Manual transmission andFuel Economy Question
09-10-2008, 12:51 PM
#1
Burning Brakes
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Manual transmission andFuel Economy Question
Like many of us, I am trying to squeeze every drop of petrol out of my little beater/commuter! lol...
My question is:
If I skip 2nd gear, or 3rd gear ( i.e. go from 1st to 3rd) while this will bring down my RPM's but would require me to give it a little more gas so that I dont get run off the road..lol... would that help my fuel economy? Ideally I'd like to take off from 2nd gear but that would eventually wear on my clutch..
your guys thoughts?
am I an idiot? hahaha
My question is:
If I skip 2nd gear, or 3rd gear ( i.e. go from 1st to 3rd) while this will bring down my RPM's but would require me to give it a little more gas so that I dont get run off the road..lol... would that help my fuel economy? Ideally I'd like to take off from 2nd gear but that would eventually wear on my clutch..
your guys thoughts?
am I an idiot? hahaha
09-10-2008, 12:58 PM
#2
Punk Rocker
Lugging the engine in a higher gear uses more fuel as it makes the engine work harder to accelerate. The best method for fuel economy is to quckly get up to speed and then maintain that speed as long as possible......
09-10-2008, 01:21 PM
#4
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The easiest thing to do is keep the RPM's under, say 3K rpms, get to a speed you feel comfortable with, preferably between 55-65 mph on the freeway and cruise. Minimize your need to down/up shift, turn the AC off, keep the windows rolled up, keep the sunroof closed and you'll start to see increases in fuel economy. Even gradual braking opposes to hard braking increases your fuel economy from what I've read.
http://www.caranddriver.com/features...economy_column
http://www.caranddriver.com/features..._counts_column
http://www.caranddriver.com/reviews/..._to_do_feature
There was an article in car and driver that specifically talked about braking and gas mileage, I have it posted in another thread but I can't find it.
09-10-2008, 01:21 PM
#5
Team Owner
You have a BMW 335 and a civic and you skip gear just to "Squeeze" another 5 miles out of your tank...
just drive normally and Don't "Waste" gas.
09-10-2008, 01:28 PM
#6
The sizzle in the Steak
Like many of us, I am trying to squeeze every drop of petrol out of my little beater/commuter! lol...
My question is:
If I skip 2nd gear, or 3rd gear ( i.e. go from 1st to 3rd) while this will bring down my RPM's but would require me to give it a little more gas so that I dont get run off the road..lol... would that help my fuel economy? Ideally I'd like to take off from 2nd gear but that would eventually wear on my clutch..
your guys thoughts?
am I an idiot? hahaha
My question is:
If I skip 2nd gear, or 3rd gear ( i.e. go from 1st to 3rd) while this will bring down my RPM's but would require me to give it a little more gas so that I dont get run off the road..lol... would that help my fuel economy? Ideally I'd like to take off from 2nd gear but that would eventually wear on my clutch..
your guys thoughts?
am I an idiot? hahaha
It's ok to say "gas".
...and lugging your engine will consume more fuel.
09-10-2008, 01:59 PM
#7
Like many of us, I am trying to squeeze every drop of petrol out of my little beater/commuter! lol...
My question is:
If I skip 2nd gear, or 3rd gear ( i.e. go from 1st to 3rd) while this will bring down my RPM's but would require me to give it a little more gas so that I dont get run off the road..lol... would that help my fuel economy? Ideally I'd like to take off from 2nd gear but that would eventually wear on my clutch..
your guys thoughts?
am I an idiot? hahaha
My question is:
If I skip 2nd gear, or 3rd gear ( i.e. go from 1st to 3rd) while this will bring down my RPM's but would require me to give it a little more gas so that I dont get run off the road..lol... would that help my fuel economy? Ideally I'd like to take off from 2nd gear but that would eventually wear on my clutch..
your guys thoughts?
am I an idiot? hahaha
I'm not entirely convinced if skipping gears will save you any money while driving. As others have mentioned, the engine needs to be operating at a particular rpm to achieve it's maximum efficiency, and lugging an engine can actually cause more fuel to be used.
