I agree with Ecotourist and Raggaemon. My Scion xb 5spd was geared more for performance than the auto that I test drove on the highway. I was pulling close to 3000 rpm @ 100kph in 5th. Whether that translates to better FE on non-hwy driving is up for debate but I doubt it. Autos with their 6+ speeds geared for FE would probably win the day. My 5spd Yaris is a different story where the auto version has only 4 speeds. Even still that highway disadvantage with the auto might be offset with my preference to keep my revs no lower than 2000 rpm. Dollars to donuts the auto would cruise less than that at a constant 60kph.
Are automatics really more efficient than sticks?
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Originally Posted By: Reggaemon
It seems in many cars the final gear ratio is lower,like 4.10, for the car
with the manual transmission. While the automatic is higher, like 3.73.
The automatic is using less rpm at cruising speeds.
It depends. My 2002 Lincoln FWD automatic has a final drive ratio of 3.56 in 3rd, and 2.47 in overdrive....falling short of my manual trans.
My 1999 Camaro with a T56 has a 3.42 final drive ratio in 4th, 2.53 in 5th, and 1.71 in 6th. Clearly similar to the Lincoln except in 6th gear where it's not even close. The Camaro is pulling far less rpm at highway speeds. The Lincoln even has a stiffer rear diff ratio than the Camaro (3.56 vs. 3.42). 75 MPH in the Camaro T56 is approx 1680 rpm in 6th....2428 rpm in 5th. Lots of room.
It seems in many cars the final gear ratio is lower,like 4.10, for the car
with the manual transmission. While the automatic is higher, like 3.73.
The automatic is using less rpm at cruising speeds.
It depends. My 2002 Lincoln FWD automatic has a final drive ratio of 3.56 in 3rd, and 2.47 in overdrive....falling short of my manual trans.
My 1999 Camaro with a T56 has a 3.42 final drive ratio in 4th, 2.53 in 5th, and 1.71 in 6th. Clearly similar to the Lincoln except in 6th gear where it's not even close. The Camaro is pulling far less rpm at highway speeds. The Lincoln even has a stiffer rear diff ratio than the Camaro (3.56 vs. 3.42). 75 MPH in the Camaro T56 is approx 1680 rpm in 6th....2428 rpm in 5th. Lots of room.
JHZR2
Staff member
Originally Posted By: Kuato
1977: no
2017: often
On what grounds? EPA MPGs, or mechanical efficiency???
The first can be gamed so to speak, by ratio selection. The later, not so much.
So the real question becomes, if, say, a 6MT is more or less efficient than a 6AT with the same ratios/final drive.
Id still argue that the 6MT is lighter, cheaper, simpler, and more efficient. Controls and logic would still play into the outcome, as human error could create shift points in the MT that are not as favorable. Of course, if one knows their vehicle and terrain well, the selections could also be as good or better. Eyes can do some amazing things that control loops cannot.
The ATs have gotten much closer as more gears lockup, but with that comes more complexity and more items to break...
1977: no
2017: often
On what grounds? EPA MPGs, or mechanical efficiency???
The first can be gamed so to speak, by ratio selection. The later, not so much.
So the real question becomes, if, say, a 6MT is more or less efficient than a 6AT with the same ratios/final drive.
Id still argue that the 6MT is lighter, cheaper, simpler, and more efficient. Controls and logic would still play into the outcome, as human error could create shift points in the MT that are not as favorable. Of course, if one knows their vehicle and terrain well, the selections could also be as good or better. Eyes can do some amazing things that control loops cannot.
The ATs have gotten much closer as more gears lockup, but with that comes more complexity and more items to break...
If you can't decide between a manual & an automatic, you could always look around for a 'robotised' manual gearbox like I have on my little Suzuki. It's basically a manual gearbox where a software controlled actuator does the gear change for you (there's a conventional friction plate clutch but no clutch pedal inside the car).
Last week on a long trip up North to see The Rellies, I clocked up 546 miles on exactly 32 litres of unleaded. That's 76.8 mpg (imperial). Just to give a comparison, my daughter's similarly sized new Hyundai i10 with it's conventional fluid drive auto box usually gives about 38 mpg!!
Last week on a long trip up North to see The Rellies, I clocked up 546 miles on exactly 32 litres of unleaded. That's 76.8 mpg (imperial). Just to give a comparison, my daughter's similarly sized new Hyundai i10 with it's conventional fluid drive auto box usually gives about 38 mpg!!
