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  1. #61
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    Quote Originally Posted by reefstar View Post
    Feel better?

    Btw, your car does not shift down when you let off the gas. Not unless you programmed it to. Show that video.

    And if you feel good about insulting me because I accidentally misspelled a word, then good for you.

    I’m done here, you guys are a bunch of dicks looking for a fight.
    My car downshifts on its own if I were to coast to a stop (in drive).



    Sent from my SM-N981U using Tapatalk

  2. #62
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    This confuses me...

    Quote Originally Posted by Vanquished View Post
    My car downshifts on its own if I were to coast to a stop (in drive).



    Sent from my SM-N981U using Tapatalk
    That’s right! But it does not shift down as a feature of “braking” just by removing your foot from the gas.

    I challenge both of them, go make a video of driving down the freeway, and lift your foot from the gas pedal and show me it shift down by simply lifting your foot.

    Just by lifting your foot, the transmission assumes you want to brake? NO! The torque converter releases lock up, (which doesn’t mean the engine isn’t slowing the car) and then the transmission downshifts as it reaches the appropriate range or it locks back up as you re-accelerate. They are intentionally misquoting me to argue. The torque converter is doing a lot of different stuff. They don’t just use fluid lockup.

    If you’re using cruise control, the trans will downshift to maintain speed, but it won’t downshift just because you simply lifted your foot while driving. If it does, that’s something entirely new to me.

    But clearly I’m a “liar” a hack, don’t know what I’m talking about, wearing blinders, spreading mis information, and everything else they say about me.
    Last edited by reefstar; 10-25-2020 at 03:17 PM.

  3. #63
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    Quote Originally Posted by reefstar View Post
    That’s right! But it does not shift down as a feature of “braking” just by removing your foot from the gas.

    I challenge both of them, go make a video of driving down the freeway, and lift your foot from the gas pedal and show me it shift down by simply lifting your foot.

    Just by lifting your foot, the transmission assumes you want to brake? NO! The torque converter releases lock up, (which doesn’t mean the engine isn’t slowing the car) and then the transmission downshifts as it reaches the appropriate range or it locks back up as you re-accelerate. They are intentionally misquoting me to argue. The torque converter is doing a lot of different stuff. They don’t just use fluid lockup.

    If you’re using cruise control, the trans will downshift to maintain speed, but it won’t downshift just because you simply lifted your foot while driving. If it does, that’s something entirely new to me.

    But clearly I’m a “liar” a hack, don’t know what I’m talking about, wearing blinders, spreading mis information, and everything else they say about me.
    Yes, the a8 is designed to downshift automatically to assist in breaking. If it's in sport mode, it does it even more aggressively. FROM THE FACTORY.

    I don't know what you've been driving, but no engine bolted to ANY transmission freewheels unless it's in neutral. It just doesn't happen. The crankshaft is ALWAYS engaged with the driveshaft unless the car is in park or neutral.

    As for your pic to prove what you said, I can do that too!!

    Watch this ..

    The moon is made of cheese. I'm serious, not rocks, cheese.

    Nice try. Thanks for playing.

  4. #64
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    Quote Originally Posted by punisher69 View Post
    Yes, the a8 is designed to downshift automatically to assist in breaking. If it's in sport mode, it does it even more aggressively. FROM THE FACTORY.

    I don't know what you've been driving, but no engine bolted to ANY transmission freewheels unless it's in neutral. It just doesn't happen. The crankshaft is ALWAYS engaged with the driveshaft unless the car is in park or neutral.

    As for your pic to prove what you said, I can do that too!!

    Watch this ..

    The moon is made of cheese. I'm serious, not rocks, cheese.

    Nice try. Thanks for playing.
    Ok This confuses me...

  5. #65
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    The hydraulic link from engine to trans input shaft when not in lockup mode only allows a small difference in rpm when above the converter stall speed, about 100-200 rpm. That is to say they are linked. Below stall speed it allows a larger rpm difference such that you can hold the car stopped at a light using the brakes without stalling the engine. But even then they are still somewhat linked as the car will move as soon as you take your foot off the brake.

    The oldest car I own or have driven is a 76. I can say that every auto trans since 76 absolutely has engine braking while the converter is above stall speed and it can be every bit as forceful as my manual trans cars. I believe the very first automatics in about 1940 had free wheeling that they advertised as a feature, but this was quickly done away with. But I can't be sure because I didn't drive any of those and I don't feel like looking up the exact details.

