SUPRISE: Installed front chin spoiler improved highway MPG?!
02-23-2014, 12:54 AM
#1
Super Member
Thread Starter
SUPRISE: Installed front chin spoiler improved highway MPG?!
To summarize...
My 2012 C350 currently has ~24k miles.
At 10k miles I did a dealer service A and followed it up by performing my 1st mod by replacing the OEM wheels with wider 8.5 fronts and 9.5 rears (in preparation for Michelin PSS later down the road). I re-mounted the original tires since I didn't want to waste them but have not observed any drastic MPG impact from the wider wheels.
At this point the biggest delta between the computer calculated combined MPG vs REAL WORLD combined MPG was no more than 0.9 and has been accurate to as much as 0.0 per tank. General average delta however, hovered around 0.4.
This meant if the computer readout said your tank average was 25.4 MPG....your REAL WORLD MPG would most likely be 25 even.
At 20k miles I did a dealer service B (which they performed an ECU update), and I immediately followed it by my 2nd mod which was also an ECU update but from OE tuning.
Although I barely noticed any MPG impact (one of the claimed benefits of the tune was better MPG), it however, DECREASED the accuracy of the trip computer reading!
Prior to the tune, the estimated max delta was 0.9 but now I've seen it as off by as much as 1.5! (example the trip computer says your getting 26.5 MPG per tank, in reality, you are STILL getting only 25)
While initially disappointing, at least real world MPG seemed to have been unaffected, and for me at least, have stabilized to a combined reading of 25-26.
Here comes the suprise part...
Roughly 3k miles later I installed a CF front chin spoiler (godhand style) purely for cosmetic reasons and below is a Fuelly.com graph of the real world MPG trend...
What you see is the results of the last 10 fuel ups (I could not record 1 or 2 because the wife filled up the tank without recording results). The OE tune was done on 12/18/2013 while the chin spoiler was installed on the night of 1/22/2014.
If you click on my sig below, you'll see a log book of the trip computer notes as well.
Notice how on my last fuel fill, I was able to break a personal record of most miles on a tank @ 447 miles! This was done on NORMAL driving (city miles as well) without the need to hyper mile and with freeway speeds in excess of 70 MPH (tire pressures regularly checked as well).
Below is a sample trip computer reading from my commute last Friday morning.
Below is a sample overall TANK computer reading prior to the fuel fill on 2/10/2014.
(in this case, the delta was 1.2, since real world MPG was 27.5)
EDIT:
Just to clarify...the spoiler in question is this...
My 2012 C350 currently has ~24k miles.
At 10k miles I did a dealer service A and followed it up by performing my 1st mod by replacing the OEM wheels with wider 8.5 fronts and 9.5 rears (in preparation for Michelin PSS later down the road). I re-mounted the original tires since I didn't want to waste them but have not observed any drastic MPG impact from the wider wheels.
At this point the biggest delta between the computer calculated combined MPG vs REAL WORLD combined MPG was no more than 0.9 and has been accurate to as much as 0.0 per tank. General average delta however, hovered around 0.4.
This meant if the computer readout said your tank average was 25.4 MPG....your REAL WORLD MPG would most likely be 25 even.
At 20k miles I did a dealer service B (which they performed an ECU update), and I immediately followed it by my 2nd mod which was also an ECU update but from OE tuning.
Although I barely noticed any MPG impact (one of the claimed benefits of the tune was better MPG), it however, DECREASED the accuracy of the trip computer reading!
Prior to the tune, the estimated max delta was 0.9 but now I've seen it as off by as much as 1.5! (example the trip computer says your getting 26.5 MPG per tank, in reality, you are STILL getting only 25)
While initially disappointing, at least real world MPG seemed to have been unaffected, and for me at least, have stabilized to a combined reading of 25-26.
Here comes the suprise part...
Roughly 3k miles later I installed a CF front chin spoiler (godhand style) purely for cosmetic reasons and below is a Fuelly.com graph of the real world MPG trend...
What you see is the results of the last 10 fuel ups (I could not record 1 or 2 because the wife filled up the tank without recording results). The OE tune was done on 12/18/2013 while the chin spoiler was installed on the night of 1/22/2014.
If you click on my sig below, you'll see a log book of the trip computer notes as well.
Notice how on my last fuel fill, I was able to break a personal record of most miles on a tank @ 447 miles! This was done on NORMAL driving (city miles as well) without the need to hyper mile and with freeway speeds in excess of 70 MPH (tire pressures regularly checked as well).
Below is a sample trip computer reading from my commute last Friday morning.
Below is a sample overall TANK computer reading prior to the fuel fill on 2/10/2014.
(in this case, the delta was 1.2, since real world MPG was 27.5)
EDIT:
Just to clarify...the spoiler in question is this...
Last edited by edgalang; 02-24-2014 at 01:20 PM. Reason: Forgot to include pics of spoiler for reference.
02-24-2014, 02:12 PM
#3
Super Member
Thread Starter
02-25-2014, 08:17 AM
#5
could u tell me what ecu update the dealer did at 20,000 miles, I have the same car and would like to get it done. They have not told me about a update when I bring the car in for service. Thanks
02-26-2014, 02:38 PM
#6
Super Member
Thread Starter