Originally Posted By: Dave Sherman
My '04 Honda CR-V had slightly lower highway mileage than the equivalent auto, because the 5th gear ratio was actually lower than the automatic's 4th gear. I guess they wanted the cruise control to be able to keep it tooling up the hills in 5th without having to lug the engine or making the driver downshift. Indeed, at 70 it was still turning about 3,200 RPM.
That is some short gearing, even shorter than my old BMW or the '86 Civic Wagon we drove for 200K.
3000 revs in fifth in my '99 Accord would give a hair over 80 mph.
You could slightly exceed 60 mph in second and 90 mph in third at redline, so the box had a decently spaced selection of ratios.
My '04 Honda CR-V had slightly lower highway mileage than the equivalent auto, because the 5th gear ratio was actually lower than the automatic's 4th gear. I guess they wanted the cruise control to be able to keep it tooling up the hills in 5th without having to lug the engine or making the driver downshift. Indeed, at 70 it was still turning about 3,200 RPM.
That is some short gearing, even shorter than my old BMW or the '86 Civic Wagon we drove for 200K.
3000 revs in fifth in my '99 Accord would give a hair over 80 mph.
You could slightly exceed 60 mph in second and 90 mph in third at redline, so the box had a decently spaced selection of ratios.
JTK
$100 Site Donor 2025
This is pretty much an impossible comparison today. You can't find enough same make, identically equipped vehicles to compare one with AT with a manual trans. I do know that any 5-6spd equipped vehicle I've seen over the past 20yrs always had lower MPG ratings than that same vehicle equipped with AT. Obviously the driver can achieve what ever MPG they want.
Heavy-duty tractor ATs are a different animal. Everything is so numbed out on them, they will get a fraction greater MPG than the same truck with a 10spd stick. We've gone back to 10spd automatics with the Freightliners at work. Weird, but they work so far.
Heavy-duty tractor ATs are a different animal. Everything is so numbed out on them, they will get a fraction greater MPG than the same truck with a 10spd stick. We've gone back to 10spd automatics with the Freightliners at work. Weird, but they work so far.
Originally Posted By: JTK
This is pretty much an impossible comparison today. You can't find enough same make, identically equipped vehicles to compare one with AT with a manual trans. I do know that any 5-6spd equipped vehicle I've seen over the past 20yrs always had lower MPG ratings than that same vehicle equipped with AT. Obviously the driver can achieve what ever MPG they want.
Heavy-duty tractor ATs are a different animal. Everything is so numbed out on them, they will get a fraction greater MPG than the same truck with a 10spd stick. We've gone back to 10spd automatics with the Freightliners at work. Weird, but they work so far.
+1
Too many variables to really say. Two different drivers with the same manual or auto trans can get different mileage because of driving habits.
I'd also venture to say that the move toward automatics in heavy duty trucks goes hand-in-hand with the increase in "steering wheel holders" behind big rigs compared to professional drivers.
This is pretty much an impossible comparison today. You can't find enough same make, identically equipped vehicles to compare one with AT with a manual trans. I do know that any 5-6spd equipped vehicle I've seen over the past 20yrs always had lower MPG ratings than that same vehicle equipped with AT. Obviously the driver can achieve what ever MPG they want.
Heavy-duty tractor ATs are a different animal. Everything is so numbed out on them, they will get a fraction greater MPG than the same truck with a 10spd stick. We've gone back to 10spd automatics with the Freightliners at work. Weird, but they work so far.
+1
Too many variables to really say. Two different drivers with the same manual or auto trans can get different mileage because of driving habits.
I'd also venture to say that the move toward automatics in heavy duty trucks goes hand-in-hand with the increase in "steering wheel holders" behind big rigs compared to professional drivers.
Originally Posted By: turtlevette
That's the thing manuals are entertaining and when driven that way are not efficient.
Autos have lock up converters so its about a wash. With lots of idling in traffic I wonder if unloaded idling uses less fuel than loading the torque converter.
It does. You use under half as much fuel while idling in neutral.
That's the thing manuals are entertaining and when driven that way are not efficient.
Autos have lock up converters so its about a wash. With lots of idling in traffic I wonder if unloaded idling uses less fuel than loading the torque converter.
