Drive A Manual Transmission? Read This.

  1. Welcome to GM Inside News Forum – General discussion forum for GM

    Welcome to GM Inside News Forum - a website dedicated to all things GM.

    You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, Join GM Inside News Forum today!
     
Results 1 to 12 of 12

Thread: Drive A Manual Transmission? Read This.

  1. #1
    News Contributor Premium Member Perian's Avatar
    Join Date
    Nov 2004
    Location
    New York
    Posts
    8,489
    Thanks
    83
    Thanked 3,341 Times in 1,190 Posts
    My Ride
    2017 Jaguar F-Type (Manual)

    Drive A Manual Transmission? Read This.

    AutoWeek.com
    October 8, 2020




    Rev hang is a term describing an engine revving decreasing slowly
    Rev hang is used on purpose to curb NOx emissions
    Your driving style could be making it worse
    Manual transmissions are great, do not complain


    I wouldn’t say that I hug trees, but I do like them an awful lot. I like shade, nuts, fruits, and leaf piles in the fall for my son. More broadly, I like the environment and do not want to cause harm if I can avoid it. If that means I have to let the engine revs drop a little slowly on a manual transmission equipped VW Golf, or most any modern manual car out there, then so be it. I’m not going to complain and neither should you.

    The phenomenon is known as rev hang. Rev hang is a delay in engines revs decreasing when you lift off the throttle. It occurs on most modern internal combustion engines, but is more noticeable on manual transmission equipped cars because you are in complete control of shifting. And it’s annoying. The engine revs staying elevated makes quick upshifts less smooth, and downshifts clumsy.

    But rev hang also plays an important role in keeping internal combustion engine’s emissions in check. And it all has to do with the stoichiometric ratio of air-to-fuel of 14.7:1. Douglas Skorupski, Volkswagen of America, Inc.'s powertrain strategy manager explains it this way.

    “As you pull your foot off the throttle, what we are trying to prevent is a big hunk of air getting into the chamber without any fuel. If air gets in that way, when you do reapply throttle, it creates a lean condition (a higher than 14.7:1 air-to-fuel ratio), which generates nitrous oxides or NOx. By delaying the fuel cut-off in the cylinder, we get some fuel in there with the air to keep the mixture correct and avoid the lean condition and prevent the NOx from occurring.”

    In literal terms, engineers delay fuel cut-off until several milliseconds after you completely lift your foot off of the throttle. Doing so adds enough fuel to keep the air from throwing off the chemical balance of clean combustion. And while it’s true that catalytic converters can reduce how much NOx leaves the tailpipe, we’re still much better off producing as little as possible in the first place. Turns out NOx is gnarly stuff.

    Wolfram Wendt, the Manager of Quality Analysis at Volkswagen, has applied the method of rev hang for years to mitigate NOx in several VW engines. And his team is constantly refining the process in an effort to make it less intrusive. Engineers don’t like the way rev hang feels any more than we do.

    Keep reading at above link.

  2. The Following 5 Users Say Thank You to Perian For This Useful Post:

    BlackGTP (10-08-2020),gkr778 (10-08-2020),smith7629 (10-08-2020),SRFCTY (10-09-2020),Z284ever (10-13-2020)

  3. Remove Advertisements
    GM Inside News
    Advertisements
     

  4. #2
    News Contributor Premium Member Perian's Avatar
    Join Date
    Nov 2004
    Location
    New York
    Posts
    8,489
    Thanks
    83
    Thanked 3,341 Times in 1,190 Posts
    My Ride
    2017 Jaguar F-Type (Manual)

    Re: Drive A Manual Transmission? Read This.











    .

  5. #3
    News Contributor BlackGTP's Avatar
    Join Date
    Jul 2008
    Location
    Connecticut
    Posts
    15,810
    Thanks
    7,654
    Thanked 10,211 Times in 4,952 Posts
    My Ride
    2013 Cadillac ATS - Black

    Re: Drive A Manual Transmission? Read This.

    My '08 Malibu LTZ V6 w/six speed auto used to drive me nuts. If I lifted my foot off the accelerator to take a turn (going uphill) and then quickly reapplied the throttle once the turn was made the car would always jam hard back into gear (did this every day to turn into my street). I wonder if this was the culprit as they said it also occurs in automatics.

