M3 Technical Topics > Engine, Transmission, Exhaust, Drivetrain, ECU Software Modifications
 
Evolve Automotive
Post Reply
 
Thread Tools Search this Thread
      02-14-2012, 04:19 PM   #23
piloto
Captain
 
Drives: 2011 E90 M3 - AW/FR
Join Date: Jun 2010
Location: Orange County, CA

Posts: 835
iTrader: (0)

If you are going WOT (or close to) and shifting at lower rpm, you're going to use up more fuel than if you go with less throttle and slightly higher rpm.

Nevertheless, I am assuming that you have changed your driving characteristcs from before when you had the OEM exhaust. It might be to avoid some bassy/boomy sound at low rpm with the new set-up, or conversly that you are going to WOT to try and duplicate such a sound at low rpm. Either way, best bet is to closely analyze your habits, as they are sometimes done so intuitively that we don't notice them ourselves.

Aside from that, as another poster mentioned, it could be something totally urelated to the exhaust itself and maybe could a leak in the fuel system, or something gone haywire with the ECU, although I would doubt this is the case as such problem are extremely uncommon and rare.
piloto is offline  
0
Reply With Quote
      02-14-2012, 04:21 PM   #24
Sean@PYSpeed.com
 
Sean@PYSpeed.com's Avatar
 
Drives: 2009 AW E92 M3
Join Date: Nov 2009
Location: Bay Area

Posts: 8,956
iTrader: (22)

Send a message via AIM to Sean@PYSpeed.com
^ this!

or just pounding for the sound!
Sean@PYSpeed.com is offline   United_States
0
Reply With Quote
      02-14-2012, 04:45 PM   #25
Seven7
First Lieutenant
 
Drives: 2011 M3 E92
Join Date: Aug 2010
Location: Vancouver BC

Posts: 348
iTrader: (1)

Quote:
Originally Posted by Sean05 View Post
hmmmm changing exhaust wont see much of a change... you must be revving the sucker a lot... hey cant blame you specially on that exhaust...

i got better results when i went full exhaust.... no primary cats.... and i got a better MPG... so its your driving habits must be the new exhaust made you press that gas more often... LOL
The problem is I havent been doing that LOL. I've been driving very conservatively ever since putting on the exhausts and I havent revved over 4-5k rpm.
Seven7 is offline   Canada
0
Reply With Quote
      02-14-2012, 08:53 PM   #26
SchnellM3
Digger
 
SchnellM3's Avatar
 
Drives: 03 E46 M3, 09 E92 M3, 09 X6 50
Join Date: Jun 2009
Location: Pa

Posts: 2,616
iTrader: (5)

Garage List
Im sooo confused...

OP puts on a new exhaust and doesn't rev the car past the rev the car or see how it sounds

I can't get enough of the exhaust sounds even when it was stock I loved taking it up to red line. That's where they sing the most
__________________
2009 E92 M3 /// Melbourne Red /// Fox Red /// M DKG

Full Innotech Exhaust - DINAN Intake - IND Engine Bay Appearance - IND Hand Stitched Boot Covers - and much more....
SchnellM3 is offline   United_States
0
Reply With Quote
      06-20-2012, 06:03 PM   #27
Seven7
First Lieutenant
 
Drives: 2011 M3 E92
Join Date: Aug 2010
Location: Vancouver BC

Posts: 348
iTrader: (1)

Update - it's been 3 months and the car is still eating a lot of gas. I average 18.5 litre/km in the city and about 12L/KM on the highway. One thing that scares me is that the car consumes more fuel when stopped and idling. It eats 39.5L/Km when I leave the engine on but car parked...Some is wrong. AND NO I DONT FLOOR IT..THATS NOT THE REASON WHY IT EATS MORE GAS. I DRIVE IT FOR A DAY KEEPING THE RPM LOWER THAN 3K AND I STILL NEED TO GET GAS EVERY 2 DAYS. WE HAVE A SERIOUS PROBLEM HERE.
Attached Images
 
Seven7 is offline   Canada
0
Reply With Quote
      06-20-2012, 06:42 PM   #28
KJ
First Lieutenant
 
Drives: 2008 E92 M3 - Alpine White
Join Date: Mar 2008
Location: Toronto

Posts: 379
iTrader: (1)

If you enable BMW Efficient Dynamics via coding, it actually tells you to shift at just under 2K rpm for the best efficiency. And that's coming from BMW directly.

