Evolution VIII and MR Cd (Coefficient of Drag)
Aug 22, 2004, 09:32 PM
#31
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not all over the car, just at the *** lol
on another ... :S ... side note lowering a car would increase downforce/ reduce lift right ? (minimally not hugely obviously) cuz my thinking is, if less air can get under the car the less lift it can create, and for example if it could run on 1mm ride height (that would be so cool) then nearly no air would get under the car so that would be like no lift right?
anyways i thought rear diffusers increase drag and downforce since the air under the car has to expand to return to it's original speed and pressure ??? i know for sure it aids in downforce afterall thats the whole principal behind ground effects but im not sure about the drag thing
on another ... :S ... side note lowering a car would increase downforce/ reduce lift right ? (minimally not hugely obviously) cuz my thinking is, if less air can get under the car the less lift it can create, and for example if it could run on 1mm ride height (that would be so cool) then nearly no air would get under the car so that would be like no lift right?
anyways i thought rear diffusers increase drag and downforce since the air under the car has to expand to return to it's original speed and pressure ??? i know for sure it aids in downforce afterall thats the whole principal behind ground effects but im not sure about the drag thing
Aug 22, 2004, 09:54 PM
#32
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let me comment on a few tihngs...
First, about the hours and hours in a wind tunnel... I say one tihng, if I spent 35 hours correcting a mistake I made on paper does that make my goal so much better? No just makes for more work and money wasted because it was started out the wrong way (how many peopel say wow that ferrari is slick through the air, no they say wow that car is hot or nice or fast) Well 400-600 HP it sure better be fast
Next, about rear diffusers, they are designed to eliminate the turbulance cause by a getto bumper panel.. as air leaves the underside of the car it gets caught and thrown around underthere the diffuser is there to allow air to flow out of the underside of the rear with easy causeing the car to sick to the ground like a suction cup, havent u heard those sayings that an F1 car could be turned upside down at so many miles per hour and still sick to the road (being the road was upside down with the car) thats how much suction and downforce it has, and how much minimal lift.
Next, how can we descreas drag well look at ways of decreasing resistance,aka find ways air can move smoothly and more efficently then it already does. Loose the hood scoop, loost the mirros, add some panels to the underside to decrease lift, lower the car.... onyl one problem this car was not designed to have that done to it becasue by removing some items and adding some items you are also loosing airflow over the engine and other components which aid in cooling.
Last that Vortex deal on the Mr is simplely there to air in keeping the air flowing over the rear of the cabin straight so it doesn't begin to casue turbulance as it flows over the rear window and trunk, this way when it hits the rear spoiler its more effective....
In closing I tihnk wind tunnels are awsome and I wish I had access to one at anytime, its fun to mess with aerodynamics just think about what u add and remove becasue everything has a pro and con to it.
First, about the hours and hours in a wind tunnel... I say one tihng, if I spent 35 hours correcting a mistake I made on paper does that make my goal so much better? No just makes for more work and money wasted because it was started out the wrong way (how many peopel say wow that ferrari is slick through the air, no they say wow that car is hot or nice or fast) Well 400-600 HP it sure better be fast
Next, about rear diffusers, they are designed to eliminate the turbulance cause by a getto bumper panel.. as air leaves the underside of the car it gets caught and thrown around underthere the diffuser is there to allow air to flow out of the underside of the rear with easy causeing the car to sick to the ground like a suction cup, havent u heard those sayings that an F1 car could be turned upside down at so many miles per hour and still sick to the road (being the road was upside down with the car) thats how much suction and downforce it has, and how much minimal lift.
Next, how can we descreas drag well look at ways of decreasing resistance,aka find ways air can move smoothly and more efficently then it already does. Loose the hood scoop, loost the mirros, add some panels to the underside to decrease lift, lower the car.... onyl one problem this car was not designed to have that done to it becasue by removing some items and adding some items you are also loosing airflow over the engine and other components which aid in cooling.
Last that Vortex deal on the Mr is simplely there to air in keeping the air flowing over the rear of the cabin straight so it doesn't begin to casue turbulance as it flows over the rear window and trunk, this way when it hits the rear spoiler its more effective....
In closing I tihnk wind tunnels are awsome and I wish I had access to one at anytime, its fun to mess with aerodynamics just think about what u add and remove becasue everything has a pro and con to it.
Aug 22, 2004, 10:11 PM
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Originally Posted by KnifeEdge_2K1
just one thing, werent ground effects banned in f1? they're limited to wings now right?
Aug 22, 2004, 10:42 PM
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Originally Posted by 1QWKEVO
I don't follow F1 racing that much to know that answer, I do however know the speeds on the cars are getting too fast and I'm sure they are going to do something to affect that, if they haven't already.
i heard something about a drop in displacement or limiting to 600 bhp
thats a bit drastic though considering thats going to be the same level of performance as the lesser formulas and the fact ralfy didnt even get that badly hurt
Aug 22, 2004, 10:45 PM
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yeah i checked it out, 350 is .30 crazy
in retrospect i think we have to change our estimate of the evo MR's Cd to about .34-.35
hmm i guess that value is due to the front bumper mostly
i still find it hard to believe the STi can have a .33 Cd, the hood scoop must deflect so much air, it's mind bogglingbut the rear window angle is less steep then the evo's, thats prolly where most of the drag is being made ...
in retrospect i think we have to change our estimate of the evo MR's Cd to about .34-.35
hmm i guess that value is due to the front bumper mostly
i still find it hard to believe the STi can have a .33 Cd, the hood scoop must deflect so much air, it's mind bogglingbut the rear window angle is less steep then the evo's, thats prolly where most of the drag is being made ...
