Miles Per Gallon

Reply

  #1  
Old 11-11-12, 08:04 AM
Member
Thread Starter
Join Date: Feb 2005
Location: USA
Posts: 339
Miles Per Gallon

I had a 2000 Buick LeSabre that got nearly 30mpg highway and over 20mpg in town. I now have a 2008 Buick Lucerne and I haven't had long enough to be sure but it seems to get considerable less mpg. This puzzles me because I thought they have basicly the same 3800 engine.

Why is the mileage so different?
 
Sponsored Links
  #2  
Old 11-11-12, 08:17 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 20,862
Well...the EPA estimates do say that the 2008 will be a bit less than the 2000 (1 or 2 mpg)....but thats based on their test driving cycle...not real life. I'd guess that the new one is probably heavier...which may affect your driving to get the same performance, that would really drop your mileage. You'd have to check the rear axle and trans gear ratios as well as the vehicle weight. All sorts of things like accessory packages and options can make a big difference.
 
  #3  
Old 11-11-12, 08:32 AM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,208
1. EPA changed their criteria and test cycle and, as a result, knocked down their guesstimates for vehicles.
2. You didn't really think they will IMPROVE gas mileage, did you? How is that "helping economy", you spending LESS on gas? Blasphemy!!
3. Should have bought Camry Hybrid.

4. Your engine is not broken in. Give it about 30 000 miles
5. LEARN HOW TO HYPERMILE
6. Install K&N air filter. Every vehicle I owned since 2001, I have this filter installed, and it improves mpg by about a mile.
7. Switch to synthetic oil
8. DO NOT BUY CHEAP GAS. Personally, I stick with Sam's brand (AKA Murphy USA) and that's where my mpgs are from.
 
  #4  
Old 11-11-12, 08:39 AM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,208
BTW, I rented LeSabre in 2001, and drove to OKC from Nashville. 724 miles I believe. That car almost made it on single tank!! Did 680 plus. I thought, gauge is broken. And it was total pleasure to drive on FWY. It's like sitting in a nice comfy chair and floating above the tarmac. No potholes, bumps, solid, large, safe. PLEASURE. By far my most favorite FWY vehicle ever.
Rented That new Regal last year, whatever the name is now, maybe Lucerne. Outside of really cool interior, in long run, turned out to be a dud. Clumsy, dead spot steering, engine had noticeable lag accelerating, and that console in the center just started killing my leg in about 4 hrs. I did 842 miles overnight, from CA to Seattle.
 
  #5  
Old 11-11-12, 09:30 AM
Member
Thread Starter
Join Date: Feb 2005
Location: USA
Posts: 339
To Gunguy45 & ukrbyk:

Yep I know a lot of things affect mpg. That's what I am trying to find out...what's the difference between the two cars?

EPA doesn't have anything to do with my question. It's not about estimates. It's the same driver, the same gas, the same town, the same air filter, the same HYPERMILE and apparently the same 3800 engine.

The Lucerne has 35,000 miles on it so it is definately broken in. The LeSabre had 103,000 miles and consistantly got 30mpg highway before ethanol and about 28mpg after ethanol.

I am ignoring the comment about "should have bought Camry hybrid".
 
  #6  
Old 11-11-12, 09:54 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 20,862
Well...looking at the basic specs on Edmunds....your new one weighs about 200-250 lbs more. Thats why I said you may be gassing it a bit harder to get the same "feel". You may not notice it...but even things like stiffer pedal feel or different suspension can make you drive differently. W/o knowing things like gears and ratios...it's kind of a crap shoot. Even changing to a new brand of tires can make a difference. Speedo/odo error can change things.

As to the EPA thing...I just stated that as what they are expected to get. It's pretty rare to even get what the estimated mileage is...but you were getting about 3 miles more on the 2000. That in itself is surprising. Normally it would be 3 miles LESS for the average person. Btw...the EPA site has converted their numbers so that older and newer vehicles can be compared. Old numbers on the 2000 were 19 and 30 (about what you were getting), revised numbers are 17 and 27 (which is what I based my prior statement on).

I remember an article in one of the car mags a while back....2 identical cars, same driver, same course.....MPG differed by 2 according to their calculations. How does that happen? I dunno...and neither did they. But it was only something like a 200 mile test....over 100K it would probably even out? Maybe?

