Pontiac Solstice Forum banner

Gas Mileage

8.8K views 38 replies 25 participants last post by  Gizmo  
#1 ·
First off, I don't REALLY care what kind of mileage this car gets, I'm still getting one. That being said...

I was looking at the Cobalt SS1 with the engine that they borrowed for the Solstice and it supposedly gets 25-34 mpg whileas the Solstice will get 20-28.

What gives? I realize that it's RWD and the Cobalt isn't but does that really make a 5-6 mpg difference? The gearing isn't THAT different.
 
#2 ·
Thraxz said:
First off, I don't REALLY care what kind of mileage this car gets, I'm still getting one. That being said...

I was looking at the Cobalt SS1 with the engine that they borrowed for the Solstice and it supposedly gets 25-34 mpg whileas the Solstice will get 20-28.

What gives? I realize that it's RWD and the Cobalt isn't but does that really make a 5-6 mpg difference? The gearing isn't THAT different.
Gearing, weight, tuning, aerodynamics, type of fuel required, it all adds up. In this case probably all factors go against the Solstice, most likely because of its flat out sports car nature it is tuned for a more radical performance profile than the Colbalt.
 
#3 ·
I have over 3300 miles on my car and I'm averaging 25-26 miles per gallon on a tank. That is a combination of mostly town driving with some open road. Just for information purposes only.
 
#4 ·
They are within 50 pounds of one another. It's the same engine... they use the same fuel. Gearing I can see... but I don't think the gearing will be so drastically different that it'd cause 5 mpg worse. Aerodynamics... maybe... 5 is still a big difference.

Oh, thanks for the info. That's about the same that my POS Sentra gets.
 
#6 ·
I would imagine that with the top down you're not getting a very clean coefficient of drag. The stream probably gets pretty dirty behind the windshield and creates a vortex which causes a bit of drag resulting in sacrificed fuel efficiency. What price cool???
 
#8 ·
brentil said:
Lets see, maybe it's that giant gaping hole caused by the roof not being there?
By George, I think he's got it!
 
#9 ·
Ex-Miata Man said:
I have over 3300 miles on my car and I'm averaging 25-26 miles per gallon on a tank. That is a combination of mostly town driving with some open road. Just for information purposes only.

How big of a tank does the car have? I was wondering how far a tank would take you.
 
#12 ·
Ok, I'm not getting looks and now my mileage isn't that great! Am I doing something wrong again?

I'm getting about 20.3-20.5 mpg. Probably because I have the top down as often as possible.

I just thought it would still be better than that...

I'm staying under 70 for the first 1k miles. And I haven't revved past 4k cept for maybe twice.
 
#13 ·
On a 240 mile trip Saturday that was about 2/3rd highway, top down for about 40 miles. I averaged 29.3 MPG, which was a new high. 1400 miles on car, and mileage has been getting better all along.
 
#14 ·
dori-san said:
Ok, I'm not getting looks and now my mileage isn't that great! Am I doing something wrong again?

I'm getting about 20.3-20.5 mpg. Probably because I have the top down as often as possible.

I just thought it would still be better than that...

I'm staying under 70 for the first 1k miles. And I haven't revved past 4k cept for maybe twice.
Anybody?

I've got just over 900 miles and my mileage has creeped up to 21.2. Is it just that my engine isn't broken in yet?
 
#15 ·
PAS22 said:
On a 240 mile trip Saturday that was about 2/3rd highway, top down for about 40 miles. I averaged 29.3 MPG, which was a new high. 1400 miles on car, and mileage has been getting better all along.
I did a 500 mile trip on Friday. When I got far enough North of Milwaukee to be out of the re-formulated gas area, I filled the tank with "normal" fuel. The rest of the trip was on "normal" gas. SO about 400 miles, mostly highway, but with a good bit of twisty, spirited driving, averaged 27.8 mpg. Just before getting on the superslab for the last 100 miles the DIC showed 28.6 mpg. The last 100 miles @ 75 mph sucked it back down to 27.8. All with top up, as the weather was not very good.

Around town driving in the rfg zone I'm averaging 22.1 mpg.

For the last several years, I've watched the mpg on my '96 Blazer, and have noticed a 20 - 25% difference between the reformulated vs non-reformulted gas.
 
