Degraded fuel economy on fixed 3.0 liters
05-24-2018, 07:20 AM
#1
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Degraded fuel economy on fixed 3.0 liters
I've been collecting the hints and guesses about the impact of the diesel fixes on my Q5 3 liter. They were vague at first, suggesting that the only impact would be an increase in urea usage. Then there was a non-commital suggestion that fuel mileage impact would be 'minimal' but in small print it defined minimal as up to 10% (I don't consider 10% as minimal in a car that I paid a five or six thousand dollar premium above the same gas engined car, in order to get the lower fuel mileage). The latest letter from Audi Canada says that fuel mileage impact should be about 1.4 liters per 100 kilometers (about 0.4 US gallons per 60 miles). What they don't say is whether this is an average splitting highway and city mileage. If it's consistent then my 6.9 liters per 100 km highway mileage is going to be 8.3 liters. I could have bought the gas-powered Q5 for that and saved myself a lot of money. Does anyone know more about this?
06-19-2018, 07:10 PM
#2
AudiWorld Junior Member
Not sure how much this contributes to your quest for knowledge, but just bought a used Q5 with the fix applied and first trip of 150 miles averaged 40 by trip computer. (Probably optimistic, I know.) One passenger, no load, 70 mph. I have no comparison to pre-fix but pretty happy with that number for such a car as this.
06-29-2018, 05:38 AM
#3
We had a 2011 Q7 TDI bought back and replaced it with a 2015 Q7 TDI. The highway fuel mileage on the new fixed one is about 1-2 mpg less best I can tell. Throttle response is different too. It seems lazier in the initial press of the throttle but then comes on really strong when you press further. It’s a bit harder to use the TDI torque smoothly.
06-29-2018, 07:46 AM
#4
We had a 2011 Q7 TDI bought back and replaced it with a 2015 Q7 TDI. The highway fuel mileage on the new fixed one is about 1-2 mpg less best I can tell. Throttle response is different too. It seems lazier in the initial press of the throttle but then comes on really strong when you press further. It’s a bit harder to use the TDI torque smoothly.
06-29-2018, 11:42 AM
#5
My 2014 after fix lost about 2-4mpg. It will of course vary from owner to owner depending on ratio of stop-go vs hwy driving. Throttle response as described, basically less power than before which makes it seem as described "lazier". I am a performance car kind of guy and I have to admit I was of course disappointed with the decrease in power but for the normal driver it would be perfectly livable. Again as a performance guy it was unacceptable so I added a Malone Stage 2 tune. The power increase is HUGE and takes it way above pre-diesel fix performance with some restoration of mileage. The power delivery is so smooth and torque is abundant making the car an absolute joy to drive. It is waaay faster than my 4.2 A8. I have a couple thousand miles of driving with the tune now and I would highly recommend it. So easy and as an engine builder I can tell you it is the cheapest hp/tq you can buy. So easy to do. Just need a Windows laptop, the Malone Flashzilla installer and you can install the tune yourself just like I did. Takes about 10-15 min and you are good to go. Stage 2 is 305hp and 490ftlb tune. You can always use the Flashzilla installer to revert back to your stock tune anytime you want.
i would love to tune it to get that low speed torque back like they had pre-fix but I hesitate for fear that I might jeopardize the 10 yr 100,000 mile TDI emissions related warranty that we got with the fix. ( not to mention our remaining 10000 miles of OEM warranty.)
07-25-2018, 10:48 AM
#6
So that I don’t mislead anyone, Our fixed 2015 has not LOST power that I can detect under hard acceleration but the power seems not to be as available at lower rpm. It is as if the ECU makes the engine wait while the transmission downshifts before it supplies fuel for more power. If I manually downshift so that the engine is up near 3000 rpm, the throttle response is instant and strong. If I simply press the throttle in D the engine response is very minimal until the trans shifts down then whoosh! Off we go! It’s like turbo lag in an older turbocharged Porsche.
i would love to tune it to get that low speed torque back like they had pre-fix but I hesitate for fear that I might jeopardize the 10 yr 100,000 mile TDI emissions related warranty that we got with the fix. ( not to mention our remaining 10000 miles of OEM warranty.)
I have a low mileage car and I think the risk is minimal for me and I just love all the new power.
08-19-2018, 05:46 PM
#7
AudiWorld Super User
It's been 7 months since my 2014 Q5 TDI had the fix. Initially it seemed like my fuel mileage suffered but then it was January here in the Northeast and mileages suffer as the norm. I dismissed it until the warmer wx set in around April. Since then I took several 200-300 mile trips and I see NO difference in mileages getting 36-38 mpg highway and 30 mpg combined as it was for me early on before the fix. The engine actually feels like it has more torque and when I select the 'S' mode the Q takes off and runs like a scared wabbit. I have 63K on the clock. .02
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