GasPods

mohawk69

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Susanne, there have been many questions asked here that are deflected if they ask for some form of proof. If he shows up he'll get a lot of questions if the scientifically minded here haven't abandoned the thread. Heres one that comes to mind though. How many different pod placements were tried before the one used in the fluid dynamics test was used?
 

AeroHance

(Susanne) Vendor , w/Business number
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No one has yet asked me that question. Are you asking how many placements were tried on vehicles or CFD, or both?

The answer is many, both on vehicles and multiple placements with CFD analysis were run as well. Not quite in the order you suggest.
 

AeroHance

(Susanne) Vendor , w/Business number
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That was already answered in the preceding thread. And, there is a proposal still pending before the administrators. Now that we're in the vendor forum, there is probably a little more latitude in how this is handled, but I'll have to check on that.
sorry but that is just not true. there are those here whom have offered to test your product whose conclusions i would trust, have any of them been given your product to test?

waltz - you don't mind if I shortcut your name? Let me restate my answer, as quite a few test team registrations came in over the weekend from TDI owners, there could be some of your trusted friends here. We'll have to wait and see the results from those who choose to share, along with Diesl. Thanks to those of you who came in from this thread. We look forward to your posting your results :)
 

Diesl

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My testing will take three months - so don't hold your breath.

Susanne, I would be interested in learning more about the results of the Golf computer simulation. For example the lift or down force at the rear of the vehicle without and with pods. Also interesting would be a pressure map or profile behind the rear window. Either a map on an up-down/forward-backward vertical plane extending from the rear of the car, or just a profile along a horizontal line extending backwards from the center of the rear window. Both without and with pods. Or just the total resulting force vector on the rear window without and with pods.
Maybe you can get permission to post excerpts from the CFD report?

Also, let me repeat my suggestion to have somebody in your company who is not afraid of Excel or Google Sheets run some basic statistical analysis on the incoming data.
 

waltzconmigo

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Susanne---I have no problem with the use of waltz or anything else. I have never (knowingly) met any member of Tdiclub in person but there are many here whose opinion's I respect. I guess I just find it a little "funny" that a member here seems to have done more mathematical analysis of your product than you have. I am interested to see the conclusions that Diesl comes to but also find it "funny" that his "pods" came from another member to test and not from your company itself.

I wish a Mod would chime in here and give everyone some guidance on what is/is not allowed in the vendor section. I hope to not be breaking any rules but feel like we may be coming very close to some "line" and this why I think the other thread should be reopened.
 

darkscout

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Oh boy. I'm only 1/2 way through this thread and having worked in both Engineering and Marketing (as "the" engineer) it's quite entertaining watching people talk past each other.

Marketing people, please talk to an engineer before answering questions directed towards engineers.

I need to go for a bike ride but I will do the reverse calculation for theoretical effect on fuel consumption.
 

Diesl

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It definitely is entertaining, and I hope everybody is keeping their humor about it.
Darkscout, Waltz, part of the problem -or misunderstanding, really- might be that Aerohance International Incorporated is much bigger in our imagination than in reality. All we know so far is that there is Susanne, who is suffering through this thread, and Bob. Maybe Bob doesn't like talking to people on the internet all that much. It's a fair guess that this thread is going to do nothing to change that. Besides, from what I've heard, Bob is an industrial designer, not an engineer.

What I've also learnt so far is that if you have a Golf it's a fairly safe bet that you are going to save some fuel with this device, unless you are puttering around mostly at 30mph. Is this the first thing you should invest in if you are looking for fuel mileage improvement? Certainly not. Upping your tire pressure and not driving like a maniac (aka looking ahead) are cheaper and will also buy you a few percent each. After that, your choices are to glue some paper maché bumps to your roof ( or worse: google kammback) , or, if you or somebody in your life cares about what your car looks like (or you ever plan on going on a second date), buy something like these gizmos.

If you don't drive a Golf, it's a bit tougher. You can try to sift through the reports on the Aerohance website, or go by gut feeling (similar rear shape is probably a good indicator). It would be in Aerohance's best interest to change that, but maybe there just is no engineer. Or maybe the stuff sells just fine. (Of course it always could sell better.) I still think they should try to find somebody (doesn't have to be an engineer, a niece or nephew or neighbor who hasn't flunked math is all they need) to sift through their incoming data.
Oh well. If it were me, maybe I'd decide that arguing with people on this website is just not a good investment of my time. Except for the entertainment factor.
 
