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Diffuser Porn


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#1 Magoo

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Posted 05 June 2013 - 18:01

Look at the size of these ones.



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The blue one is the front-engine Mustang IMSA GTP car of circa 1983-84, while the raw black one is its mid-engined Mustang Probe counterpart. Both were encountered yesterday during a visit to Jack Roush's private car collection in Livonia. More photos from the visit here...

A Visit to the Jack Roush Collection | Mac's Motor City Garage.com


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#2 Greg Locock

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Posted 05 June 2013 - 22:40

The divergence angle in the top one is way more than 7 degrees, any aero opinions?

Mind you I am reminded of the saying if it's stupid and it works it's not stupid.

#3 MatsNorway

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Posted 06 June 2013 - 08:38

It is also opens up to the sides. One could consider it the equal of one with straight sides but with greater angle.





#4 Scotracer

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Posted 06 June 2013 - 15:56

The divergence angle in the top one is way more than 7 degrees, any aero opinions?

Mind you I am reminded of the saying if it's stupid and it works it's not stupid.


F1 diffusers are also greater than 7 degrees. It's all about how you energise the boundary layer on the upper surface of the diffuser to keep it attached.


#5 MatsNorway

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Posted 06 June 2013 - 16:40

Some air from the engine bay helps. But nothing like the clean overside like a F1 car got.

Edited by MatsNorway, 06 June 2013 - 16:41.


#6 JimboJones

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Posted 06 June 2013 - 20:12

The divergence angle in the top one is way more than 7 degrees, any aero opinions?

Mind you I am reminded of the saying if it's stupid and it works it's not stupid.


What's stupid is thinking 7degrees has any relevance to generating downforce on a racing car

#7 Greg Locock

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Posted 06 June 2013 - 20:49

What's stupid is thinking 7degrees has any relevance to generating downforce on a racing car

yes, apparently vortex management needs a whole new attitude to diffuser design, and I'd ignored the rear wing's effect on the diffuser as well. Flicking through Katz I see that 14 degrees is a typical upper limit for the experiments there, although the CL is still increasing even at that value.

#8 carlt

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Posted 07 June 2013 - 16:34

Both were encountered yesterday during a visit to Jack Roush's private car collection in Livonia. More photos from the visit here...


The Cunningham prototype looks really cool -
very Aston-esque

#9 Fat Boy

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Posted 07 June 2013 - 20:19

I love GTP car tunnels. Massive things.

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The 7 deg. thing is really a non-starter. For the most part, you just stick as much tunnel on the car as possible. Yes, your efficiency drops, but it's still better than the next best thing, so you for for it. It's basically a function of packaging or the rules.

#10 Magoo

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Posted 10 June 2013 - 12:48

I love GTP car tunnels. Massive things.


I like big ground-effect tunnels and I cannot lie.


#11 munks

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Posted 10 June 2013 - 14:44

I must say, you really could run with just about any crowd.

#12 MatsNorway

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Posted 10 June 2013 - 15:53

How about this one.

NSX from last years Pikes peak. (NSX in a lose term) Hes making a new car now who is lighter and has a LS something engine.
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Edited by MatsNorway, 10 June 2013 - 15:53.


#13 Henri Greuter

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Posted 23 June 2013 - 09:32


I can't post pictures and I have given up on learning how to.
But in 1999 I was in the museum at Bedford where I saw the Hurtibise built Roadster.
Out of the bodypanels of the last versions of that car they built up another car. But man that particular version of that old roadster had a large tunnel ......

Watching the tunnels on the Indycars of the early 80's up to about, say '87....
To this day it still surprises me that the cars of that era could surpass 200 mph averages because the downforce on the straights must have been tremendous: good for corners but on the straight....


Henri

#14 meb58

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Posted 25 June 2013 - 20:48

I would think that one has to analyze the diffuser, wing and body work as a whole to establish how effective a diffuser is?


#15 Greg Locock

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Posted 25 June 2013 - 23:24


Yes definitely. The interaction of the rear wing and the diffuser is very important.

#16 Powersteer

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Posted 01 July 2013 - 13:37

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blow me! with a cheeky mounted red light

:cool:

#17 Tony Matthews

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Posted 01 July 2013 - 16:25

So THAT'S where Flymo got their inspiration.

#18 gruntguru

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Posted 02 July 2013 - 03:46

blow me! with a cheeky mounted red light


It sucks actually.

Does that also explain the red light?