Gas Mileage
Senior Member
Joined: 03-31-2008
Posts: 772
From: CLEVELAND
I recently made a 500 mile trip from IL to MI - nice weather all the way. I have the 2.4 automatic and was using 93 octane fuel. The first several hours I had the cruise set at 60 and the DIC showed the average mileage had worked its way up to 34.0 mpg. The last few hours I bumped the speed to 70 and the average mpg shown on the DIC dropped 2.5+ mpg.
Now I know the DIC numbers are not necessarily accurate, but they are useful to show trends. My HHR seems to show "significant" decreases in mileage above 60, more than I would have anticipated.
Now I know the DIC numbers are not necessarily accurate, but they are useful to show trends. My HHR seems to show "significant" decreases in mileage above 60, more than I would have anticipated.
55mph =37mpg
60mph=35mpg
65mph=32.5mpg
70mph=29.5mpg
75mph=25mpg
80..well i never drive that fast long enough to know.
This is what I believe youll see if you use cruise. I dont use cruise so my number will be 2-3mpg higher across the range.
Drag is everything. Speed=fuel consumption.
Senior Member
Joined: 03-31-2008
Posts: 772
From: CLEVELAND
Nope I reset it every time. I'm anal about tracking gas milage since owning cars with faulty gas guages and running out of gas a few times. I have an EXCEL spread sheet tracking the mileage of the HHR since new. The running average mileage is 30.4 mpg for nearly 36K miles. The tank to tank varies from a low of 25 to a high of 36.
Does anyone have information on how the DIC calculates the milage figure?
Does anyone have information on how the DIC calculates the milage figure?
Platinum Member
Joined: 05-09-2006
Posts: 6,805
From: "Upland" Mesa, Arizona
Hey Cleveland....
As I mentioned in a previous post, I just completed my 4000+ mile vacation.
This is the summary of the results on gas mileage. But first a few parameters....
My intent, on this trip, was to determine if an appreciable increase in MPG would be recognized in using Premium Unleaded vs. Regular Unleaded. No extenuating driving methods were employed to gain additional MPG's.....just normal driving.
2.4 lte, 2lt, auto trans, with GMPP intake. I also have roof rails and the engineers tell me they account for a half to 1 mpg decrease.....depending on speed. Cruise Control was used exclusively for almost the entire trip and was set at whatever the legal maximum speed limit was for that section of Interstate (65, 70, 75 MPH). A/C was used on the entire trip, no exceptions. Windows were always up, unless lowering was necessitated for some action....toll booths, etc. Tire pressure was checked AND adjusted each morning, to 37 PSI, cold. Packed weight, including me, the spouse and a 20 pound dog, was 692# (weighed the luggage and boxes plus our weight).
The route from Mesa, AZ....State 87, 260, 277, 377 while climbing from an elevation of 1600ft to Interstate 40 at about 5000 ft. Although I passed through areas of 7500 ft).
I-40 to I-44 in OKC to I-70 in St. Louis to I-69 in Indianapolis to Ft. Wayne. The exact same route was used in the opposite direction (return) except, obviously, the other side of the road
.
Top Tier, Premium Unleaded, of the highest octane at the station pump, was used in the west to east journey. On return, east to west, I used Top-Tier Regular Unleaded of at least 87 (had to use 88 at one location because of the non recommended 86).
Departed home with 19260 on the odom and a full tank of Chevron 91 Octane.
Albuquerque.....12.68 gal....91 Chevron...417 miles......32.9 mpg
El Reno, OK.......15.88 gal....91 Shell.........514 miles......32.3 mpg
Cuba, MO..........14.32 gal....93 Mobil.........452 miles......31.5 mpg
Mryland Hts, MO 2.67 gal....91 76 ............ 87 miles......32.5 mpg
Huntertwn, IN...11.92 gal....87 Sun...........391 miles......32.8 mpg.
On the return.....
