Go Back   AudiWorld Forums > Audi Models > Audi Q3 /Q5 / Q7 > Q5/SQ5 Discussion
Sign in using an external account
Register Forgot Password?


Q5/SQ5 Discussion Discussion forum for the Audi Q5 SUV
Sponsored by: Audi

Welcome to AudiWorld Forums!
Welcome to AudiWorld.com.

You are currently viewing our forums as a guest, which gives you limited access to view most discussions and access our other features. By joining our community you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is fast, simple and absolutely free so please, join the AudiWorld Forums community today!


Reply
 
 
 
 
LinkBack Thread Tools Search this Thread Display Modes
Old 09-10-2013, 11:50 AM   #1
AudiWorld Expert
Account #: 139
 
Join Date: Mar 2000
Location: Raleigh, NC
Posts: 28,900
Default Got 37.9mpg (per computer) for 45 miles and noticed only ~0.6 Avg MPG increments?

First off, leaving Queens headed for CT, I achieved 37.9 mpg (per computer, which I'll verify for accuracy after ~5 tanks) for 45 miles. This included starting the car from cold overnight, moving it a few blocks, loading it with luggage, and then continuing on. That was followed by some stop and go traffic getting out of Queens, then highway travelling <70 mph, which is likely the ideal range for the Q5 TDI as 50-60 corresponds to about 1200-1400 rpms in 8th, and keeps aerodynamic drag down.

Click the image to open in full size.


However while driving, I happened to look down and noticed the Average MPG jump from 36.7 to 37.3 and back to 36.7. At first I thought this was some screw up in the computing of average perhaps averaging in some large number (200 mpg seems to be the highest the instantaneous will show). But then after keeping an eye on it going forward, I noticed that the increments for which it would change were a minimum of about 0.6 MPG. This seems really strange, and unlike anything I've seen on other Audi/VW/Porsche's I've owned. I'm almost positive all others have shown 0.1 MPG increments for Average MPG.

Indeed, these were the only values I saw within this time of driving - it just jumped from one to the next:

35.6
36.1
36.7
37.3
37.9

I'll watch each time I drive to capture others as well.

Has this been noticed/discussed before? At first I thought it strange that if this were to happen that it wasn't being done with 0.5 increments. Then when I saw that most of those ranges were 0.6, but one was 0.5, I realized it's likely due to conversion from metric. Sure enough 0.6 mpg is 0.9656 kilometers per gallon. So then I thought it was only incremented every 1.0 km/gal and that it would get rounded up or down every so often and that would account for the 0.5 and 0.6 values. However 1.0 km/gal is 0.62 mpg, so it would round between 0.6 and 0.7 (not 0.5) so that doesn't make sense either. I also tried comparing to L/100km, but that would come to be 400, which seems like an odd value as well. So I'm at a bit of a loss here to the rationale behind this or the increment value/metric used. It seems like a step backwards. Of all the things this car is capable of, why not 0.1 mpg average increments? It feels like choosing between a poor and good bathroom scale or tire pressure meter that have 0.5 or 0.1 increments for their relative measures.

Here are those values:

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.

Click the image to open in full size.
__________________
Mark P





Present:
'14 Audi Q5 TDI, Glacier, S Line, Sport Int, Nav, B&O, Tow - website - 15k miles
'04 Porsche 911 Turbo, Speed Yellow, X50 - website - 45k miles
'09 VW Tiguan 2.0T, Candy White - Hers - 69k miles
Past:
'08 Audi A3 2.0T, Ibis White, DSG, S-line - website - 54k miles
'02 Audi S4 Avant, Imola Yellow, APR Stg3 - website - 191k miles
'01.5 VW Golf 4dr 1.8T, Satin Silver, APR Stg3 - website - 203k miles
'00 Audi A4 1.8T, Silver, APR Stg2 - website - 61k miles
Mark P is offline   Reply With Quote
Old 09-10-2013, 12:46 PM   #2
AudiWorld Senior Member
Account #: 226959
 