If you do decide to skip gears while upshifting, be very careful to match revs correctly. If done incorrectly, the input shaft does not slow down quickly enough, and the synchros are not able to handle the additional load and will often mushroom. Not good. Very similar to a very quick 1-2 shift that will cause grinding on engagement and damage to be caused to the synchros. If you take time the match your revs and allow the input shaft to slow down, you should be fine if you choose to skip a gear. I really don't know if this will equate to increased fuel mileage however.
Terry
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09-10-2008, 02:13 PM
#8
Drinking Beer In
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Nothing makes you more cognizant of gas mileage than driving a big V8 when gas is $4/gal.
I learned from my GTO that the main thing that killed gas mileage was rowing through the gears. Skipping gears is not nearly as important as picking a speed that minimizes braking and throttle position changes. I found myself setting up the next few lights and keeping the revs below 2,000 at all times.
That car had CAGS, which forces a 1-4 shift for better economy, but it also had 400 ft lbs of twist, so "lugging" was not a problem. Even so, I hated it and when it locked me out of 2 I went for 3 instead of 4.
On the freeway, drag and its impact on MPGs is an exponential function. It takes more additional gas to move from 75 to 80 than it does from 65 to 70. As much as we all love to go fast, nothing kills MPGs faster.
I learned from my GTO that the main thing that killed gas mileage was rowing through the gears. Skipping gears is not nearly as important as picking a speed that minimizes braking and throttle position changes. I found myself setting up the next few lights and keeping the revs below 2,000 at all times.
That car had CAGS, which forces a 1-4 shift for better economy, but it also had 400 ft lbs of twist, so "lugging" was not a problem. Even so, I hated it and when it locked me out of 2 I went for 3 instead of 4.
On the freeway, drag and its impact on MPGs is an exponential function. It takes more additional gas to move from 75 to 80 than it does from 65 to 70. As much as we all love to go fast, nothing kills MPGs faster.
09-10-2008, 02:33 PM
#10
Evil Mazda Driver
When I drive my friend's Audi Allroad and get onto the freeway on-ramp, I will sometimes go straight from 3rd or 4th into 6th. I do this simply because 5th gear on that car is so redundant it actually sucks something fierce.
The damn thing pulls like a locomotive in 6th gear (at freeway speeds) anyway.
The damn thing pulls like a locomotive in 6th gear (at freeway speeds) anyway.
09-10-2008, 02:35 PM
#11
Burning Brakes
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Thanks for all the comments everyone! this is one of the reasons i love forums!
soo many great opinions, some founded and some not!
I'm just trying to maximize the MPG in my little commuter!
I'll replace the air filter and see how that goes!
09-10-2008, 05:47 PM
#12
Safety Car
When I really try to save gas, I don't go beyond 2k rpm for 1st through 5th gear. And 6th gear, I just go at 65 without cruise control. Somehow cruise control feels like waste more gas than manually going at 65.
09-10-2008, 05:50 PM
#14
teh Senior Instigator
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I keep mine in 4th....hell I can even take off from a stop in 4th if I want
but usually around town...1 -> 4.....4 handles me from about 18 mph to 100+
but usually around town...1 -> 4.....4 handles me from about 18 mph to 100+
09-10-2008, 06:08 PM
#15
The sizzle in the Steak
Cruise control only saves you gas when you are on a "flat" road....if there are grade changes on your route, using cruise control will actually consume more fuel.
09-10-2008, 06:44 PM
#18
The sizzle in the Steak
1)Downhill
When you are on CC and you see that the freeway goes downhill your car will keep the same speed. When the car starts going downhill and the hill is too steep your MPH will rise and your car will use the lower gearing to slow/keep the same speed. It will shift which is a waste of gas and keep it in lower gear till the downhill is gone, then it will upshift which is another waste of gas and continue on it's way.
Solution:
Keep the foot on the gas, press the Cancel button on the steering wheel(not the brakes because when you press the brakes your car will start shifting when you get your foot back on the gas) and as you start going downhill accelarate slightly, this will keep your car in the same gear. When the downhill is over slowly start releasing the gas pedal until you're back to your CC speed and press the set or accel. button on the CC. You just went downhill without the car shifting gear and you got back to your cruise speed without the car shifting gears.
