EcoModder Forum VW Beetle TDI Kammback

Register Now
 Remember

Master EcoModder

Join Date: Jul 2010
Location: Belgium
Posts: 4,683

The SCUD - '15 Fiat Scudo L2
Thanks: 178
Thanked 649 Times in 514 Posts
Quote:
 Originally Posted by dieselbeetle I couldn't agree more, this would improve flow greatly. However, I ran into big problems because of the convex shape of the beetle's rear window. I'm mathematically perplexed.
If you look at the pic from behind, you'll see the top corners are near to or even outside the car's outline - that's where you could improve things a bit further.

If you loosen the connection between the vertical and horizontal panels at their corners, you can angle in the side panels.

If the curve gives a problem, make a straight score a bit above the curvature of the panel, and angle it in along that straight line.
The curve would still fit the rear window, and you get to angle in the sides.

The top panel will then automagically drop down towards the rear.
Don't make the top slope down too much - say 10-12 degrees - see if it's symmetrical left and right, fix temporarily, mark where the sides touch the top, and cut the top panels to shape.

__________________
Strayed to the Dark Diesel Side

 Today Popular topics Other popular topics in this forum...
Master EcoModder

Join Date: Jul 2010
Location: Belgium
Posts: 4,683

The SCUD - '15 Fiat Scudo L2
Thanks: 178
Thanked 649 Times in 514 Posts
Quote:
 Originally Posted by dieselbeetle I agree with you, there are a lot of variables at play here. However, I wholeheartedly achieved 55.4 miles per gallon with my kammback. No ifs, ands, or buts about it.
It's what you registered of course.
The only question is what the experimental error on that measurement is

The smaller the values you register (fuel quantity and miles driven) the higher the error will be.
The fuel pump cut-off will introduce the biggest - unknown - variable.

Quote:
 I did run into a problem concerning the theory of testing: So I guess what I mean is...with a scanguage, how do you know the moment is right to take a readout?
The instant readings don't get used.
The recording is started (i.e. SG trip is reset) at a fixed point along the route.
The reading taken is the recorded average, again read out at a fixed point along the route (say an exit sign).

Even then, as with any road-side testing, there'll always be errors due to conditions beyond the control of the tester or his equipment.
__________________
Strayed to the Dark Diesel Side

 05-02-2012, 05:56 PM #23 (permalink) This is the year   Join Date: Apr 2010 Location: Columbus, OH Posts: 36 Bug - '06 Volkswagen Beetle TDI PKG1 90 day: 37.04 mpg (US) F-350 - '11 Ford F-350 Lariat 90 day: 16.23 mpg (US) Thanks: 1 Thanked 2 Times in 2 Posts Any more recorded mileage done with this setup? __________________
 05-02-2012, 08:27 PM #24 (permalink) Easter McoModder     Join Date: Mar 2010 Location: West Texas, US Posts: 363 '99 Subaru OLL 2.5L - '99 Subaru Outback Legacy Limited 90 day: 22.57 mpg (US) Rabbit - '08 VW Rabbit S 90 day: 32.93 mpg (US) Thanks: 212 Thanked 28 Times in 26 Posts nope, sold it. I really only did the kammback for a school project. feel free to read the paper on my blog: blog
16 Ferret Circus

Join Date: May 2009
Location: Ecru, Mississippi
Posts: 95

GrumblyDavidson - '00 Harley Davidson Road King FLHRP-I
90 day: 38.37 mpg (US)

Golf - '04 Volkswagen Golf GL-TDI
90 day: 38.29 mpg (US)
Thanks: 11
Thanked 7 Times in 6 Posts
Quote:
 Originally Posted by SwamiSalami That's a good point. What I'd really like, though, is to have someone design a kammback and 3d print it!
I will help you get a 3d model ready for print if you can find someone to print it.
__________________

