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Technical FORMULA FOR "QUARTER MILE" CONVERSION?

Discussion in 'The Hokey Ass Message Board' started by wingspread7, Jul 1, 2019.

  1. I often wonder about the ETs of the original 1320 ft. 1/4 mile drags vs. today's 1,000 ft. drags. Is there a conversion so we can tell how fast those old guys really were by today's standards? I doubt we could just use a ratio because engine tuning, gearing and other power train changes would be needed to optimize that missing 320 ft.. If not, it would be a fun project to take a common SBC in a common car and optimize each way to come up with a realistic formula.
     
  2. onetrickpony
    Joined: Sep 21, 2010
    Posts: 753

    onetrickpony
    Member
    from Texas

    I thought only the nitro classes were 1000ft to reduce the top speeds
     
    31Vicky with a hemi likes this.
  3. greybeard360
    Joined: Feb 28, 2008
    Posts: 2,074

    greybeard360
    Member

    NHRA web site should have a chart.
     
  4. rooman
    Joined: Sep 20, 2006
    Posts: 4,045

    rooman
    Member

    Correct
     

  5. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,230

    Mimilan
    Member

  6. Try multiplying 1000' times how much i care about the modern NHRA drag racing= jack shit! I understand why they didn't just shorten the pro cars to 1\8th mile like all the big names in the 405 run? :rolleyes:
     
    Ned Ludd likes this.
  7. squirrel
    Joined: Sep 23, 2004
    Posts: 55,933

    squirrel
    Member

    pretty low on the 1/4 mile MPH, compared to what they really run. (I'm talking about modern top fuel cars)
     
  8. 03GMCSonoma
    Joined: Jan 15, 2011
    Posts: 314

    03GMCSonoma
    Member

    The formula I use is 1/8 mile time multiplied by 1.56. If you could get 1/8 mile time when you are running on a 1/4 mile track, that would make it too simple. My OT 4.3 Sonoma ran an 8.2 on an 1/8 mile track and 12.8 on a 1/4 mile. I realize conditions change on each run but maybe this will be a good SWAG for you.
     
  9. The nitro cars are faster at 1000 feet than they were at 1320.
    It’s all math, rpm and actual revolutions of the engine at full power in 3-4 seconds with tire circumference to cover 1320 or 1000 and pushing the engine hard enough to win and stay together for 1320 feet. Theoretically they can push the same engine harder because it’s only got to stay together for 1000 feet. That theory has now become fact.

    Shortening the track didn’t slow them down but they do have 320 feet more to stop.
    Toyota, the official car of the NHRA.
     
    Last edited: Jul 2, 2019
    els and VANDENPLAS like this.
  10. 41rodderz
    Joined: Sep 27, 2010
    Posts: 6,540

    41rodderz
    Member
    from Oregon

    Old school 1/4 mile heads up racing or it didn't happen.
     
    cactus1 likes this.
  11. Mike VV
    Joined: Sep 28, 2010
    Posts: 3,029

    Mike VV
    Member
    from SoCal

    The math for "most" cars isn't going to work with any nitro powered cars.
    WAY...to many variables. Plus you'd have to remove the rpm limiters.
    Hell, even the tires might not stand up to 1/4 mile any longer since they've been redesigned for 1000' if you removed the rpm limiters, along with the rest of the engine..!

    Mike
     
  12. town sedan
    Joined: Aug 18, 2011
    Posts: 1,290

    town sedan
    Member

    A metric quarter mile. No wonder the NHRA is irrelevant to me.
    -Dave
     
    VANDENPLAS likes this.
  13. I’d be interested in seeing some other nitro racing, what you got?

    The old cars don’t race too much but you can go see them cackle.

    The nostalgia AA gassers are pretty damn cool to watch but most tracks want them old heaps shut down at 1/8 mile now.
     
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  14. squirrel
    Joined: Sep 23, 2004
    Posts: 55,933

    squirrel
    Member

    United Nitro Funny Cars, and Western Fuel Altereds, are putting on small shows out here...it smells good when they run
     
  15. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,476

    dreracecar
    Member
    from so-cal

    The Current NHRA Nos. T/F Dragster Champion running (high gear only) , sees 11,200 RPMs through the lights @ 1320'

    [​IMG]
     
    slayer likes this.
  16. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,476

    dreracecar
    Member
    from so-cal

    Getting back to the question, Most of the teams data recorder have an acceleration graph that you can continue (in theory) because these cars do not flatten out , they continue accerating till they blow up, even past the finish line
     
  17. RmK57
    Joined: Dec 31, 2008
    Posts: 2,659

    RmK57
    Member

    On a good run a modern top fuel is almost 300 mph in the 1/8 so their not picking up as much in the last 330 ft.
     
  18. wisdonm
    Joined: Jun 20, 2011
    Posts: 444

    wisdonm
    Member

    It that truly "11,200 RPMs " or a total of 1,200 crank shaft revolutions for the whole run?
     
  19. rooman
    Joined: Sep 20, 2006
    Posts: 4,045

    rooman
    Member

    It is turning at the rate of 11,200 revolutions per minute but it will turn over just over 1,000 times (1024.8 to be exact) from when it starts the clocks to when it crosses the finish line only 5.49 seconds later. The motor does get to turn over a lot more during the burnout, while backing up and then staging for the run. With the idle generally at about 2,300-2500 rpm on a fuel car the number of crankshaft rotations add up quickly.

    Roo
     
  20. Only Approximate or "close".
    This only represents relatively "normal" situations.
    Obviously if your car has something unusual such as gearing that makes you top out at 1/8 th mile speeds, then the second half of the 1/4 mile will take a bit longer, etc etc
    it may translate a bit differently, but unless you have an unusual prob, this will translate pretty closely.


    26992559_389111844874459_531037490749283936_n.jpeg

    WHY BE ORDINARY ?
     
    Last edited: Jul 2, 2019
  21. dreracecar
    Joined: Aug 27, 2009
    Posts: 3,476

    dreracecar
    Member
    from so-cal

    At the March Meet this year they had a driveshaft issue at 800ft killed the engine (among other things) Data showed 12,500 rpm. Remember these cars use 4.10 gears and a shorter tire
     

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