I personally don't shift at that low of an RPM because you accelerate too damn slow that way, but technically, it is the RPM to shift at to get the best fuel economy (according to BMW).
KJ is offline   Canada
0
Reply With Quote
      06-21-2012, 04:22 AM   #29
Canuckles
Private First Class
 
Canuckles's Avatar
 
Drives: MW 2011 E92 M3
Join Date: Feb 2011
Location: British Columbia

Posts: 185
iTrader: (0)

Quote:
Originally Posted by Seven7 View Post
Update - it's been 3 months and the car is still eating a lot of gas. I average 18.5 litre/km in the city and about 12L/KM on the highway. One thing that scares me is that the car consumes more fuel when stopped and idling. It eats 39.5L/Km when I leave the engine on but car parked...Some is wrong. AND NO I DONT FLOOR IT..THATS NOT THE REASON WHY IT EATS MORE GAS. I DRIVE IT FOR A DAY KEEPING THE RPM LOWER THAN 3K AND I STILL NEED TO GET GAS EVERY 2 DAYS. WE HAVE A SERIOUS PROBLEM HERE.
Idling while stationary theoretically has 0 mpg, seriously though you bought a guzzler what did you expect.

I get around 16.2l/100 with 90%/10% city/highway respectively.
Canuckles is offline   Canada
0
Reply With Quote
      06-21-2012, 04:53 AM   #30
Autobahn335i
Lieutenant Colonel
 
Autobahn335i's Avatar
 
Drives: E92 335i
Join Date: Mar 2009
Location: Luxembourg

Posts: 1,599
iTrader: (5)

Quote:
Originally Posted by Seven7 View Post
Update - it's been 3 months and the car is still eating a lot of gas. I average 18.5 litre/km in the city and about 12L/KM on the highway. One thing that scares me is that the car consumes more fuel when stopped and idling. It eats 39.5L/Km when I leave the engine on but car parked...Some is wrong. AND NO I DONT FLOOR IT..THATS NOT THE REASON WHY IT EATS MORE GAS. I DRIVE IT FOR A DAY KEEPING THE RPM LOWER THAN 3K AND I STILL NEED TO GET GAS EVERY 2 DAYS. WE HAVE A SERIOUS PROBLEM HERE.
lol

In fact you're eating WAY more fuel than 39,5l/100km when you car is stationary

Because if the car doesn't move...well...it takes an infinite amount of time to reach that 100 km. And you'll consume an infinite amount of fuel.

But to not scare the crap out of you, BMW usually makes the gauge switch to 0,00 when you're stationary

On a serious note, the M3 is known to be quite a gas guzzler. But you should check your driving habits.
__________________
Performance Seats, Exhaust, Splitters, Pedals, Steering Wheel / RB Turbos / M3 CF Roof / Brembo GT BBK 355/345 / Rollcage / Forge FMIC / Quaife LSD / ÷hlins Road & Track / M3 Suspension Parts / Powerflex Bushings / Vorshlag Camberplates / Megan Racing Toe Links / LeatherZ Gauges / Extended M3 DCT Paddles / ER Sports OC / AR OC / Aux Radiator / AR DPs / Alpina TCU / COBB Pro-Tune
Autobahn335i is offline   Luxembourg
0
Reply With Quote
      06-21-2012, 08:31 AM   #31
1sikbmr
Brigadier General
 
1sikbmr's Avatar
 
Drives: E90 M3 6MT
Join Date: Mar 2010
Location: New York

Posts: 3,277
iTrader: (14)

Im way too lazy to actually figure out what the conversion to mpg would be. So i cant help
__________________

E90 ///M3 6MT Atlantis Blue - Fox red
ESS VT1-550|Gloss black grilles/Gold gills|V1 hardwire|Filled reflectors|ZHP lighted shift knob|Volk TE37 Gloss Black|Mode Carbon GT4 Lip|Umnitza V4 full blackout kit|Agency Power exhaust|Sosi x-pipe|BMW Performance Steering Wheel V1|
1sikbmr is offline  
0
Reply With Quote
      06-21-2012, 09:08 AM   #32
Seven7
First Lieutenant
 
Drives: 2011 M3 E92
Join Date: Aug 2010
Location: Vancouver BC

Posts: 348
iTrader: (1)

Dammit you guys, you guys are missing the point. My point is that after installing my new exhaust, the car started eating gas noticeably more (and it is said that with better exhausts, the car should be even more fuel efficient).
Seven7 is offline   Canada
0
Reply With Quote
      06-21-2012, 10:24 AM   #33
Singletrack
4th down; 4th quarter? Renegade.
 
