E90Post
 


TireRack
 
BMW 3-Series (E90 E92) Forum > E90 / E92 / E93 3-series Powertrain and Drivetrain Discussions > N54 Turbo Engine / Drivetrain / Exhaust Modifications - 335i > Experiencing Bad MPG



Reply
 
Thread Tools Search this Thread
      05-14-2013, 12:54 PM   #1
BD_F22
BD_e92
United_States
20
Rep
1,115
Posts

 
Drives: 2015 m235i xDrive
Join Date: Nov 2012
Location: NYC

iTrader: (8)

Experiencing Bad MPG

Hello everyone, so I am running the HPF gen 2 exhaust and bms dci right now as my only bolt ons and no tune yet.. I went from averaging about 17-19mpg with the HPF exhaust and now after installing the dci I'm down to about 14.5 mpg.. can anyone shed some light on if the dci could affect my mpg that drastically?
Appreciate 0
      05-14-2013, 12:55 PM   #2
E90Company
Major General
E90Company's Avatar
No_Country
72
Rep
6,137
Posts

 
Drives: Car
Join Date: Mar 2012
Location: FL

iTrader: (2)

Not related.
Appreciate 0
      05-14-2013, 12:57 PM   #3
BD_F22
BD_e92
United_States
20
Rep
1,115
Posts

 
Drives: 2015 m235i xDrive
Join Date: Nov 2012
Location: NYC

iTrader: (8)

Quote:
Originally Posted by E90Company View Post
Not related.
any advice as to what it could be?
Appreciate 0
      05-14-2013, 12:58 PM   #4
E90Company
Major General
E90Company's Avatar
No_Country
72
Rep
6,137
Posts

 
Drives: Car
Join Date: Mar 2012
Location: FL

iTrader: (2)

Quote:
Originally Posted by #teambimmer View Post
any advice as to what it could be?
Could be quite a bit of things. Are you stepping on the throttle more to hear that exhaust/intake? That would do it.
Appreciate 0
      05-14-2013, 01:01 PM   #5
BD_F22
BD_e92
United_States
20
Rep
1,115
Posts

 
Drives: 2015 m235i xDrive
Join Date: Nov 2012
Location: NYC

iTrader: (8)

Quote:
Originally Posted by E90Company View Post
Could be quite a bit of things. Are you stepping on the throttle more to hear that exhaust/intake? That would do it.
lol definitely did that in the beginning and figured that was why it decreased significantly, but after my last fill up i reset the mpg in the vehicle info and drove normal for a week with very little hard acceleration and it averaged out to be about the same
Appreciate 0
      05-14-2013, 01:08 PM   #6
Envuks
Captain
Envuks's Avatar
8
Rep
718
Posts

 
Drives: '08 e92 335xi
Join Date: Apr 2012
Location: MA

iTrader: (2)

I average 18.9mpg and I drive mostly highway. Your mpg seems normal to me
__________________
Jet black e92 6mt 335xi:

18" BBS RGRs, KW v1, ESS Stage 2 flash, VRSF 7" FMIC, VRSF downpipes, JG Mods m-tech front, mtec V3 AEs, BMS OCC, hardwired valentine 1, p3cars gauge, amber delete, sport seats, factory oil cooler.
Appreciate 0
      05-14-2013, 01:10 PM   #7
marv85
Colonel
marv85's Avatar
United_States
25
Rep
2,558
Posts

 
Drives: '07 335i MT
Join Date: Jun 2010
Location: Portland

iTrader: (5)

heavy foot... bets way to measure MPG is do it yourself. fill the tank and reset the trip counter.

drive around till it's less than half at least (or whenever, but the more the drive the more accurate the measurement would be).

Refill and divide the trip counter number by the # number of gallons it took to refill.

Also take it easy
__________________
'10 E92 335i , COBB
Appreciate 0
      05-14-2013, 03:35 PM   #8
Jeff@TopGearSolutions
BimmerPost Supporting Vendor
Jeff@TopGearSolutions's Avatar
United_States
242
Rep
18,297
Posts


 
Drives: C6 Z06, GSXR-750, 09 335i
Join Date: Dec 2008
Location: TopGearSolutions.com

iTrader: (32)

Send a message via AIM to Jeff@TopGearSolutions
I found your problem...

Your foot is too HEAVY with the new intake and exhaust sounds.

My MPG average over the course of 20,000 miles was 21.0. Your drive habits can sway this number largely. I know a few N54 locals that get about 23-24 Average MPG and others who have a heavier foot with more city driving in the 17-18 range.
Appreciate 0
      05-14-2013, 04:13 PM   #9
BD_F22
BD_e92
United_States
20
Rep
1,115
Posts

 
Drives: 2015 m235i xDrive
Join Date: Nov 2012
Location: NYC

iTrader: (8)

Quote:
Originally Posted by Jeff@TopGearSolutions View Post
I found your problem...

