[jagamajajaran]

Coming back from the Lone Star Corvette Classic today, I decided to cruise at a higher RPM in 6th instead of the usual lower RPM in 7th. Set all new highs on my "Last 25 miles" and "Last 50 miles" on the same tank of gas that I went down on running in 7th at the same speed (and I wasn't running the A/C on the way down).

Cruise set at 77 mph
Driving in 6th
90 degrees outside
A/C set at 74 degrees on auto
Seat ventilation on
Driver (me), passenger, and a hatch full of luggage and gear

Best "Last 50 miles" = 35.8 mpg

Best "Last 25 miles" = 37.2 mpg

I know that these are never 100% on spot accurate, but they have always been close when I manually calculate my fuel economy.

 

[53Vette]

I just want to know where you had the extra passenger?

 

[jagamajajaran]

I just want to know where you had the extra passenger?

LOL I guess I need to correct that...haha!

 

[Vigilance247]

Hey Jag, I can't remember if you have the A6 or M7?

 

[Dasyatis]

Hey Jag, I can't remember if you have the A6 or M7?

He's got the M7.

 

[jagamajajaran]

Hey Jag, I can't remember if you have the A6 or M7?

I'm not sure if you are joking around or if you are asking a serious question. But I'm going to give you a serious answer nonetheless. I have the M7, as Dasyatis has correctly replied. A6 is the Automatic 6-Speed. M7 is the Manual 7-Speed. The A6 does not have a 7th gear. However, the 2015 A8 will have 8 gears.

 

[Vigilance247]

I'm not sure if you are joking around or if you are asking a serious question. But I'm going to give you a serious answer nonetheless. I have the M7, as Dasyatis has correctly replied. A6 is the Automatic 6-Speed. M7 is the Manual 7-Speed. The A6 does not have a 7th gear. However, the 2015 A8 will have 8 gears.

Lol, I'm home recovering from pneumonia and didn't notice the obvious.

 

[jagamajajaran]

Lol, I'm home recovering from pneumonia and didn't notice the obvious.

Hope you are back to 100% soon!

 

[FormulaRedline]

Have you done this experiment in 7th? Or have other forum members done something similar? In other words, what should I be comparing these numbers to?

 

[jagamajajaran]

I've never received higher numbers in 7th at any speed. Thus the new highs. The best I had seen previously in 7th was 34 mpg on the "Last 25 miles" gauge.

 

[regguy1]

In 6th the AFM 4 cyl mode doesn't kick in with 7MT (?) so you're always on 8 cyls?

 

[stanton]

So what's the point of 7th? I suppose when we're on the autobahn cruising at 150.

 

[Charlie Dog]

So what's the point of 7th? I suppose when we're on the autobahn cruising at 150.

If you check this out, he hits 150 in 4th gear. In fact, he never goes beyond 4th.

 

[Mobius]

If you check this out, he hits 150 in 4th gear. I fact he never goes beyond 4th.

Nice footage. It makes me wonder if the PDR can be run in a "overwrite" mode where a constant stream of data is written to the SD Card, with the newest data overwriting the oldest data, and the driver can interrupt the stream when desired. Many security video systems operate on this principle.

This way the PDR data could be used to potentially get you out of a false ticket. Showing the PDR data using a laptop would certainly be a rare break for the judge from the tedium of traffic court! He might let you off just for making his day more interesting.

Also, I wonder if the police could access and use the PDR data against you in a court of law? (assuming they could catch you first, of course).

 

[rdslon01]

I've never received higher numbers in 7th at any speed. Thus the new highs. The best I had seen previously in 7th was 34 mpg on the "Last 25 miles" gauge.

Jeremy, I have seen reports from others as well with the M7 transmission that they get better fuel economy in 6th than 7th. So, I think with multiple independent reports, it must be true.

I don't understand why it is true, however. What are your ideas, or do you exactly know why this is the case?

 

[jagamajajaran]

Jeremy, I have seen reports from others as well with the M7 transmission that they get better fuel economy in 6th than 7th. So, I think with multiple independent reports, it must be true.

I don't understand why it is true, however. What are your ideas, or do you exactly know why this is the case?

I believe it is due to the engine operating at a more efficient RMP at highway speed in 6th instead of the lower RPM in 7th.

 

[stanton]

7th is for getting better gas mileage at 130 mph

Sent from my EVO using Corvette Stingray Forum mobile app

 

[rdslon01]

I believe it is due to the engine operating at a more efficient RMP at highway speed in 6th instead of the lower RPM in 7th.

Does the engine lug a little in 7th at, let's say, 65 MPH?

 

[jagamajajaran]

Does the engine lug a little in 7th at, let's say, 65 MPH?

Yes, it does at times.

 

[Ateupjoe]

Jagamajajaran - man loved that detail cockpit screen shot, I didnt know we had that feature on last 50 or last 25 miles! WOO HOO, I need to start tracking MPG, etc. Thanks for teaching me some new things about this car.....and did you make the Track Day this year? It was EMPTY - run after run after run with no lines and no waiting. Too cool