Low Fuel Economy

[Chevrolet Customer Svc]

Originally Posted by PalmerGA

Believe it or not, high gear driving at low speeds is "lugging" your engine and makes for VERY inefficient fuel usage. IMO, you shouldn't skip those lower gears. These are very heavy cars and you are not helping the engine perform properly by lugging it at lower rpms - especially if you are dealing will hilly, low speed roads.

Plus - William R's driving tips are pretty important. Especially, believe it or not, properly inflated tires is a biggie. If those big fat tires are just a few pounds under-pressure, with that 4,000 pound car on 'em, it can definitely make a difference in mpgs. I do my best to be at 36 psi on factory RS tires... and they do loose air. Check 'em once a week at least.

,

Thanks a lot PalmerGA!

William R.
Chevrolet Customer Care

[Emvici]

Some engines are broken-in better then other engines. just my opinion, but I think that plays a role in it.

[Supreme Leader]

Originally Posted by ChrisBlair

If you want to get maximum gas mileage from your LS3 I certainly won't give you a hard time. Gas costs money and if I were rich I'd be driving a Ferrari, not a Chevy. If a wiseass tells me "why'd you get an SS if you care about mileage?" My answer is "To piss you off, tough-guy. Now give me 50 bucks for gas."

But you have to remember, getting good mileage isn't a matter of just picking a higher gear when you can take a higher gear

As far as I'm concerned, your 1-4 shift is suspect. Yeah sure, the skip shift does this too. But if you are choosing to do it, that's not the computer deciding the factors are right for a 1-4 shift, that's just you putting the car into a gear that will "dog" or "lug" the engine way too much. As well, downshifting when going up a hill- as long as you stay within the range of rpms in which you get good economy- is better than being in a higher gear sometimes, and for the same reason- you're lugging the engine if the rpms are too low. And if you speed up, that's an economy hit. And if you slow down, you eventually need to speed back up- economy hit. You need to be in the most economical gear, not just a high gear.

You should start paying attention to the rpm ranges in which you shift and why you're shifting, and not the mph you shift at. I have an LS3. And yes, I see a combined average of 20 mpg. On an extended trip, all highway at 60-65 mph, I have seen a displayed 27 mpg. In the mornings if I take backroads to work I see 23 mpg. This trip includes multiple stop lights and stop signs.

Your 13 mpg is partly because you're in the wrong rpms at the wrong times. And it can also be your driving habits. If you're in 5th gear at 35 mph, good, great. That doesn't mean you can just hit the gas hard and still get good mileage. Your car is also just barely broken in which isn't helping.

Let's say you're driving along on a flat road at 40 mph for a two mile stretch, with no traffic. What gear are you cruising in and what rpms are you pulling?

It actually depends. When I first got the car I was told to shift at 3000 and downshift at 1000 (I learned to drive manual on this car like a month ago). What should the best RPM range be?

But now when I take back roads (a lot of hills) I am going around 50 mph in 6th gear and when it gets way too low like under 1000 RPM I go to 5th. I guess I'll stop doing that.

I don't see how I would be able to ever get 20 mpg in the SS with town driving. (Like this one guy said on another thread) or this guy said he gets like 17 with a HEAVY foot.

[Obzen]

You won't get over 20 in town driving so don't even worry about it. Anyone who says they get 20 in town obviously uses the word "town" loosely. Don't bog the engine down by running at such low RPMs. Keep 5th and 6th for cruising not accelerating.

[Steven13]

I get 17mpg driving where I live, but the roads are a mix of straights (I live in the sticks) and stop-n-go redlights. I keep the rpm above 1000 but less than 2500. I sometimes accel quick, although it doesn't seem to affect the mpg, and at speeds of 60mph on average cruising with rpm less than 1000 may cause the car to burn rich. but rpms between 1000 and 1500 should yield similar gas mileage.

id try the fuse pull trick, and make sure your pumping 91/93 octane in the tank. if each gas pump has only one hose for all 3 grades of octane, chances are you got a little low octane residual to jack up your fuel mapping.

if you have a tune then most likely its mapped for high octane all around, if it is make sure you use the octane that was used to tune it with.

