Miura, a lightweight aerodynamic body over a Volkswagen frame
 

https://fbcdn-sphotos-c-a.akamaihd.n...52155917_n.jpg
Look how low it is compared to an Opel Corsa C.
https://fbcdn-sphotos-b-a.akamaihd.n...75190082_n.jpg
And has a nice Kammback.
https://fbcdn-sphotos-h-a.akamaihd.n...45652270_n.jpg

It was made in my hometown from '77 to '85, using the Volkswagen platform, as usual with many artesanal Brazilian fiberglass-bodied cars from the 70s and 80s when imports were extremely restricted.

Vw beetle?

Those side scoops seem to be the only source for cooling the air-cooled engine.

Compare to a Type-2 wagon.

OLD PARKED CARS: 1970 Volkswagen 1500 Squareback Wagon.
http://3.bp.blogspot.com/_TsdjySqKQl...agon.++-+2.jpg

I do not think it would have a cooling problem after all (white car, not orange car).

Looks to be fairly aerodynamic outside of vortexes forming at the rear corners.

Gotta love those old VW Beetle based kit cars.

Shame the boxer is such a gas guzzler, could do for a nice looking efficient ride ...

As I understand it the boxer layout is lower in low end torque than lets say a "V", and harmonic vibrations cancel each other out.

I owned a 1976 Super Beetle which got good gas mileage, and currently own a 1977 Porsche 911 which gets 26 mpg hwy - not bad for a 0-60 in seven seconds car (and boxer layout).

Are you sure you are not thinking of a Rotary (Wankel) engine, renault_megane_dci?

I red here and there that the VW flat four is no good for FE, is it the Beetl aerodynamic or the engine itself I don't know.

Thing is in standard trim they have a very low CR being air cooled, at the back of the car and dedicated to burn pretty much anything.
This alone does not help FE

That's because it's an ancient engine design.

Properly designed, boxers can be efficient.
But as most of the boxer designs end up in sporty or sports cars, the engines usually aren't designed for highest FE.

The aero of the OP seems to be exactly backward? Turn it around, and it would be much better.

It does look like it would be fairly aerodynamic backwards too.

Subaru's uses boxer layouts on their engines. I believe the reason they don't get great fuel mileage is because they are AWD.

Air-cooled VW Beetle engine, pre-WWII technology for the most part. Not a modern engine example to be sure.

I am not throwing stones to the boxer design for engines, I was saying the vehicle shown can difficultly be made to be some FE champion since it is using the VW flat 4 engine and FE is not one of the strong points of these engines.

One of the benefits of boxer engines is the low center of gravity, but working on them is difficult. I needed to remove a few other parts to change my spark plugs.

There is a definite mileage hit with all-wheel drive, although the 2,014 Forester is rated 32 highway.

That was then, this is now.
Subarugears
http://ecomodder.com/forum/member-fr...592-951771.jpg
kach22i -- The Type III cooling is superior to the Beetle, but mine always ran hot with those big honkin' Webers.

You could incrementally improve the boxer with MSD ignition and Claude's Buggies fuel injectors; but IMHO the big returns would be as a base for a Scuderi Split-cycle conversion. Compressed air hybrid, here we come!

http://upload.wikimedia.org/wikipedi...ne_-_Cycle.gif

Those Miura (Lamborghini knock-off?) vents are innies, like the Vanagon.

That Subaru tranny setup would be perfect for me to fit 4WD into a Kombi :thumbup:

Regarding the VW air-cooled engine, altough it's old tech I still like it, mostly for being boxer, air-cooled and featuring a gear-driven valvetrain with no timing chain or belt to fail, no wonder there are still some light aircraft engines with a similar layout. And there is still room for improvement while keeping its basic concept.

I've mentioned this before elsewhere but it bears repeating here:

http://www.cbperformance.com/Articles.asp?ID=312

That's pretty far along in a series of articles from Hot VWs Magazine on how to squeeze good mileage out of a Beetle.

The first thing they did was give the whole car a good chassis tune. That picked up about 7mpg right there, jumped from 22 to 29mpg if I recall.

In the referred article they were averaging over 36mpg in busy, high-speed California traffic. 70-year-old design or not, that's pretty good no matter how you slice it. Add in the fact that they enjoyed a big jump in power and torque for a significant improvement in driveability and I don't see a downside.

The stated goal was to achieve 40mpg in traffic, which they never did though they were getting close. And ultimately the articles just sort of stopped, like everybody lost interest. I don't remember there being a final wrap-up, which is too bad. That could have included a final What Works vs. What Sucks chart, which would have been really great for people in the VW community.

Right, it's CB Performance nowadays. It was a great series, built on John Karcey's specs, but HVW is driven by their advertisers. :( And they never touched the aerodynamics of the test car. :mad:

Here's a discussion on theSamba.com on the Karcey specs, cam timing & etc. It discusses the Mankato 2-cylinder car, and includes this tidbit:
[Copy]cRiPpLe_rOoStEr[Paste] -- Agreed. How about Subaru AWD in this?
http://ecomodder.com/forum/member-fr...1373422495.jpg

Weird. When I hear Miura, I think of this:
http://static.cargurus.com/images/si...-pic-4504.jpeg
Which first came about in the 60's...

It's not really impossible to set a Beetle to achieve 50MPG in highway just with engine mods and the higher differential gears of the SP2 (another Brazilian sports car assembled with the Volkswagen platform, but with a steel body and made by Volkswagen itself), but it would be too optimistic to expect that in city traffic without a major aerodynamic job.

I can't find it.