    The hydraulic control autos had very conservative downshift signals from the factory so engine braking only happened at higher speeds or when manually selecting a lower gear. The early electronic autos were set up to behave the same way for customer expectations. The newer electronic systems have moved to a much more aggressive downshift system especially in the performance trim cars. It makes the driving experience better, performance better, and I expect it's better for the life of the trans to shift when torque is low rather than after you hit the gas and torque is high. The first car I noticed this in was my Dad's 92 BMW, but I think BMW was an early adopter of this method of shift control.
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  6. #66
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    Quote Originally Posted by doublechaz View Post
    The hydraulic link from engine to trans input shaft when not in lockup mode only allows a small difference in rpm when above the converter stall speed, about 100-200 rpm. That is to say they are linked. Below stall speed it allows a larger rpm difference such that you can hold the car stopped at a light using the brakes without stalling the engine. But even then they are still somewhat linked as the car will move as soon as you take your foot off the brake.

    The oldest car I own or have driven is a 76. I can say that every auto trans since 76 absolutely has engine braking while the converter is above stall speed and it can be every bit as forceful as my manual trans cars. I believe the very first automatics in about 1940 had free wheeling that they advertised as a feature, but this was quickly done away with. But I can't be sure because I didn't drive any of those and I don't feel like looking up the exact details.

    The hydraulic control autos had very conservative downshift signals from the factory so engine braking only happened at higher speeds or when manually selecting a lower gear. The early electronic autos were set up to behave the same way for customer expectations. The newer electronic systems have moved to a much more aggressive downshift system especially in the performance trim cars. It makes the driving experience better, performance better, and I expect it's better for the life of the trans to shift when torque is low rather than after you hit the gas and torque is high. The first car I noticed this in was my Dad's 92 BMW, but I think BMW was an early adopter of this method of shift control.
    You guys are implying something I DID NOT SAY.

    The original issues that was talked about (which has NOTHING to do with my OP) was the statement that letting off the gas caused the car to downshift and brake. That’s it!

    We weren’t talking about coasting or disengagement to the transmission, or whether or not the transmission does (eventually) downshift or not. When you let off the gas, the transmission DOES NOT go into downshift “brake assist” mode. It just doesn’t happen. I don’t have “Sport mode” but we weren’t talking about a car in sport mode.

    This is stupid.

  7. #67
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    This confuses me...

    Quote Originally Posted by doublechaz View Post
    The hydraulic link from engine to trans input shaft when not in lockup mode only allows a small difference in rpm when above the converter stall speed, about 100-200 rpm. That is to say they are linked. Below stall speed it allows a larger rpm difference such that you can hold the car stopped at a light using the brakes without stalling the engine. But even then they are still somewhat linked as the car will move as soon as you take your foot off the brake.

    The oldest car I own or have driven is a 76. I can say that every auto trans since 76 absolutely has engine braking while the converter is above stall speed and it can be every bit as forceful as my manual trans cars. I believe the very first automatics in about 1940 had free wheeling that they advertised as a feature, but this was quickly done away with. But I can't be sure because I didn't drive any of those and I don't feel like looking up the exact details.

    The hydraulic control autos had very conservative downshift signals from the factory so engine braking only happened at higher speeds or when manually selecting a lower gear. The early electronic autos were set up to behave the same way for customer expectations. The newer electronic systems have moved to a much more aggressive downshift system especially in the performance trim cars. It makes the driving experience better, performance better, and I expect it's better for the life of the trans to shift when torque is low rather than after you hit the gas and torque is high. The first car I noticed this in was my Dad's 92 BMW, but I think BMW was an early adopter of this method of shift control.
    You guys are implying something I DID NOT SAY.

    The original issues that was talked about (which has NOTHING to do with my OP BTW) was the statement that letting off the gas caused the car to downshift and brake. That’s it!

    We weren’t talking about coasting/decelerating or disengagement to the transmission, or whether or not the transmission does (eventually) downshift or not. When you let off the gas, the transmission DOES NOT immediately downshift and go into a “brake assist” mode. It just doesn’t happen. Sure the engine will begin to slow the car down, but the tq converter releases mechanical lock up and uses hydraulic engagement. There is no direct 1 to 1 positive relationship to rpm and speed at that point.

