burner50
Pinlifter
Premium,VIP
join:2002-06-05
Broken Rail
 ·Mediacom
 ·FrontierNet Intern..
| Chevy 3.5 Vs. 3.9
Getting a new Impala, I have no experience with these engines.
I'm going to be doing mostly (90%) Highway driving at speeds greater than 60MPH.
Will the AFM Even kick in at those speeds on the 3.9? If it does will the mileage be better than the 3.5?
I'm debating between the LT2 and LTZ packages...
Any suggestions would be appreciated. Cost isnt really the deciding factor here, just fuel mileage.
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I'm tired of killing stupid people just trying to do my job and go home! |
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mattmag
Premium,ExMod 2000-03
join:2000-04-09
NW Illinois
clubs: |
As long as you aren't pulling a grade, the AFM will activate. It does it more than I thought it would, really. Some of the local police departments have the AFM version and it even made a significant mileage improvement in city driving. |
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GDATL
Premium
join:2002-02-08
Atlanta, GA
·AT&T Southeast
| reply to burner50
I got my 2007 Impala 3LT (basically the 2LT with a 3.9L V6) new on 4 Jan 2008. In 6 months and 11,500 miles I have had no problems at all -- no warranty work, no rattles, no warning lights! The main difference between the 2007 and 2008 is that all 2008s are "flex-fuel" vehicles, designed to operate on ethanol.
Most of my driving is highway (7 round trips of about 1200 miles each). On those trips, averaging 60+ miles per hour (the speed limit or 5 mph over on interstates) I averaged 27-28 mpg. On a 1350 mile trip in June (with A/C on the entire trip, my mileage was 27.7 mpg and that included 150 miles of in-town driving.
Will the mileage beat the 3.5L on highway? EPA mileage on the 3.5L is 18/29. compared to 18/28 for the 3.9L. So the EPA says "no" - they say the 3.5L will get better highway mileage. But I don't know the specifics of their tests. I don't know if they take AFM, terrain, etc. into account.
The EPA mileage estimates above are based upon gasoline, not E85/ethanol. The EPA estimates with E85 instead of gasoline are 13 mpg city/20 mpg highway. Check where you purchase fuel and you will find that most dealers have started to deliver gasoline mixed with 10% ethanol (Sometimes it is posted, often it is not. My Chevron dealer admitted that even they now add 10% ethanol.) As a result, many drivers are finding their fuel mileage has dropped and new cars may not deliver the EPA estimate.
The AFM drops down to 3 cylinders going downhill or on level ground when not accelerating. It kicks back up to 6 cylinders with any acceleration and on a slight incline. The switch from 3 cyl to 6 cyl (and from 6 cyl to 3 cyl) is immediate, smooth and completely undetectable. The only way I can tell it is to have the computer set for "instant fuel economy reading" which tells you which AFM mode the car is operating.
My 3.9L Impala LT3 has plenty of power, the ride is comfortable, handling is good and the trunk is huge. I do miss 2 things from other cars I have owned: 1) automatic climate control (it's so easy to get spoiled when you can set the temp to 72 degrees and never have to fiddle with it!) and 2) the tighter suspension of my previous Impala, which was a police-package model.
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GDATL - Atlanta GA |
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burner50
Pinlifter
Premium,VIP
join:2002-06-05
Broken Rail
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| I live in iowa, I know all about ethanol and flex fuel and all the lies associated with it... But thats another topic...
Thanks for the replies, I think I'll try and find one with the 3.9 around here. I have to buy off the lot for my supplier pricing  |
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Langning
Premium
join:2003-04-28
Marlborough, MA
 ·Verizon FIOS
| reply to burner50
I just bought a 08 Impala LT (with luxury package) for $19,000 - trade-in + taxes/fees. So far for 2 weeks and close to 1000 miles of driving, I am still loving the car. I have 3.5L engine and the 3.9L is usually in the LTZ package which means extra thousands of $$$. |
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burner50
Pinlifter
Premium,VIP
join:2002-06-05
Broken Rail
·Mediacom
·FrontierNet Intern..
| said by Langning  :I have 3.5L engine and the 3.9L is usually in the LTZ package which means extra thousands of $$$. As I said the up front cost isnt as big of deal to me and its not really that much of a difference for me. Maybe 1000. And you dont have to get the LTZ You can get it in the LT2 |
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GDATL
Premium
join:2002-02-08
Atlanta, GA | Made a purchase yet?
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GDATL - Atlanta GA |
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burner50
Pinlifter
Premium,VIP
join:2002-06-05
Broken Rail
·Mediacom
·FrontierNet Intern..
| said by GDATL :Made a purchase yet? Nah, work is kicking my ass... Havent been home during the day since I looked at one initially |
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