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Quick question on new 2012 gt

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Old 09-14-2011, 01:11 PM
  #11  
Napoleon85
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Originally Posted by VistaBlue View Post
The '11-'12 has a much more extreme form of engine braking that uses little to no fuel. It slows the car down a lot faster, and is more efficient.
Interesting ... I usually press the clutch in before/during hard braking. I'll have to try to remember not to do that a few times and see if I feel a big difference.
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Old 09-14-2011, 01:19 PM
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shoeys08dkcandygt
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yes i know how engines work but this one just does it a lot quicker than my last 3 mustangs (06,07,08)
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Old 09-14-2011, 04:58 PM
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VistaBlue
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Originally Posted by potman View Post
Does engine braking with a manural transmission hurt the engine or clutch? (aside from extreme braking)

The only way I can think of that you could damage your clutch by engine braking would be if you're downshifting to a lower gear (to continue engine braking further) and don't rev match properly. Even then, that's really no more wear than everyday driving, slipping the clutch to leave stop lights, etc.
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Old 09-15-2011, 01:53 AM
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Engine braking places more wear and tear on a motor through the life of the motor. I use very little engine braking and take the car out of gear when braking to a stop. When you are in neutral coasting of braking to stop, the engine is close to idle and not loaded. When decel engine braking, you are placing the under load while the RPMs drags the car to a stop. Not only does this increase frictional drag on the motor, but the transmission as well. Over time, it probably won't matter too much since engine and drivetrain technology has improved over the years and you probably will not experience premature failure while you own the car due to engine braking. But to answer your question, it does place additional stress on the motor and transmission.
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Old 09-15-2011, 08:44 AM
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Using the same logic, driving your car causes more wear and tear, so you might as well just park it and never start it to make it last the longest.
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Old 09-15-2011, 08:48 AM
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Originally Posted by VistaBlue View Post
Using the same logic, driving your car causes more wear and tear, so you might as well just park it and never start it to make it last the longest.
Not at all ... I see a very clear distinction between normal operation, and operating the car in such a way as to cause additional wear-and-tear.
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Old 09-15-2011, 02:09 PM
  #17  
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My car does this every once an a while and it's a auto. Did it once and my girlfriend thought I hit something.
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Old 09-15-2011, 06:12 PM
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Originally Posted by Napoleon85 View Post
Not at all ... I see a very clear distinction between normal operation, and operating the car in such a way as to cause additional wear-and-tear.
Good point.

Aside from wear and tear, I also notice the MPG counter read out better MPG when you coast in idle vs coast in gear with the engine braking.
Apparently, while coasting in gear, the PCM has to dump more fuel in to prevent the engine from leaning out where when you coast out of gear engagement, you go to idle and therefore idle fuel consumption.
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Old 09-15-2011, 07:03 PM
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Originally Posted by JIM5.0 View Post
Good point.

Aside from wear and tear, I also notice the MPG counter read out better MPG when you coast in idle vs coast in gear with the engine braking.
Apparently, while coasting in gear, the PCM has to dump more fuel in to prevent the engine from leaning out where when you coast out of gear engagement, you go to idle and therefore idle fuel consumption.
That's funny, as the PCM actually shuts off all fuel to the injectors when coasting in gear. The engine turns into an air pump, and since there's no fuel to combust, lean conditions aren't really an issue.
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Old 09-16-2011, 10:38 AM
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Originally Posted by Napoleon85 View Post
Not at all ... I see a very clear distinction between normal operation, and operating the car in such a way as to cause additional wear-and-tear.
If engine braking wasn't normal operation, Ford wouldn't have spent so much time developing and making such a big fuss about how advanced their new engine braking computer calibration is.

Originally Posted by hawkeye18
That's funny, as the PCM actually shuts off all fuel to the injectors when coasting in gear. The engine turns into an air pump, and since there's no fuel to combust, lean conditions aren't really an issue.
It also depends on what RPM you're engine braking at. Many (modern) cars completely cut fuel above 1500ish RPM, but have a wee bit of fuel injected below 1500ish RPM, presumably to ease the transition/surging going back on throttle.
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