Aug 22, 2004, 11:04 PM
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[QUOTE=1QWKEVO]
Last that Vortex deal on the Mr is simplely there to air in keeping the air flowing over the rear of the cabin straight so it doesn't begin to casue turbulance as it flows over the rear window and trunk, this way when it hits the rear spoiler its more effective....
you are correct in saying that it directs flow to the wing (not spoiler), but any disturbance to the flow, such as the vortex generator will cause turbulence. the turbulence will reduce separation from the rear window and direct flow over the wing. without the generator, the wing might still be in the wake region, hence lower pressure and less downforce.
Last that Vortex deal on the Mr is simplely there to air in keeping the air flowing over the rear of the cabin straight so it doesn't begin to casue turbulance as it flows over the rear window and trunk, this way when it hits the rear spoiler its more effective....
you are correct in saying that it directs flow to the wing (not spoiler), but any disturbance to the flow, such as the vortex generator will cause turbulence. the turbulence will reduce separation from the rear window and direct flow over the wing. without the generator, the wing might still be in the wake region, hence lower pressure and less downforce.
Aug 23, 2004, 12:00 AM
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Originally Posted by Captain EVO
BACK ON TOPIC:
So that small little window spoiler on the MR drops Cd by .01? I thought that it was to increase downforce. I admit it looks lame, but Mitsubishi could have solved both the downforce problem and the looks problem at the same time if they had given us the adjustable rear wing like they were supposed to.
So that small little window spoiler on the MR drops Cd by .01? I thought that it was to increase downforce. I admit it looks lame, but Mitsubishi could have solved both the downforce problem and the looks problem at the same time if they had given us the adjustable rear wing like they were supposed to.
Originally Posted by KnifeEdge_2K1
woops, the evo 6 has a cd of .34 my source was mistaken
Aston
Aug 23, 2004, 12:32 AM
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you are correct in saying that it directs flow to the wing (not spoiler), but any disturbance to the flow, such as the vortex generator will cause turbulence. the turbulence will reduce separation from the rear window and direct flow over the wing. without the generator, the wing might still be in the wake region, hence lower pressure and less downforce.
I itnhk the MR's drag shoud be less than that of the evo viii's so i'd have to say its atleast under .30 I believe the evo viii is .29-.31 I can't find a definite answer
Last edited by 1QWKEVO; Aug 23, 2004 at 12:42 AM.
Aug 23, 2004, 05:56 AM
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Originally Posted by 1QWKEVO
What? can you rephrase that
I itnhk the MR's drag shoud be less than that of the evo viii's so i'd have to say its atleast under .30 I believe the evo viii is .29-.31 I can't find a definite answer
I itnhk the MR's drag shoud be less than that of the evo viii's so i'd have to say its atleast under .30 I believe the evo viii is .29-.31 I can't find a definite answer
i expected the VIII to have a Cd between .31-.32 but apparently this is not so, until we can get our hands on either a wind tunnel or a computer program to calculate this for us we cant be sure
afterall the manufacturers can claim their car has a Cd of .0001 and we'd never be able to prove em wrong
Aug 23, 2004, 06:00 AM
#43
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the main factor which causes the Evo VIII to have such bad drag is the front bumper and rear window, the front bumper is just full of obstructions while on the sti its more or less smooth although the Sti does have a huge bonnet scoop
the rear window screen on the Evo slants down much steeper then the STi's which increases the turbulence which is somewhat handled by the rear wing although the MR's "vortex generators" aka the little shark fins at the back
if i had to take a guess on the Evolution MR's drag coefficient it would be between .33-.34
the rear window screen on the Evo slants down much steeper then the STi's which increases the turbulence which is somewhat handled by the rear wing although the MR's "vortex generators" aka the little shark fins at the back
if i had to take a guess on the Evolution MR's drag coefficient it would be between .33-.34
Aug 23, 2004, 06:14 AM
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http://www.carsdirect.com/research/m...02/es/features
scroll down and look at the drag coefficient for the lancer ...
no way in hell the Evolution could have a Cd .6 over it
again im changing my hypothesis to .32-.33 for the MR
scroll down and look at the drag coefficient for the lancer ...
no way in hell the Evolution could have a Cd .6 over it
again im changing my hypothesis to .32-.33 for the MR
Aug 23, 2004, 06:53 AM
#45
Originally Posted by KnifeEdge_2K1
http://www.carsdirect.com/research/m...02/es/features
scroll down and look at the drag coefficient for the lancer ...
no way in hell the Evolution could have a Cd .6 over it
again im changing my hypothesis to .32-.33 for the MR
scroll down and look at the drag coefficient for the lancer ...
no way in hell the Evolution could have a Cd .6 over it
again im changing my hypothesis to .32-.33 for the MR
Oh really? Why not? The Evo has tons of things to increase downforce over the Lancer. How could it NOT have a higher Cd? You're one crazy misinformed dude!