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Impact of removing spoiler

29K views 252 replies 47 participants last post by  Rampant 
#1 ·
So two questions:

What is the impact on handling of removing the rear spoiler on an Evo VII. Mainly day-to-day driving, a few blasts here and there and maybe 6x300mile (x2) motorway trips a year? (at times topping 120 mph)

Also, what impact on handling would having lowering springs (eibach) on the front (bilstein B6) and standard springs (std shocks) on the rear?

Thanks
 
#112 ·
End of the day mitsubushi developed the evo for group n rallying if the spoiler
Didn't have any meaningful effect I'm sure the rally teams would of taken them off the cars to save weight when they rallyed them, if you look at the rally cars 3/4/5/6/all have the standard rear spoiler. So they must be there for a reason
 
#113 ·
Anyone ever remember when the Audi TT was 1st released? It didn't have a spoiler fitted and loads where get stacked at speed due to no down force on the rear at speed.

They recalled them all to fit a boot spoiler and manufactured all TTs since with them fitted.

I've driven one of my old evos years ago without a spoiler due to refurb, back end was considerably light at high mph.
 
#114 ·
Hey :cool:

Page 4 of this thread you'll find this pic....



Interesting for something that some claim doesn't do anything ... though i think by now we all realise it actually does :)

In my case i lifted off the throttle and the rear end just came around. One person claimed on a subsequent thread that i had lifted too fast .... just how fast your expected to lift at those speeds approaching the end of the runway is beyond me..... load of rubbish anyway as the other runs within a few mph had been dandy as you would expect.

I removed the spoiler to reduce drag. I'd seen on previous runs how much it had been bending (and also creating an almighty roaring noise too IIRC) ... and i mean really bending in the same manner as you can see in the pic of Simon above. What could possibly go wrong? :lol:

I did hear a rumour that someone's spoiler had actually snapped on a high speed run a week or so later, not sure how true that is though.

Anyway some great info on this thread, makes it easy to understand how my spin happened .... in the days following the spin it was explained to me just how powerful the forces are that play upon a vehicle at high speed by someone in the know, it was a bit late at that point mind :smthumbup

Is this the reason manufacturers limit a lot of powerful cars to 155mph? :confused:
 
#123 ·
After a brief Google search it would seem it was a gentlemans agreement between the big German companies to appease the Greens and to prevent Government legislation - sounds more like it.

No mention of it due to being design / airflow issues.
Yep, exactly the same as the gentlemans agreement to cap BHP for superbikes. That didn't last long! :lol:

Pretty well all 'sporty' 155mph speed restricted cars can be 'unrestricted' as a customer option when buying the car. (another way to extract money from the punter!)
 
#130 · (Edited)
Lol

Awwww you feel insulted now

Sad how op or anyone but You & your tag mate is allowed to feel insulted

The replies show how hurt ppl are

I frankly don't give a ****

And posting facts from Wikipedia or any part of net is off subject but when you two old ladies want a chat at someone else's expense it's fine

Apologies for my bantering

I don't care about your terminologies of a cars ability to stay on the ground

It's boring it's why I couldn't be arsed to write but cut & paste

Whatever lol
 
#132 ·
evosick going back to the fact of the evo not needing a rear spoiler is just simply wrong . And mitsubushi delvoped the evo for rallying and they would not have put a big wing on the cars if they didn't have a effect and most rally cars are not doing more that 130 top speed if the rally teams thought they didn't need a big spoiler the would of just ditched it for a little boot lip to save weight/drag
 
#158 ·
I removed the spoiler on my e6 late last year as i needed to fit my car cover for the rainy season and the wing always made the cover do an upskirt when it rained hard but now that the wings been off for awhile i have a few observations
1. Getting things in and out of the boot is easier who knew that stock wing could add such weight to the lid
2. I can clearly see behind me
3. I dont get random cars revving at me at stoplights and on the freeway
4. Car wash times have gone down same with waxing time since there no double decker wing to do
5. My car cover fits perfectly no upskirt in a heavy downpour
So for my very personal opinion i like the way it looks now alot better than with the wing but that could also just be me getting older i purchased the car when i was 25 and im 30 now and im definetly not into the same things that i was back then and so the wing was part of that phase of my life tho i will say that i will be putting it back on for track days but as a day to day and occasional vacation car then the wing will be off.
 