    I don’t have “Sport mode” but we weren’t talking about how the transmission works in sport mode now we’re we?

    This is stupid. And I assume this is why 3.5L owners don’t post on this forum.
    Last edited by reefstar; 10-25-2020 at 05:58 PM.



  8. #68
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    Quote Originally Posted by reefstar View Post
    You guys are implying something I DID NOT SAY.

    The original issues that was talked about (which has NOTHING to do with my OP BTW) was the statement that letting off the gas caused the car to downshift and brake. That’s it!

    We weren’t talking about coasting/decelerating or disengagement to the transmission, or whether or not the transmission does (eventually) downshift or not. When you let off the gas, the transmission DOES NOT immediately downshift and go into a “brake assist” mode. It just doesn’t happen. Sure the engine will begin to slow the car down, but the tq converter releases mechanical lock up and uses hydraulic engagement. There is no direct 1 to 1 positive relationship to rpm and speed at that point.

    I don’t have “Sport mode” but we weren’t talking about how the transmission works in sport mode now we’re we?

    This is stupid. And I assume this is why 3.5L owners don’t post on this forum.
    You have a serious reading comprehension issue.

    Nobody said the trans downshifts as soon as you let off the throttle. Where did you even see someone say that? It does, however downshift to assist in breaking as speed decreases. If you're actually on the brakes, it does it faster.

    Now, if you want to quote what *I* said...

    I said it does it automatically and more aggressively in sport mode.


    Let me break that down for you so you can comprehend it:

    It downshifts to assist in breaking when in normal/eco/default mode.

    When in sport mode, it does this even more aggressively.

    I thought you were done with this forum anyhow. Why are you still arguing with us instead of accepting you don't know all these is to know about every subject and just leaving like you said?
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  9. #69
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    Quote Originally Posted by punisher69 View Post
    You have a serious reading comprehension issue.

    Nobody said the trans downshifts as soon as you let off the throttle. Where did you even see someone say that? It does, however downshift to assist in breaking as speed decreases. If you're actually on the brakes, it does it faster.

    Now, if you want to quote what *I* said...

    I said it does it automatically and more aggressively in sport mode.


    Let me break that down for you so you can comprehend it:

    It downshifts to assist in breaking when in normal/eco/default mode.

    When in sport mode, it does this even more aggressively.

    I thought you were done with this forum anyhow. Why are you still arguing with us instead of accepting you don't know all these is to know about every subject and just leaving like you said?
    K This confuses me...


  10. #70
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    Quote Originally Posted by reefstar View Post
    K This confuses me...

    Sweet Christmas, you really do have reading comprehension trouble!

    Nowhere in that post did it say a doggone thing about downshifting. :facepalm:

    Nothing, zip, zero, nada, nein

    He said modifying the PCM to shut off fuel to assist in engine braking.

    NEWSFLASH!! The PCM doesn't control the transmission, the TCM does.

  11. #71
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    This confuses me...

    Quote Originally Posted by punisher69 View Post
    Sweet Christmas, you really do have reading comprehension trouble!

    Nowhere in that post did it say a doggone thing about downshifting. :facepalm:

    Nothing, zip, zero, nada, nein

    He said modifying the PCM to shut off fuel to assist in engine braking.

    NEWSFLASH!! The PCM doesn't control the transmission, the TCM does.
    You’re right! But the problem is, you DIDN’T READ THE OTHER POSTS! You have no idea what proceeded that post, or where it went to.

    So why am I arguing with you?

    The stupid part is that for the most part we agree. But you’re so busy looking for a fight, you can’t even see it. If you have a question about what I said... why not just ask? I’d be happy to clarify it for you.
    Last edited by reefstar; 10-25-2020 at 08:03 PM.

  12. #72
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    Quote Originally Posted by reefstar View Post
    I’m out this crap is not worth it


    Sent from my iPhone using Tapatalk
    I sure read this post...

    Richard
    06 Silverado ISS / 06 Silverado SS / 06 300C SRT8
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  13. #73
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    Quote Originally Posted by someotherguy View Post
    I sure read this post...

