Heard this rumor before | FerrariChat

Heard this rumor before

Discussion in 'Boxers/TR/M' started by Enzo Belair, Oct 2, 2020.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, Skimlinks, and others.

  1. Enzo Belair

    Enzo Belair Formula 3

    Jul 27, 2004
    1,315
    New Jersey
    Full Name:
    Scott
  2. rpissm

    rpissm Formula 3

    Aug 11, 2013
    1,620
    Salt Lake City, UT
    Full Name:
    Joe
    Why couldn't a real boxer engine handle high rotational speeds? Anyone know?

    Sent from my Moto Z2 Play using Tapatalk
     
  3. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    The "problem" with a true boxer flat-12 design (in the same overall block length) is that the crankshaft is much more "flexible" (i.e. less torsional stiffness) due to having more throws and thinner webs -- which could drop the torsional resonant frequency of the crankshaft down low enough that it could limit having a high rotation rate and/or high cylinder firing rate.
     
    rpissm and Grease Donkey like this.
  4. Steve Magnusson

    Steve Magnusson Two Time F1 World Champ
    Lifetime Rossa

    Jan 11, 2001
    25,040
    30°30'40" N 97°35'41" W (Texas)
    Full Name:
    Steve Magnusson
    I'll add that while using a true "boxer" layout on a flat-12 is not such a good idea, it makes very good sense for an air-cooled flat-4 or air-cooled flat-6 configuration (like VW and Porsche do/did) because:

    1. They are already fairly short block lengths -- so increasing the block length another 25~30% in order to have a beefier crankshaft design isn't much of a penalty (unlike it is on an already longish flat-12),

    2. The block length of an air-cooled flat-4 or air-cooled flat-6 needs to be increased anyway (because the bore spacing has to be increased) in order to have enough cooling fin surface area on each cylinder (and have good cooling between cylinders), and

    3. The boxer layout solves the vibration issues that a flat-4 or flat-6 would have if using 2 connecting rods on each crankshaft journal (whereas, all 2-bank 12-cylinder engines are very well-balanced regardless of which type of crankshaft is used).
     
    ingegnere, rpissm and Grease Donkey like this.
  5. turbo-joe

    turbo-joe F1 Veteran

    Apr 6, 2008
    8,866
    southwest germany and thailand
    Full Name:
    romano schwabel
    agree, that is why porsche used 2 crankshafts for the porsche 917 and the power pick up has been in the middle, not at the end of the crankshaft
     
  6. greyboxer

    greyboxer F1 World Champ

    Dec 8, 2004
    12,282
    South East
    Full Name:
    Jimmie
  7. OLDBENZ

    OLDBENZ Rookie

    Dec 7, 2016
    24
    UK and Caribbean
    Indeed. Plus they show a pic of the rear of a 512BB although captioned 365BB - an April fool clue perhaps?
     
    turbo-joe likes this.
  8. rovexienus

    rovexienus Formula Junior
    Silver Subscribed

    Jun 10, 2010
    562
    Sainte Colombe, France (near Lyon)
    Full Name:
    Jean-Michel Savary
    The 365 BB prototype shown at the Turin Motor Show in 1971 did not have rear lights 512BB style?
     
  9. miurasv

    miurasv F1 World Champ

    Nov 19, 2008
    10,016
    Cardiff, UK
    Full Name:
    Steven Robertson
    #9 miurasv, Oct 4, 2020
    Last edited: Oct 4, 2020
  10. OLDBENZ

    OLDBENZ Rookie

    Dec 7, 2016
    24
    UK and Caribbean
    Thanks - I have learned something today.
     
  11. cgt000

    cgt000 Formula Junior
    Silver Subscribed

    May 2, 2014
    732
    Northeast
    I thought the BB really stood for Brigitte Bardot!
     
    Elsi and TestaDDS like this.

Share This Page