It does. You use under half as much fuel while idling in neutral.
Originally Posted By: demarpaint
I think driving conditions play a big part. In heavy stop and go traffic where getting into 3rd gear is a rarity I'd give the auto the advantage.
for driving comfort, absolutely, but if the lock-up converter doesn't engage efficiency isn't good for a torque converter automatic.
double clutch automatics have the edge under those conditions, but their no good if you keep crawling forward in 1st gear.
I think driving conditions play a big part. In heavy stop and go traffic where getting into 3rd gear is a rarity I'd give the auto the advantage.
for driving comfort, absolutely, but if the lock-up converter doesn't engage efficiency isn't good for a torque converter automatic.
double clutch automatics have the edge under those conditions, but their no good if you keep crawling forward in 1st gear.
Originally Posted By: Pop_Rivit
Originally Posted By: BrocLuno
Short answer - NO ...
If they were, big rigs would be all over it. They count 1% fuel mileage as a huge increase. They are almost all sticks, unless working in stop and go or urban environments where they'd burn a clutch down in a week ...
Interesting. Then why are automatic transmissions in tractors growing by about 3% each year? And Volvo's I-Shift accounts for about 47% of their production? The take rate for Mack's mDrive is about 40%, and Eaton's UltraShift Plus has a 25% take rate.
I even found this in one article-it's a rather interesting quote:
Quote:
“I can understand why fleets like ATs,” he says. “It’s all about fuel economy. You know – ‘Instead of teaching new drivers how to drive, just give them all an automatic transmission, and turn them loose on the highway.’ ”
And I also found this odd quote.
Quote:
For fleets, though, the appeal of automatics goes far beyond driver preferences, with safety and fuel economy topping the list. “We’ve found that automatics help with driver recruitment and retention,” Spurlin adds. “They are also a large help with safety because the drivers can stay focused on the road or the task at hand instead of shifting gears.” Also, drivers do not get as fatigued with an automatic since they do not have to shift gears constantly, he says.
And this weird quote from a trucking article. Why do you suppose these articles, written by people who actually research sales figures and talk to trucking companies, would write something like this?
Quote:
Automatic transmissions continue to make inroads in trucking. Now, engines and transmissions are sharing more data, so performance issues are getting smoothed out. ATs now are being spec’d on a significant share of new trucks for reasons including fuel economy and easier driver training – and the trend is likely to continue.
I read it as the available drivers aren't very good with manuals and will actively seek an employer with AT trucks, so it can make financial sense to get AT trucks.
Originally Posted By: BrocLuno
Short answer - NO ...
If they were, big rigs would be all over it. They count 1% fuel mileage as a huge increase. They are almost all sticks, unless working in stop and go or urban environments where they'd burn a clutch down in a week ...
Interesting. Then why are automatic transmissions in tractors growing by about 3% each year? And Volvo's I-Shift accounts for about 47% of their production? The take rate for Mack's mDrive is about 40%, and Eaton's UltraShift Plus has a 25% take rate.
I even found this in one article-it's a rather interesting quote:
Quote:
“I can understand why fleets like ATs,” he says. “It’s all about fuel economy. You know – ‘Instead of teaching new drivers how to drive, just give them all an automatic transmission, and turn them loose on the highway.’ ”
And I also found this odd quote.
Quote:
For fleets, though, the appeal of automatics goes far beyond driver preferences, with safety and fuel economy topping the list. “We’ve found that automatics help with driver recruitment and retention,” Spurlin adds. “They are also a large help with safety because the drivers can stay focused on the road or the task at hand instead of shifting gears.” Also, drivers do not get as fatigued with an automatic since they do not have to shift gears constantly, he says.
And this weird quote from a trucking article. Why do you suppose these articles, written by people who actually research sales figures and talk to trucking companies, would write something like this?
Quote:
Automatic transmissions continue to make inroads in trucking. Now, engines and transmissions are sharing more data, so performance issues are getting smoothed out. ATs now are being spec’d on a significant share of new trucks for reasons including fuel economy and easier driver training – and the trend is likely to continue.
I read it as the available drivers aren't very good with manuals and will actively seek an employer with AT trucks, so it can make financial sense to get AT trucks.
on paper, the manual transmission by itself will be more efficient, and this is because it has no hydraulic pressures which must be maintained to stay engaged. It is a passive device in every gear, whereas the auto must have a clutch or three engaged and a brake or three engaged all of the time.
