I want to build a 100-mpg car (and I want it to look vintage)

[freebeard]

The big question is WHAT vintage car to chose... I'm actually planning to let my next car project be an extreme eco-vehicle, based on an old Saab 96

Sounds like a good choice, if you have one. No a fan of those offset cabs. How about center steer?

Instead of boat-tailing the too-fast cabin, how's about Bertone BAT inward canted tail fins?

I like the Beetle because the B-pillar is wider than the A-pillar (and I have one. ). The windshield header doesn't have sharp corners.

[Grant-53]

Was it SAAB that years ago recommended the optimum of 36 lb/hp? Power requirements increase as velocity is increased. The function is V cubed for air drag and V squared for weight.

[aerohead]

Apology if already mentioned.
Alex Tremulis ( Duesenberg, Cord, Tucker, FoMoCo ) designed and tested the X-100 Gyronaut for Subaru in the 1980s. At Ontario Motor Speedway, the car returned 100-mpg at 55-mph on the straightaways, and 80-mpg in the curves.
It has Cd 0.20, and projected frontal area of ten-square-feet, and around 600-pounds curb weight. I believe it was a 27-horsepower, Subaru Rex powertrain.

[freebeard]

Apologies, but I think the X-100 had twin Triumph engines. I saw it in downtown Wendover the year it was there.





The whole story is here. http://www.gyronautx1.co

[JulianEdgar]

Originally Posted by freebeard

Apologies, but I think the X-100 had twin Triumph engines. I saw it in downtown Wendover the year it was there.





The whole story is here. http://www.gyronautx1.co

Different car. Aerohead is referring to this - https://www.facebook.com/AlexTremuli...0497045988127/

[freebeard]

I inadvertently clicked on a Facebook page.

X-1? X-100? I'm only off by two orders of magnitude.

[rmay635703]

Modified Subaru 360 = 100mpg

https://www.carthrottle.com/post/VYpXf4/

[some_other_dave]

Any way you cut it, 100 MPG at 60 MPH steady-state is gonna be a tall order!

Vintage looks will make it even tougher, since almost all vintage cars have poor cD and even the ones with a decent cD have a pretty large frontal area.

This point has probably been made, but I'm way too lazy to read through 20 pages:
The recipe will probably require something very light weight and very aero, with rock-hard skinny tires and a tiny engine with a rather tall top gear that can just barely propel the car along at 60 MPH in top gear. Low RPM and 80% throttle opening, or WOT if you can disable WOT enrichment, will give you the most efficient power. Diesel might be a better answer since it doesn't really have a throttle restriction.

-soD

[racprops]

Originally Posted by some_other_dave

Any way you cut it, 100 MPG at 60 MPH steady-state is gonna be a tall order!

Vintage looks will make it even tougher, since almost all vintage cars have poor cD and even the ones with a decent cD have a pretty large frontal area.

This point has probably been made, but I'm way too lazy to read through 20 pages:
The recipe will probably require something very light weight and very aero, with rock-hard skinny tires and a tiny engine with a rather tall top gear that can just barely propel the car along at 60 MPH in top gear. Low RPM and 80% throttle opening, or WOT if you can disable WOT enrichment, will give you the most efficient power. Diesel might be a better answer since it doesn't really have a throttle restriction.

-soD

GOD GOD I hope not, after all such a car would be worthless as a everyday car..."require something very light weight and very aero, with rock-hard skinny tires and a tiny engine with a rather tall top gear that can just barely propel the car along at 60 MPH in top gear."

Heaven help you in any crash, and such tires would not be able to really stop a car not be driven in any weather other pure dry.

I still am a believer in Gasoline Vapor what about that?

Rich

[aerohead]

1) @ 100-mpg & 60-mph
2) we're talking 0.60-gallons / hour
3) @ 6.138 pounds per gallon, that's 3.6828-pounds / hour
4) with Regular Unleaded, E10, that's 111,836-Btu / gallon
5) or 67,101.6 Btu / hour available
6) and @ 2,542.58-Btu / hour per horsepower = 26.391146 Bhp
7) and behind an overdrive driveline, 24.27985-horsepower road load.
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8) @ 3.6828-pounds / hour divided by 26.391146 Bhp
9) that leaves a BSFC of 0.1395 pounds per brake horsepower-hour.
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10) there's no I.C.-engine known with a BSFC that low. Only an electric motor.
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11) If we took 0.36 BSFC as a reasonable minimum ( gasoline direct injection turbo Atkinson cycle )
12) The brake horsepower would have to drop to 9.408
13) That is going to require a small frontal area, very low drag, and low mass.
14) And some other dave's comment about a diesel engine is spot-on, as this was Volkswagen's solution for their XL1.