I would swear on a stack of Bibles that I read the builders had found a NOS "highway helper" wing - no, I'm not confused with the "freeway flyer" tranny - that improved cooling and aero. I keep looking back through the articles, I just can't find it.

And I was wrong about the initial mileage, too. The original Type 3 whistled up 28, it got 29.9 with a chassis tune.

Hey, CR: my favorite VW-based sports car: the Puma.
http://carphotos.cardomain.com/ride_...0001_large.jpg

Not the convertible, though. The proportions get weird in a hurry.

I got to see one in person a few years ago at the Ypsilanti Orphan Car Show in Michigan a couple of years ago. A very satisfying design.

Look for "Herrod helper". I'm pretty sure there is at least one post about it here on this forum.

-soD

Is that a Brazilian fiberglass kit car? I was in Rio about 35 years ago, saw one, and loved it. Made inquiries about importing it to the US. Is it a VW based design? Anybody import kits or make them here?

IIRC, not a kit. The Puma was a factory rebody, a native Brazilian project. Brazil's economy was closed to foreign-built vehicles, so the only vehicles for sale were those built locally. That left only VW and I think GM and AMC? Not sure about that last one, that might have been Mexico.

Anyway, Puma used VW chassis but built their own stylish fiberglass bodies to go over the mechanicals. They offered a few different things including a larger coupe with a Chevy six-pot mill under the hood, the usual VW aircooled four-banger out back, and I'm not sure what else. I've heard mention of a truck but never thought to go look at it.

(pause) Okay, I went to look at it. It resembles a contemporary VW medium-duty cabover. No big deal.

So while it isn't precisely factory - Puma didn't do the mechanicals or running gear - it isn't a kit either. The fit and finish were better than your typical backyard mechanic (that said, I've seen some gloriously detailed kit cars) and there was plenty of aftermarket support. And like I said, of the assorted things that have been draped over VW underpinnings, this one is nicely proportioned and looks good from most angles.

If I had my druthers, a lowered Puma car with Subaru flat 6 would be the ticket, with covered headlights and smoother windshield trim.

I'll just leave this here, then....

TheSamba.com :: VW Classifieds - 1977 Puma Gte - Strong Runner

-soD

The Puma is nice too, and is still available in South Africa, altough made by a different company, and IIRC it's also available there as a kit-car. There was also an older FWD Puma made with a DKW frame, the Puma GT Malzoni. I've seen one in my hometown a few times but never had the chance to take some pictures of it. The bigger, Chevrolet-based one, is the GTB, which uses a dedicated frame and looks quite like a Camaro.

I can't make my mind around that, the inlet phase of the power cylinder is so bloody short, even with compressed (heated up along the way and loaded with some oil) air, you can't fill the cylinder that fast !

That would get you awfully close to an Acura NSX, esp. if you made necessary modifications to move the engine to mid- instead of rear-mount configuration.

I've seen a convertible version in person too, also handsome from all angles.

View topic - Michigan Vintage Volkswagen Festival - 2011
More from my photobucket album:
http://s184.photobucket.com/user/kac...?sort=3&page=1
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http://i184.photobucket.com/albums/x...w/DSCF1077.jpg
http://i184.photobucket.com/albums/x...w/DSCF1079.jpg
http://i184.photobucket.com/albums/x...w/DSCF1080.jpg

In the 1970s, what I wanted was the Amanté. It is very similar:
http://ecomodder.com/forum/member-fr...43-index2b.jpg
_____

renault_megane_dci -- If there is a running engine based on this principle, it's kept pretty well under wraps. :)

OTOH I don't know if you can trust an animated GIF for the timing information. I just noticed the compression cylinder doesn't show an exhaust valve.

The complete design has a compressed air-hybrid mode where there is a big air tank available to the interconnect passage. It can be fed from the compression side, or used to drive one side or the other in air mode.

They also talk about an intercooler in the interconnect passage. While I can see a tank, it's hard to imagine an intercooler that could withstand the peak cylinder pressure/volume. Maybe a carbon fiber tank with aluminum fins strapped to it and a shrouded cooling fan?

The inlet phase unfortunately has to be short because it fires right after !
The only way it could be done is with very much compressed air and even then the valve event needs to be short.

And what is more, how the engine is throttled, I can't figure it out either.

The conclusion is tough, I am not smart enough ...

Look at it this way—neither is Scuderi. :)

It looks plausible to me, did you read the whole wikipedia article? Generally, the air compressed in one compression cycle is not necessarily used in the corresponding ignition cycle. As for the valve timing, not much compression takes place in the lower part of the cycle it's mostly in the upper part anyway, the compression cylinder is oversized compared to the ignition cylinder, and valve lift, timing and size can all be tailored to the requirement.

All IMHO of course, standard disclaimers apply.

Now I understand my mistake, I was trying to read the concept through adaptation on an existing engine which means identical capacity.

Anyway, there is more potential if you start from a diesel since this inlet valve event is happening at the beginning of the power stroke when you also inject fuel.

What's the residual pressure at the end of a standard exhaust stroke ?

And yes I did read the Wikipedia article.

The more I think about it, the least I can figure out how to squeeze induction and this ATDC spark.

I don't know. Equal to ambient? I'm more curious about the peak pressure in the interconnect passage.

Thanks for bringing up diesels. cRiPpLe_rOoStEr probably wants his thread back.

That uncle of mine who had a Simca 8 traded it for.. guess what.. a front-engined Miura X8. Pics to come soon. It looks like a Mazda RX-7 from the 80s, but uses the same driveline of the Volkswagen Santana, which was known in the U.S. as Volkswagen Quantum (back here, only the Santana wagon was known as Quantum).