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AeroHance

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Snip
Oh well. If it were me, maybe I'd decide that arguing with people on this website is just not a good investment of my time. Except for the entertainment factor.
Or maybe I"m just traveling and won't have time to do but quick responses until after I get back and catch up. Do try to keep it germane to the topic. The Bob Evans Restaurants pieces are a bit off topic. Although we have provided their management with corporate gifts of "Bob Evans" genre, it really does not mean much to those viewing this thread, and you all are talking to more than me here. I'll be back soon. Until then have fun!
 
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darkscout

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Hello Computer.
Just use the keyboard.
*Cracks Knuckles*
Like I said, I've worked in engineering. I've also worked in marketing. There's massaging data and then there's seedy "happy ending" massaging of the data.
First. Some math.
Lets use your provided Cd numbers. With a frontal area of 1.910 m^2 (number I found online)
Lets just punch in some stuff. Everything is metric until the end, the original version of the spreadsheet looks like this. Then I punched it into Matlab to do some napkin calculations.
First lets estimate the parasitic load. That's drivetrain losses, AC, alternator, pumping losses. It's a really complicated function of speed, load and ambient conditions. For simplicity sake it's going to be summed up into a single number:
0W Parasitic Load, this is a bit unreasonable:
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5000W Parasitic load. This gets at least a bit better looking.

10,000W Parasitic load. Closer.

15,000W. ~26 HP. Parasitic load. This looks good. ~55 MPG at 100 kph. 65 MPG at ideal conditions around 65 kph.

20,000W. This is a bit too far. So from here on out lets use 15kW.

I can do pretty graphs too. One line is your "Before" Cd, one is your "After".

I'll get to some more analysis in the morning. (Hint, claims aren't looking good).
 

Diesl

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Before I forget, the C_v for the Sportwagon is apparently a bit lower than that of the Golf: (from http://www.netcarshow.com/volkswagen/2008-golf_variant/
"Typical Volkswagen design characteristics, analogous to those of the Passat Variant, are the rear window that wraps around to the D pillars (also an indicator of large load width) and the roof edge spoiler that acts as a trailing edge to optimize aerodynamics (increased tread pressure, better fuel economy). Air resistance coefficient: cW = 0.31. "
This (which sounds like its copied straight from a VW advertisement/press release) fuels my suspicion that at racetrack/Autobahn speeds the gaspods might lighten the rear end a bit. (According to the same source, the car is apparently good for 210 km/h; that's just over 130 mph. Now I feel bad for my car, eternally condemned to puttering around on U.S. highways...)

Darkscout, thanks for getting those numbers together. No need for all those F-bombs though. That parasitic loss is a constant only for a given speed (140 km/h), and otherwise proportional to speed, I assume?

In other news, I finished my first tank with pods, and am now again pod-less (for one tank).
 

AeroHance

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OK - I'm back online - Where did I leave off... oh, here:

I would guess (and Aerohance/Susanne should chime in if they have that information from the computer simulations) that adding the pods increases lift at the rear (reduces downforce). This probably doesn't matter at our speeds, but at 100 mph and beyond it might.
I'll pull out the studies to answer your later request. A little overwhelming, but I can say about this one is that one of our first clients, and a repeat client at that, was from McLaren. - susanne
 

AeroHance

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Darkscout - I'm not an engineer, but I am good enough at math not to switch columns, and I'm good enough at copy writing not to change "consumption" with "efficiency." When corrected your conclusions match ours.... the CFD on Golf predicts a 4.8% reduction in fuel, which is less than the numbers that you calculated.
 

AeroHance

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Diesl, I'll deal with your request regarding rear pressure, and see if I can pull any half/side views of flow, I think that would respond to it, as soon as I finish with completing statistical analysis of some fleet results that just came in. 8 vehicles without and with GasPods, 4 without throughout the term of the test. They are all Dodge Vans.
 