#16 ·
SolWhat? said:
For the last several years, I've watched the mpg on my '96 Blazer, and have noticed a 20 - 25% difference between the reformulated vs non-reformulted gas.
Wow, that seems high. The EPA says only "minimal" diffs should occur. http://www.epa.gov/region02/faq/refgas.htm

"KGO-TV has also been investigating this issue, and has reported that based on several sets of tests they have had performed by independent testing facilities, the reduction in mileage is typically 6%, the horsepower reduction is about 5%." http://www.pushback.com/environment/autos/CARB/RFG2.html

"A slight (3%) but noticeable drop in gas mileage occurred when reformulated gasoline was introduced into southeastern Wisconsin, due the required use of an oxygenate, usually ethanol." http://www.dnr.state.wi.us/org/aw/air/reg/lowsulfurfuelfaq.html#Q4
 
#17 ·
Solace said:
Wow, that seems high. The EPA says only "minimal" diffs should occur. http://www.epa.gov/region02/faq/refgas.htm

"KGO-TV has also been investigating this issue, and has reported that based on several sets of tests they have had performed by independent testing facilities, the reduction in mileage is typically 6%, the horsepower reduction is about 5%." http://www.pushback.com/environment/autos/CARB/RFG2.html

"A slight (3%) but noticeable drop in gas mileage occurred when reformulated gasoline was introduced into southeastern Wisconsin, due the required use of an oxygenate, usually ethanol." http://www.dnr.state.wi.us/org/aw/air/reg/lowsulfurfuelfaq.html#Q4
I can only report what I observe. I have been driving the same route to the north woods of Wisconsin for 20 years. The last two years, since the inception of the newer RFG formulations, there has been a marked difference in the performance of both my wife's and my vehicles, and both exhibit a noticeable difference in fuel economy.

The first trip I took with the newer gas, I was so concerned about the loss of fuel economy I took the car into a garage to have it checked for a fuel leak. The difference was that noticeable. Before the newer gas I could get almost 400 miles on a full tank. After, it's more like 300 miles.

It's possible that since my daily driver is a '96, the onboard computer cannot fully compensate for the differences in the gas. My wife's daily driver is an '01 and doesn't exhibit as great a difference, but it's enough to be noticeable.

I don't know anyone around my area that believes the 3% - 5% that the EPA and DNR tries to sell us as the additional cost of the "new" gas.
 
#18 ·
dori-san said:
Anybody?

I've got just over 900 miles and my mileage has creeped up to 21.2. Is it just that my engine isn't broken in yet?
Have you reset the DIC? You should once the break-in is over. You might also want to try some different brands of gas - unless you are flogging your car regularly (just he way she likes it :thumbs: ) you should see some better numbers :yesnod:
 
#19 · (Edited)
dori-san said:
Anybody?

I've got just over 900 miles and my mileage has creeped up to 21.2. Is it just that my engine isn't broken in yet?
Dori - as MAKsys said, reset your DIC. If I remember correctly you only utilize Chevron (are you using Premium grade?)

I reset me DIC after about 1800 miles and I am now at 2500 +/- and average 25-26 mpg (using Shell premium only) I have not changed the oil yet either and will be going to full synthetic (Mobile 1)

By the way - have you had the chance to take your car for a long cruise - not just in and around Jax (stop and go)
 
#20 ·
gator99 said:
Dori - as MAKsys said, reset your DIC. If I remember correctly you only utilize Chevron (are you using Premium grade?)

I reset me DIC after about 1800 miles and I am now at 2500 +/- and average 25-26 mpg (using Shell premium only) I have not changed the oil yet either and will be going to full synthetic (Mobile 1)

2500 miles on a your car and you put more than 1/2 of that in the first two days. HAHA
 
#21 ·
dealernut said:
2500 miles on a your car and you put more than 1/2 of that in the first two days. HAHA
Yep - and they were well worth it -- the car keeps getting better and better
 
#24 ·
http://www.fueleconomy.gov/mpg/MPG.do

It's a really great system. Lets you put all your information in and if you want to you can share the results so people can see your real world results. Makes nice pretty graphs like the one I attached too. So far I've averaged 23 MPG and my best tank was 27.7 MPG driving with the top up 100 miles and down 200 miles on I4 to Tampa.
 

Attachments

#25 ·
dori-san said:
Anybody?

I've got just over 900 miles and my mileage has creeped up to 21.2. Is it just that my engine isn't broken in yet?
Probably has more to do with the weight of your right foot :)
 
#26 ·
We have oxyginated fuel here in the winter, with my 89 bronco II I go from 23 mpg to 18 mpg (22%). My 01 Frontier with the SC goes from 16 to 15 (7%), Plus it cost more to put air in the gas :brentil: