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

[sgtlethargic]

Originally Posted by JulianEdgar

And you've got the mechanical and electronics background to do that? Turbo selection; fabrication of the exhaust manifold, intake plumbing, intercooler plumbing; development of engine management, changing the fuel system and injectors - and so on?

Maybe I am pretty slow, but just turbocharging my Insight and fitting and mapping the engine management was, for me, a year-long project on its own.

And I have done turbo and electronics work on cars plenty of times before!

It won't necessarily be turbocharged, gasoline, nor EFI. My previous project was a propane turbo (non-EFI) 2.3 L Ford in a '61 Comet.

[sgtlethargic]

Originally Posted by freebeard

Thanks for not getting half done before asking for opinions.

Personally, I'd be most comfortable with a Beetle floorpan.

I know you like Bugs. If my brother would kick down the free Karmann Ghia he got 30 years ago ...

[freebeard]

They're modular. My son gave away the Ghia I bought for him when he needed a car [in 2012].

But, '61 Comet?

[JulianEdgar]

Originally Posted by sgtlethargic

It won't necessarily be turbocharged, gasoline, nor EFI. My previous project was a propane turbo (non-EFI) 2.3 L Ford in a '61 Comet.

Great!

(It was just that you said you wanted 'an efficient engine operating at its peak' and to get that, engine management is obligatory.)

[Tahoe_Hybrid]

Originally Posted by sgtlethargic

And I want it to look vintage.

100 mpg at 60 mph. What do you think it would take to accomplish this? Single-seater, center-steer, possibly mid-engine, probably a 4-cylinder.

I love the looks of the BOCruiser. And the Phantom Corsair. Hudson Hornets. This custom Metropolitan (they weigh 1750 pounds).

this

do forget to knit your self some seatbelts

[Ecky]

As mpg_numbers_guy said earlier, the Insight is a great point of reference. In stock form, using exreme LRR tires which sacrifice handling and traction, with the inflation pressure raised to 45+, and a few minor aero mods (partial grille block), the Insight is capable of 100mpg @ 50mph. As speed increases, that fuel economy drops significantly. I want to say that at 60mph, it's closer to 80mpg.

https://ecomodder.com/wiki/Vehicle_C...t_of_Drag_List

The Insight has a 0.25 drag coefficient (very low), a frontal area of ~20 sq ft (very low), and an engine whose peak thermal efficiency is just as good as the best from Toyota and Honda today (~40%) - albeit with a lower output than Toyota and Honda's current best.

My thinking is, you'll need an engine that is no less efficient than the Insight's, which is a very short list. You will also need to beat it in both coefficient of drag and frontal area. Diesel helps - the fuel contains ~15% more energy content, but you also usually pay more for it so it may not win in cost per mile.

If the goal is cost per mile per unit energy, going electric in an area with cheap electricity may be the easiest way to achieve this, but you have the upfront costs of the batteries.

From the Urban Centurion thread,

Originally Posted by changzuki

The original Centurion reported 128mpg@35mph.

^ While that's impressive, drag increases with the square of the speed. Using a simple drag calculator, the drag at 60mph is 3x higher than at 35mph, while the speed has only increased by 70%. Meaning that, if drag is the sole difference between MPG at the two speeds (RR and mechanical loss stay constant), that 128mpg @ 35mph might be 75mpg @ 60mph. Still very respectable, but the decently aerodynamic Centurion with its 37hp-at-the-flywheel engine is still well short of your target.

[sgtlethargic]

Originally Posted by Tahoe_Hybrid

this

do forget to knit your self some seatbelts

Is there hostility in this reply?

[freebeard]

Many 'do' was a typo and it's just incoherent otherwise?

[aerohead]

Originally Posted by sgtlethargic

And I want it to look vintage.

100 mpg at 60 mph. What do you think it would take to accomplish this? Single-seater, center-steer, possibly mid-engine, probably a 4-cylinder.

I love the looks of the BOCruiser. And the Phantom Corsair. Hudson Hornets. This custom Metropolitan (they weigh 1750 pounds).

See if you can find Doug Malewicki's 'California Commuter, or Alex Tremulis' Subaru X-100, both of the 1980s.
I abandoned my project simply considering how traffic behaved around me when on a motorcycle.
Americans are sociopaths by default. They won't follow at a safe distance and going up against a 3.5-ton projectile is more than I want to contemplate.
The guy who bought Three-Wheeler's 1st-gen Insight boat-tail is routinely seeing 80-mpg on the open road. And it's 5-star safety rated.
Pay attention to Julian's wisdom on this one! I've already lost a brother to an SUV. I don't want to hear about you.

[freebeard]

Pay attention to Julian's wisdom on this one! I've already lost a brother to an SUV. I don't want to hear about you.

That's a nice thought.

Build to pass a tech inspection at some race track, SCCA, NHRA, 24 Hrs of Lemons, etc.