50 mpg at 80 mph (project 2013 Golf TDI aero mods)

[cfd_guy]

Finished my initial test model. I am going to clean up the model a little and get it ready for cfd. I will post data when I finish the the initial run

[bitmap]

Since I have basicly the same car, hope I can share my underbody modifications here. I'm not trying to hijack thread or anything

I raised stock engine cover about 3cm (less frontal area and more air going under the car), removed central portion of stock "airdam", covered whole exhaust and rear axle and created something that resembles a diffuser.

For those wondering what car it is, it's a Skoda Octavia AKA Jetta Station Wagon with slightly different body

EDIT: I attached two pictures with my reply but I can't see them in the post.
Could someone help me with this, please?

[JasonG]

Originally Posted by COcyclist

cfd, I wish you luck on achieving your goal with your VW. I am working toward my personal goal of 70@70 but I am not there yet. I have done some extensive stealthy mods but I think I am about at my max unless I do more visible mods such as fender skirts and a boat tail. I have a full belly pan, inner and outer side skirts and a homemade diffuser underneath. I am closing in on 60 mpg but at about 60 mph.

Also, my wife's 2011 A3 TDI with DSG does not get as good mpg as my older TDI with the 5 speed manual transmission. I will be eager to see your mods. Good luck.

Just sold my 2003 JSW and bought a 2012 Jetta.
The 2012 Jetta is larger than a friends 2004 Passat.
Your wife's 2011 is much larger than your MKIV.

[freebeard]

EDIT: I attached two pictures with my reply but I can't see them in the post.
Could someone help me with this, please?

Are the pictures in a Ecomodder album, other online source or on your hard drive? Do the pictures appear in a Preview of the post? It should look like this, unobfuscated:

[I*M*G]http://i1291.photobucket.com/albums/b551/paul-hanchagroup/initial_assembly_zpsaa5fa056.jpg[/I*M*G]

—using cfd_guy's example.

[deejaaa]

wait with interest.

[COcyclist]

Originally Posted by JasonG

Your wife's 2011 is much larger than your MKIV.

Actually they are pretty similar. The A3 is the baby Audi here in the States. I took a tape measure to them both in the garage the other night and they are essentially the same width. The Audi is 2" lower roof height so less frontal area. The Audi is slightly longer but has better plan taper than the Golf.

I believe the biggest difference is the particulate filter/regeneration and increased use of EGR on the Audi affecting the mileage.

[PressEnter[]]

Good luck! I like to see what these TDI's are capable of, but for my part I'll just keep my speed down. I've seen averages around 60 mpg at 60 mph.

[JasonG]

Originally Posted by COcyclist

Actually they are pretty similar. The A3 is the baby Audi here in the States. I took a tape measure to them both in the garage the other night and they are essentially the same width. The Audi is 2" lower roof height so less frontal area. The Audi is slightly longer but has better plan taper than the Golf.

I believe the biggest difference is the particulate filter/regeneration and increased use of EGR on the Audi affecting the mileage.

So sorry, my mistake.
I was comparing mkiv jetta to mkvi jetta.
Completely missed that out was a3.

Anyone willing to share pictures of their diffusers ?

With a Malone stage 2, dpf delete and intake flappers delete I'm hearing of 6-9mpg increases......of course not on USA/EPA regulated roads