2)Uphill
Usually when you're on the CC and when you get to a hill your engine works more by keeping the same speed by increasing rpm. The RPM usually gets increased 2000-2500rpm. Not only that but your car just shifted twice. Once when going uphill and the second time after the hill to get into the top gear.
Solution:
When you see the uphill in front of you click the cancel button while keeping your foot on the gas pedal and start to slowly accelarate BEFORE the hill. Once you hit the hill you should be 5-8mph over your cruise speed. While the car is going uphill slowly release the gas so that way the car doesn't shift. Using this method will keep the car in the same gear. Once you're on the top of the hill you should be 5-8mph below your cruise speed because you were slowing down when going uphill. Then slowly accelarate to your cruise speed and press the SET or ACCEL. button. Your foot should never leave the gas pedal while going uphill. And your car should not shift while going uphill.
When you are on CC and you see that the freeway goes downhill your car will keep the same speed. When the car starts going downhill and the hill is too steep your MPH will rise and your car will use the lower gearing to slow/keep the same speed. It will shift which is a waste of gas and keep it in lower gear till the downhill is gone, then it will upshift which is another waste of gas and continue on it's way.
Solution:
Keep the foot on the gas, press the Cancel button on the steering wheel(not the brakes because when you press the brakes your car will start shifting when you get your foot back on the gas) and as you start going downhill accelarate slightly, this will keep your car in the same gear. When the downhill is over slowly start releasing the gas pedal until you're back to your CC speed and press the set or accel. button on the CC. You just went downhill without the car shifting gear and you got back to your cruise speed without the car shifting gears.
2)Uphill
Usually when you're on the CC and when you get to a hill your engine works more by keeping the same speed by increasing rpm. The RPM usually gets increased 2000-2500rpm. Not only that but your car just shifted twice. Once when going uphill and the second time after the hill to get into the top gear.
Solution:
When you see the uphill in front of you click the cancel button while keeping your foot on the gas pedal and start to slowly accelarate BEFORE the hill. Once you hit the hill you should be 5-8mph over your cruise speed. While the car is going uphill slowly release the gas so that way the car doesn't shift. Using this method will keep the car in the same gear. Once you're on the top of the hill you should be 5-8mph below your cruise speed because you were slowing down when going uphill. Then slowly accelarate to your cruise speed and press the SET or ACCEL. button. Your foot should never leave the gas pedal while going uphill. And your car should not shift while going uphill.
Use your cruise control: There are times when cruise control isn't appropriate, such as in areas with heavy traffic or in bad weather. Also, using cruise control on hilly roads can actually use more fuel, not less, as your vehicle struggles to maintain speed while driving up hills.
09-10-2008, 06:59 PM
#20
The sizzle in the Steak
^^ I thought it was pretty obvious 
..and I've tested the theory...and it is true....on my commute on the Freeway w/ several grade changes, NOT using CC got me better MPG.
..and I've tested the theory...and it is true....on my commute on the Freeway w/ several grade changes, NOT using CC got me better MPG.
09-10-2008, 08:01 PM
#21
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Is the whole skipping gears messing up the tranny synchronizes thing a myth or is it true?
I will often skip gears while accelerating quick... i.e. from 20 in 2nd speed up to 40 then go straight to 4th
I will often skip gears while accelerating quick... i.e. from 20 in 2nd speed up to 40 then go straight to 4th
09-11-2008, 02:09 AM
#22
Team Owner
i rarely use CC, simply because i dont feel safe without having foot on the pedals.
09-11-2008, 02:53 AM
#23
Safety Car
But this article is for automatic transmissions..?
In manual transmissions, I don't see how it relates to uphill, downhill or flat road.. for example, going uphill on CC on 6th gear to keep at 65mph and going uphill without CC on 6th gear to keep at 65mph.. there is no higher rev involved in either cases.. they should use same rev to maintain the speed in either cases IMO
09-11-2008, 05:25 AM
#24
it's a car-drive it
But this article is for automatic transmissions..?
