Potentially stupid question about *gasp* fuel economy

[Msthomp]

Okay...I have a 2010 Camaro 2SS/RS and I'm terribly bothered by my MPGs, but I like to try and keep it as low as possible so that my quick acceleration and need to have a little fun doesn't COMPLETELY devour all my fuel.

I'm not the biggest gear head, but I think I know a bit about how engines work, but would like some other opinions. I was reading on a website that "most cars" reach optimum fuel efficiency at around 55 and then it starts to drop after about 60 or 65. However, if the revs are low, shouldn't the driving be more fuel efficient than if they were high...regardless of speed?

I'll give you an example. On my drive to work there is a long, 2-lane road with a posted speed of 60 mph. If I do 60 mph in 5th, it's at about 2100 rpm...if I shift up, it's tough to keep it at 60 because the revs are so low, the car just wants to die, so I generally will shift up to 6th and stay at about 65 or 67 mph...then the revs are usually at 15-1800 rpm. Is this practice saving or wasting fuel?

Also, the friend who taught me to drive stick told me that whenever possible, he'll just push his clutch in and coast if he can. I'm in the hill country and can sometimes coast at speed for quite a long way, so...if putting in the clutch, letting the revs drop, and just coasting a good way to save fuel or is that wasteful?

Like I said in the title...this is probably a stupid question, but I don't know as much about engines as I probably should and was curious about the answer.

[Mr. Wyndham]

Originally Posted by Msthomp

I'm not the biggest gear head, but I think I know a bit about how engines work, but would like some other opinions. I was reading on a website that "most cars" reach optimum fuel efficiency at around 55 and then it starts to drop after about 60 or 65. However, if the revs are low, shouldn't the driving be more fuel efficient than if they were high...regardless of speed?
Little things like temperature and load can impact fuel economy, too...but in general -- you're absolutely right!

I'll give you an example. On my drive to work there is a long, 2-lane road with a posted speed of 60 mph. If I do 60 mph in 5th, it's at about 2100 rpm...if I shift up, it's tough to keep it at 60 because the revs are so low, the car just wants to die, so I generally will shift up to 6th and stay at about 65 or 67 mph...then the revs are usually at 15-1800 rpm. Is this practice saving or wasting fuel?
You're just wasting some fuel economy. You should be able to shift into 6th with an SS at 45 and have enough grunt to get you around...no reason to stay in 5th at 60mph. There should be plenty of passing power...just not ton of emergency power, so keep that in mind.

Also, the friend who taught me to drive stick told me that whenever possible, he'll just push his clutch in and coast if he can. I'm in the hill country and can sometimes coast at speed for quite a long way, so...if putting in the clutch, letting the revs drop, and just coasting a good way to save fuel or is that wasteful?
If you keep the clutch engaged and coast, the computer will sense that the throttle is closed, and cut fuel to near-idle levels, anyways...some suggest the engine employs a deceleration fuel cut-off to completely stop gas consumption...but I haven't looked into it personally....the only problem you would run into with holding the clutch in is not having power in case you need it. (when moving, it's always a good idea to stay engaged in case an emergency maneuver is required)

Like I said in the title...this is probably a stupid question, but I don't know as much about engines as I probably should and was curious about the answer.

I'm no expert either...just some things I've been taught over time that seems to make sense. Everyone has their own little 'methods'...you just have to play around with each tank of gas....figure out what works best.

[Ronn]

Originally Posted by Msthomp

Okay...I have a 2010 Camaro 2SS/RS and I'm terribly bothered by my MPGs, but I like to try and keep it as low as possible so that my quick acceleration and need to have a little fun doesn't COMPLETELY devour all my fuel.

I'm not the biggest gear head, but I think I know a bit about how engines work, but would like some other opinions. I was reading on a website that "most cars" reach optimum fuel efficiency at around 55 and then it starts to drop after about 60 or 65. However, if the revs are low, shouldn't the driving be more fuel efficient than if they were high...regardless of speed?

I'll give you an example. On my drive to work there is a long, 2-lane road with a posted speed of 60 mph. If I do 60 mph in 5th, it's at about 2100 rpm...if I shift up, it's tough to keep it at 60 because the revs are so low, the car just wants to die, so I generally will shift up to 6th and stay at about 65 or 67 mph...then the revs are usually at 15-1800 rpm. Is this practice saving or wasting fuel?

Also, the friend who taught me to drive stick told me that whenever possible, he'll just push his clutch in and coast if he can. I'm in the hill country and can sometimes coast at speed for quite a long way, so...if putting in the clutch, letting the revs drop, and just coasting a good way to save fuel or is that wasteful?