Join Date: Dec 2011
Location: New England
Posts: 884
Default

The difference between your last 2 pictures is 17 miles in 11 minutes. That's a pretty brisk pace if you're trying to save gas!
__________________
Hers: 2012 Audi Q5 2.0T Ibis White/Cinnamon
Mine: 2006 Honda Ridgeline RTL
Parsec is offline   Reply With Quote
Old 09-10-2013, 12:58 PM   #3
Audiworld Junior Member
Account #: 263990
 
Join Date: Aug 2013
Posts: 62
Default

The quantization error appears to be happening because the computer is calculating tenths of a L/100km (or whole numbers of liters per 1000km).

Here is a conversion of L/100km to mpg. The display is just truncating (not rounding) to tenths of mpg.

Code:
L/100km mpg             truncated mpg
------- ---             -------------
7.0	33.60227992	33.6
6.9	34.08926948	34.0
6.8	34.59058227	34.5
6.7	35.10685961	35.1
6.6	35.63878173	35.6
6.5	36.18707068	36.1
6.4	36.75249366	36.7
6.3	37.33586657	37.3
6.2	37.93805797	37.9
6.1	38.55999335	38.5
6.0	39.2026599	39.2
amstrad is offline   Reply With Quote
Old 09-10-2013, 12:58 PM   #4
AudiWorld Member
Account #: 88945
 
soonerfan's Avatar
 
Join Date: Mar 2005
Posts: 437
Default

I cannot wait to hear the results of this! And I didn't have to wait long!
__________________
2014 Q5 TDI Ibis White/Black
S-Line Plus Pkg., Sport Pkg,. MMI Nav Plus, B&O, Side Assist, Tow Hitch, Protection Pkg.

Gone but not forgotten: 2011 Q5 P+ 2.0TFSI
soonerfan is offline   Reply With Quote
Old 09-10-2013, 01:24 PM   #5
AudiWorld Senior Member
Account #: 243111
 
Join Date: Sep 2012
Location: Pflugerville, TX
Posts: 1,281
Default

So I guess those of us **** enough to want to have the computer be correct should be basing our adjustments on L/100km or waiting until the significance of the conversion and truncation gets small enough to not matter. Good to keep in mind for when mine comes in.
idale is online now   Reply With Quote
Old 09-10-2013, 02:38 PM   #6
AudiWorld Expert
Account #: 139
 
Join Date: Mar 2000
Location: Raleigh, NC
Posts: 28,900
Default

Quote:
Originally Posted by amstrad View Post
The quantization error appears to be happening because the computer is calculating tenths of a L/100km (or whole numbers of liters per 1000km).

Here is a conversion of L/100km to mpg. The display is just truncating (not rounding) to tenths of mpg.

Code:
L/100km mpg             truncated mpg
------- ---             -------------
7.0	33.60227992	33.6
6.9	34.08926948	34.0
6.8	34.59058227	34.5
6.7	35.10685961	35.1
6.6	35.63878173	35.6
6.5	36.18707068	36.1
6.4	36.75249366	36.7
6.3	37.33586657	37.3
6.2	37.93805797	37.9
6.1	38.55999335	38.5
6.0	39.2026599	39.2
Ahh thanks! I forgot to account for them being inverse calculations. One can't merely convert 0.6 mpg to L/100km because that represents a horrible efficiency, and not an increment. It's not like converting inches to cm for instance.