  6. The Following User Says Thank You to BlackGTP For This Useful Post:

    eklauss (10-12-2020)

  7. Remove Advertisements
    GM Inside News
    Advertisements
     

  8. #4
    6.0 Liter L76 V8 dannyg's Avatar
    Join Date
    Apr 2009
    Location
    Empire State, USA
    Posts
    2,005
    Thanks
    1,619
    Thanked 1,286 Times in 707 Posts
    My Ride
    2015 Sonic

    Re: Drive A Manual Transmission? Read This.

    The Engineering Explained guy had a video about rev hang awhile back, it's pretty interesting:



    I treat my manual pretty gently, all you have to do is pause a second or so if you are short shifting from say 3 to 5. No a big deal for my more relaxed driving style anyway.
    Current ride: 2015 Chevy Sonic 1.8L 5sp manual sedan
    Previous ride: 1998 Subaru Legacy Wagon AWD 2.2L 5sp manual
    Next ride, pre-pandemic: Maybe a 2021 2.0T CT4, weekend car, keep the Sonic as DD
    Next ride, post-pandemic: Keep driving the Sonic!

  9. The Following User Says Thank You to dannyg For This Useful Post:

    Perian (10-08-2020)

  10. #5
    GMI Staff Member Premium Member vanshmack's Avatar
    Join Date
    Jan 2003
    Location
    78°14′46″N 15°27′56″E
    Posts
    4,241
    Thanks
    825
    Thanked 959 Times in 523 Posts

    Re: Drive A Manual Transmission? Read This.

    How I drive a manual...
    1987 Pontiac Trans Am GTA
    1958 Chevrolet Apache - The wife's project
    1988 Chevrolet Camaro IROC-Z L98
    2015 BMW X1 xDrive35i M-Sport
    2020 GMC Sierra 1500 Elevation

  11. The Following 2 Users Say Thank You to vanshmack For This Useful Post:

    JimmyDiablo (10-09-2020),Mr.Buttons (10-12-2020)

  12. #6
    6.0 Liter L76 V8 rand49er's Avatar
    Join Date
    Feb 2006
    Location
    South Lyon, MI
    Posts
    2,044
    Thanks
    845
    Thanked 1,039 Times in 583 Posts

    Re: Drive A Manual Transmission? Read This.

    Funny hearing a VW engineer being concerned about NOx emissions. Hilarious even.
    2005 CTS-V, LS6, supercharged, L-T headers, etc SOLD !!!
    2011 Cruze ECO, 1.4T, 6-spd manual. (my DD) SOLD !!!
    2012 SRX, 3.6, AWD (wife's car)
    2017 Volt Premier Iridescent Pearl Tricoat (son has taken it over)
    2016 ATS Premium 6MT (my DD)

  13. The Following 9 Users Say Thank You to rand49er For This Useful Post:

    1958carnut (10-12-2020),BlackGTP (10-09-2020),buildacariwant (10-09-2020),Cphelps (10-09-2020),JimmyDiablo (10-09-2020),mbukukanyau (10-12-2020),Mr.Buttons (10-12-2020),RedSkyBlackDream (10-09-2020),StarCruiser (10-09-2020)

  14. #7
    5.3 Liter Vortec V8
    Join Date
    May 2010
    Location
    Chicago
    Posts
    1,286
    Thanks
    3,206
    Thanked 672 Times in 343 Posts
    My Ride
    '05 300C - '09 G8

    Re: Drive A Manual Transmission? Read This.

    Quote Originally Posted by rand49er View Post
    Funny hearing a VW engineer being concerned about NOx emissions. Hilarious even.
    After reading I immediately came to the comments searching for someone that was going to mention that. Lol

  15. #8
    2.4 Liter SIDI ECOTEC
    Join Date
    Dec 2018
    Posts
    147
    Thanks
    12
    Thanked 102 Times in 52 Posts

    Re: Drive A Manual Transmission? Read This.

    Emissions is bogus. The whole EPA is really unnecessary. Seriously. My Grandparents - and great grand parents - all died well into their 80s and they all were born in and grew up from young childhoods in an era when cars no only had no emission controls, you would sweep the steps off to your front door every day from all the factory soot.