However, the overall SYSTEM can be as efficient or more. The newer trans won't build more pressure than it needs to hold the gear, and with DBW throttles, the ECU can bias the engine towards higher gear / open throttle without the driver knowing. They push the go pedal and the algorithms provide proper "feel" to the driver while manipulating throttle and gear selection in accordance with the known output curve for that selection to achieve the desired output.
A manual driver could provide the same throttle and gear selection, but wouldn't want to. for one, in a manual we'd probably feel it lugging, whereas I suspect automakers can bias engine mounts towards expected "lugging" frequencies and tune them out, which would be harder with a manual. Manual drivers would feel the slop in the driveline mounts, I suspect, which probably doesn't show to an auto.
I'm just spitballing here, of course. But I suspect the overall system can be optimized with the auto in ways that it can't with a manual, and while some manual drivers paying attention to mpg could certainly beat the automatic, most won't. Who actually shifted in the '80s when the yellow shift light came on? I didn't!
-m
However, the overall SYSTEM can be as efficient or more. The newer trans won't build more pressure than it needs to hold the gear, and with DBW throttles, the ECU can bias the engine towards higher gear / open throttle without the driver knowing. They push the go pedal and the algorithms provide proper "feel" to the driver while manipulating throttle and gear selection in accordance with the known output curve for that selection to achieve the desired output.
A manual driver could provide the same throttle and gear selection, but wouldn't want to. for one, in a manual we'd probably feel it lugging, whereas I suspect automakers can bias engine mounts towards expected "lugging" frequencies and tune them out, which would be harder with a manual. Manual drivers would feel the slop in the driveline mounts, I suspect, which probably doesn't show to an auto.
I'm just spitballing here, of course. But I suspect the overall system can be optimized with the auto in ways that it can't with a manual, and while some manual drivers paying attention to mpg could certainly beat the automatic, most won't. Who actually shifted in the '80s when the yellow shift light came on? I didn't!
-m
Originally Posted By: meep
on paper, the manual transmission by itself will be more efficient, and this is because it has no hydraulic pressures which must be maintained to stay engaged. It is a passive device in every gear, whereas the auto must have a clutch or three engaged and a brake or three engaged all of the time.
However, the overall SYSTEM can be as efficient or more. The newer trans won't build more pressure than it needs to hold the gear, and with DBW throttles, the ECU can bias the engine towards higher gear / open throttle without the driver knowing. They push the go pedal and the algorithms provide proper "feel" to the driver while manipulating throttle and gear selection in accordance with the known output curve for that selection to achieve the desired output.
A manual driver could provide the same throttle and gear selection, but wouldn't want to. for one, in a manual we'd probably feel it lugging, whereas I suspect automakers can bias engine mounts towards expected "lugging" frequencies and tune them out, which would be harder with a manual. Manual drivers would feel the slop in the driveline mounts, I suspect, which probably doesn't show to an auto.
I'm just spitballing here, of course. But I suspect the overall system can be optimized with the auto in ways that it can't with a manual, and while some manual drivers paying attention to mpg could certainly beat the automatic, most won't. Who actually shifted in the '80s when the yellow shift light came on? I didn't!
-m
I think that's a lot more accurate....it's system vs. system and not strictly manual vs. automatic. My model year car supposedly got 18% better mileage than the previous version and it's a manual. That was mostly due to the switch over to DI but the "helpers" like adding dual CVVT changed along with it. Supposedly, the next most influential component after DI in that 18% is the use of a smart alternator. I think that kind of componentry can mean more in a "system" than whether it's an automatic or a manual if there's less difference in mpg to begin with...so apples to apples might be a bit harder these days.
on paper, the manual transmission by itself will be more efficient, and this is because it has no hydraulic pressures which must be maintained to stay engaged. It is a passive device in every gear, whereas the auto must have a clutch or three engaged and a brake or three engaged all of the time.
However, the overall SYSTEM can be as efficient or more. The newer trans won't build more pressure than it needs to hold the gear, and with DBW throttles, the ECU can bias the engine towards higher gear / open throttle without the driver knowing. They push the go pedal and the algorithms provide proper "feel" to the driver while manipulating throttle and gear selection in accordance with the known output curve for that selection to achieve the desired output.
