Air Flow Seperation Question... (where to mount roof VG's on Nissan Cube)

[ChopsQube]

I just got in my VG's for my Cube. I know where they mount and how they mount on a regular car, but what about on a box like my Cube, xB, Element, etc, etc...?

I'm not holding my breath on how much these will help if at all, but I at least want to install them in the proper location.

Any ideas, suggestions? Many thanks in advance!

[DonR]

If you are unsure, I would consult the manufacture of the devices.

That being said, I would guess, guess they should go in front of the trailing edge that you are trying to minimize airflow seperation over. The distance in front of that edge & the spacing, I would assume to the the same as on a regular car.

Hope they work for you.

Don

[cfg83]

ChopsQube -

Originally Posted by ChopsQube

I just got in my VG's for my Cube. I know where they mount and how they mount on a regular car, but what about on a box like my Cube, xB, Element, etc, etc...?

I'm not holding my breath on how much these will help if at all, but I at least want to install them in the proper location.

Any ideas, suggestions? Many thanks in advance!

Did the VG's come with instructions or did you make them yourself? You can see instructions for the airtab gizmos at airtabs.com :

http://www.airtab.com/vm/newvisual/a...tallV78pdf.pdf

This is product-specific, but maybe it will provide some hints.

There is also the famous Evo-Article, but EVO VG's are intended to reattach flow from the roof of a sedan to a monster Evo-spoiler.

CarloSW2

[Bicycle Bob]

I don't see any surfaces there on which attached flow could be restored by VGs. I'd leave them in the box, unless some model-specific wind tunnel testing has pinpointed some quirks.

[ChopsQube]

Originally Posted by DonR

If you are unsure, I would consult the manufacture of the devices.

That being said, I would guess, guess they should go in front of the trailing edge that you are trying to minimize airflow seperation over. The distance in front of that edge & the spacing, I would assume to the the same as on a regular car.

Hope they work for you.

Don

That's what I'm thinking too, just the normal location like on most vehicles. Thanks!

Originally Posted by cfg83

ChopsQube -
Did the VG's come with instructions or did you make them yourself? You can see instructions for the airtab gizmos at airtabs.com :

http://www.airtab.com/vm/newvisual/a...tallV78pdf.pdf

CarloSW2

I didn't make them, they are made by Vortekz and come with instructions. However, nowhere online can I find anything about mounting them on a car like mine or an xB, etc, etc where the rear window just drops almost perfectly vertical.

[ChopsQube]

Originally Posted by Bicycle Bob

I don't see any surfaces there on which attached flow could be restored by VGs. I'd leave them in the box, unless some model-specific wind tunnel testing has pinpointed some quirks.

I'm not wanting to use them to reattach air flow to the rear of my car, but to reduce the amount of vacuum (drag) at the rear.

[RobertSmalls]

MetroMPG did a very thourough study on a Pontiac Montana, which is almost the same shape as the Cube. You can check out his placement and results here:

Tested: Airtabs on a mini van, A-B-A - no measurable effect

So don't put them where he did.

[ChopsQube]

Yeah, I've seen that thread, but those are Air Tabs, mainly meant for big rigs and box trucks.

[ChazInMT]

Chops....You're under the common misconception that there is something you can do about the "Vacuum" behind your cube shaped mode of transport. Well, All vehicles have to deal with this, and it has to do with the overall cross section your car presents. The difference between an aero shape, and one which isn't, has to do largely with how this air is managed after it makes it past the "Fattest" part of the car. More aero shapes tend to come together gradually after this fat part thus allowing the air to make a gradual transition to what it was doing before you violated it by ramming through it at high speed.

So bottom line, your Cube creation does very little to ease this transition. Any thing the air tabs may do to "Break the Vacuum" will be more than off set by the drag created in producing the effect.

Air tabs may have some effect on Very specific automobile shapes, these shapes would be ones which the flow separation occurs due to the rear slope of the vehicle being just a bit too much for the flow to remain attached. These vehicles are not common, and your Cube is clearly far outside this group.

You have a wicked cool car though which is maximized for interior space for the size that it is. Enjoy it just the same.

[NeilBlanchard]

AirTabs hurt my FE, on my Scion xA. I put them on the rear top and sides. I would not waste your time.