Singletrack's Avatar
 
Drives: 09 SSII E92 M3; 12 AW X5d
Join Date: Aug 2008
Location: Pittsburgh, PA

Posts: 3,812
iTrader: (3)

Quote:
Originally Posted by Seven7 View Post
Dammit you guys, you guys are missing the point. My point is that after installing my new exhaust, the car started eating gas noticeably more (and it is said that with better exhausts, the car should be even more fuel efficient).
Rear section will make virtually no difference in terms of fuel adjustment.

I wouldn't lug the transmission around under 2k on a regular basis either. Not revving out the engine is actually bad for it - will lead to build up.
Singletrack is offline   United_States
0
Reply With Quote
      06-21-2012, 11:53 AM   #34
Seven7
First Lieutenant
 
Drives: 2011 M3 E92
Join Date: Aug 2010
Location: Vancouver BC

Posts: 348
iTrader: (1)

Quote:
Originally Posted by Singletrack View Post
Rear section will make virtually no difference in terms of fuel adjustment.

I wouldn't lug the transmission around under 2k on a regular basis either. Not revving out the engine is actually bad for it - will lead to build up.
One my buddies told me that there might be a problem between the computer and the exhaust. Something about the computer not being able to pick up the new exhaust system. Is this true? If it is, should I bring it in for service and have them check it out? Maybe reprogram the car in any way?

Last edited by Seven7; 06-21-2012 at 12:00 PM.
Seven7 is offline   Canada
0
Reply With Quote
      06-21-2012, 12:33 PM   #35
Singletrack
4th down; 4th quarter? Renegade.
 
Singletrack's Avatar
 
Drives: 09 SSII E92 M3; 12 AW X5d
Join Date: Aug 2008
Location: Pittsburgh, PA

Posts: 3,812
iTrader: (3)

Quote:
Originally Posted by Seven7 View Post
One my buddies told me that there might be a problem between the computer and the exhaust. Something about the computer not being able to pick up the new exhaust system. Is this true? If it is, should I bring it in for service and have them check it out? Maybe reprogram the car in any way?
There might be people living on the moon. I cannot say for certain.

Based on what we know about this engine, there is very little chance that a rear-section-only exhaust is going to have any significant impact on fuel delivery. You can change the entire exhaust out and the programming does a very competent job of adapting.
Singletrack is offline   United_States
0
Reply With Quote
      06-21-2012, 12:49 PM   #36
Jbook
Major
 
Jbook's Avatar
 
Drives: '11 ESS E90 M3
Join Date: Sep 2010
Location: South Bay Area

Posts: 1,268
iTrader: (20)

Garage List
2011 BMW E90 M3  [4.72]
Did you try what I mentioned in my previous post on the first page of this thread? Shifting at low RPMs makes the car get worse gas mileage! When cruising on the freeway at 70-75 mph and 3k rpm, my car gets better mpg than if I stay at the same speed in top gear at 2k or 2.5k rpm.
__________________
ESS VT2-625 w/ DCT Software | Awron Gauge | 19" BBS FI | Ohlins R&T w/ Vorshlag Camber Plates | Alekshop Subframe Bushings | RD Sport Sway Bars F&R | Dinan Strut Braces & Pedals | Brembo GT 380 F&R w/ Endless Pads | Akrapovic GT4 | Vorsteiner GTS-V Lip | 3D Design Diffuser | Platte Forme CF Side Skirt Extensions | BMW Performance Seats, CF Spoiler, CF Mirror Covers & Steering Wheel
Jbook is offline  
0
Reply With Quote
      06-21-2012, 02:18 PM   #37
tibra1
Banned
 
Drives: 2011 ZCP M3 - 2007 335i crashd
Join Date: Apr 2009
Location: NYC

Posts: 6,777
iTrader: (4)

More air ..more fuel?

I too have noticed this car chomps less gas when you live in the higher RPM range.
tibra1 is offline   No_Country
0
Reply With Quote
      06-23-2012, 02:37 AM   #38
Seven7
First Lieutenant
 
Drives: 2011 M3 E92
Join Date: Aug 2010
Location: Vancouver BC

Posts: 348
iTrader: (1)

Quote:
Originally Posted by Jbook View Post
Did you try what I mentioned in my previous post on the first page of this thread? Shifting at low RPMs makes the car get worse gas mileage! When cruising on the freeway at 70-75 mph and 3k rpm, my car gets better mpg than if I stay at the same speed in top gear at 2k or 2.5k rpm.
I did today actually, I shifted my gears at 2.5- 3k rpm and I did 13km (8 miles) in half a quarter tank. Im going to fucking smash my car because this is so fucking frustrating.
Seven7 is offline   Canada
0
Reply With Quote
      06-23-2012, 10:01 AM   #39
Stealth ///M
Banned
 