    Richard
    I asked him about that, but he was so busy trying to dispute what I said he must've missed it lol

  14. #74
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    Quote Originally Posted by reefstar View Post
    You guys are implying something I DID NOT SAY.

    The original issues that was talked about (which has NOTHING to do with my OP BTW) was the statement that letting off the gas caused the car to downshift and brake. That’s it!

    We weren’t talking about coasting/decelerating or disengagement to the transmission, or whether or not the transmission does (eventually) downshift or not. When you let off the gas, the transmission DOES NOT immediately downshift and go into a “brake assist” mode. It just doesn’t happen. Sure the engine will begin to slow the car down, but the tq converter releases mechanical lock up and uses hydraulic engagement. There is no direct 1 to 1 positive relationship to rpm and speed at that point.

    I don’t have “Sport mode” but we weren’t talking about how the transmission works in sport mode now we’re we?

    This is stupid. And I assume this is why 3.5L owners don’t post on this forum.
    Last f'n chance to learn something...

    Every single Mercedes-based transmission does this:
    - Full throttle acceleration, then lifting off the gas pedal will hold current gear until gas pedal is re-engaged or speed drops to regular / commanded next-down gear
    - Full throttle acceleration, then lifting off and touching the brake pedal will immediately(!) generate a down shift event - if down next-down gear rpm will not exceed TCM-based redline - and will continue to aggressively down-shift as speed drops with brake pedal still engaged - without a human touching the gearshift lever
    - The vehicle's dynamic CoG-based system, ABS system and steering wheel positioning system will work in unison (through the PCM) to command the above aggressive transmission down-shift events to ensure the human behind the wheel does not induce loss of traction / sliding by applying independent brake application at each wheel.

    No sport mode required, nothing, just normal integrated smarts on all platforms (LX / LX-based platforms to present) equipped with really f'n smart / high performance Mercedes-based transmission-equipped platforms.

    Quote Originally Posted by punisher69 View Post
    You have a serious reading comprehension issue.

    Nobody said the trans downshifts as soon as you let off the throttle. Where did you even see someone say that? It does, however downshift to assist in breaking as speed decreases. If you're actually on the brakes, it does it faster.

    Now, if you want to quote what *I* said...

    I said it does it automatically and more aggressively in sport mode.


    Let me break that down for you so you can comprehend it:

    It downshifts to assist in breaking when in normal/eco/default mode.

    When in sport mode, it does this even more aggressively.

    I thought you were done with this forum anyhow. Why are you still arguing with us instead of accepting you don't know all these is to know about every subject and just leaving like you said?
    Quote Originally Posted by reefstar View Post
    K This confuses me...


    Agreed Billy; however, as I just mentioned (Smart Mode aside) during panic stop situations, which includes simply lifting off from WOT application (trans simply anticipating an upcoming braking event will immediately hold last gear position - actually every single transmission offering will do this on our rides). If no braking event occurs and the throttle is re-engaged, transmission operation returns to normal. All this - without any action by the driver - as you point out will automatically downshift - while vehicle dynamics believe the car is travelling in a straight (safe) line. Hell - it'll even do this on ice! During loss of traction, dry or ice, the system will assist the car regain traction (try and straighten any yaw). More(!) Daimler-Benz / Mercedes technology / componentry - gifted to DCX at the time.

    Finally, as you and others correctly(!) understood what I wrote, we successfully cut fuel directly after taking my foot off the gas to enhance engine braking - prior to brake application to enter corners. In stock mode, all PCMs are commanding some fuel flow after drivers take their foot off the gas. This is to assist extending coast-down range, thereby stretching fuel mileage (seems counter-intuitive - but its not) to meet EPA mandates as well as reduce NOx emissions by ensuring catalytic operating temperatures remain within their operating window. The final reason is NVH (to a much lesser degree) to reduce discomfort that occurs when older / typical engine braking (no fuel present - like carbs) that pushed drivers / passengers into the seat belts.

    Regarding that off-throttle fuel cut changes I perfected; here's why...

    At my track, approaching turn #1 at the end of the 1/4 mile track (integrated as the front straightaway), I would typically come out of the last corner and pass the christmas tree well in excess of 60mph. At the point of throttle-off I was at or over 170mph. Even with the HUGE BAER monoblocks and 16.5" front rotors, they were working hard after a few laps to slow the land yacht for entry. Pad wear was significant and required constant monitoring during the day.

