Downshifting to Slow the Car Down?
03-17-2009, 11:55 AM
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Originally Posted by CWS530' post='819384' date='Mar 17 2009, 03:50 PM
Shift to accelerate, brake to slow down, in most cases. At the track or maintaining torque exiting a turn is another matter. Downshifting for sound effects at every stoplight will cause needless wear. Brakes are cheap, a new tranny isn't.
03-17-2009, 12:13 PM
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Truck drivers would tell us that they downshift extensively in preference to braking. One of the reasons is that the wear on transmissions from downshifting results in a lower upkeep expense (on average) than brake-wear if they were not downshifting.
Their situation is admittedly a little different than ours, as most of them have manual transmissions, and downshifting also helps with other cargo-specific braking issues like fishtailing. But, I still think the data would support downshifting as a more economical way to reduce speed than braking, over the long term. But I still just hit the brakes.
Their situation is admittedly a little different than ours, as most of them have manual transmissions, and downshifting also helps with other cargo-specific braking issues like fishtailing. But, I still think the data would support downshifting as a more economical way to reduce speed than braking, over the long term. But I still just hit the brakes.
03-17-2009, 12:18 PM
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Originally Posted by craigm1841' post='819382' date='Mar 17 2009, 08:48 PM
the plus to using your engine/transmission to brake, you save your brakes!
03-17-2009, 12:31 PM
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Originally Posted by bobr2001' post='819412' date='Mar 17 2009, 03:18 PM
the minus is you use more fuel to slow down....use the brakes!
During downshift (even engine rpm is high), the injector duty cycle is 0% (isn't spraying much fuel as much as accelerating)
Check your MPG level when you downshift decelerating. It's max mpg.
Try accelerate and step on the gas, or you are climbing up hill, then it's the lowest mpg
I downshift only when it's NEEDED as long it's reasonable and I always use my brake first option then downshift kicks in when I need faster stopping power.
Brake is cheaper than clutch/transmission
03-17-2009, 12:43 PM
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Originally Posted by salaki' post='819421' date='Mar 17 2009, 10:31 PM
I don't know if it's true but I read somewhere that when no throttle is applied and the car is in gear, the car goes into fuel cut.
During downshift (even engine rpm is high), the injector duty cycle is 0% (isn't spraying much fuel as much as accelerating)
Check your MPG level when you downshift decelerating. It's max mpg.
Try accelerate and step on the gas, or you are climbing up hill, then it's the lowest mpg
I downshift only when it's NEEDED as long it's reasonable and I always use my brake first option then downshift kicks in when I need faster stopping power.
Brake is cheaper than clutch/transmission
During downshift (even engine rpm is high), the injector duty cycle is 0% (isn't spraying much fuel as much as accelerating)
Check your MPG level when you downshift decelerating. It's max mpg.
Try accelerate and step on the gas, or you are climbing up hill, then it's the lowest mpg
I downshift only when it's NEEDED as long it's reasonable and I always use my brake first option then downshift kicks in when I need faster stopping power.
Brake is cheaper than clutch/transmission
I use engine braking a lot (manual though), and they teach it in every single driving school in here.
03-17-2009, 12:47 PM
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Krozi, if you really want to F up your brakes, drive like all these snowbirds from Canada. Keep your left foot on the brake... then accelerate and Up shift, all the while... applying more pressure to the brake. 
Since you live in So Fla, I am sure you can relate 
Since you live in So Fla, I am sure you can relate
03-17-2009, 12:52 PM
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Originally Posted by rogerj' post='819430' date='Mar 17 2009, 04:47 PM
Krozi, if you really want to F up your brakes, drive like all these snowbirds from Canada. Keep your left foot on the brake... then accelerate and Up shift, all the while... applying more pressure to the brake. Since you live in So Fla, I am sure you can relate
Since you live in So Fla, I am sure you can relate 
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