If:
3 /----------
--\ / hp x 234 = S
\/ ----------
(wc+wd)
where
hp = horse power
wc = weight of car
wd = weight of driver
S = speed at end of 1/4 mile
Would it then follow (for those of us who don't have dyno's) that....
Speed in a 1/4 mile = 79
Weight of car = 1600
Weight of driver = 196 (yes, I really do fit in a Spitfire!)
then:
Calculated hp ~= 70
Everything else being fairly equal (driver reaction, traction, ect. ect.).
Of course these are only arm-chair figures, I would NEVER exceed the posted
limit! &;o)>
Thanks,
Paul Mostrom
'77 Spitfire 1500
'Black holes, where God divided by zero......'
-----Original Message-----
From: DANMAS@AOL.COM [mailto:DANMAS@AOL.COM]
Sent: Thursday, December 03, 1998 3:56 PM
To: mikew@turbopower.com; Spitfires@autox.team.net
Subject: Re: rude and crude - more calculations
In a message dated 98-12-03 16:34:41 EST, mikew@turbopower.com writes:
> The numbers are cool...but how about showing us the equation?
Willdo!
Divide the weight by the HP, take the cube root of this, and multiply by
5.825.
To get the speed in the traps at the end of the 1/4 mile:
Divide the HP by the weight, take the cube root of this, and multiply by 234.
These equations have been around for quite a few years, and show up from time
to time in the various hot rod related magazines. They have pretty well been
established as valid. The source I am using for them at this time is a 1993
issue of Car Craft.
The numbers?
Nigel: 99.32 MPH
Me: 117.93
Ro-Spit: 121.68
Me (on a diet): 122.14
Dan (armchair engineer) Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/index.html
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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