News

Engine rev

Discussion in 'Technical Q&A' started by jwbest, Jul 4, 2009.

  1. jwbest

    jwbest Rookie

    Oct 14, 2008
    23
    Southeast
    Full Name:
    Walt
    While at outdoor exotic car show, the sponsor would have all of the owners rev their engines every hour for the crowd. Although it sounded cool, I have always been told this is not good for the engine while in neutral. Is this true? Thanks in advance for you comments!
     
  2. To remove this ad click here.

  3. st@ven

    st@ven F1 Rookie
    Silver Subscribed

    Aug 4, 2008
    3,061
    Netherlands
    Full Name:
    Steven
    as long as it is hot when you rev it and you do not take it to far it will not harm it.
    (but don't make it a habit)
     
  4. mackb61

    mackb61 Karting
    BANNED

    May 17, 2008
    80
    I was told a number of years ago that if the engine can rev to say 8,000 rpm while under load, there would be no harm in revving the engine to 8,000 rpm with no load. There is no difference. I'm not sure if I believe it. I see the logic, however. True or False and Why?
     
  5. TLKIZER660

    TLKIZER660 Formula Junior

    Jul 30, 2004
    315
    Québec
    #4 TLKIZER660, Jul 5, 2009
    Last edited: Jul 5, 2009
    I've been taught that in an engine under load (more than just friction load) and at high RPM , the piston inertial loads (deceleration loads at TDC) are partly offset by gas loads (exhaust backpressure or compression loads). At no load (or only friction load), the piston inertial loads at high RPM (not reduced by gas loads) can cause piston failure. I've also been taught that most high RPM piston failures occur at the instant when the throttle is closed, unless the engine is over-revved. I don't know by personal experience or testing, but that's what an automotive piston design engineer told me in the late 1960s/early 1970s when I was dyno-developing engines for Ford.


    Tom Kizer
     
  6. vincenzo

    vincenzo F1 Rookie

    Nov 2, 2003
    2,928
    +1
    as explained by an automotive engineering instructor - but without any detail.
    full 'on throttle' to full 'off' throttle with the engine in gear

    I'd love to hear 'why'?

    rgds,
    Vincenzo
     
  7. To remove this ad click here.

  8. VIZSLA

    VIZSLA Four Time F1 World Champ
    Owner

    Jan 11, 2008
    41,198
    Sarasota
    Full Name:
    David
    #6 VIZSLA, Jul 5, 2009
    Last edited: Jul 5, 2009
    What's with these how can I abuse my car threads that are popping up lately?
     
  9. Rifledriver

    Rifledriver Two Time F1 World Champ

    Apr 29, 2004
    27,128
    Austin TX
    Full Name:
    Brian Crall
    People just want to be told it is OK to act like an idiot 17 year old.
     
  10. VIZSLA

    VIZSLA Four Time F1 World Champ
    Owner

    Jan 11, 2008
    41,198
    Sarasota
    Full Name:
    David
    I hope we're not seeing the market down turn put these cars in the hands of too many idiots.
     
  11. SonomaRik

    SonomaRik F1 Veteran
    Silver Subscribed

    Dec 15, 2006
    6,715
    Sonoma, CA
    worse, I hope those idiots are not flooding the market with their thrashed eingines.
     
  12. To remove this ad click here.

  13. anthonyh

    anthonyh Rookie

    Oct 13, 2008
    29
    I don't think this is necessary to do every hours what the owner has done. This is harmful to the engine while in neutral.
     
  14. AceMaster

    AceMaster Three Time F1 World Champ

    Feb 6, 2009
    31,041
    Calling a penalty
    Full Name:
    Mike
    I wouldn't rev period, let alone every hour, no matter how much you paid me.
     

Share This Page