#161 · (Edited)
This guy has some fairly decent maths etc on the subject, also some stuff on vortex generators but I CBA putting that video up, you could easily find it if you looked but they're touched on briefly here. Anyways long story short the MLR "experts" in this field seemed to be wrong an Marios was actually right :)

edit: though this guy also pretty much echoes what I said myself right at the start...a few mph cornering difference at very high speed on the limit cornering.





He doesn't mention the balance of the car obviously but he's an aerospace engineer and works in the industry so if it was that significant he'd probably mention it.

TL;DW spoilers have no effect on road cars due to the speed the cars go and their weight, and while vortex generators help downforce the one on the evo is of a poor design in order to meet manufacturing and safety demands and not very effective.
 
#162 ·
He doesn't mention the balance of the car obviously but he's an aerospace engineer and works in the industry so if it was that significant he'd probably mention it.
He does mention balance. For the sake of his argument (and gross over-simplicity) he "assumes" that the spoiler should be placed in the centre of the car in order that any downforce generated would be evenly distributed. In other words balanced.

Check out his video about rear spoilers on FWD cars. Balance gets a mention there.

I disagree with you entirely about your message that the Evo spoiler does nothing.

Here's why.

An Evo VIII generates downforce over the front axle. The amount of downforce produced increases with increasing speed (non-linearly with the square of airspeed increase).

If there was no spoiler at the rear, the car would produce lift over the rear axle. The amount of lift would increase with increasing airspeed.

There would therefore be a handling disparity at different speeds throughout the Evo performance envelope.

I remind everyone again that Audi recalled ALL of the original TTs, at staggering cost to themselves, just to fit a very small spoiler that some people shallowly say "does nothing"...

Thanks for the videos, though.

Cheerz

Mark H
 
#165 · (Edited)
You are wrong mate, it is a simple as that.

The theory you present above, which is not even that, as you take bits and pieces of theoretical aerodynamics , along with certain terms which you clearly do not fully understand, and you manipulate these, in an effort to present yourself right. Even if the theory of aerodynamics was as you presented it and it actually was applied to the Evo at the degree you are struggling to make it seem, in applied pragmatical action things would not be as such, as it is not even close to what you are trying to make people here believe.

I will repeat my initial statement, if you want an airfoil type that actually makes use of the air speed and velocity at higher speeds, replace the stock item with a well designed one. Also removing the rear evo spoiler, either that is from an fq360 or from an Evo260, it will make some difference, not worth the while, only in very high speeds. In simple words the bigger the size and the better the design of the spoiler, the more air ( more air as in higher speed ,volume and velocity) you take advantage,the more downforce the airfoil will create. Also buy rear spoiler that do incorporate an adjustable blade, as the attack angle plays an important role in the effectiveness of the airfoil.

Below is a video of my personal car , some years back when I had her on an fp black setup, now is cosmetically different and it has a different engine and turbo setup.The car was roughly in UK DD figures at 650-700 hp on pump gas, a lot more on race gas.

Now I run a custom 6868 billet turbo and it sits around 800-820hp, pump gas.

The pictures present the car with the spoiler, and in the small runs is also with one. But the highway high speed run, which was done in an other night, was done with another person at the front of the car ( added elevation of front axle pressure) and no spoiler at the back. It was removed to avoid additional cause of drag.

There were no issues of instability of any sort. The highway run does include a couple of open high speed cornering as the road route of it dictates.



I still run the car without a spoiler with the current setup on spirited night drives, and there are no issues at all.

All the runs were done on b-roads and highway, during night time where there was no traffic, as there is no race track of any sort where I live.

Marios
 
#185 ·
You are wrong mate, it is a simple as that.

The theory you present above, which is not even that, as you take bits and pieces of theoretical aerodynamics , along with certain terms which you clearly do not fully understand, and you manipulate these, in an effort to present yourself right. Even if the theory of aerodynamics was as you presented it and it actually was applied to the Evo at the degree you are struggling to make it seem, in applied pragmatical action things would not be as such, as it is not even close to what you are trying to make people here believe.

<snip>

Marios
The reason I asked for any credentials was to establish why you think that the stuff I posted wasn't an established truth of aerodynamics.

