Downshifting bad for MPG?
#1
Joined: Apr 2005
Posts: 3,395
Likes: 21
From: Carteret, NJ
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Yeah, using the engine to slow the car is really bad for it.
Why I downshifted for 90% of the stops I made on my 93 Grand Am, for over
100,000 miles, and I had to do zero work on the tranny and engine.
Downshifting to slow down is so bad, you'll see every trucker use lower gears
on a hill to avoid wearing out their brakes
Seriously though, using the engine inertia to slow down or hold a lower speed
won't hurt your car unless you overrev it. You may lose 1 mpg.
Matching revs on a downshift is unnecessary, our transmissions are synchronized so rev matching isn't needed.
Why I downshifted for 90% of the stops I made on my 93 Grand Am, for over
100,000 miles, and I had to do zero work on the tranny and engine.
Downshifting to slow down is so bad, you'll see every trucker use lower gears
on a hill to avoid wearing out their brakes
Seriously though, using the engine inertia to slow down or hold a lower speed
won't hurt your car unless you overrev it. You may lose 1 mpg.
Matching revs on a downshift is unnecessary, our transmissions are synchronized so rev matching isn't needed.
Last edited by BracketRacerSteve; 12-01-2005 at 08:55 PM.
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#8
Joined: Apr 2005
Posts: 3,395
Likes: 21
From: Carteret, NJ
Whoever said downshifting is bad for the motor is ignorant and uninformed. You know, all the JDM racers you hear about, they just use their brakes and keep it in the same gear to stay in their powerband...
But anyways, all i wanted to know is if it hurt mpg, from the revs spiking up. Thanks for your input Patton, it seems youre the only poster with knowledge on this thread...
But anyways, all i wanted to know is if it hurt mpg, from the revs spiking up. Thanks for your input Patton, it seems youre the only poster with knowledge on this thread...
#9
truckers have to downshift on hills..... there is so much weight to stop that the safest way to actually stop is to downshift, not to mention they are running huge, huge turbo deisel motors that do get checked out much sooner than commuter cars.
but yes... obviously downshifting does affect mpg, higher rpms mean more gas and air is needed for faster combustion.
but yes... obviously downshifting does affect mpg, higher rpms mean more gas and air is needed for faster combustion.
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Originally Posted by chilibowl
Whoever said downshifting is bad for the motor is ignorant and uninformed. You know, all the JDM racers you hear about, they just use their brakes and keep it in the same gear to stay in their powerband...
But anyways, all i wanted to know is if it hurt mpg, from the revs spiking up. Thanks for your input Patton, it seems youre the only poster with knowledge on this thread...
But anyways, all i wanted to know is if it hurt mpg, from the revs spiking up. Thanks for your input Patton, it seems youre the only poster with knowledge on this thread...
#15
Joined: Apr 2005
Posts: 3,395
Likes: 21
From: Carteret, NJ
Originally Posted by trackmagic
O im sorry for me being unimformed about downshifting. The whole racing world must be stupid also. Ask anyone that actually knows how to drive a performance car and ask them if they downshift without blipping the throttle. I have been racing cars for awhile and my father races professionally in grand am, so I must not know anything about downshifting. We dont do it constantly or anything.