Departed Huntertown, IN with 21425 on the odom. and a full tank of Sunoco 87.
Mryland Hts, MO 12.91 gal....87 Shell.........396 miles......30.6 mpg
Springfield, MO.... 6.82 gal....87 QT .........215 miles......29.1 mpg
OKC....................10.17 gal....87 Shell.........291 miles......29.7 mpg
Santa Rosa, NM..13.19 gal....88 Conoco.....420 miles......31.4 mpg
Payson, AZ..........only pumped enough 87 of Brand X into the tank to get home. I do not use "no name" or non top-tier gas in my cars. And I have not used the car or topped the tank yet.
Considerations.......on the filled tank from OKC to Santa Rosa I was stopped in a line of traffic about 4 miles long. A fatal accident occurred just inside of the NM/Tex State line. I idled the car, with A/C running, for about 1 hour. Remarkably that was the best regular unleaded MPG I recognized.
Cost of Premium Unleaded was .15 to .25 cents more than the 87 Regular Unleaded. So the 6-8% gain in mileage is probably a "wash" for most people.
Personal thoughts.....I would probably use Premium Unleaded for the trip again, IF the cost remains consistant with the difference noted above. I also will probably drive the same route at 5 mph UNDER the posted max...just to see what the difference, overall, would be.
Oh, forgot to say...the DIC was within .2 mpg of my manual calculations. But I did take my time and stuff the tank.
As I mentioned in a previous post, I just completed my 4000+ mile vacation.
This is the summary of the results on gas mileage. But first a few parameters....
My intent, on this trip, was to determine if an appreciable increase in MPG would be recognized in using Premium Unleaded vs. Regular Unleaded. No extenuating driving methods were employed to gain additional MPG's.....just normal driving.
2.4 lte, 2lt, auto trans, with GMPP intake. I also have roof rails and the engineers tell me they account for a half to 1 mpg decrease.....depending on speed. Cruise Control was used exclusively for almost the entire trip and was set at whatever the legal maximum speed limit was for that section of Interstate (65, 70, 75 MPH). A/C was used on the entire trip, no exceptions. Windows were always up, unless lowering was necessitated for some action....toll booths, etc. Tire pressure was checked AND adjusted each morning, to 37 PSI, cold. Packed weight, including me, the spouse and a 20 pound dog, was 692# (weighed the luggage and boxes plus our weight).
The route from Mesa, AZ....State 87, 260, 277, 377 while climbing from an elevation of 1600ft to Interstate 40 at about 5000 ft. Although I passed through areas of 7500 ft).
I-40 to I-44 in OKC to I-70 in St. Louis to I-69 in Indianapolis to Ft. Wayne. The exact same route was used in the opposite direction (return) except, obviously, the other side of the road
.Top Tier, Premium Unleaded, of the highest octane at the station pump, was used in the west to east journey. On return, east to west, I used Top-Tier Regular Unleaded of at least 87 (had to use 88 at one location because of the non recommended 86).
Departed home with 19260 on the odom and a full tank of Chevron 91 Octane.
Albuquerque.....12.68 gal....91 Chevron...417 miles......32.9 mpg
El Reno, OK.......15.88 gal....91 Shell.........514 miles......32.3 mpg
Cuba, MO..........14.32 gal....93 Mobil.........452 miles......31.5 mpg
Mryland Hts, MO 2.67 gal....91 76 ............ 87 miles......32.5 mpg
Huntertwn, IN...11.92 gal....87 Sun...........391 miles......32.8 mpg.
On the return.....
Departed Huntertown, IN with 21425 on the odom. and a full tank of Sunoco 87.
Mryland Hts, MO 12.91 gal....87 Shell.........396 miles......30.6 mpg
Springfield, MO.... 6.82 gal....87 QT .........215 miles......29.1 mpg
OKC....................10.17 gal....87 Shell.........291 miles......29.7 mpg
Santa Rosa, NM..13.19 gal....88 Conoco.....420 miles......31.4 mpg
Payson, AZ..........only pumped enough 87 of Brand X into the tank to get home. I do not use "no name" or non top-tier gas in my cars. And I have not used the car or topped the tank yet.