In manual transmissions, I don't see how it relates to uphill, downhill or flat road.. for example, going uphill on CC on 6th gear to keep at 65mph and going uphill without CC on 6th gear to keep at 65mph.. there is no higher rev involved in either cases.. they should use same rev to maintain the speed in either cases IMO
In manual transmissions, I don't see how it relates to uphill, downhill or flat road.. for example, going uphill on CC on 6th gear to keep at 65mph and going uphill without CC on 6th gear to keep at 65mph.. there is no higher rev involved in either cases.. they should use same rev to maintain the speed in either cases IMO
09-11-2008, 07:49 AM
#26
For those who really want to skip gears, you'll have to get used to it. I rarely accelerate slowly enough to even activate the CAGS in my car, but when I do, I usually have to keep the clutch pedal down a bit longer or the car will buck when the clutch engages. I noticed it does help a little bit skipping gears, but rowing them is just too fun, so I just shift normally
09-11-2008, 08:49 AM
#27
I now drive an accord....
When on the highway I leave my car in 6th gear and set the cruise. The RPM's never change. CC uses the least gas in my car because it only gives enough gas to maintain the speed, where if im controlling the gas I will speed up more than is needed
09-11-2008, 10:05 AM
#28
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using cruise control in the wife's 4runner is a pita when driving here in pa. When you are on the flat, it is fine and sips the gas. When going up a mountain it downshifts more than if i would just use the gas to help maintain the speed.
If i have the cc set at 75 mph, it will stay there on the flat roads. When going up the hills it will downshift and by the time it shifts to the higher gear it may be going 80.
Then it will keep repeating the process until i crest the hill.
I beleive that it will use more fuel when at highway speed at the lower gear with higher rpm, compared to lower rpm and me keeping my same speed up the hill, but the gas pedal depressed a bit further than when on flat road.
If i have the cc set at 75 mph, it will stay there on the flat roads. When going up the hills it will downshift and by the time it shifts to the higher gear it may be going 80.
Then it will keep repeating the process until i crest the hill.
I beleive that it will use more fuel when at highway speed at the lower gear with higher rpm, compared to lower rpm and me keeping my same speed up the hill, but the gas pedal depressed a bit further than when on flat road.
09-11-2008, 10:07 AM
#29
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i also had a 2002 nissan frontier 6 cylinder king cab 5 speed. No matter what i did, i consistently got 15-16 mpg. i could short shift @ 2k, i could go to 2500-3k rpm and skip a gear, use only the brakes to slow down and not downshift, and i would still get the same mileage.
09-11-2008, 10:45 AM
#31
The sizzle in the Steak
But this article is for automatic transmissions..?
In manual transmissions, I don't see how it relates to uphill, downhill or flat road.. for example, going uphill on CC on 6th gear to keep at 65mph and going uphill without CC on 6th gear to keep at 65mph.. there is no higher rev involved in either cases.. they should use same rev to maintain the speed in either cases IMO
In manual transmissions, I don't see how it relates to uphill, downhill or flat road.. for example, going uphill on CC on 6th gear to keep at 65mph and going uphill without CC on 6th gear to keep at 65mph.. there is no higher rev involved in either cases.. they should use same rev to maintain the speed in either cases IMO
Uphill however, the theory is true...you will use more fuel using CC (6th gear) CC will increase the throttle to maintain speed up the hill...thus using more fuel.
09-11-2008, 11:53 AM
#32
Safety Car
you have to increase throttle in either case of CC or no CC going uphill... in my opinion, it's nothing about going uphill or downhill.. it's just the way CC works that it maintain the constant throttle level vs need-basis by our foot on pedal
09-11-2008, 12:26 PM
#33
The sizzle in the Steak
Using CC means additional fuel consumption due to the car trying to maintain a constant speed.
09-11-2008, 02:19 PM
#35
I would not call any of that hard data. It depends on the car, & conditions.
I will agree that CC use may use more gas on a car that doesn't have much power or is heavy. But in today's cars I really don't see it. And if it does, it doesn't matter to me since I'd rather have a relaxed non stiff leg/foot/ankle then save $2 on gas.
I will agree that CC use may use more gas on a car that doesn't have much power or is heavy. But in today's cars I really don't see it. And if it does, it doesn't matter to me since I'd rather have a relaxed non stiff leg/foot/ankle then save $2 on gas.
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