It isn't the optimum behaviour to try to contribute to a discussion about aerodynamics by telling someone with a degree in Aeronautical Engineering with the opening statement that they are wrong and that they know nothing about aerodynamics.

Agreed?

Lift and downforce is actually the same thing. In one case the air is going up and in the other the air is directed downwards using the proper aero parts.
The only way to reduce lift is by increasing downforce, period.
Not necessarily. Lift can be negated in 2 ways:

One is by adding an aerodynamic device or devices to a lifting body in order to create downforce that then *counteracts* the inherent lift a body possesses when moving through the air.

The second is to redesign the body itself in order to eliminate the inherent lift. This is *not* the same as creating downforce. You could be left with an aerodynamically neutral body or one that possesses one tenth or one hundredth of the original lift. No downforce is being created, but lift has been eliminated.

The drag coefficient has nothing to do with lift and all to do with the mass of the body of the car.

Marios
Drag has ZERO dependency on mass.

Drag comprises a few elements. None of them are related in any way to mass. A couple of elements of drag from memory...

Form drag: the shape of the body. A circular flat plate of surface area 1, when placed "normal" to an airflow creates a lot of drag. A sphere, with the same surface area exhibits around 1/2 to 1/3 of that drag. A shere front end with an elongated tail that ends in a point exhibits around 1/20 to 1/50 the drag. With the same frontal area.

Interference drag: the joins between certain elements. The spoiler strakes on the Evo will have a certain Cd in isolation, on their own, in free stream air of Cd = "s". When stuck onto the boot of a spoilerless Evo with a Cd of "n", the Evo and spoiler strake combination will have a Cd that is greater than n + s. The extra drag is called interference drag. Interference drag can also be negative. Vortex generators produce drag. But when added to an overall system, the entire system can experience a reduction in overall drag. Lexus exploited interference drag in their LFA wing mirrors to shape the flow along the flanks of the car to reduce drag and increase downforce. The vortices that are sometimes visible emanating from the corners of F1 car spoilers in saturated air are an example of how interference drag can also be manipulated.

Induced drag: also known as parasitic or lift dependent drag. This is the drag created as a direct consequence of producing lift (or downforce). The action of creating lift (or downforce) depends on deflecting the airflow in a certain direction. This creates drag all of its own.

Form drag and parasitic drag increase linearly with airspeed increase. Double the speed, double the form drag.

Induced drag increases with the square of the airspeed increase. Double the speed, four times the induced drag.

Cheerz

Mark H
 
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#166 ·
A stock Evo spoiler would create almost no drag at its normal angle of attack so removing it for a high speed run would be relatively moot. If you look into the effectiveness of spoilers on a three box saloon shape you should see that they improve airflow in two important ways:

1) They reduce lift; please note that lift reduction and downforce are not the same thing. The blade isn't designed to be pushed down by the flowing air, rather it changes the air flow around the car and reduces areas of lower pressure.

2) By reducing lift they could also improve the drag coefficient, which would actually be beneficial for top speed runs.

I've seen no good arguement in here to counter this other than "I ran without one and it was ok"
 
#168 ·
A stock Evo spoiler would create almost no drag at its normal angle of attack so removing it for a high speed run would be relatively moot. If you look into the effectiveness of spoilers on a three box saloon shape you should see that they improve airflow in two important ways:

1) They reduce lift; please note that lift reduction and downforce are not the same thing. The blade isn't designed to be pushed down by the flowing air, rather it changes the air flow around the car and reduces areas of lower pressure.

2) By reducing lift they could also improve the drag coefficient, which would actually be beneficial for top speed runs.

I've seen no good arguement in here to counter this other than "I ran without one and it was ok"
I have to report that my Evo IX spoiler gets very badly twisted and warped at 150mph. Leading edge twisted downwards by the air flow. This has got to be the source of a large amount of drag. The frontal area has almost doubled and the angle of attack (angle of incidence) has increased markedly over a significant width of the blade.

Using the formula Drag = 1/2 x rho x velocity² x Cd x S it is clear that S (frontal area) and Cd (Coefficient of drag - which we can assume to be proportional to the angle of attack) make significant increases to the overall drag created by the spoiler when it is twisted like this.