Considerations.......on the filled tank from OKC to Santa Rosa I was stopped in a line of traffic about 4 miles long. A fatal accident occurred just inside of the NM/Tex State line. I idled the car, with A/C running, for about 1 hour. Remarkably that was the best regular unleaded MPG I recognized.
Cost of Premium Unleaded was .15 to .25 cents more than the 87 Regular Unleaded. So the 6-8% gain in mileage is probably a "wash" for most people.
Personal thoughts.....I would probably use Premium Unleaded for the trip again, IF the cost remains consistant with the difference noted above. I also will probably drive the same route at 5 mph UNDER the posted max...just to see what the difference, overall, would be.
Oh, forgot to say...the DIC was within .2 mpg of my manual calculations. But I did take my time and stuff the tank.
Last edited by Snoopy; Aug 12, 2008 at 01:23 PM.
Senior Member
Joined: 03-31-2008
Posts: 772
From: CLEVELAND
Hey Cleveland....
As I mentioned in a previous post, I just completed my 4000+ mile vacation.
This is the summary of the results on gas mileage. But first a few parameters....
My intent, on this trip, was to determine if an appreciable increase in MPG would be recognized in using Premium Unleaded vs. Regular Unleaded. No extenuating driving methods were employed to gain additional MPG's.....just normal driving.
2.4 lte, 2lt, auto trans, with GMPP intake. I also have roof rails and the engineers tell me they account for a half to 1 mpg.....depending on speed. Cruise Control was used exclusively for almost the entire trip and was set at whatever the legal maximum speed limit was for that section of Interstate (65, 70, 75 MPH). A/C was used on the entire trip, no exceptions. Windows were always up, unless lowering was necessitated for some action....toll booths, etc. Tire pressure was checked AND adjusted each morning, to 37 PSI, cold. Packed weight, including me, the spouse and a 20 pound dog, was 692# (weighed the luggage and boxes plus our weight).
The route from Mesa, AZ....State 87, 260, 277, 377 while climbing from an elevation of 1600ft to Interstate 40 at about 5000 ft. Although I passed through areas of 7500 ft).
I-40 to I-44 in OKC to I-70 in St. Louis to I-69 in Indianapolis to Ft. Wayne. The exact same route was used in the opposite direction (return) except, obviously, the other side of the road .
Top Tier, Premium Unleaded, of the highest octane at the station pump, was used in the west to east journey. On return, east to west, I used Top-Tier Regular Unleaded of at least 87 (had to use 88 at one location because of the non recommended 86).
Departed home with 19260 on the odom and a full tank of Chevron 91 Octane.
Albuquerque.....12.68 gal....91 Chevron...417 miles......32.9 mpg
El Reno, OK.......15.88 gal....91 Shell.........514 miles......32.3 mpg
Cuba, MO..........14.32 gal....93 Mobil.........452 miles......31.5 mpg
Mryland Hts, MO 2.67 gal....91 76 ............ 87 miles......32.5 mpg
Huntertwn, IN...11.92 gal....87 Sun...........391 miles......32.8 mpg.
On the return.....
Departed Huntertown, IN with 21425 on the odom. and a full tank of Sunoco 87.
Mryland Hts, MO 12.91 gal....87 Shell.........396 miles......30.6 mpg
Springfield, MO.... 6.82 gal....87 QT .........215 miles......29.1 mpg
OKC....................10.17 gal....87 Shell.........291 miles......29.7 mpg
Santa Rosa, NM..13.19 gal....88 Conoco.....420 miles......31.4 mpg
Payson, AZ..........only pumped enough 87 of Brand X into the tank to get home. I do not use "no name" or non top-tier gas in my cars. And I have not used the car or topped the tank yet.
