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Group C aerodynamic balance

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#1 raintyre

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Posted 10 January 2015 - 12:48

   Hi, i've got a question about aerodynamic settings for Group C cars.


Following Mulsanne's corner data, sprint configuration (high downforce) had more % of front downforce than Le Mans configuration (low downforce).  That means high downforce configuration is more 'aero-oversteering' than low downforce config. Right?




However I also heard that front downforce had only a few different adjustments available, and not much influence, while rear wing had many differente angle positions and much more influence on lift and drag. 

If rear wing setting changes have a bigger effect on aeros, then high downforce settings should be more 'aero-understeering'.  

  How they achieved such front downforce increase, which actually is bigger than rear?

   Is due to ride height or rake?  Thank you!

Edited by raintyre, 10 January 2015 - 12:51.


#2 bigleagueslider

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Posted 12 January 2015 - 05:00

One cosideration with design of Group C cars of this period was that they could be used for IMSA GTP racing. IMSA GTP had different rules regarding the aero configuration for group C cars vs IMSA GTP cars. The biggest difference was the design of the underbody and diffuser.

#3 raintyre

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Posted 13 January 2015 - 23:12

Great! Thanks a lot

#4 ray b

ray b
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Posted 16 January 2015 - 16:58

the older can-am and others like the gt-40

had a rad vent with wing shape in the mid front top of the hood area


and my street ride a mid-eng [fiero] with V-8 swapped in car many guys cut in such a wing vent in the hood behind the rad

to reduce front lift at higher speeds and get more airflow thru the rad  and up and out too

hopefully some downforce too but at a minimum it does reduce lift at speeds


is that a better street mod then trying to get under body flow with diffusers and/or front airdamms

as the car is much higher then a group C off the ground


or would the vent/"louvers" over the front wheels work better on a street ride height car ?

if the over wheel louvers are used WITH  the mid hood wing shaped rad vent

will they add to downforce or hurt it by interactions ?

any car use both ? as the hood vent seem to have disappeared from the newer cars ?

#5 mariner

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Posted 16 January 2015 - 17:58

Its slightly OT but once I saw the inside of the nose of  the Le Mans winning Jag group C car. There is a very clever mesh screen which shows how details can help win endurance races.


Rather than a simple vertical screen it is a series of mesh wedges laid on the splitter floor. With the flat end of the wedge open and facing forwards. As air flows in it can escape up and to the side but any rubbish, being heaver, carries up the wedge and gets collected harmlessly in the sharp end of the wedge at the rear.


So no need to keep clearing rubbish at pit stops and a lot of rubbish can be swallowed without blockingt he cooling flow.


BTW those Jags had power mirrors off a production Jag , Tony Southgate fitted them to save time at pit stops while drivers had the mirrors tweaked.

#6 raintyre

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Posted 08 February 2015 - 19:38

Great info 

And what about diffuser?  Is it possible that diffuser center of forces is more to the front than to the rear?  What is the common distance from rear axle? 

#7 dynatune

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Posted 07 June 2015 - 18:49

And what about Drag ? Drag does unload the front and load up the rear, so it would make it a balanced aero package after all ?