    If car emissions were half as bad as they say people born between 1860-1980 would have all died by the time they were 20. Seriously.

  16. #9
    Firebird Concept (the turbine one) VS Ute 5Litre's Avatar
    Join Date
    Oct 2009
    Location
    Wagga NSW
    Posts
    12,466
    Thanks
    635
    Thanked 2,573 Times in 1,597 Posts
    My Ride
    MY16 Holden Colorado LS-X Man

    Re: Drive A Manual Transmission? Read This.

    Quote Originally Posted by fastbal1 View Post
    Emissions is bogus. The whole EPA is really unnecessary. Seriously. My Grandparents - and great grand parents - all died well into their 80s and they all were born in and grew up from young childhoods in an era when cars no only had no emission controls, you would sweep the steps off to your front door every day from all the factory soot.

    If car emissions were half as bad as they say people born between 1860-1980 would have all died by the time they were 20. Seriously.
    There were also way less cars in the world then too

    Emissions control isn't a bad thing at all
    Who the hell approved this abomination? Hidden Content

    I bet it was some dumbarse in Detroit Hidden Content

  17. The Following User Says Thank You to VS Ute 5Litre For This Useful Post:

    sdotjeezy (10-12-2020)

  18. #10
    6.2 Liter LS3 V8 sdotjeezy's Avatar
    Join Date
    Jan 2017
    Posts
    3,484
    Thanks
    1,082
    Thanked 2,951 Times in 1,536 Posts

    Re: Drive A Manual Transmission? Read This.

    Quote Originally Posted by fastbal1 View Post
    Emissions is bogus. The whole EPA is really unnecessary. Seriously. My Grandparents - and great grand parents - all died well into their 80s and they all were born in and grew up from young childhoods in an era when cars no only had no emission controls, you would sweep the steps off to your front door every day from all the factory soot.

    If car emissions were half as bad as they say people born between 1860-1980 would have all died by the time they were 20. Seriously.
    My Rides:
    '19 Buick Enclave
    '07 Dodge Magnum SRT-8
    '19 Mazda 6

  19. The Following 2 Users Say Thank You to sdotjeezy For This Useful Post:

    bicentennialcadillac (10-13-2020),JimmyDiablo (10-12-2020)

  20. #11
    6.0 Liter L76 V8 rand49er's Avatar
    Join Date
    Feb 2006
    Location
    South Lyon, MI
    Posts
    2,044
    Thanks
    845
    Thanked 1,039 Times in 583 Posts

    Re: Drive A Manual Transmission? Read This.

    Quote Originally Posted by fastbal1 View Post
    Emissions is bogus. The whole EPA is really unnecessary. Seriously. My Grandparents - and great grand parents - all died well into their 80s and they all were born in and grew up from young childhoods in an era when cars no only had no emission controls, you would sweep the steps off to your front door every day from all the factory soot.

    If car emissions were half as bad as they say people born between 1860-1980 would have all died by the time they were 20. Seriously.
    I'm old enough to recall the air during the '50s and '60s. We are far better off now.
    2005 CTS-V, LS6, supercharged, L-T headers, etc SOLD !!!
    2011 Cruze ECO, 1.4T, 6-spd manual. (my DD) SOLD !!!
    2012 SRX, 3.6, AWD (wife's car)
    2017 Volt Premier Iridescent Pearl Tricoat (son has taken it over)
    2016 ATS Premium 6MT (my DD)

  21. The Following User Says Thank You to rand49er For This Useful Post:

    bicentennialcadillac (10-13-2020)

  22. #12
    2.4 Liter SIDI ECOTEC
    Join Date
    Mar 2012
    Location
    KY
    Posts
    257
    Thanks
    49
    Thanked 74 Times in 48 Posts
    My Ride
    '15 Impala 2LTZ silver topaz

    Re: Drive A Manual Transmission? Read This.

    I can tell when I'm driving behind an old car or truck from the 70's or older. The raw gas smell is terrible. Or a big diesel truck with a malfunctioning engine. Back in the day, all of the big rigs smelled bad like that. Modern gas and diesel engines have way more power than the old days, and are much, much cleaner.

  23. Remove Advertisements
    GM Inside News
    Advertisements
     

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBadvanced CMPS v4.1.2