Drives: 2008 E92 M3
Join Date: May 2012
Location: NYC

Posts: 283
iTrader: (0)

put the stock setup back on.
Stealth ///M is offline  
0
Reply With Quote
      06-23-2012, 10:58 AM   #40
Moxie
Lieutenant Colonel
 
Moxie's Avatar
 
Drives: AW 328d Touring/SG 335d
Join Date: Jul 2009
Location: Stuttgart

Posts: 1,859
iTrader: (11)

Quote:
Originally Posted by Seven7 View Post
Update - it's been 3 months and the car is still eating a lot of gas. I average 18.5 litre/km in the city and about 12L/KM on the highway. One thing that scares me is that the car consumes more fuel when stopped and idling. It eats 39.5L/Km when I leave the engine on but car parked...Some is wrong. AND NO I DONT FLOOR IT..THATS NOT THE REASON WHY IT EATS MORE GAS. I DRIVE IT FOR A DAY KEEPING THE RPM LOWER THAN 3K AND I STILL NEED TO GET GAS EVERY 2 DAYS. WE HAVE A SERIOUS PROBLEM HERE.
Tenderfoot - it's not the exhaust. If you leave the car parked & it doesn't move, you will get 39.5L/KM....because it's not freking moving. F@ck me -
Moxie is offline   Germany
0
Reply With Quote
      06-23-2012, 12:04 PM   #41
doc19
Second Lieutenant
 
doc19's Avatar
 
Drives: 2011 e90 M3 6MT
Join Date: Aug 2011
Location: Maryland

Posts: 220
iTrader: (0)

Quote:
Originally Posted by Seven7 View Post
Update - it's been 3 months and the car is still eating a lot of gas. I average 18.5 litre/km in the city and about 12L/KM on the highway. One thing that scares me is that the car consumes more fuel when stopped and idling. It eats 39.5L/Km when I leave the engine on but car parked...Some is wrong. AND NO I DONT FLOOR IT..THATS NOT THE REASON WHY IT EATS MORE GAS. I DRIVE IT FOR A DAY KEEPING THE RPM LOWER THAN 3K AND I STILL NEED TO GET GAS EVERY 2 DAYS. WE HAVE A SERIOUS PROBLEM HERE.
I think you mean 18.5 litre/100km city and 12 litre/100km highway. For us imperialists that is about 13mpg and 19mpg

I don't know seven7, that is about right for the m3. I do mainly highway driving (live and work right off a major highway) and I get about 18.5mpg. What were you getting before?

Unless you really meant 18.5L/km, which is .12mpg. Then you really have a problem.
__________________
"This is like having a house-cat thatís a bengal tiger." - Todd Deeken, everydaydriver.com, on owning an e90 m3.
doc19 is offline   United_States
0
Reply With Quote
      06-23-2012, 12:07 PM   #42
Sean05
Putcha ang ganda...
 
Sean05's Avatar
 
Drives: 08 MR E92 M3
Join Date: Feb 2010
Location: Los Angeles, Brea CA.

Posts: 5,331
iTrader: (9)

Send a message via Yahoo to Sean05
OP: i guarantee you that its not the exhaust. replacing the rear will not change your MPG... I have no clue on why your car is eating more gas but here is what i suggest...

1. put the stock back on ... drive as normal work home work home.... until you are at 1/4 or when the warning low fuel comes up... I suggest to wait for the second warning...
2. now when the second warning fuel beeps comes up... check how many total miles you have used on a full tank...
3. do the same on your new exhaust.. if you are really worried this is the only way we can test the car if its really your exhaust but i guarantee you its not your exhaust.


Even with my Akra SLip on and my Full catless and restless i was only loosing about 5-10MPG.... which is not a big difference and no i wasnt tune...

Now when i had my Akra paired with 200 cell and resonator... i was able to get 5-10mpg on a full tank... not sure why or what would cause it but with an Akra 200 cell cat and res works a lot better..

now I have a Slip on AKra with OEM xpipe... I get the same MPG with my OEM exhaust...

FYI: this is just my experience
Sean05 is offline   Philippines
0
Reply With Quote
Post Reply

Bookmarks

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -5. The time now is 01:55 PM.




m3post
Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
1Addicts.com, BIMMERPOST.com, E90Post.com, F30Post.com, M3Post.com, ZPost.com, 5Post.com, 6Post.com, 7Post.com, XBimmers.com logo and trademark are properties of BIMMERPOST