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Diesl

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study in progress

Just a quick update: I'm 40% done (two of five pod on/pod off sequences) with my gaspod test. So far no obvious trend jumps out. Remember that I'm placing the pods pretty close to the rear roof end for this. Of course it's too early for conclusions. This plot shows the single tank data.
As usual, I'm throwing out tanks with a significantly different driving pattern (defined as 'whenever I go on a business trip').
 

DieselBruce

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Just a quick update: I'm 40% done (two of five pod on/pod off sequences) with my gaspod test. So far no obvious trend jumps out. Remember that I'm placing the pods pretty close to the rear roof end for this. Of course it's too early for conclusions. This plot shows the single tank data.
As usual, I'm throwing out tanks with a significantly different driving pattern (defined as 'whenever I go on a business trip').
This is on your '12 Jetta wagon correct?
 

AeroHance

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This plot shows the single tank data.
As usual, I'm throwing out tanks with a significantly different driving pattern (defined as 'whenever I go on a business trip').
Can you post a picture with placement? Recommended on a station wagon is 7"-10" forward of the rear roof end, unless you have a spoiler.
 

AeroHance

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As usual, I'm throwing out tanks with a significantly different driving pattern (defined as 'whenever I go on a business trip').
At the end, can you show plot with all data?
 

burpod

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you live in one of the most beautiful cities in the US. and hock gaspods. ugh :( what did i do wrong in life....
 

AeroHance

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you live in one of the most beautiful cities in the US. and hock gaspods. ugh :( what did i do wrong in life....
Burpod - Just finished a swim, in our Olympic size outdoor city pool, watching the sunrise over the Pacific Ocean. That is the way we start everyday. Not to gloat, but it is quite beautiful in Santa Barbara.
 

Diesl

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Hi Susanne, I thought I already posted pics. Apparently not...
I put the pods closer to the end of the roof. If this test leads nowhere, I'll run a second one with the pods further forward.
 

burpod

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Burpod - Just finished a swim, in our Olympic size outdoor city pool, watching the sunrise over the Pacific Ocean. That is the way we start everyday. Not to gloat, but it is quite beautiful in Santa Barbara.
ha. i know. i've been there before years ago... it's a beautiful place. sigh :(
 

Windex

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Burpod - Just finished a swim, in our Olympic size outdoor city pool, watching the sunrise over the Pacific Ocean. That is the way we start everyday. Not to gloat, but it is quite beautiful in Santa Barbara.
The sun doesn't rise over the Pacific, not in Santa Barbara anyway.

That's OK, we've come to expect embellishment more than substance in this thread.

Edit - Well, I'll be blasted - There is a section of SB that extends south down into the pacific, and the Los Banos Del Mar pool will allow one to watch a sunrise, on the west coast over the Pacific.

I stand corrected, at lease on the sunrise.
 
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burpod

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The sun doesn't rise over the Pacific.

That's OK, we've come to expect embellishment more than substance in this thread.
rofl. i didn't think of that. however, the sky opposite of the sunrise is still quite nice.... here on cape cod the sun rises on the atlantic ;)
 

AeroHance

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Edit - Well, I'll be blasted - There is a section of SB that extends south down into the pacific, and the Los Banos Del Mar pool will allow one to watch a sunrise, on the west coast over the Pacific.

I stand corrected, at lease on the sunrise.
When you stand on the end of Stearns Wharf, and look out over the Pacific what is the first land mass you'll hit, after passing the California Channel Islands?
 

AeroHance

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Hi Susanne, I thought I already posted pics. Apparently not...
I put the pods closer to the end of the roof. If this test leads nowhere, I'll run a second one with the pods further forward.
With our volvo station wagon, which is, of course, boxier than your jetta, we saw little when the GasPods were placed as you have Diesl. Optimum placement turned out to be in front of the hatch cover seam - or between 7"-10" forward of the rear edge. Here is a picture of a Golf (staying germane to the forum) with recommended placement:
 

Diesl

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After finishing the third pod run, and the reference run, I moved the pods a bit forward across the roof/hatch gap. Their rear edge is about 8" from the rear end of the roof (hatch cover).
 

mohawk69

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Diesl, your pods are facing in toward the center of the hatch. For better or worse, how does that reflect in your numbers? Certainly it's not a uniform test since even the test mule
"devices" are installed differently.
 
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