A manual driver could provide the same throttle and gear selection, but wouldn't want to. for one, in a manual we'd probably feel it lugging, whereas I suspect automakers can bias engine mounts towards expected "lugging" frequencies and tune them out, which would be harder with a manual. Manual drivers would feel the slop in the driveline mounts, I suspect, which probably doesn't show to an auto.
I'm just spitballing here, of course. But I suspect the overall system can be optimized with the auto in ways that it can't with a manual, and while some manual drivers paying attention to mpg could certainly beat the automatic, most won't. Who actually shifted in the '80s when the yellow shift light came on? I didn't!
-m
I think that's a lot more accurate....it's system vs. system and not strictly manual vs. automatic. My model year car supposedly got 18% better mileage than the previous version and it's a manual. That was mostly due to the switch over to DI but the "helpers" like adding dual CVVT changed along with it. Supposedly, the next most influential component after DI in that 18% is the use of a smart alternator. I think that kind of componentry can mean more in a "system" than whether it's an automatic or a manual if there's less difference in mpg to begin with...so apples to apples might be a bit harder these days.
Originally Posted By: Malo83
Would auto transmissions with a shift kit installed have any effect on efficiency?
If the "Kit" raises line pressure, It will have a negative impact on fuel economy.
Would auto transmissions with a shift kit installed have any effect on efficiency?
If the "Kit" raises line pressure, It will have a negative impact on fuel economy.
Originally Posted By: BrocLuno
Short answer - NO ...
If they were, big rigs would be all over it. They count 1% fuel mileage as a huge increase. They are almost all sticks, unless working in stop and go or urban environments where they'd burn a clutch down in a week ...
Then please explain why so many automated transmissions of Volvo Class 8 truck sales in the U.S. Also by 2011, 80% of Volvo truck sales specs included their iShift automated transmission. In N. America in 2015, 83% of Volvo Class 8 trucks sold were spec'd with their automated transmission. The numbers aren't quite as significant for the other heavy truck OEM's, but automated transmissions from Allison, Eaton, Detroit, are really becoming a major percentage of class 8 truck specs. Many OTR fleets have moved over to automated transmissions almost completely. And it wasn't just because of new drivers that were not skilled with manuals. The carrier I do business with moved a lot of truck specs over to automated, and they do not hire new drivers, only experienced drivers and their standards are pretty high.
It really comes down to driving style. A good driver who understands the power curves of the engine they are operating can beat a auto in fuel economy. But the vast majority of folks have no clue about the relationship of HP, Torque, and fuel consumption mapping of their engine. For the majority, a auto will beat a manual any day of the week and twice on Sunday when it comes to fuel economy in a class 8 truck. And the spread is typically more than 1%. In actuality, fleets have seen 5% or better fuel economy of autos vs manuals. That is thousands of dollars per year per truck. Multiply that throughout the fleet. And given the majority of drivers, even drivetrain longevity is improved by using autos. Only the best drivers have an edge using a manual compared to an auto.
If I buy another Class 8 truck, it is likely to be spec'd with an auto. Not sure which one, Most of the bugs have been worked out of autos now, and I am just plain tired of shifting my truck. Almost 40 years shifting in class 8 trucks is long enough. Time to work smarter not harder.
Short answer - NO ...
If they were, big rigs would be all over it. They count 1% fuel mileage as a huge increase. They are almost all sticks, unless working in stop and go or urban environments where they'd burn a clutch down in a week ...
Then please explain why so many automated transmissions of Volvo Class 8 truck sales in the U.S. Also by 2011, 80% of Volvo truck sales specs included their iShift automated transmission. In N. America in 2015, 83% of Volvo Class 8 trucks sold were spec'd with their automated transmission. The numbers aren't quite as significant for the other heavy truck OEM's, but automated transmissions from Allison, Eaton, Detroit, are really becoming a major percentage of class 8 truck specs. Many OTR fleets have moved over to automated transmissions almost completely. And it wasn't just because of new drivers that were not skilled with manuals. The carrier I do business with moved a lot of truck specs over to automated, and they do not hire new drivers, only experienced drivers and their standards are pretty high.