As to the 680 on a single tank stated earlier......uh, well, I'll take that with a grain of salt. That would be almost 37 mpg.
 
  #7  
Old 11-11-12, 10:22 AM
Member
Join Date: Nov 2012
Location: United States
Posts: 20
The way you drive in real life and the way they drive when they test vehicles for this purpose are going to differ. They obviously tested the 2008 model differently then they tested the 200 model.
 
  #8  
Old 11-11-12, 11:02 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 20,862
TB...Welcome to the Forums.

Just to be clear...I was the one that brought up EPA measurements...not Fred. As he stated...the EPA numbers and what he was getting were irrelevant, it was just the difference for a very similar (but not the same) car that was the issue. I was just using it as a comparison.
 
  #9  
Old 11-11-12, 11:16 AM
iceman681's Avatar
Member
Join Date: Jul 2012
Location: usa
Posts: 435
i will say stricter emissions= less mpg. the 2000 had less tail pipe emission guidelines then the 2008. call around and see if you can have your pcm reflashed with the most up to date calibration. as car "break-in" they tend to wonder out of their perfect mpg range to keep emissions at factory spec. once a car is over 1-2 years old Federal emission standards longer apply and only have to meet local standards. all auto manufacturers know this and come out with updates to satisfy customers. i have seen many get almost 5 more mpg's.
 
  #10  
Old 11-11-12, 11:27 AM
Gunguy45's Avatar
Super Moderator
Join Date: Dec 2007
Location: USA
Posts: 20,862
Basically...it boils down to though they may be the same drive train (with changes) they aren't the same car.

I don't doubt you could swap drivetrains on the same car for a used one with similar mileage and the MPG wouldn't be the same anymore.
 
  #11  
Old 11-11-12, 11:47 AM
Member
Join Date: Oct 2010
Location: USA
Posts: 563
In my experience, if the new car feels peppier off the line it's probably partially due to differential gearing.

If GM used roughly the same 3800-series engine and the same transmission, but with a heavier car due to safety systems and whatever they chose for the current design, then that, to me, would go a long way to explaining lesser fuel economy. Obviously there's an engine break-in period to account for too, but I wouldn't think that it would be too extreme.
 
  #12  
Old 11-11-12, 04:14 PM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,208
I am afraid, EPA actually has much to do with this, as they are the ones mandating emissions to car manufacturers, right? And it is beyond any doubt, that they choke engines. Resulting in worse mpg.
2nd thing is - if you just bought it, you might have been hit by winter gas.
Otherwise, you must have identical everything: curb weight, horse power, transmission gearing, even pedal response, everything, to expect exactly same mpg coming out of those two. ECM is programmed differently, most likely it's drive by wire now, so you do not really control throttle anyway, and so on and so on.
Personally, I'd rather be looking into how improve mpg with a new car, than to how to find "why" it is different.
Funny. You can ignore my comment all you want to. Mpg speaks for itself though. Of course, you saw my 2 posts on a lot of respect to LeSabre. So it's no offense and such. But if one buys car for good mpg - one does not buy a Buick. Or one does not care about mile or 2 difference. I am not griping about my Silverado mileage - it is what it is. I knew what I was buying.
 
  #13  
Old 11-12-12, 05:55 AM
Member
Join Date: Jan 2012
Location: Canada
Posts: 2,541
iceman681 nailed the reason on the head.
Emmissions rules have changed, which means something has to give. In most cases, the car manufactures will setup their vehicles for the toughest regulation (California I believe), which means the rest of us suffer.

It should also be noted that two exact cars (make, model, year) will never get the exact same millage.

On the topic of the testing (window sticker data)... This is only to be used to assist consumbers when comparing new vehicles to new vehicles. It should never be used to compare with real world as it's not.
Vehicles are tested on a dyno, which means weight and arodynamics has zero impact.
The testing schedules used also do not have much real world comparison. Below is a chart I grabed from the US testing firm when I looked this info up a year or so ago. I'll need to dig up the web address as I forgot to save the address when I saved the image.
Name:  milageTests.jpg
Views: 641
Size:  49.2 KB
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
'