Mystery Car... ("58 - 166 MPG" streamlined Geo Metro)

[Trekintosh]

Originally Posted by Xist

Thanks for the updates and introduction! Do you mind telling us how tall you are?

There have been many cylinder-deactivation discussions here. I do not know if anyone has successfully modified an engine like that. I am sure that people just deactivate the deactivation, because who needs fuel economy?

Basjoos has front skirts. I do not know if you can make a more efficient version, but it sure could be prettier! Aerocivic - how to drop your Cd from 0.31 to 0.17 He made a huge number of other modifications, but it does not seem like any were with sheet metal.

Well there's the old 4-6-8 Cadillac V8 from a long time ago that was waaaay too early for prime time. As for the dodge MDS (multiple displacement system), some people turn it off, most don't. It's fairly effective other than cylinder wear being much higher on the 4 most-used ones.

And yeah I saw the Aero Civic while googling around. He still has the stock roofline which is unnecessarily tall, so I bet I can beat him when I reshape things and do some tuning up. His site is actually where I got the idea for inside mirrors as a supplement to side cameras. If you see this Basjoos, thanks mate!

Originally Posted by freebeard

Here's an idea hat no-one has stolen from me yet, prolly because it's so poorly represented:

The cylinders represent four-bars linkages. The top two are connected to prevent racking or binding as it moves. Instead of hinging at the top the whole skirt lifts against gravity.

I don't think I understand how it works. Is the idea for the wheel to press against the skirt while steering and push it out? Not a fan of that. I'd rather use a mechanism to push.

[Xist]

This is proof that I stole it!

Originally Posted by Xist

I made this!

[California98Civic]

Another alternative to front wheel well covers would be a fairing that continues the body contour the point of contact with the tire, but make the last inch or two soft, perhaps brushes. You want to consider not just the aerodrag of the wheel but also the ventilation drag, which has been shown to be important to total drag in some applications. Full disc covers are good, but sometimes slightly vented covers are better because of how they address ventilation drag. Something similar is also probably true of wheel well covers, though the specific application would have to be tested to know what works best... one can also always guess!

Btw, too, the tail is a little fast, I think. You might look up some spoiler tests Julain Edgar posted here on EM (& probably on his YouTube channel). He claims good results on a Gen1 Insight, so probably worth a look.

Fabulous car.

Start a fuel economy log here so we can watch the progress?

[Trekintosh]

Originally Posted by California98Civic

Another alternative to front wheel well covers would be a fairing that continues the body contour the point of contact with the tire, but make the last inch or two soft, perhaps brushes. You want to consider not just the aerodrag of the wheel but also the ventilation drag, which has been shown to be important to total drag in some applications. Full disc covers are good, but sometimes slightly vented covers are better because of how they address ventilation drag. Something similar is also probably true of wheel well covers, though the specific application would have to be tested to know what works best... one can also always guess!

Btw, too, the tail is a little fast, I think. You might look up some spoiler tests Julain Edgar posted here on EM (& probably on his YouTube channel). He claims good results on a Gen1 Insight, so probably worth a look.

Fabulous car.

Start a fuel economy log here so we can watch the progress?

I'm sure that even though ventillated hubcaps might be better than solid ones, a full wheel fairing would be better. I'm not going to use any solution that lets the tire touch the cover, I much prefer one that will move via a connection to the steering knuckle in some way, even it's just as simple as having a pair of sticks welded/bolted to the knuckle that go around the wheel and just poke the fairing.

I have a small Discord (video game social communications platform) server that I am logging fuel in, but I stupidly put a tank of premium in first (the gas station had premium in the opposite spot as most do) and need to burn all that out and it's taking FOREVER because the car gets so much MPG. I also have Fuelly and will track every (infrequent) fuel-up. A spoiler might work, and I'll look into it in the future. I still have a lot of TLC to give the car before I get to significant body modifications like that.

[freebeard]

Cylinder deactivation on a three-cylinder engine?

I don't think I understand how it works. Is the idea for the wheel to press against the skirt while steering and push it out? Not a fan of that. I'd rather use a mechanism to push.

I'm agnostic about the activating mechanism. Rollers, inner cycle fenders, complex linkages are all possible. The point is that the full skirt is lifted instead of hinged. If it hinges at the top, aerodynamic forces are largest at the end of a lever arm. And gravity can't assist recovery.

That and (like James Watts) I'm just a fan of four-bars.

[Xist]

These buses had front skirts of sorts. They moved with the wheels: https://ecomodder.com/forum/showthre...bus-10004.html

[Trekintosh]

Originally Posted by Xist

These buses had front skirts of sorts. They moved with the wheels: https://ecomodder.com/forum/showthre...bus-10004.html

Quick look through the thread, seems like they probably just attached to the steering knuckle and went all around the wheel. Probably the best way to do things, I just really wanted to make completely flush skirts for the sleekness/spaceship factor. Especially since eventually I might get a coilover suspension for the car in order to lower it and reduce drag further.

[freebeard]

Ford Probe IV used an inner cycle fender with a flexible fabric outer.


www.conceptcarz.com/vehicle/z2023/Ford-Probe-IV-Concept

One of Probe IV's most distinctive features are its fully-skirted wheels and tires which utilize membranes between the outer covers and the body. The membranes flex when the front wheels are turned and allow Probe IV to be driven normally, but drastically reduce wheel well turbulence and resulting aero drag.

Journalists, amirite?

[Trekintosh]

Originally Posted by freebeard

Ford Probe IV used an inner cycle fender with a flexible fabric outer.


www.conceptcarz.com/vehicle/z2023/Ford-Probe-IV-Concept

Journalists, amirite?

Probe IV achieved a drag coefficient of 0.152

Woah. Now that's about a holy grail level of efficiency. It's even rear wheel drive with a turbo 4 so it would actually be fun on occasion.

[redneck]

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Thanks for replying.


I have another request.

If and when you have some extra time, please go to a scrap yard or somewhere else that has a scale and weigh the car for us.


🙃

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