Diffusors

Top speed versus downforce
Firebass
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Re: EK9 body kit

Post by Firebass »

Up the Rev Limiter !!!!!!

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saxophonias
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Post by saxophonias »

Firebass wrote:i got this one http://yfrog.com/5mdsc00398sxj
this isn't a real diffusor right? Have you seen any difference?

Firebass
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Re: Diffusors

Post by Firebass »

nop its just a rear bumper and it looks cool , they fron bumper is also very nice but the problem is that for greece its not worth i ll try to find a pic
Up the Rev Limiter !!!!!!

Firebass
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Re: Diffusors

Post by Firebass »

thats it http://www.youtube.com/watch?v=wmZ0xN8WVbg
i ve seen one ej9 black in patras , and lowered but i guess this guy would drive only in central streets and even though he will have probleps and a lot of scratches down there
Up the Rev Limiter !!!!!!

flimmer
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Re: Diffusors

Post by flimmer »

Is the result of af diffusor not more drag and more downforce?
I will agree, that an underbody will reduse drag, but not the diffusor?
Please explain.
Thanks

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mynameisowen
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Re: Diffusors

Post by mynameisowen »

A Diffuser normally fulfills the following roles:

*To guide fast-flowing underbody air into the negative pressure region behind the body thereby disturbing the large negative pressure there: reducing drag.

*To expand the fast flowing underbody air to more normal speeds by increasing flow cross-sectional area. This ensures that air flow exits the car in a controlled manner.

In answering your question, a diffuser alone will reduce downforce (since it increases pressure due to area expansion) but it has the effect of vastly reducing drag downstream (negative presure region behind the car). The important thing to realise is that in aerodynamics there is a large amount of interaction between different components and so for example a diffuser has to be tuned along with the rear wing for the desired effects.

On our cars the underbody is no where near an ideal shape and as the addition of the diffuser is mostly pointless in my opinion. Maybe the removal of the rear bumper cavity and addition of a diffuser-like shape would be a benefit but I don't think it would be very noticeable.
1996 EJ9 Civic
1998 BB8 Prelude Motegi VTi
1998, B16A2 EK4 Civic VTi

Aims:
EJ9 - Now my GF's car.
BB8 - Rebuild after crash damage to front end.
EK4 - Daily driver. Strip and track prep once prelude project complete

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BETEK
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Re: Diffusors

Post by BETEK »

Sergeant Japan rear diffusor
Image


Seeker Japan Modified rear wing
Image

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saxophonias
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Re: Diffusors

Post by saxophonias »

ek9's diffuser seems very neat but it must way too expensive

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mynameisowen
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Re: Diffusors

Post by mynameisowen »

Looks beautiful! Shame about the big gap around exhaust though.
1996 EJ9 Civic
1998 BB8 Prelude Motegi VTi
1998, B16A2 EK4 Civic VTi

Aims:
EJ9 - Now my GF's car.
BB8 - Rebuild after crash damage to front end.
EK4 - Daily driver. Strip and track prep once prelude project complete

archyman
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Re: Diffusors

Post by archyman »

It looks ok, but i don't think its functional. They are using the lip to create the diffuser, but that way the angle is too small to let the air escape before the bumper. In addition, to be effective in guiding the air in a controlled manner the small vertical wings on the diffuser should be a lot bigger and formed earlier. In order to create downforce the air beneath the car have to travel and exit faster than the air above. They have actually created a semi flat bottom, which is better then stock but sitll not a diffuser...and if the price tag is what i think it is then :shock:

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