M5 aerodymanic underbody panels - Page 2

firebird400 · 23rd December 2009, 15:43

I think this is an awesome idea. A lot of people don't realize how how significant a low drag underbody can be. I bet at high speeds (over 130 mph or so) the difference would be night and day between stability. Our cars already feel awesome at high speed, but I'm confident they can be improved upon a lot. Even a completely flat underbody would be a big improvement, but if you add in venturi's then you get into downforce. On race cars, the underbody can produce more downforce than those huge wings you see. Go for it!

M5 London · 23rd December 2009, 16:23

Quote:

Originally Posted by PedM5

A while back there was a guy who got the fastest stock E46 M3 pass in the quarter mile when the car was relatively new. He did so by taking the seats and tool kit, and all the extra weight out. He even went so far as to use the valet key instead of the regular key. What difference does it make on its own? Who knows, but every little bit helps. When you do rolling starts on the freeway, high speeds come fast and just like people put lightweight batteries in their M5's to get that little bit of help, so shall I seek a way to get an underpanel that will aid the aerodynamics of my car so it can cut through the air more readily. Without going in to too much detail, anything over 165mph sounds like you are in a tornado, you really see that power can only get you so far before aerodynamics halt your acceleration. There are people who remove their side mirrors for drag racing purposes, all I'm after is to replace my stock piece with something a little more appropriate for my needs. Please don't turn this into a "why drive fast" thread, I have a modded M5 not a 528 and furthermore, I would probably not be around if I tried to hit 200mph on a daily basis. Every now and then I line up with a car that is just so close to me in speed that I had to think about what might be holding me back. Regardless of opinions, my search will continue

I think my point is, try doing the more tried and tested performance gain methods before tackling your underbody panels with the aim of improving downforce and/or reducing drag....

Please keep us posted on your findings !

kindanutz · 23rd December 2009, 16:33

it is very nessesary to have the belly pans on the M5.... not only does it aid in aerodynamics but it also is a very imperitive piece in controlling underhood temps as well as coolant and oil temps... the belly pan is designed to creat a vacuum and pull out hot air and aid in pulling in cool air from the kidney grills... if you leave it off while driving around you will notice oil and coolant temps alittle higher then normal... try it... good luck!!

m5 deamon · 23rd December 2009, 16:39

good point also if you look at the belly pan of our cars it also directs air to the transmisson for cooling

sor118 · 23rd December 2009, 16:53

Perhaps I'm over simplifying the manufacturing process but I don't see how this can be that difficult to achieve. You could use a large piece of cardboard as a template, find areas on the underside that you can tap into for securing the final product, source suitable lightweight but rigid material, and use the template to make the final piece.

Ya, that is way too simple. You also have to take into account air flow to the components that would be covered up like exhaust, rear diff and create air channels just like the OEM cover has to the tranny. Shouldn't be too hard right?

It sounds like a good challenge to come up with something but I would have to wait for warmer weather before tackling anything like this. Don't take this post as me volunteering to do this for everyone like Timmay is doing for his custom exhaust tips though!

vantaam5 · 23rd December 2009, 18:44

Quote:

Originally Posted by kindanutz

it is very nessesary to have the belly pans on the M5.... not only does it aid in aerodynamics but it also is a very imperitive piece in controlling underhood temps as well as coolant and oil temps... the belly pan is designed to creat a vacuum and pull out hot air and aid in pulling in cool air from the kidney grills... if you leave it off while driving around you will notice oil and coolant temps alittle higher then normal... try it... good luck!!

Now we are talking about one of my favorite topics!
Sorry,what you wrote is completely wrong!!!!!!!!!!!!!!!!!!!!
The last thing you want under the car is hot air(given its density you reverse the downforce effect)!The M5 has no openings to "suck" away the hot air from the engine bay!This is why race cars have openings in the hood to release the air from the radiators and engine bay!Why do you think hot air is on race cars always tried to get it above the car or on the side of the car?
The closed undertray the M5 has is as efficient as it can be made in a large production car.
The only way to make it more efficient would be to add side skirts and a real diffusor(I am not talking about that bolt on stuff for the bumper that is sold,this is only optics and nothing else).I am talking about a diffusor that starts with fins in bottleneck style(Venturi effect,to accelerate the air) at about the middle of the rear axle.
Downforce is about channeling and accelerationg airflow to create a "vaccum" under the car.
Then also getting away the hot air out of the wheel arches starts getting an issue(see race cars).

All these mods have to be tried in the wind tunnel,otherwise it is only a waste of time,money and resources...

And then you still have a 1.8 ton heavy pig that will be maybe with these mods and a pro driver .2 seconds(if) faster on the track...
As I stated,The M5 will never ever be a real race car,no matter how much money and time you invest!
The best you can get out of it is having a "track toy" and nothing else!

But before starting with all that aerodynamics,money is better invested in suspension and brake parts and semi-slick tires......

DouglasABaker · 23rd December 2009, 19:50

This whole conversation is interesting, but ultimately pointless without a wind-tunnel. Does anyone have one of those laying around that we can use? Because trust me, the theoretical design and the real-world design are not the same for something like this. You simply cannot model the underbody aerodynamics of our cars unless you are the mfg OR have a crapload of time to put into building a full 3-D CAD model. And even then... you need a wind-tunnel to prove your design.

The manufacturing process is not the hard part of this equation. Creating something that is better in practice than the stock body panels is the hard part...

d-

vantaam5 · 23rd December 2009, 19:59

It is not only pointless without a wind tunnel,it is also pointless for this car!

firebird400 · 23rd December 2009, 20:40

Quote:

Originally Posted by DouglasABaker

This whole conversation is interesting, but ultimately pointless without a wind-tunnel. Does anyone have one of those laying around that we can use? Because trust me, the theoretical design and the real-world design are not the same for something like this. You simply cannot model the underbody aerodynamics of our cars unless you are the mfg OR have a crapload of time to put into building a full 3-D CAD model. And even then... you need a wind-tunnel to prove your design.

The manufacturing process is not the hard part of this equation. Creating something that is better in practice than the stock body panels is the hard part...

d-

I have access to a small wind tunnel at college

Would be cool to find a scale model and do some testing