Still disappointing this is the accuracy they've reduced the trip computer down to. I'll be keeping track of it manually anyway so no real issue here, just annoying with all the other technology going on
__________________
Mark P





Present:
'14 Audi Q5 TDI, Glacier, S Line, Sport Int, Nav, B&O, Tow - website - 15k miles
'04 Porsche 911 Turbo, Speed Yellow, X50 - website - 45k miles
'09 VW Tiguan 2.0T, Candy White - Hers - 69k miles
Past:
'08 Audi A3 2.0T, Ibis White, DSG, S-line - website - 54k miles
'02 Audi S4 Avant, Imola Yellow, APR Stg3 - website - 191k miles
'01.5 VW Golf 4dr 1.8T, Satin Silver, APR Stg3 - website - 203k miles
'00 Audi A4 1.8T, Silver, APR Stg2 - website - 61k miles

Last edited by Mark P; 09-10-2013 at 02:56 PM.
Mark P is offline   Reply With Quote
Old 09-10-2013, 02:55 PM   #7
AudiWorld Expert
Account #: 139
 
Join Date: Mar 2000
Location: Raleigh, NC
Posts: 28,900
Default

17.5 minutes. That's a "1:08"
__________________
Mark P





Present:
'14 Audi Q5 TDI, Glacier, S Line, Sport Int, Nav, B&O, Tow - website - 15k miles
'04 Porsche 911 Turbo, Speed Yellow, X50 - website - 45k miles
'09 VW Tiguan 2.0T, Candy White - Hers - 69k miles
Past:
'08 Audi A3 2.0T, Ibis White, DSG, S-line - website - 54k miles
'02 Audi S4 Avant, Imola Yellow, APR Stg3 - website - 191k miles
'01.5 VW Golf 4dr 1.8T, Satin Silver, APR Stg3 - website - 203k miles
'00 Audi A4 1.8T, Silver, APR Stg2 - website - 61k miles
Mark P is offline   Reply With Quote
Old 09-10-2013, 03:27 PM   #8
AudiWorld Super User
Account #: 169569
 
uberwgn's Avatar
 
Join Date: Sep 2009
Location: MA
Posts: 3,166
Default

Mark, get that fuel consumption displayed calibrated! They're typically 10% optimistic.
uberwgn is online now   Reply With Quote
Old 09-10-2013, 04:18 PM   #9
AudiWorld Expert
Account #: 139
 
Join Date: Mar 2000
Location: Raleigh, NC
Posts: 28,900
Default

Quote:
Originally Posted by uberwgn View Post
Mark, get that fuel consumption displayed calibrated! They're typically 10% optimistic.
I will. As noted, I need data first to do the calibration. I should complete 3 tanks by the time I'm home next week. I'll likely wait for 5 to have more datapoints. Oh and I need to get a newer VCDS interface too.
__________________
Mark P





Present:
'14 Audi Q5 TDI, Glacier, S Line, Sport Int, Nav, B&O, Tow - website - 15k miles
'04 Porsche 911 Turbo, Speed Yellow, X50 - website - 45k miles
'09 VW Tiguan 2.0T, Candy White - Hers - 69k miles
Past:
'08 Audi A3 2.0T, Ibis White, DSG, S-line - website - 54k miles
'02 Audi S4 Avant, Imola Yellow, APR Stg3 - website - 191k miles
'01.5 VW Golf 4dr 1.8T, Satin Silver, APR Stg3 - website - 203k miles
'00 Audi A4 1.8T, Silver, APR Stg2 - website - 61k miles
Mark P is offline   Reply With Quote
Old 09-11-2013, 04:27 AM   #10
AudiWorld Super User
Account #: 169569
 
uberwgn's Avatar
 
Join Date: Sep 2009
Location: MA
Posts: 3,166
Default

Quote:
Originally Posted by Mark P View Post
I will. As noted, I need data first to do the calibration. I should complete 3 tanks by the time I'm home next week.
I've tracked my displayed vs. manual calculation over the life of my A4 and found that I can get an accuracy of +/- .3mpg around the city, but more variance on long trips. Most of my driving is in the city so I accept the fact that the highway displayed value is still a bit higher than it should be.
uberwgn is online now   Reply With Quote
Old 09-11-2013, 04:27 AM
AudiWorld
Audi R8




Paid Advertisement
 
 
 
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

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 On
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -8. The time now is 05:43 AM.


Copyright 2014 AudiWorld.com Audi Enthusiast Community

Personal Contacts

SEO by vBSEO ©2011, Crawlability, Inc.