: who needs a V6 for fuel economy ;-)



mhamilton
11-22-10, 09:36 PM
Made a round trip from Durham to Charlotte today, was absolutely stunned by the fantastic mileage I got! Previous best I've ever seen was high 28s, exact same trip last December.

I did not cheat by resetting the avg mpg while coasting down a hill lol... I filled up my tank with 89 octane, reset the trip, mpg, and gallons used. Got on I85 S and set the cruise between 70 and 75 mph for the entire trip, lots of hills, no traffic. No ac, outside was about 65 degrees and slightly humid.

The return trip at 5pm had me in stop and go traffic for 30 minutes, and my average went down to 29.5. Still not bad! :)

Tomorrow I'll see how much oil I consumed, guessing half a quart :hmm:

http://img219.imageshack.us/img219/777/30mpg1.jpg

http://img821.imageshack.us/img821/9251/copyof30mpg3.jpg

gdwriter
11-23-10, 12:03 AM
I once averaged 30 MPG on the roughly 55 mile freeway trip from Salem to the Portland Airport with the cruise set at 70 MPH.

Jesda
11-23-10, 12:07 AM
Impressive :cool:

My right foot is heavy (I blame the boots). I dont think I've seen over 22 on the drive to and from school, but I have a lumpy idle that needs some attention.

I~LUV~Caddys8792
11-23-10, 12:50 AM
Wow! Nice! You've got a 300hp V8 and get 29-30, I've got a 240hp V6 and I get 27-28. WTF guys. :)

Koooop
11-23-10, 12:53 AM
I drove my V8 Eldo about 150 miles on Thursday and Friday, the computer claimed 28+MPG.

I'm going with the computer is busted.

mhamilton
11-23-10, 10:26 AM
My right foot is heavy (I blame the boots). I dont think I've seen over 22 on the drive to and from school, but I have a lumpy idle that needs some attention.

In a STS that's not bad. I drove an ETC and that was only pulling 24 mpg highway. I think the 3.11 gear in the ESC really makes all the difference. It just loafs along at 2k rpm @ 75 mph. But with a heavy foot in my car the economy drops very quickly into the low 20s lol.


Wow! Nice! You've got a 300hp V8 and get 29-30, I've got a 240hp V6 and I get 27-28. WTF guys.

Haha, technically only 275 hp, but I'm happy :-) If you want to hear about mad, my friend has a '08 Cobalt with a 2.2L that can't get out of its own way. He set the cruise to 70 mph on a long hwy trip and only got 28 mpg! He might be annoyed at me for a while ;)

gdwriter
11-23-10, 04:39 PM
I think people tend to forget that a V8 pretty much loafs at highway speed:

http://sphotos.ak.fbcdn.net/hphotos-ak-snc1/hs181.snc1/6010_121251123093_776743093_2221936_3129969_n.jpg

http://sphotos.ak.fbcdn.net/photos-ak-snc1/v2329/117/61/776743093/n776743093_1309043_7929.jpg

According to the GasBag app, which I've been using for over a year, I've averaged 22.12 MPG in 15,000 miles of driving, which I consider quite excellent for a car of this size and performance.

ben.gators
11-23-10, 05:13 PM
Well, these cars are perfect to get excellent gas millage if you can control your temper! But the problem is when you are not patient enough and you have a heavy foot, and by considering the 300HP beast that begs for acceleration, you can easily end up in gas millages like 20MPG in highway! Once I drove from Phoenix to LA and there was almost a heavy traffic which required me accelerate and reduce speed too much to get my way through slow cars. And guess what, at the end my average MPG was just 20!

EcSTSatic
11-23-10, 05:22 PM
I think people tend to forget that a V8 pretty much loafs at highway speed:

.

I agree. It's moving the hulk from stoplight to stoplight that eats up gas. Once you get the weight in motion consumption drops.

mhamilton
11-23-10, 06:56 PM
I think people tend to forget that a V8 pretty much loafs at highway speed:


I agree. It's moving the hulk from stoplight to stoplight that eats up gas. Once you get the weight in motion consumption drops.

Sure, that's true, but a loafing V8 doesn't guarantee good economy. Otherwise the 500ci Cadillacs would be economy cars. Brake Specific Fuel Consumption is the key to mpg... I think the non-touring N* drivetrains hit on a very good combination. In actuality the touring model engines are under less load with the 3.7 gear ratio (mechanical advantage), yet they consume more fuel because of the higher rpm. This is also why a small 4 cylinder might get abysmal fuel economy if lugged at 1500 rpm, but (if designed properly) can do very well cruising at 3000 rpm on the highway.

http://www.autospeed.com/cms/A_110216/article.html

I~LUV~Caddys8792
11-24-10, 06:49 PM
Wow, interesting! I never knew that. I thought fuel economy was dependent entirely on RPM.

Koooop
11-25-10, 03:07 AM
500ci gets crappy MPG at 1,200 RPM and crappier MPG at 3,000 RPM. But I sure didn't buy my 500ci Caddy's for MPG.