Like I said in the title...this is probably a stupid question, but I don't know as much about engines as I probably should and was curious about the answer.

When you go faster things like wind resistance come into play. The amount of energy needed to move your car etc. It's physics which I wasn't very good at. I've noticed with mine when cruising as long as the rpm's are below 1800 I'm getting decent fuel mileage on the highway. I would probably go faster myself and keep the rpm's lower in 6th. Try your mpg meter on the DIC. Reset it and drive for a bit both ways and see what the car says.

As for pushing in the clutch, that's not a good idea, you should never coast in neutral. It's actually wasteful too, the car has a fuel shutoff when decelerating. I just can't remember what it's called.

[Msthomp]

Originally Posted by Dragoneye

I'm no expert either...just some things I've been taught over time that seems to make sense. Everyone has their own little 'methods'...you just have to play around with each tank of gas....figure out what works best.

Thanks -- I know what you mean about the "emergency maneuvers", but I always shift to match my speed even when I'm coasting, so if something arises, I just have to hit the gas, let off the clutch and GO!

[Msthomp]

Originally Posted by Ronn

When you go faster things like wind resistance come into play. The amount of energy needed to move your car etc. It's physics which I wasn't very good at. I've noticed with mine when cruising as long as the rpm's are below 1800 I'm getting decent fuel mileage on the highway. I would probably go faster myself and keep the rpm's lower in 6th. Try your mpg meter on the DIC. Reset it and drive for a bit both ways and see what the car says.

As for pushing in the clutch, that's not a good idea, you should never coast in neutral. It's actually wasteful too, the car has a fuel shutoff when decelerating. I just can't remember what it's called.

I use the mpg meter all the time...until I hit school traffic a few weeks ago, I was getting close to 18 mpg in town, so that's not bad, I guess.

[Kurushio]

I wouldnt hold in the clutch all the time. At a stop light if i know that its going to be a minute i will just put it in neutral and when i see the other lights go red i will get ready to go again. The lower the RPM's while cruising will mean better MPG so if you can cruise in 6th at all possible then you should. Even in my V6 i no problems going as low as about 40mph in 6th but of course there wont be much power but its MPG your after.

[76z28]

well one thing is when you are at lower rpms compression isnt doing its job as efficiently, so sometimes a little higher rev will get you better mileage because the engine is working more efficiency
the more you coast the better your mileage will be as my moms camery hybrid...if i dont coast i only get 33 if i do...a great 40 and its a blast to drive surprisingly

[proj3ktpat]

I live in san antonio and I use 6th gear for 55mph and up with no problems. I can even go up hills just fine. I have found that as long as i keep the rpms at about 1200 and above the engine doesn't lug or anything. Granted there isn't much power there, but if you're just cruising it should be fine. 18mpg for city/highway combined driving is actually pretty good, and you really can't expect much more without really babying it. These cars are epa rated at 16/24 city/highway. I have found that 65 in 6th gear seems to get really good gas mileage for me, and i can exceed that 24mpg mark doing so(according to the DIC). Coasting as much as possible is always a good option, and yes it does save fuel compared to staying on the pedal until you have to stop.

[ketel0ne]

http://www.cleanmpg.com/forums/showthread.php?t=1510

Hypermiling can be done in any car.

[h2oplay]

disconnect 2 of the spark plugs

[usa1camaro1969]

Coasting is not wasteful. I personally don't like the idea of pressing and holding the clutch in for any length of time, so I will pull it out of gear.

Traveling at lower rpms will get better mileage than higher rpms in every case.

Attempt to avoid the stop/starts whenever possible. It takes more fuel to get the 3800+ pound vehicle moving from a dead stop than if it's already moving as slow as 2mph. When you do have to start from a dead stop, attempt to gradually get in it(which may seem hard, since these are what they are).

[stray bullitt]

Msthomp: Forgive my impertinance, but why would anyone worried about fuel economy buy a 6.2 litre engined vehicle?
P.S. I love coming over to the 'states, your gas is soooo cheap. UK = $8.00/ gallon.

[chevyman57]

I think that everyone with an SS faces some of the same problems. I have have had a 2010 2SS A6 and you don't have all of the chances to save gas like you do with a stick. It is almost limited to driving like your grandma. I have found with my 2011 2SS with a stick, I can do many more things to improve or have more control over the MPG. Keeping it in sixth gear, coasting and put it in neutral and disengage the clutch at stop lights and all of the things previously mentioned help. Remember you bought a SS Camaro and gas mileage probably didn't play a part in your purchase. I just drive and enjoy it and worry about the MPG maybe 1% of the time.

[CamaroFemme]

I hear a cold air intake and a tune increases mpg.

*halo*