Listers,
ASSUMPTIONS:
a) Car: Triumph Spitfire MKIII
b) Trans: stock Spitfire 4 speed, non O/D
c) Diff: stock Spitfire MKIII, 4.11:1
e) Tires: stock 145SR 13
f) engine redline: better than stock 6,500 RPM
g) engine horse power: hopped up - 1million gazillion HP
COMPUTED:
Top speed equals 104 MPH. Triple horse power to 3 million gazillion and top
speed becomes 104 MPH. Add quadruple superchargers, twin turbos, and nitrous
oxide, and top speed becomes 104 MPH. Top speed in first is, in all cases, 28
MPH. 48 MPH in second, and 75 in third.
Let the engine rev to 8,500 RPM, and top speed in fourth is 136 MPH.
With a stock redline of 5,500, top speed is 88 MPH - add a 0.80 O/D, and top
speed is 110.
Change the rear end to 3.63, and top speed at 5,500 RPM becomes 99 MPH. 117
MPH at 6,500 RPM.
With a 3.63 S1500 diff, 6,500 RPM redline, and 215/70 tires, top speed is 132
MPH. 165 MPH with a 0.80 O/D.
etc.
Slightly detune the engine to a more realistic 65 -150 HP, and the top speeds
may be a bit less in each case.
Horse power is only part of the speed equation.
Take a 4.5 second, 320 MPH dragster, swap the slicks for a pair of 145SR 13s,
swap to a 4.11 rear axle, use an 8,500 RPM redline, and it will cruise through
the timing lights at a sedate 136 MPH (if the engine doesn't explode first!
In a normal 4.5 second run, at 8500 RPM, the engine in a dragster turns over
only 637.5 times).
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://members.aol.com/danmas/
'74 MGBGT---3000mile/year driver, original condition - slated for a V8 soon
'68 MGBGT---organ donor for the '74
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