Thanks for the response. Boy, I didn't realize the 5.3/6 speed does so poorly in stop and go city traffic for mpg. 10-13 mpg isn't very good. That's where I do most of my driving. My current truck, a 2000 Sierra 2500 with the 6.0L V8 and old 4 speed gets about the same in stop and go traffic too. Would the 4.8/4 speed or even the 4.3/4 speed be any better in the city?At 60 mph-pure hy with cruise control on- you should get an honest 20-22 mpg.
At 65 mph-pure hy-18mpg-20 mpg
At 75 mph- pure hy- 16-17 mpg
In pure city/suburban stop and go-10-13 mpg tank averages are about right-the tall gearing doesn't make any difference in stop and go driving, but it helps hy mpg a bit.
Most folks in mixed driving will get 13mpg tanks- but on hy trips will get about 17-18mpg tanks
PS I would guess you will turn maybe 1500 rpms at 60 mph-top gear??
My 98 Suburban 2wd-5.7 1/2 ton gets an honest 21 mpg on long hy trips averaging 62 mph-I turn 1700 rpms-your more modern vehicle could get 1-2 mpg better hy despite the 4x4-at 70 mph you might get 19mpg
Thanks again for the response. You have great information. I like the 5.3 but as it's a $2 000 option if you buy it here in Canada, that's where I live, on a new truck. I'll have to see if I can find a used 2010 with the 5.3 and 6 speed combination. Is there any other way to improve mpg? I've heard that tonneau cover helps with mpg? Any truth to that?The recent 5.3-driven the same way- is MUCH better FE wise than the 2000 6.0.
I WAS JUST GIVING AVERAGE SORT OF NUMBERS-I am a mpg fanatic.
Driven the same way-and if your 2500 is a 4x4- you will get 2-3 mpg better city with the 5.3 six speed.
You will also get as much as 3-4 mpg better hy.
A current 5.3 -in same sort of truck(but it will be lighter than a same same 2500 6.0) GETS MUCH BETTER FE THAN A 6.0 2500.
If your 6.0 2500 is a 4x4 you will get DRAMATICALLY BETTER FE with a 2011 5.3 .
Dramatically better means 2-3 city and maybe 3-4 hy.
No one brags about a 6.0 FE(except to say it is better than a 454)- lotta folks brag about the 5.3's FE.
Forget about the 4.8 or the 4.3 for FE.The 5.3 matches them in FE(or is so close it doesn't matter) and is BETTER in every other way.
The only reason to choose a 4.3 or 4.8 over the 5.3 is they are cheaper to buy.Now cheaper to buy is a decent reason- but if you have the extra $$-always go 5.3 over those 2. GM puts lots of engineering(and $$) into maxing the 5.3 in respect to FE.Nothing wrong with the 4.8 4.3 but they are there to keep down cost-a good reason.
PS Like Enkeiavalanche says- the driver makes A HUGE DIFFERENCE in actual FE numbers.
I've read that when the new 1500 series debuts in 2014, the 5.3 is expected to get 4 valves per cylinder over the current 2. That might improve mpg a bit. I wish they would update the 4.8 or 4.3 and at least offer them with the 6 speed found on the 5.3. Makes no sense as to why the 4 speed is still standard on these engines when GM's major competitors Dodge, Ford, and Toyota all carry 5 and 6 speed automatics as standard equipment. My guess is that the 4.8 and 6 speed combo would probably equal or surpass the 5.3 in mpg. Then GM wouldn't be able to charge extra for a 5.3.Not much- a cover cost mpg in the city-extra weight(tiny decrease hard to measure)- but it could very slightly-tests I've seen show no benefit to small-1/2 mpg- hy improvement.
Many folks CLAIM 2 mpg better but that is wrong. The open bed-tailgate CLOSED- aero wise acts like it is already covered-yeah it doesn't make sense, but all tests I've read say keep the tailgate closed, and just get a cover to protect your tools- it won't net improve mpg-city decrease and hy increase cancel one another.
Bottom line-OEM engineers have pretty much maxed the 5.3 for FE- CAI fancy exhausts-waste of $$ for PART THROTTLE FE.
Modifying driving habits- Pulse and glide in city traffic and staying under 70 mph will improve fe maybe 15% without costing more than 2-3% in trip time.
PS With the cruise control set to 62 mph you could get 21mpg
Yes it is probably intentional-using the 4 speed makes them a tiny bit less costly to build, but it allows GM to put a premium price on the 5.3.
The 4.8 now has cylinder shutdown feature-making it more desirable than the 4.3
4 valve heads -
Will it retain pushrods??In the very old days I think there were racing motorcycles with pushrods and 4 valve heads.
Does the 4.8 have cylinder shutdown in this year's Sierra model?
I found a couple of used 2008 Sierra 2500 with the 6.0 V8 and 6 speed. Do you know how good/bad these things do in the city for mpg?
Thanks for the information. It's great as usual and greatly appreciated. On the side, do you know anything about that 5.7L Hemi in the Dodge Ram? Any good on fuel with their MDS system?The 2010 4.8 c1500-2wd- is 14/19 epa
The 2010 5.3 C1500 2WD 6 SPEED is 15-22 epa.
I suspect the 5.3 has cyl shutdown- active management GM calls it.
Hard to believe but the 5.3 6 speed just beats the smaller motors.
Nowadays a reasonable driver can get-in city- pretty close to dead on epa(maybe 1 mpg less).
A reasonable driver can slightly beat hy if he stays at about 65mph- he can match epa hy if he drives under 70mph.
PS Pretty much no one who bought the 5.3 regrets it- some 4.8 buyers regret it.
If performance-acceleration- is important to you- look for a 5.3.Some 4.8 buyers try to make it preform like a 5.3- throwing aftermarket stuff at it-
If initial buying price is important-the 4.8 is just fine.They are equally reliable-and the 5.3 can get VERY VERY slightly better mpg-and it is easier to resell.
But $$ is $$ so just depends on buying price.
Thanks for your feedback. I was asking about the HEMI because a local dealer has a big sale going on for 2011 Dodge Rams with both the 4.7 and 5.7. The prices are attractive. They're $3000 cheaper than an equivalent GM. On the flip side, I've read and heard that the HEMI is expensive to maintain and requires 89 octane. Both the HEMI and 4.7 on the Dodge need their spark plugs replaced every 2 years. I'm also not sure about the long-term reliability of the Dodge Ram. I usually keep my vehicles for 8-10 years. I know GM might be outdated compared to Dodge and Ford but they'll likely still be running 8-10 years down the road.The older 5.7 Hemi- before the cyl shutdown(around 2008 or so??) they got HORRIBLE MPG with the 5.7 hemi(the old 426 hemi got horrible mpg also- but no one who owned one ever complained).Folks would get 10-11 mpg city-maybe 16-17 mpg hy,
With the new setup- the 5.7 is much better- probably 2 mpg hy down vs the 6 speed 5.3-and maybe the same 2 mpg less city.EPA is-from memory 14-20 now I think)
Not bad now- but they were real guzzlers before the latest version.
PS If you plan on keeping it a long time the GMs are hard to beat -cheap parts that are easily available in every town city autozone etc.
I've owned MOPAR-1971 CUDA 383 1980 D-100 longbed 318 I liked them.Did most of my early driving in a 1965 Plymouth Fury 3 318 V-8 stationwagon-family car- it would show 111mph WOT (probably was doing maybe 100 mph-waaaaay too fast considering those drum brakes and pitiful tires!