It really comes down to driving style. A good driver who understands the power curves of the engine they are operating can beat a auto in fuel economy. But the vast majority of folks have no clue about the relationship of HP, Torque, and fuel consumption mapping of their engine. For the majority, a auto will beat a manual any day of the week and twice on Sunday when it comes to fuel economy in a class 8 truck. And the spread is typically more than 1%. In actuality, fleets have seen 5% or better fuel economy of autos vs manuals. That is thousands of dollars per year per truck. Multiply that throughout the fleet. And given the majority of drivers, even drivetrain longevity is improved by using autos. Only the best drivers have an edge using a manual compared to an auto.
If I buy another Class 8 truck, it is likely to be spec'd with an auto. Not sure which one, Most of the bugs have been worked out of autos now, and I am just plain tired of shifting my truck. Almost 40 years shifting in class 8 trucks is long enough. Time to work smarter not harder.
Couple of points...
* Automotive General Topics (not OTR rigs)
* automatic versus stick
* efficiency
* Automated Manual
The automatic versus stick, implies as JHZR2 points out a lot more complexity, weight, and "spinny stuff".
Torque converters that intentionally turn mechanical energy into heat could be defined as entropy generators when talking about efficiency in the original context of the thread.
All things being absolutely equal, an automatic can't be as "efficient" as a manual.
In the OTR sense, an automated manual can be more efficient than the average distracted driver.
That being said...Colorado, I wanted the auto after driving the auto and rowing the manual in test drives. It's a good combination, and I know that in the manual, I would have been holding in a lower gear than I should in just about every mode of operation, just in case I needed that little bit of lag free squirt.
Besides 500NM of torque for the auto and 440NM in the manual made a big test drive difference.
* Automotive General Topics (not OTR rigs)
* automatic versus stick
* efficiency
* Automated Manual
The automatic versus stick, implies as JHZR2 points out a lot more complexity, weight, and "spinny stuff".
Torque converters that intentionally turn mechanical energy into heat could be defined as entropy generators when talking about efficiency in the original context of the thread.
All things being absolutely equal, an automatic can't be as "efficient" as a manual.
In the OTR sense, an automated manual can be more efficient than the average distracted driver.
That being said...Colorado, I wanted the auto after driving the auto and rowing the manual in test drives. It's a good combination, and I know that in the manual, I would have been holding in a lower gear than I should in just about every mode of operation, just in case I needed that little bit of lag free squirt.
Besides 500NM of torque for the auto and 440NM in the manual made a big test drive difference.
It's not really "automatics vs manuals", it's about a fluid coupling vs a direct, mechanical coupling. How the gears are shifted is irrelevant.
Unfortunately in NA it's hard to do an apples to apples comparison because the take on stick shift is so low that most offerings are geared towards enthusiasts and have much shorter gearing.
Go to Europe where most everyday vehicles have proper gearing to maximize fuel economy and only the DCTs can match the manual transmission.
A fluid coupling can never have higher efficiency than a direct, mechanical one. Not unless you give a mechanical one a severe handicap in the form of short gearing, thus create an illusion that the automatic offerings have caught up or even surpassed it.
Unfortunately in NA it's hard to do an apples to apples comparison because the take on stick shift is so low that most offerings are geared towards enthusiasts and have much shorter gearing.
Go to Europe where most everyday vehicles have proper gearing to maximize fuel economy and only the DCTs can match the manual transmission.
A fluid coupling can never have higher efficiency than a direct, mechanical one. Not unless you give a mechanical one a severe handicap in the form of short gearing, thus create an illusion that the automatic offerings have caught up or even surpassed it.
^^^ that comparison is good until the TC is locked, which is what they do as soon as they can... at that point it's not a fluid coupling. The loss at that point is pumping losses; it's having to maintain the hydraulic pressures needed to keep appropriate clutches/brakes engaged.
Originally Posted By: meep
^^^ that comparison is good until the TC is locked, which is what they do as soon as they can... at that point it's not a fluid coupling. The loss at that point is pumping losses; it's having to maintain the hydraulic pressures needed to keep appropriate clutches/brakes engaged.
versus not having to do it as quick as they can, and not pumping...manual are more efficient.
^^^ that comparison is good until the TC is locked, which is what they do as soon as they can... at that point it's not a fluid coupling. The loss at that point is pumping losses; it's having to maintain the hydraulic pressures needed to keep appropriate clutches/brakes engaged.
versus not having to do it as quick as they can, and not pumping...manual are more efficient.
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