[ChrisBlair]

Originally Posted by Supreme Leader

It actually depends. When I first got the car I was told to shift at 3000 and downshift at 1000 (I learned to drive manual on this car like a month ago). What should the best RPM range be?

But now when I take back roads (a lot of hills) I am going around 50 mph in 6th gear and when it gets way too low like under 1000 RPM I go to 5th. I guess I'll stop doing that.

I don't see how I would be able to ever get 20 mpg in the SS with town driving. (Like this one guy said on another thread) or this guy said he gets like 17 with a HEAVY foot.

If you are trying to keep up a constant speed at under 1,000 rpms, you're definitely lugging in my opinion

The best rpm range depends on your driving habits. I could tell you to drive exactly like me, and take my car on the same trips I do, and you could get a different economy. However, I recommend not using 'upshift at 3,000 rpm' are a rule that cannot be broken. Taken literally, you could be cruising around at say 2,800 rpms in 4th when you could very happily be in 5th or 6th. The car won;t mind it, but you're not at an economical cruising rpm. When downshifting, do you mean you won;t drop a gear until you hit 1,000? really? That could be another problem:

Let's say you're in 5th and you need to slow down. You stay in 5th as you slow. At 1500 rpm, you can speed back up. You are still in 5th. That's not such a bad thing although...5th? I would have dropped a gear. Let's say you're in the same situation but you slow down and you're still in 5th and you get down to about 1200 rpm. You can now speed back up as traffic starts moving. You're lugging the engine by bringing your rpms up from 1200, while staying in 5th.

Over 20 mpg "in town"? No, you won't. I'm not sure if you read my post as saying I get 20 mpg around town, but if you did you're mistaken. I get 20 mpg combined. I'd get more but about half of my 'highway' driving is at 30 mph or less, in stop and go traffic.

Always remember that every car- every car ever made- will get zero mpg while stopped. Also remember that your heavy car will be inefficient as you pull away from a stop.

[13ashengrey]

I average about 20 mostly city, and I have no cats and 3.91 gears. But I've been in customer's cars who are getting 13 bone stock as well. Also I never skip gears and stay in high rpm going through town just to hear the ls3 scream. I would think exhaust would help out on your mpg.

[Supreme Leader]

Well I'm straight piping it this weekend w/resonator delete. I know that wont help lol. People say they lose like 1mpg when they go straight pipes.

[ChrisBlair]

Originally Posted by 13ashengrey

I average about 20 mostly city, and I have no cats and 3.91 gears. But I've been in customer's cars who are getting 13 bone stock as well. Also I never skip gears and stay in high rpm going through town just to hear the ls3 scream. I would think exhaust would help out on your mpg.

I feel you would have to admit that this seems hard to believe.

[Supreme Leader]

See all these people saying 20 mpg

[13ashengrey]

Originally Posted by ChrisBlair

I feel you would have to admit that this seems hard to believe.

I wouldn't expect it either but I wouldn't lie about mpg, I could care less if it got that good.

[JimE]

Originally Posted by PalmerGA

He said in his initial post that he uses premium and has done the fuse pull. Read!

Good grief. I'm sorry I missed it. The first reply pointing out my mistake was enough.

Thanks

[Twoblindsheep]

alright i have a 2011 LS3 and im avdg 21.6 right now.. mostly town drive since i live so close to the base. i usually go through all gears and even hit 6th going around 40mph..(okay i actually hit around 56mpg then i slow down to 40s in 6th) i might have a different situation tho.. i have cai, headers, 3'catback with HF cats. also just got 3.91 gears in. im sure my advg in "town is around 15.2-16.5mpg. unless you have a v6 you are not going to get 20mpg+ in "town/city" i had both.. v6 and v8.
also i usually shift around 2000rpm but its funny someone told me to shift around 3000RPM+ too lol
but im still a new manual driver too.. learned it last year, 5 mins before picking the car up which was 2hours away... lol

[Mmar88]

Consistent 14.6 mpg since I bought the car. Now have 2300 miles on it. Better than the 13.9 I was getting with my G8 GT...active fuel management my ass...