Rember the intake port texture debates?

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Post Reply
User avatar
bigblockmopar
New Member
New Member
Posts: 47
Joined: Fri Mar 25, 2016 8:53 pm
Location: Netherlands
Contact:

Re: Rember the intake port texture debates?

Post by bigblockmopar » Sun Oct 15, 2017 7:58 pm

The Radius Kid wrote:
Sun Oct 15, 2017 7:30 pm
Let's try this again.
Any thoughts on what might be happening here? https://www.youtube.com/watch?v=zl7jk85D2sE

You mean, besides the seamingly perfect streamlined belly @ 0:11 ?

User avatar
MadBill
Guru
Guru
Posts: 12614
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Rember the intake port texture debates?

Post by MadBill » Sun Oct 15, 2017 9:47 pm

Well for one thing, they've got the smoke wand in the wrong place when they're checking the front fender air extractors. They should be going into the wheel well to see how well they evacuate the area..
There's a ton of info to be had by watching where the smoke stream goes. For example, being at ~ 0° incidence to the ground, the un-cambered wings would appear to produce zero downforce, but from the smoke path it's clear the air is turning perhaps 10° down over the rear window, so the effective incidence is 10°, probably getting up near the stall point of such a basic airfoil.
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

The Radius Kid
Expert
Expert
Posts: 663
Joined: Mon May 28, 2012 6:46 pm

Re: Rember the intake port texture debates?

Post by The Radius Kid » Sun Oct 15, 2017 11:50 pm

I'm thinking around the 2:20 mark forward.I know if a dummy like me can see it...........
The Nazis didn't lose WWII,they just changed uniforms.Now they run the place.

User avatar
MadBill
Guru
Guru
Posts: 12614
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Rember the intake port texture debates?

Post by MadBill » Sun Oct 15, 2017 11:55 pm

I believe they're exploring the point at which the airflow down the rear glass detaches from the surface and forms vortices.
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

The Radius Kid
Expert
Expert
Posts: 663
Joined: Mon May 28, 2012 6:46 pm

Re: Rember the intake port texture debates?

Post by The Radius Kid » Mon Oct 16, 2017 12:57 am

Exactly Bill.It looks like the air is reversing back up the glass to try and fill the void.
The Nazis didn't lose WWII,they just changed uniforms.Now they run the place.

GARY C
Guru
Guru
Posts: 3335
Joined: Tue May 14, 2013 10:58 pm

Re: Rember the intake port texture debates?

Post by GARY C » Mon Oct 16, 2017 1:29 am

The Radius Kid wrote:
Mon Oct 16, 2017 12:57 am
Exactly Bill.It looks like the air is reversing back up the glass to try and fill the void.
I was wondering if that was due to the down force on the deck lid they were trying to create?
I also noticed the front end sits way in the air and wondered if it drops at speed due to down force?
If so I don't think they are getting correct readings without pulling the car down to ride height.

The Radius Kid
Expert
Expert
Posts: 663
Joined: Mon May 28, 2012 6:46 pm

Re: Rember the intake port texture debates?

Post by The Radius Kid » Mon Oct 16, 2017 2:31 am

GARY C wrote:
Mon Oct 16, 2017 1:29 am
The Radius Kid wrote:
Mon Oct 16, 2017 12:57 am
Exactly Bill.It looks like the air is reversing back up the glass to try and fill the void.
I was wondering if that was due to the down force on the deck lid they were trying to create?
I also noticed the front end sits way in the air and wondered if it drops at speed due to down force?
If so I don't think they are getting correct readings without pulling the car down to ride height.
To be honest Gary,the main thing i was focusing on was the back window part.
That reversing air got me thinking.
The Nazis didn't lose WWII,they just changed uniforms.Now they run the place.

User avatar
bigblockmopar
New Member
New Member
Posts: 47
Joined: Fri Mar 25, 2016 8:53 pm
Location: Netherlands
Contact:

Re: Rember the intake port texture debates?

