Long trip ahead, little prep time - best aero mod?

[NachtRitter]

Originally Posted by Cd

Metro : I noticed one of the guys here at Ecomodder that came to your GreenGrandPrix had a hunter green Jetta TDI the same generation as this car. I remember it because it had a white ABS " catfish whiskers " style airdam which covers the wheels from the front, but is open in the middle, thereby decreasing frontal area.
I can't locate the image, but I know some of you guys will know the car.

Ya, that makes sense. Direct the air around the front suspension and tires. The skid plate does a pretty good job of preventing the air flow from getting into the engine compartment. Would love to see the pic if you can find it!

[NachtRitter]

Ah, hitch mounted boat tail!
http://ecomodder.com/forum/showthrea...-3l-18044.html

Long(er) term goal...

[aerohead]

My SWAG is to modify the lower portion of the existing bumper fascia/airdam such that no air is directed under the nose at all,but rather to the sides and maybe up just a little.
When viewed from the side it would appear more like a rounded wedge,more like what NASCAR is doing,but without the splitter.
Then watch your driveway ramps 'n such.

[Sven7]

Originally Posted by NachtRitter

Partial kammback I'm not so sure about... I'd looked at this thread closely: http://ecomodder.com/forum/showthrea...etta-5976.html. Seemed like the flow tests showed little benefit for a partial kammback. Or at best it was inconclusive.

It would take you about a half hour to tuft the rear window and determine if there are gains to be had. CFD is great but it can't replicate the real world. I don't think he ever compared the models to the real world to verify the results... but then I didn't have the patience to browse through 25 pages of CFD

Go ahead and test it. You could set it up at night and look at the tufts on the way to work the next morning. Since it's on the glass you wouldn't even need a camera! Just remember which tufts showed separation.

[NachtRitter]

Ya, I see what you're saying... might be worth the effort though probably not something I'd want to spend 'trial & error' effort on during the one day I have to work on stuff... partial kammback is at the bottom of my list at the moment.

Based on the feedback, I'd probably prioritize the work in this order:
- rear (axle-back) undertray
- front 'contoured' air dam
- passenger mirror delete
- wheel skirts

If I have time / materials left, I'll look at:
- trip skirts (looks like they could be inside the taillights even)
- partial kammback (would need some verification time too)

Thanks for the great feedback!

[NachtRitter]

Originally Posted by MetroMPG

One or two days?

Oh, did you mean work time or travel time?

[MetroMPG]

Keep us posted! Even if they're going to be temporary mods, it'll be good to see what you do & find out your trip MPG at the end.

[NachtRitter]

Originally Posted by Cd

This isn't an aeromod, but I assume that you have already planned the trip using Google Earth.
As you of course know, you can plan for changes in elevation ( to seek out flat roads versus hills, or roads with lots of turns. ) and population density ( more chance of a slow down in traffic )
You might even find a shortcut which saves both time and fuel.

OK, figgered out the elevation part:


Looks like I ought to be able to EOC for pretty much the 2nd half of the trip...

Haven't played much with Google Earth for this kind of thing...

[Cd]

Originally Posted by NachtRitter

OK, figgered out the elevation part:


Looks like I ought to be able to EOC for pretty much the 2nd half of the trip...

Haven't played much with Google Earth for this kind of thing...

I was honestly about to reply to your previous comment about Google Earth .
Looks like you have it figured out .

I'll try to search for the image of the TDI Jetta I spoke of with the catfish style spoiler.
If I find it I will edit this post and attach it for you.

Edit : I looked for the image i was spoke about earlier, but could not find it.
Here is an example of what I'm talking about though : The sides cover the wheels, yet the air dam is trimmed in the center to reduce frontal area.



I haven't used the feature myself, but noted that others here have made reference to using Google Earth to measure even slight elevation changes when doing coast down testing.

[NachtRitter]

Thanks Cd! That's pretty much what I imagined when you described it... makes perfect sense!