    The addition of immediate engine-braking and aggressive down shifting prior / entry to turn #1, as well as the last corner off the backside straightaway, that immediate engine brake assist mod high up in the rpm range put the brake system workload back into the sweet spot. It took a few minutes to find the original thread (goes back to 2011): Off-throttle Fuel Cut-off Prior to Corner Entry


    This thread is tedious; unless other Members elect to chime in that deserves a response, I'm done trying to enlighten the OP.
    Last edited by Hemissary; 10-25-2020 at 09:56 PM.
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  15. #75
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    Quote Originally Posted by Hemissary View Post
    Last f'n chance to learn something...

    Every single Mercedes-based transmission does this:
    - Full throttle acceleration - and lifting off the gas pedal completely WILL IMMEDIATELY shift down or hold gear until rpm drops enough to allow for an immediate shift down to the next lowest gear without exceeding redline.
    - Full throttle acceleration, lifting off and depressing the brake pedal will continue to aggressively(!) down-shifting without human interaction
    - The vehicle's dynamic system, ABS system and steering wheel positioning systems will work in unison to control aggressive transmission down-shift events to ensure the human behind the wheel does not induce slippage / sliding / event by applying independent(!) brake application to whichever wheel(s)

    No sport mode is required, nothing, just normal integrated smarts on all platforms (LX and forward) platforms equipped with really f'n smart / high performance Mercedes-based equipped platforms :^)





    Agreed Billy; however, as I just mentioned, during panic stop situations, which includes simply lifting off from WOT application (trans simply anticipating an upcoming braking event - will immediately hold last gear position - actually every single transmission offering will do this on our rides) the transmission will - without any action by the driver - as you point out will automatically downshift - while vehicle dynamics believe the car is travelling in a straight (safe) line.

    Finally, as you and others correctly(!) understood what I wrote, we successfully cut fuel directly after taking my foot off the gas to enhance engine braking - prior to brake application to enter corners. In stock mode, all PCMs are commanding some fuel flow after drivers take their foot off the gas. This is the assist extending the coast-down, thereby stretching fuel mileage (seems counter-intuitive - but its not) to meet EPA mandates as well as reduce NOx emissions by ensuring catalytic operating temperatures remain within their operating window. The final reason is NVH (to a much lesser degree) to reduce discomfort that occurs when typical (no fuel present - like carbs) engine braking did that pushed drivers / passengers into the seat belts.

    Regarding that off-throttle fuel cut changes I perfected; here's why...

    At my track, approaching turn #1 at the end of the 1/4 mile track integrated as the front straightaway, I would typically come out of the last corner and pass the christmas tree well excess of `60mph. At the point of throttle-off I was at or over 170mph. Even with the HUGE BAER monoblocks and 16.5" front rotors, they were working hard after a few laps to slow the land yacht for entry. Pad wear was significant and required constant monitoring during the day.

    The addition of immediate engine-braking and aggressive down shifting at turn #1 as well as the last corner off the backside straightaway, that engine brake assist high up in the rpm range put the brake system workload back into the sweet spot. It took a few minutes to find (goes back to 2011): Off-throttle Fuel Cut-off Prior to Corner Entry


    These kind of threads are tiring and demotivating; unless other Members elect to chime in that deserves a response, I'm done trying the enlighten the OP :^(
    Thanks for that. And I totally agree. We are essentially saying the same thing!

    All I’ve been saying (and said many times) is that lifting your foot from the accelerator does not make the transmission downshift. It can’t. There are too many other factors involved.

    I wasn’t clear on the “free wheeling” comment as I assumed you would understand what I was referring to when I used “transmission” as a general term. The TC releases mechanical lock when the throttle is lifted. Yes, there is still a hydraulic engagement (Sport mode may be different, I don’t have sport mode) and that would still create engine braking. No... the transmission does not “free wheel” as if it’s in neutral if you let up on the gas.

    That’s why I made the comment about manual transmission, because a manual clutch would be better for engine braking. (I also commented about being in full automatic, not auto stick mode). Remember this all started while talking about intake manifold vacuum? Using auto stick, or manually selecting a gear would provide better engine braking than just having it in Drive.

    Is that correct? Did I miss something?

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