Post by bigblockmopar » Mon Oct 16, 2017 7:30 am

Aside from the 'Daytona'-models, in '69 Dodge brought out their Charger 500-model, which had the rear window 'bulged' inline with the roof, compared to the regular Charger-model, where the rearwindow is recessed way back.

Image


The '71 Plymouth rearwindow angles down to steeply and is too flat for the airflow to stay attached.
I would think if Plymouth had actually brought out a '71 Nascar model, they would/should have mostlikely installed a more bulged window, like the pervious year's Superbirds had.

Cubic_Cleveland
Guru
Guru
Posts: 1107
Joined: Thu Feb 23, 2012 11:44 pm
Location: Australia

Re: Rember the intake port texture debates?

Post by Cubic_Cleveland » Fri Oct 20, 2017 1:55 am

The Radius Kid wrote:
Mon Oct 16, 2017 12:57 am
Exactly Bill.It looks like the air is reversing back up the glass to try and fill the void.
I wonder what would happen if vortex generators were attached to the roof in front of the rear screen? Would the flow stay more attached on the screen and not reverse :-k

User avatar
MadBill
Guru
Guru
Posts: 12614
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Rember the intake port texture debates?

Post by MadBill » Fri Oct 20, 2017 9:30 am

Like these? http://www.airtab.com/
I'll see if I can dig up the pix, but I fitted them along the back of the roof of a road race Merkur, initially on only one half, and put blobs of hand cleaner down the glass. The half with the tabs smeared the blobs down the slope; the other did not, clearing indicating that they 'steered' the air down the deck. At the time we didn't have the car well enough sorted to know if they helped and when it was repainted they were discarded.. :(
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

Cubic_Cleveland
Guru
Guru
Posts: 1107
Joined: Thu Feb 23, 2012 11:44 pm
Location: Australia

Re: Rember the intake port texture debates?

Post by Cubic_Cleveland » Sat Oct 21, 2017 7:55 am

MadBill wrote:
Fri Oct 20, 2017 9:30 am
Like these? http://www.airtab.com/
I'll see if I can dig up the pix, but I fitted them along the back of the roof of a road race Merkur, initially on only one half, and put blobs of hand cleaner down the glass. The half with the tabs smeared the blobs down the slope; the other did not, clearing indicating that they 'steered' the air down the deck. At the time we didn't have the car well enough sorted to know if they helped and when it was repainted they were discarded.. :(
Yes, either like those or the OEM Evo style : https://www.maperformance.com/products/ ... mz380295ex
Would be great to see some pictures, looking at getting some for my mx5. How steep is the Mercur rear screen? Did any of the blobs go up the screen?

User avatar
MadBill
Guru
Guru
Posts: 12614
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Rember the intake port texture debates?

Post by MadBill » Sat Oct 21, 2017 6:06 pm

Here's a couple of shots of them*. (and my patented 3D tuft test yarns, which also showed the re-direction of the flow.) *(They're manufactured about 2 hours away from me in Canada, but we had to buy them from Wisconsin. Go figure.. #-o .)

The blobs on the 'un-tabbed' side all stayed where they were placed, but on the side with the tabs the upper row moved down ~ 1", the second row ~1/2" and the lowest not at all.



Merkur Tuft Tests 001.JPG
Merkur Tuft Tests 003.JPG
You do not have the required permissions to view the files attached to this post.
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

Cubic_Cleveland
Guru
Guru
Posts: 1107
Joined: Thu Feb 23, 2012 11:44 pm
Location: Australia

Re: Rember the intake port texture debates?

Post by Cubic_Cleveland » Mon Oct 23, 2017 2:13 am

Thanks for the pics and explanation Bill, love the low tech aero rake too!! Where should I send the licence fee when I steal your idea? :lol:

User avatar
MadBill
Guru
Guru
Posts: 12614
Joined: Tue Nov 15, 2005 10:41 am
Location: The Great White North

Re: Rember the intake port texture debates?

Post by MadBill » Mon Oct 23, 2017 10:01 pm

The Wright Stuff Home for Former Flyers in Dayton, Ohio would be happy to accept any contributions... :D
Felix, qui potuit rerum cognscere causas.

Happy is he who can discover the cause of things.

Post Reply