Ultimate Fail

Join Date: Feb 2008
Location: Austin,Texas
Posts: 3,344
Thanks: 2,694
Thanked 943 Times in 559 Posts
Quote:
 Originally Posted by SwamiSalami I couldn't agree more, this would improve flow greatly. However, I ran into big problems because of the convex shape of the beetle's rear window. I'm mathematically perplexed.
Quote:
 Originally Posted by Piwoslaw Spot the differences between the picture above and the one below: Answer: The sides are angled inward at the same angle that the top is sloped down. The teardrop we are after is a three-dimensional shape, not just 2D. When you work on the permanent version, try to get rid of the corners, like MetroMPG did:
Bingo !
I'm glad you mentioned this .
Very important to not only round off the edges, but taper the tail in the plan view and not just the side - just as you mentioned here .

 05-03-2012, 10:47 AM #27 (permalink) Easter McoModder     Join Date: Mar 2010 Location: West Texas, US Posts: 363 '99 Subaru OLL 2.5L - '99 Subaru Outback Legacy Limited 90 day: 22.57 mpg (US) Rabbit - '08 VW Rabbit S 90 day: 32.93 mpg (US) Thanks: 212 Thanked 28 Times in 26 Posts i LOVE that firefly and it's respective mods.
This is the year

Join Date: Apr 2010
Location: Columbus, OH
Posts: 36

Bug - '06 Volkswagen Beetle TDI PKG1
90 day: 37.04 mpg (US)

F-350 - '11 Ford F-350 Lariat
90 day: 16.23 mpg (US)
Thanks: 1
Thanked 2 Times in 2 Posts
Quote:
 Originally Posted by SwamiSalami nope, sold it. I really only did the kammback for a school project. feel free to read the paper on my blog: blog
I don't see anything related to the Beetle testing.

Why didn't you do any extended testing for a more thorough proveout?
__________________

 05-03-2012, 02:12 PM #29 (permalink) Easter McoModder     Join Date: Mar 2010 Location: West Texas, US Posts: 363 '99 Subaru OLL 2.5L - '99 Subaru Outback Legacy Limited 90 day: 22.57 mpg (US) Rabbit - '08 VW Rabbit S 90 day: 32.93 mpg (US) Thanks: 212 Thanked 28 Times in 26 Posts welllllll it was a humanities course... "ancient engineers" was the course. the project was to make something. (emphasis on the period.) i ran into some time constraints. really i would've liked to have done more in terms of testing, but i just didn't have the time (at the time). I was taking 5 classes and now i'm a stay-at-home-dad! living in korea and owning 1 vehicle that's an suv makes things harder now, too. for me, the project WAS about improvement, of course. the paper in itself was more about the history of such efficiencies and engineering feats. but, ultimately, it was about obtaining a big number, which i did! that beetle got pretty good mileage to begin with and i tracked it pretty avidly on another website, which is how i knew where to begin. i'm aware that my test wasn't as scientific as perhaps it should've been, which i guess i kind of regret, but hey, we live and we learn. and also to the scientific bit, i'm very well educated as to how scientific concepts work. I think at the time i did the experiment i was more excited than anything and very green in my understanding of aerodynamics and "ecomodding", if you will.
Easter McoModder

Join Date: Mar 2010
Location: West Texas, US
Posts: 363

'99 Subaru OLL 2.5L - '99 Subaru Outback Legacy Limited
90 day: 22.57 mpg (US)

Rabbit - '08 VW Rabbit S
90 day: 32.93 mpg (US)
Thanks: 212
Thanked 28 Times in 26 Posts
Quote:
 Originally Posted by bnmorgan I will help you get a 3d model ready for print if you can find someone to print it.
thanks, man. unfortunately, though...I don't own the beetle anymore. honestly, i can't say i'm all that sad about it. that car was very expensive to maintain and the interior was just completely falling apart. a great example of this was I went to visit my parents across country and my dad got in the car, pulled the door handle and it came off in his hand!

whoever the knucklehead was that owned the car before me really screwed up the interior (of course i probably didn't help matters much)

 Tags aerodynamics, kammback, new beetle, tdi, volkswagen