Is this drivetrain drag normal?
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 48
Likes: 15
From: Mesa AZ
Is this drivetrain drag normal?
My 2016 Z51 A8, with 32K miles, is new to me. I moved up from a 2012 Grand Sport M6 a couple of months ago and I’m still trying to adjust to the A8. (I had the triple flush done 6 weeks ago and that made a noticeable improvement to my up shifts and other glitches. I also installed a Range device at that time).
On a recent 250 mile road trip through the mountains here in AZ, I noticed that on long, steep downhill grades I still had to have my foot on the gas while in 8th gear or else the car would slow. On the same roads in the 2012 M6 I would have had to manually downshift to 4th to keep my speed under control, or continually tap the brakes. The same applies to our 2016 Cadillac XTS, A6. As a test, the car would gain speed on the downhill grades when shifted into Neutral. Our fellow C7 traveling friends noticed I was only using my brakes when I was coming to a complete stop on this trip and thought I was manually downshifting the A8 the whole time. I was not. Overall trip MPG was 22.5 where it probably would have been closer to 26+ MPG in the 2012 M6.
Is this normal for a C7 A8?
On a recent 250 mile road trip through the mountains here in AZ, I noticed that on long, steep downhill grades I still had to have my foot on the gas while in 8th gear or else the car would slow. On the same roads in the 2012 M6 I would have had to manually downshift to 4th to keep my speed under control, or continually tap the brakes. The same applies to our 2016 Cadillac XTS, A6. As a test, the car would gain speed on the downhill grades when shifted into Neutral. Our fellow C7 traveling friends noticed I was only using my brakes when I was coming to a complete stop on this trip and thought I was manually downshifting the A8 the whole time. I was not. Overall trip MPG was 22.5 where it probably would have been closer to 26+ MPG in the 2012 M6.
Is this normal for a C7 A8?
Race Director
Joined: Apr 2007
Posts: 16,025
Likes: 1,656
From: Toronto, Canada
C7 of the Year - Unmodified Finalist 2021
My 2016 Z51 A8, with 32K miles, is new to me. I moved up from a 2012 Grand Sport M6 a couple of months ago and I’m still trying to adjust to the A8. (I had the triple flush done 6 weeks ago and that made a noticeable improvement to my up shifts and other glitches. I also installed a Range device at that time).
On a recent 250 mile road trip through the mountains here in AZ, I noticed that on long, steep downhill grades I still had to have my foot on the gas while in 8th gear or else the car would slow. On the same roads in the 2012 M6 I would have had to manually downshift to 4th to keep my speed under control, or continually tap the brakes. The same applies to our 2016 Cadillac XTS, A6. As a test, the car would gain speed on the downhill grades when shifted into Neutral. Our fellow C7 traveling friends noticed I was only using my brakes when I was coming to a complete stop on this trip and thought I was manually downshifting the A8 the whole time. I was not. Overall trip MPG was 22.5 where it probably would have been closer to 26+ MPG in the 2012 M6.
Is this normal for a C7 A8?
On a recent 250 mile road trip through the mountains here in AZ, I noticed that on long, steep downhill grades I still had to have my foot on the gas while in 8th gear or else the car would slow. On the same roads in the 2012 M6 I would have had to manually downshift to 4th to keep my speed under control, or continually tap the brakes. The same applies to our 2016 Cadillac XTS, A6. As a test, the car would gain speed on the downhill grades when shifted into Neutral. Our fellow C7 traveling friends noticed I was only using my brakes when I was coming to a complete stop on this trip and thought I was manually downshifting the A8 the whole time. I was not. Overall trip MPG was 22.5 where it probably would have been closer to 26+ MPG in the 2012 M6.
Is this normal for a C7 A8?
Burning Brakes
Joined: May 2007
Posts: 965
Likes: 13
From: turn 12 at Road America or TX
My 2016 Z51 A8, with 32K miles, is new to me. I moved up from a 2012 Grand Sport M6 a couple of months ago and I’m still trying to adjust to the A8. (I had the triple flush done 6 weeks ago and that made a noticeable improvement to my up shifts and other glitches. I also installed a Range device at that time).
Pro
Joined: May 2021
Posts: 500
Likes: 433
From: Queen Creek, AZ
Based on my 2018 Corvette manual, I would say your condition is not normal:
Hill and Mountain Roads
Driving on steep hills or through mountains is different than driving on flat or rolling terrain. Tips include: . Keep the vehicle serviced and in good shape. . Check all fluid levels and brakes, tires, cooling system, and transmission. . Shift to a lower gear when going down steep or long hills. { Warning Using the brakes to slow the vehicle on a long downhill slope can cause brake overheating, can reduce brake performance, and could result in a loss of braking. Shift the transmission to a lower gear to let the engine assist the brakes on a steep downhill slope. { Warning Coasting downhill in N (Neutral) or with the ignition off is dangerous. This can cause overheating of the brakes and loss of steering. Always have the engine running and the vehicle in gear. . Drive at speeds that keep the vehicle in its own lane. Do not swing wide or cross the center line. . Be alert on top of hills; something could be in your lane (e.g., stalled car, accident). . Pay attention to special road signs (e.g., falling rocks area, winding roads, long grades, passing or no-passing zones) and take appropriate action.
Hill and Mountain Roads
Driving on steep hills or through mountains is different than driving on flat or rolling terrain. Tips include: . Keep the vehicle serviced and in good shape. . Check all fluid levels and brakes, tires, cooling system, and transmission. . Shift to a lower gear when going down steep or long hills. { Warning Using the brakes to slow the vehicle on a long downhill slope can cause brake overheating, can reduce brake performance, and could result in a loss of braking. Shift the transmission to a lower gear to let the engine assist the brakes on a steep downhill slope. { Warning Coasting downhill in N (Neutral) or with the ignition off is dangerous. This can cause overheating of the brakes and loss of steering. Always have the engine running and the vehicle in gear. . Drive at speeds that keep the vehicle in its own lane. Do not swing wide or cross the center line. . Be alert on top of hills; something could be in your lane (e.g., stalled car, accident). . Pay attention to special road signs (e.g., falling rocks area, winding roads, long grades, passing or no-passing zones) and take appropriate action.
Thread Starter
Intermediate
Joined: Nov 2015
Posts: 48
Likes: 15
From: Mesa AZ
Didn't think of looking in the manual!! Thank you. Yeah, doesn't seem normal to me either. I have about 10 days left on my CarMax 3 month warranty so I'm looking to take it in to them this week.
Wasn't using Cruise Control as I was in fairly heavy traffic and curves on the downgrade. I know my 2016 A6 Cadillac will apply the brakes on a steep downgrade when the speed builds up in Cruise Control. That didn't come in to play on the C7.
Wasn't using Cruise Control as I was in fairly heavy traffic and curves on the downgrade. I know my 2016 A6 Cadillac will apply the brakes on a steep downgrade when the speed builds up in Cruise Control. That didn't come in to play on the C7.
