Reason with me before I destroy a classic

[MetroMPG]

Originally Posted by omgwtfbyobbq

Chopped Metro would prolly get better mileage, but the spitfire would be cooler.

What he said.

Actually, I think that chopped Metro EV looks pretty sweet. (But then I'm an aero nerd).

I'd love to know what kind of mileage it would deliver in ICE form with ALL the detail work done (skirts, belly pan, mirror/wiper delete, etc etc.)

[bzipitidoo]

I know all about Lucas, the Prince-of-Darkness, why-do-Brits-like-warm-beer-because-they-have-Lucas-refrigerators, crap parts that break down for the strangest reasons. Like the time my generator quit because the terminal broke off!?!

Anyway, yeah, some people are ultra purist about antiques, even down to having the same color plastic parts and wires even if the original wire coloring scheme was a screwed up mess with no matching colors and no plugs (let alone idiot proof plugs) that would get you shot today in any factory you demanded wire it up right. Purity is good if you plan on donating it to a museum someday, and for scoring points at some kinds of car shows, but otherwise, don't go out of your way for it.

I put it this way to myself. What would the original designers have done if they could've? Electronic ignition system? Yep! Alternator instead of generator? Check! Instead of real rubber, synthetic rubber brake parts that won't rot and need replacing in 3 or 4 years? Definitely. So go ahead and gut those worthless hunks of scrap metal and fit them out with a real power train.

And, it's all in the eye of the beholder. Most people will pick the Spitfire over the Metro for sexier car. I'm one of those weirdos who get a kick out of efficiency and sparse minimalist design, not flashy peacock "look-at-meeee" that so often would be a big disappointment and let-down upon a closer look, except I expect that from such nonsense. So, yeah, to me, the Metro is the cooler car, no question. More honest.

[baddog671]

I think a Metro with the chopped top would be very cool. Weight is decent to remove too. Ive removed 91 pounds so far without much visual difference except the backseat and radio headunit. That 91 lb has made a good improvement and I think the chop would boost mpg nicely.

[mustngr]

It appears that "purists" come in all stripes.

Ok, let's simplify. This ain't about sex. I got no dog in this fight cuz I have the same dollar amount in either car.

Let's face it, both of these cars are pieces of crap, as cars go. One is a poor attempt at a sports car but it happens to be light and reasonably aerodynamic. The other is basic, frugal transportation that was intended to have a given service life, but is light and reasonably aerodynamic. We already know that after the basic mods are done the Geo requires major surgery to its roofline to take it any further in terms of aerodynamics. Less is known about the aero potential of the Spit and it, too may require major surgery. The reason I'm not dazzled with the idea of cutting it up is not due to its value, but that I don't know how far it can be taken aerodynamically BEFORE I need to start cutting it up. That's the tiebreaker and I should have been more clear.

Assume we've already converted the Triumph to the Geo motor and trans, but have done nothing else, and both cars are at roughly equal weight.

[MetroMPG]

I'd say you could surpass Insight Cd territory (0.25) with the chopped/teardropped/fully aeromodded Metro. I can't comment on the Triumph because I'm not familliar with it beyond recognizing one on the street.

Assuming a starting point of .32 for the Metro (I've always been working from a starting point of .34 - but then I've never found an authoritative source of information on the car's Cd):

- the aero mods I tested (grille block, rear wheel skirts, mirror delete, kardboard kammback, undertray) made a total improvement in fuel consumption of 12.5%. Most of the tests were at 50-55 mph.

- that equates to a change in Cd of approx. -0.045, for a final Cd of 0.275 with all mods in place

- With the windshield angle increased, dramatic rear taper & reduced base drag that would come from the chop, losing at least several more counts off that figure is a gimme.

- Add more mods: wiper delete, lowering, front skirts/gap fillers, shaved excrescences, etc. etc. etc., and next thing you know you're leaving the Insight behind and approaching EV1 territory (0.19).

A slipperier than an Insight Metro? Do it!

[skewbe]

Ahh, you are hoping to avoid doing body chopping? a-la:


Well that's simpler, I think the metro has something like a .32 (unconfirmed) coefficient of drag and the spitfire has a .42 (per wikipedia). unless the frontal area of the spitfire is porportionally less, the geo will have less drag.

If both cars are running, you can compute the CdA for each with a series of coastdown tests and determine it that way.

http://www.gassavers.org/showthread.php?t=4419&p=64771

[mustngr]

Most sources list the Spit at .38 and the GT6 fastback version at .32.

Most of the Spitfire info concerns what you can or cannot do in terms of aerodynamics in the various SCCA classes, rather than the Cd numbers which will result. I'm told that the Wiki number is for an open car (no top) but I can't verify that. One thing that seems to have helped to kill off the Spit on the later cars like mine was the additional drag from the bulbous rubber bumpers and maybe that accounts for the higher numbers.

I've got more homework to do. My Geo needs to be converted to a 5-speed before I chop the top, and I'll need a mockup motor if I decide to go with the Triumph. Either way I need a parts car standing by.

Seems we've made no progress in glass cutting since I last chopped a top, and it remains a major expense or a lot of broken glass if you try to do it yourself. I would have thought by now we could cut the things with a laser, 'er sumpin. In looking at Dave Cloud's car it appears that he MAY have engineered the chop around that obstacle by "canting" he stock side windows in their frames. But his is a race car rather than a street car and they may be cut from polycarbonate or may not even be functional.
The rear of his car is totally open. It would take some time and thought to incorporate the hatch door and some rear side glass into the chop but I wouln't be happy with the results if I didn't.

Frankly my eyes are crossed from staring at my Geo as a geometry problem. I need a break, and I'm not yet convinced that a much less problematic 3-4" top chop and a fiberglass gizmo on the deck lid of the Spit won't accomplish nearly the same thing.

If you guys don't mind playing along I'd still like to hear suggestions on either idea while I scrounge up another car.

[Dynamically Aero]

Save the Spitfire and go gonzo on the Geo!

In other words, coddle the classic and utilize the utilitarian.

[mustngr]

Originally Posted by theclencher

Spitfire engine/trans weighs 100 lbs more?!? That Triumph stuff is already so spindly and light... that's amazing

Cast iron motor and trans vs. aluminum, 4-popper vs. 3. Everything from the master cylinders to the heater core to the turn signal flasher is easily DOUBLE the size and weight of the Suzuki stuff.

This what is tipping my scales to the Triumph right now.

It has more potential to be the lighter car by far by just replacing a lot of major (and minor)components with the Suzuki items where possible. I'm gonna venture based on this that the bare shell may be 100-200 pounds lighter than the Geo if both were stripped of their hard parts.

I'm new to he fuel economy game but not to the weight game, and I'm really good at sorting the baby from the bathwater in that respect.

I've got more scales than Beethoven from my bike days.

[GasSavers_Ryland]

I really like the body style of the spitfire, and agree with the opinion that the engine they have is simply poor design, and that you shouldn't wast your time rebuilding a bad design, insted replace it with something better! and if you feel like you know how to do it, and really make it work, then do it, otherwise the spitfire will continue to be a bucket of parts, I would imagine that there is someone out there who races them or something, who has made up carbon fiber body panals as well, alowing for even more weight loss.