Considerations.......on the filled tank from OKC to Santa Rosa I was stopped in a line of traffic about 4 miles long. A fatal accident occurred just inside of the NM/Tex State line. I idled the car, with A/C running, for about 1 hour. Remarkably that was the best regular unleaded MPG I recognized.
Cost of Premium Unleaded was .15 to .25 cents more than the 87 Regular Unleaded. So the 6-8% gain in mileage is probably a "wash" for most people.
Personal thoughts.....I would probably use Premium Unleaded for the trip again, IF the cost remains consistant with the difference noted above. I also will probably drive the same route at 5 mph UNDER the posted max...just to see what the difference, overall, would be.
Oh, forgot to say...the DIC was within .2 mpg of my manual calculations. But I did take my time and stuff the tank.
As I mentioned in a previous post, I just completed my 4000+ mile vacation.
This is the summary of the results on gas mileage. But first a few parameters....
My intent, on this trip, was to determine if an appreciable increase in MPG would be recognized in using Premium Unleaded vs. Regular Unleaded. No extenuating driving methods were employed to gain additional MPG's.....just normal driving.
2.4 lte, 2lt, auto trans, with GMPP intake. I also have roof rails and the engineers tell me they account for a half to 1 mpg.....depending on speed. Cruise Control was used exclusively for almost the entire trip and was set at whatever the legal maximum speed limit was for that section of Interstate (65, 70, 75 MPH). A/C was used on the entire trip, no exceptions. Windows were always up, unless lowering was necessitated for some action....toll booths, etc. Tire pressure was checked AND adjusted each morning, to 37 PSI, cold. Packed weight, including me, the spouse and a 20 pound dog, was 692# (weighed the luggage and boxes plus our weight).
The route from Mesa, AZ....State 87, 260, 277, 377 while climbing from an elevation of 1600ft to Interstate 40 at about 5000 ft. Although I passed through areas of 7500 ft).
I-40 to I-44 in OKC to I-70 in St. Louis to I-69 in Indianapolis to Ft. Wayne. The exact same route was used in the opposite direction (return) except, obviously, the other side of the road
.Top Tier, Premium Unleaded, of the highest octane at the station pump, was used in the west to east journey. On return, east to west, I used Top-Tier Regular Unleaded of at least 87 (had to use 88 at one location because of the non recommended 86).
Departed home with 19260 on the odom and a full tank of Chevron 91 Octane.
Albuquerque.....12.68 gal....91 Chevron...417 miles......32.9 mpg
El Reno, OK.......15.88 gal....91 Shell.........514 miles......32.3 mpg
Cuba, MO..........14.32 gal....93 Mobil.........452 miles......31.5 mpg
Mryland Hts, MO 2.67 gal....91 76 ............ 87 miles......32.5 mpg
Huntertwn, IN...11.92 gal....87 Sun...........391 miles......32.8 mpg.
On the return.....
Departed Huntertown, IN with 21425 on the odom. and a full tank of Sunoco 87.
Mryland Hts, MO 12.91 gal....87 Shell.........396 miles......30.6 mpg
Springfield, MO.... 6.82 gal....87 QT .........215 miles......29.1 mpg
OKC....................10.17 gal....87 Shell.........291 miles......29.7 mpg
Santa Rosa, NM..13.19 gal....88 Conoco.....420 miles......31.4 mpg
Payson, AZ..........only pumped enough 87 of Brand X into the tank to get home. I do not use "no name" or non top-tier gas in my cars. And I have not used the car or topped the tank yet.
Considerations.......on the filled tank from OKC to Santa Rosa I was stopped in a line of traffic about 4 miles long. A fatal accident occurred just inside of the NM/Tex State line. I idled the car, with A/C running, for about 1 hour. Remarkably that was the best regular unleaded MPG I recognized.
Cost of Premium Unleaded was .15 to .25 cents more than the 87 Regular Unleaded. So the 6-8% gain in mileage is probably a "wash" for most people.