Your foot is too HEAVY with the new intake and exhaust sounds.

My MPG average over the course of 20,000 miles was 21.0. Your drive habits can sway this number largely. I know a few N54 locals that get about 23-24 Average MPG and others who have a heavier foot with more city driving in the 17-18 range.
hahaha I definitely agree that sometimes my foot can be a bit heavy but like you said people with a heavier foot are around 17-18, that doesnt explain how I am as low as 14.5mpg.. Should I possibly change my spark plugs being I have 36k miles and they have never been changed?
Appreciate 0
      05-14-2013, 04:33 PM   #10
RandomHero
Private First Class
United_States
4
Rep
137
Posts

 
Drives: 2008 335i e92
Join Date: Apr 2013
Location: Austin,tx

iTrader: (0)

The n54 doesn't have a MAF sensor so there' really no explanation of why the DCI filters themselves would have any effect on your fuel economy.

Have you checked to make sure you didn't accidentally knock your charge pipe loose?

The charge pipe is in the general vacinity of the intake location and if you fought trying to get the DCI to fit, you might have knocked it loose. The MAP sensor is located on the charge pipe and if there's a leak, it could in theory cause a loss in performance/fuel economy (although you'd likely throw a code).

Aside from knocking something loose, there's really no other explanation I can think of aside from a change in your driving habits, bad gasoline, or a significant change in weather.
Appreciate 0
      05-14-2013, 04:51 PM   #11
Jeff@TopGearSolutions
BimmerPost Supporting Vendor
Jeff@TopGearSolutions's Avatar
United_States
242
Rep
18,297
Posts


 
Drives: C6 Z06, GSXR-750, 09 335i
Join Date: Dec 2008
Location: TopGearSolutions.com

iTrader: (32)

Send a message via AIM to Jeff@TopGearSolutions
Quote:
Originally Posted by #teambimmer View Post
hahaha I definitely agree that sometimes my foot can be a bit heavy but like you said people with a heavier foot are around 17-18, that doesnt explain how I am as low as 14.5mpg.. Should I possibly change my spark plugs being I have 36k miles and they have never been changed?
I know the Bronx a bit and I would imagine in local traffic that 14.5 with a heavy foot seems reasonable. This car under accel in traffic averages about 10-12 MPG in stop and go traffic.

How much highway do you do? I woudn't sweat anything. Most of the spark plugs changes at 25K are for vehicles with a tune. 50,000 would be for a non tuned vehicle. There is really nothing a cat back exhaust or a dual cone intake can do that would tell your ECU just to waste more gas and spit out more fuel.
Appreciate 0
      05-14-2013, 04:55 PM   #12
135Pats
Turbo's Here
135Pats's Avatar
United_States
61
Rep
5,676
Posts

 
Drives: 135i
Join Date: May 2012
Location: Maryland

iTrader: (2)

With 90% city driving I get 15mpg or so in my 1er.....so yea :/
__________________
E88 N54 Alpinweiss/Coral Red/Motiv HTA 3586R/Meisterschaft Race/Berk Resonated/ER CP/Synapse/VRSF FMIC/FFTEC LPFP/HFS-4 DO Stainless Lines/BMS Thermostat Delete/Rob Beck PCV Valve + Cap/BMS OCC/ST Coilovers/M3 FCA + Tension Rods/M3 Subframe Bushings/M3 FSB/DINAN Camber Plates/Apex ARC-8/Project Kics/VAC Hubs/Rogue Transmission Mounts/Alpina TCU Flash/Icarbon/Kerscher/BMW Performance
Appreciate 0
      05-14-2013, 04:55 PM   #13
Sick335
Major
United_States
17
Rep
1,048
Posts

 
Drives: 335i
Join Date: Oct 2011
Location: Tarzana, CA

iTrader: (1)

I averaged 23 over the last 1000 miles... heavy foot you have
__________________

JB4 G5 ISO+BMS Flash+RB Turbos+Meth=
Appreciate 0
      05-14-2013, 05:02 PM   #14
BD_F22
BD_e92
United_States
20
Rep
1,115
Posts

 
Drives: 2015 m235i xDrive
Join Date: Nov 2012
Location: NYC

iTrader: (8)

Quote:
Originally Posted by Jeff@TopGearSolutions View Post
I know the Bronx a bit and I would imagine in local traffic that 14.5 with a heavy foot seems reasonable. This car under accel in traffic averages about 10-12 MPG in stop and go traffic.

