Aeromodability of a VW Bug?

[gtkid2002]

I hadn't thought of using a tractor engine. I'd probably have to get a custom adaptor plate, but that really might be something to consider.

Clev - According to the Aerocivic website,

In the summer on a level road the new engine gets 100 mpg at a steady 60 mph and 120 mpg at 40 mph.

And that's with the lean burn engine. I know there's a lot of differences between a new Honda engine and a VW bug engine, but hopefully the VW engine with a two cylinder fuel cutoff would work closely to the Honda engine.

[Joenavy85]

check out kennedy engineering, they make tons of adapters for the VW transaxles for different engines.

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[Frank Lee]

Originally Posted by gtkid2002

I know there's a lot of differences between a new Honda engine and a VW bug engine, but hopefully the VW engine with a two cylinder fuel cutoff would work closely to the Honda engine.

Whoa- what? If you've been around here at all you know that's a dead end.

Previously... lotsa numbers floating around that look like they came outta thin air... kinda pointless until you have a plan...

[Clev]

Originally Posted by Joenavy85

check out kennedy engineering, they make tons of adapters for the VW transaxles for different engines.

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That includes the diesel engines from the early Rabbits. Another option.

[euromodder]

Originally Posted by gtkid2002

Okay - wrote up some basic goals I want to hit for now.
Use a stock(ish) VW Bug chassis*
I want to hit 80mpg highway

Unlikely to ever happen with the regular thirsty VW Bug engines.

Don't forget Mike's Aerocivic is a lean-burn Honda, that he aeromodded to get and keep it in the lean-burn mode despite going faster.
He started out with a far more efficient engine than the Beetle.

* Bug chassis can be modified if needed, but not like chop the whole thing apart and just use parts of it. Although shortening it could be interesting too.

Shortening of the body will generally result in worse aerodynamics if width and height are kept the same.
Additionally, the short length will force you towards steeper angles while you want smooth curves.

The bulbous front isn't the real problem on a Beetle - it's the back.

[Joenavy85]

Originally Posted by euromodder

Additionally, the short length will force you towards steeper angles while you want smooth curves.

The bulbous front isn't the real problem on a Beetle - it's the back.

and that "hood"-windshield angle doesn't help much either.

i would say keep the stock body, chop the top a couple inches (not so low that you can't sit comfortably) and slant the windshield back by about 10 degrees

[Joenavy85]

Also, as far as swapping in a Diesel, depending on how much torque you're planning on having you may want to put a 1st gear lockout on the tranny, one of my dad's friends swapped a small block chevy into a Porsche 914 and the torque was enough to strip the teeth out in 1st gear (luckily it didn't damage much else and he was able to use the trans, after he took it apart and pulled the chunks out)

[Frank Lee]

Originally Posted by Joenavy85

and that "hood"-windshield angle doesn't help much either.

i would say keep the stock body, chop the top a couple inches (not so low that you can't sit comfortably) and slant the windshield back by about 10 degrees

And then what? Will the Cd be much better? Another dead end that just won't die... Chances are, the only improvment from those actions will come from frontal area reduction and it will still have +30 or even +35 Cd. The entire rest of the car, especially the rear, is still a disaster, except for the relatively smooth underpan and lack of forward compartment venting.

It is the windshield/roof transition angle that matters; if and only if there's a problem there that's solved by re-angling, will re-angling help.

[euromodder]

Originally Posted by Joenavy85

and that "hood"-windshield angle doesn't help much either.

Lifting up the rear of the hood so it's angled could relatively easily cure that - to some degree.

[gtkid2002]

Originally Posted by Frank Lee

Whoa- what? If you've been around here at all you know that's a dead end.

... Seriously? I'm on here but I guess I missed that one. I tried it with my Prelude, but I was never able to get a definitive result. I guess I'll search around and try and do some more reading before doing that again then.

Right now I'm more focused on the body than anything else. I know the engine plays a huge role as well, but for right now my concern is with the body. I was playing around with the idea of using a prowler style front end, but I think the distance between the front wheels and the chassis is too short. I am gonna try and do at least 3 revisions of the car if I have to (not the entire body though), but that way I can change engines and such.

But,
Joenavy - If I used one of those adapters, I would try and use an old diesel Rabbit engine. I don't think I'd need a first gear lockout with one of those because they're not super-powerful as far as I know. Having a hard time bringing up specs on one, go figure.