Personal thoughts.....I would probably use Premium Unleaded for the trip again, IF the cost remains consistant with the difference noted above. I also will probably drive the same route at 5 mph UNDER the posted max...just to see what the difference, overall, would be.
Oh, forgot to say...the DIC was within .2 mpg of my manual calculations. But I did take my time and stuff the tank.
I'm at 34.4mpg at an average of 11.7 miles per cold-start trip to stop&park. Average speed 37mph, on 87 octane. Ill update my absurd mileage thread tomorrow.
Later
Platinum Member
Joined: 05-09-2006
Posts: 6,805
From: "Upland" Mesa, Arizona
Yeah Cleveland, as I mentioned in another thread, MY best mileage is generally in the stretch of road between Holbrook AZ and Amarillo, TX. That part of I-40 tends to be RELATIVELY FLAT with slight rolling hills. I think the largest grades are entering and exiting the Rio Grande Valley.
My belief is the elevation difference has very little effect on mileage, especially when we have a computer, maf, map, etc. to measure and adjust for those various conditions. It's not like the old mechanical carb days.....when, I believe, lose of approx. 8% efficiency for every 1000 feet (you're the engineer, correct me if I'm wrong), is accepted.
My belief is the elevation difference has very little effect on mileage, especially when we have a computer, maf, map, etc. to measure and adjust for those various conditions. It's not like the old mechanical carb days.....when, I believe, lose of approx. 8% efficiency for every 1000 feet (you're the engineer, correct me if I'm wrong), is accepted.
Last edited by Snoopy; Aug 13, 2008 at 01:06 PM.
New Member
Joined: 07-05-2008
Posts: 27
From: canada
snoppy's serious about data. nice.
i did a straight drive there and back, 390 miles at around 70 mph, and got 31.5 mpg. 87 octane, 2.4 litre LT, odometer 59,000 miles.
i think that's awesome for a hot rod hauler.
anyone here tried the "fuel saver 7000-MPG"? the concept is good.
the tests were done on a 2.4 litre HHR, according to the site.
here's a link (i'm not selling these things, but i would consider buying one, and if it works, THEN maybe selling them)
"fuelconcepts"
i did a straight drive there and back, 390 miles at around 70 mph, and got 31.5 mpg. 87 octane, 2.4 litre LT, odometer 59,000 miles.
i think that's awesome for a hot rod hauler.
anyone here tried the "fuel saver 7000-MPG"? the concept is good.
the tests were done on a 2.4 litre HHR, according to the site.
here's a link (i'm not selling these things, but i would consider buying one, and if it works, THEN maybe selling them)
"fuelconcepts"
Last edited by i like!; Aug 12, 2008 at 12:37 PM. Reason: to add link
Joined: 06-30-2008
Posts: 6
From: Lexington, KY
what am I doing wrong?
I've got about 2500 miles on mine and I've been averaging about 17 mpg for daily driving. I do get on it a bit from time to time, but even when I am conscience about it and stay off the throttle I still don't get much better. I ran a full tank without gettin on the gas at all and still didn't crack 18 mpg. I bought an CGS intake and it didn't change much after that.
Senior Member
Joined: 11-20-2006
Posts: 931
From: Peoria, IL
Im coming off of a 2003 Saturn Ion 3 and my mileage at 80mph on the Expressway was about 31 mph with the 2.3 Ecotec engine in it.
I certainly wont travel that fast in my 2008 HHR, but at 73 MPH with the cruise control set, I sure would expect to get 27-28 MPG.
Its just not happening. I think when I take a quick trip to Detriot this Wednesday, I'll go up to a tank of 91 Octane and see what happens.
Bill
I certainly wont travel that fast in my 2008 HHR, but at 73 MPH with the cruise control set, I sure would expect to get 27-28 MPG.
Its just not happening. I think when I take a quick trip to Detriot this Wednesday, I'll go up to a tank of 91 Octane and see what happens.
Bill