How much highway do you do? I woudn't sweat anything. Most of the spark plugs changes at 25K are for vehicles with a tune. 50,000 would be for a non tuned vehicle. There is really nothing a cat back exhaust or a dual cone intake can do that would tell your ECU just to waste more gas and spit out more fuel.
thanks for all the help, I appreciate your detailed responses
Appreciate 0
      05-14-2013, 05:06 PM   #15
Astephens94
Slightly modified...
Astephens94's Avatar
United_States
3
Rep
287
Posts

 
Drives: 2007 335i
Join Date: Mar 2012
Location: Probably work.

iTrader: (3)

Garage List
2007 335i  [3.00]
This happened to me after I installed my intake - turns out it was my foot
Appreciate 0
      05-14-2013, 05:31 PM   #16
happy4nk8er
Second Lieutenant
2
Rep
277
Posts

 
Drives: 335i E92
Join Date: Jan 2009
Location: Milky way galaxy

iTrader: (0)

I am averaging 24.5 mpg and have gotten as high as 32 mpg on road trips.
I have intake,cat-back exhaust, Helix IC, Vishnu Procede and charge pipe.
I have 85k miles and this has been consistent through out that mileage.

14-15 mpg would bum me out.
Appreciate 0
      05-15-2013, 06:31 AM   #17
CannonFodder
Private
0
Rep
68
Posts

 
Drives: 07 335i
Join Date: May 2012
Location: Maryland

iTrader: (0)

Daily driving 100 mile round trip, all highway I average 29.3 mpg... It is all in how you drive it.
Appreciate 0
      05-15-2013, 08:15 AM   #18
335sRus
Private
0
Rep
65
Posts

 
Drives: 2007 335xi
Join Date: Feb 2013
Location: Milwaukee, WI

iTrader: (1)

Garage List
2007 BMW 335xi  [0.00]
Quote:
Originally Posted by marv85 View Post
heavy foot... bets way to measure MPG is do it yourself. fill the tank and reset the trip counter.

drive around till it's less than half at least (or whenever, but the more the drive the more accurate the measurement would be).

Refill and divide the trip counter number by the # number of gallons it took to refill.

Also take it easy
+1
I thought I was getting 17 mpg (according to the car), after calculating myself I found that I'm actually getting 22.5 mpg.
Appreciate 0
      05-16-2013, 04:23 AM   #19
geterdone
Private First Class
United_States
1
Rep
143
Posts

 
Drives: 2007 335i
Join Date: Mar 2011
Location: Yukon, Oklahoma

iTrader: (1)

22 no ethanol.
Appreciate 0
      05-16-2013, 11:56 AM   #20
HeavyMetalRocker
Lieutenant
HeavyMetalRocker's Avatar
United_States
6
Rep
520
Posts

 
Drives: 2007 BMW 335i E90 6MT
Join Date: Nov 2012
Location: Dallas, Texas

iTrader: (0)

I've got a tune on top of what you've got and a moderately heavy foot getting 21.7 avg mpg... something is wrong with your foot or car!
__________________
2007 335i e90 6mt | RB Turbo Billet+ 11blade | RB PCV | JB4 G5 | BB e85 Flash | Walbro 255lph | DCI | VRSF CP & Tial BOV | NGK Plugs | HPF Exhaust | VRSF DP's | CxRacing FMIC | Spec 2+ & SSMFW | StopTech Drilled/Slotted Rotors | Hawk Performance Pads | DEFIV Lockdown kit | Mtec V3 angels | 35/15% Llumar ceramic
Appreciate 0
      05-16-2013, 12:24 PM   #21
ken1137
Brigadier General
ken1137's Avatar
United_States
41
Rep
3,697
Posts

 
Drives: a slow 2009 e90 335i
Join Date: Jun 2011
Location: Chicago

iTrader: (7)

Garage List
2009 e90 335i  [3.20]
I drive mostly stop-and-go in suburbs. I've noticed my mileage avg dropping per model of BMW i have owned

325ci - 25 mpg
328xi - 24 mpg
135i - 18 mpg
335i - 19.4 mpg

Ok, so I have improved with my 335i over my 135i
__________________

BMWCCA member
Appreciate 0
      05-16-2013, 02:05 PM   #22
catcher22
First Lieutenant
5
Rep
361
Posts

 
Drives: 2008 335xi Coupe
Join Date: May 2008
Location: Virginia

iTrader: (1)

When I was getting MPG like that my plugs/coils were starting to go bad. Replaced em and getting like 21-25 now.


14-15 did really bum me out, especially after a few quick tanks.
Appreciate 0
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 09:24 PM.




e90post
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