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Old 08-06-2007, 12:37 PM   #41
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I'm back.

I need a reality check from the collective here.

Im neither mathematician nor aerodynamicist but it seemed counterituitive that the Spit would be less aero than the Geo. (Incidently, my garage CD calculations indicate that the Spit's overall number is about .39, rather than the published numbers which vary from .38 to .42). Based on CD alone, the Geo wins.

Admittedly I was looking for support for my thinking, but when I searched for it I actually found some info which was quite profound.

A lot of aerodynamicist types downplay he CD aspect unless it is compared against frontal area. The equation can be pretty complex, but in simplest form you can just multiply the drag coefficient by the frontal area, and that constitutes a more realistic view of a car's aerodynamic potential.

Once again, in stock form the Geo wins, but only by a slight margin. I used the published numbers for each:

Geo: 19.2 sq. ft. X .32 CD= 6.144

Spit: 15.2 " " X .42 " = 6.384

If we begin with stock vehicles, then reduce the overall CD it starts to get more interesting. Let's say we reduce the overall CD of the Spit to something like .36, which seems doable with some pretty basic aero mods, maybe by simply replacing the 5 mph bumpers:

15.2 X .36= 5.47

We have already beaten the Geo (at .32) in the real world, yet the Spit still has a higher CD of .36.

If this is correct, The Geo will never catch up to the Spit, mod-for-mod. In fact things will only improve exponentially against the Geo, and if all other factors are the same, he car that begins with the least frontal area will always win the aero game.

Anyone care to shoot holes in this? I got no dog in this fight, either. Just stuff from the 'net.

Everyone wants to live inTheory. Because everything works THERE.
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Old 01-28-2008, 04:13 PM   #42
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Talking Finally got all the parts.

Assembled most of the basic parts to convert the Triumph, so tonight I broke out the scales.

Geozuki 1.0 w/manifolds,alternator, fuel injection, Samurai flywheel, pressure plate, less starter: 145.5 lbs.

Samurai transmission: 54.5 lbs.

TOTAL 200.0 lbs. even.

Published engine weight for Spit 1500 from various sources on the 'net, LESS smog equipment and manifolds: 275.5 lbs.

Spit trans.: 92.5 lbs.

TOTAL 368.0 lbs.

We're talkin good 'ol British cast iron here.

I once put a small bock Chevy and a Muncie in place of an Austin Healy straight 6. Afterward the front end sat over an inch higher. As I recall 302 Z28 motor weighed over 100 pounds LESS than the 3.0 six. (That car ran like stink, BTW)

Decided to redo both cars (Spit first). Still need a donor 5 speed car for the ECM, fuel pump, wiring harness, etc. etc., and also to provide the bones for converting the Geo to 5 spd.

Every danged car I call about turns out to be an automatic.

I'll start a separate thread if anyone's interested. This week I'll just focus on getting it mounted up.

Everyone wants to live inTheory. Because everything works THERE.
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Old 01-29-2008, 02:04 AM   #43
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Thumbs up

Hooray! Mod the Spitfire. (Late vote since you're starting but I wasn't on the forum last year)

Ever hear of the expression, "I don't know how to define _____, but I can sure tell it when I see it!"? (I believe originally defined as porn by a Federal judge in a pornography case.)

The Spitfire looks like it can be aero modded better mod for mod, because it wasn't designed as aero in the first place.

There is DEFINITELY something to be said for coolness factors - if it just looks and feels better, that is worth a bit of your money and effort in this short life. The Spitfire should be a whole lot more fun than the Geozuki *to you* - it sounds like you'll have a lot of fun with this project, and isn't life all about everything BUT money?

ENJOY. Keep us posted. I'd love to see the results and the fun in getting there.

Looking to trade for an early 1988 Honda CRX HF (Pillar mounted seat belts)
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