I am assuming that the aerofoil section of the Evo IX wing and the associated angle of attack was tuned so that at some speed below the maximum speed of the (standard) vehicle it would generate "an amount" of downforce that is the maximum desired amount. Consider this as the "target". Call it 140 mph. Above this it warps out if design specification.

Now half the speed to 70mph. The downforce reduces to quarter of target. This is a marked reduction from the max "target". That is not to say it's "insignificant". Particularly when you would have had an amount of lift on the rear axle without the presence of the spoiler. (Allied to an asdociated amount of downforce at the front.)

I am at a complete loss as to why people are naysaying this as "insignificant" because the ultimate point is that the spoiler is there to perform a specific function *exactly when that function is required most*. I don't follow why this is difficult to understand. A car that is driven no faster than 80 is still affected by the influence of the spoiler. Not as much as a car driven at 80 or 90 or 100, but still influenced nonetheless by a positive and measurable amount.

Marios. If you were referring to me as the one who is wrong, may I ask what your credentials are to state this?

Cheerz

Mark H
 
#175 ·
The weight of an object is the gravitational force between the object and the Earth. The more mass the object has the greater its weight will be. Weight is a force, so it's measured in newtons. On the surface of the Earth an object with a mass of 1 kg has a weight of about 10 N.


mmmmmmm!

which has a lower cd

a sphere of 1000kg or 2 box of 1000kg


mmmmmmmmm
marky
 
#177 ·
also, talking about surface area when speaking about aero drag is not right, as when talking about cars the important factor is frontal projected area and not total surface area... that is why you can have a 6 metre barge that has good coefficient of drag...

I quite like how he manages to read all this stuff online and then miss the basic concept alltogeather.. REminds me of a certain individual on evom who thinks long rod engines are more prone to knock and that the earth is flat..
 
#180 · (Edited)
Yes I have read online on this and in books and have tried things about aerodynamics for the last 17 years or so, and for those that are like you who instead of focussing on the essence of what I posted are always trying to diminish the posts, creating insignificant and bul**** arguements, I attached the wiki link, which I see you have read as you corrected yourself. As for the term itself, either drag, area, front surface area, frontal area, or frontal projected it makes no difference to someone who has a bit of i.q, he gets it lol.

Marios
 
#178 ·
Wow, this thread is still going :lol:

One thing that hasn't been mentioned, unless I've missed it, is the wing uprights will provide straight line stability as soon as air starts flowing around them, increasing effect with speed. At speeds over 100mph the stabilising effect of both uprights will be significant in itself to help keep the car straight even if the rear goes light when the throttle is lifted.

If the OP wants to remove the wing blade, at least keep the uprights on as they will certainly help stability at big numbers.
 
#183 ·
Wow, this thread is still going :lol:
Yes. It is a threasd ressurection by Aidy who appears to have an agenda. Took him weeks to find ONE source on the internet which may or may not agree with his agenda and he posted it after 1am a couple of nights ago.

One thing that hasn't been mentioned, unless I've missed it, is the wing uprights will provide straight line stability as soon as air starts flowing around them, increasing effect with speed. At speeds over 100mph the stabilising effect of both uprights will be significant in itself to help keep the car straight even if the rear goes light when the throttle is lifted.

If the OP wants to remove the wing blade, at least keep the uprights on as they will certainly help stability at big numbers.
Yes mate, I thought I had already mentioned it previously - all wrapped up under the topic of Balance.

Yours Aye

Mark H
 
#184 ·
Rampant you asked about my qualifications. I'm not certified in aerodynamics nor have a diploma on it. I can though call my self a knowledgable person on the matter, as I've been dealing with it for the last 17 years, i,e I know how to use CFD software and how to design aerodynamic parts, such a turbocharger compressor wheel, or any exterior body parts which is more relevant to this thread.








Marios
 
#188 ·
Rampant you asked about my qualifications. I'm not certified in aerodynamics nor have a diploma on it. I can though call my self a knowledgable person on the matter, as I've been dealing with it for the last 17 years, i,e I know how to use CFD software and how to design aerodynamic parts, such a turbocharger compressor wheel, or any exterior body parts which is more relevant to this thread.

Marios
That's cool. :smthumbup I salute you for this. I respect this. Much more than your previous answers, some of which demonstrated you had a misunderstanding yourself.

Yours Aye

Mark H
 
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