E46 M3 Track car mega build & development

[Rutkowski]

absolutely awesome build!! very inspiring

[Pooky]

Originally Posted by alexk

My point has to do with the use of cardboard.

When I see/hear a downfore of 80, 100, 120 kg, I expect that if you put 80kg of weight on this cardboard flap it's going to hold it.
Because if it cannot hold this weight when it's static, it will not have 80kg of downforce.
I don't underestimate what a flap, extension etc can do, but it's critical for it to be properly attached to the car and do not flex whatsoever.

Try out the front flaps of a CSL to see how much weight they can hold.
They are strong and properly attached.

I am sure if you make carbon or polyester spoilers, the result will be realistic.
With cardboard, I seriously doubt it.

PS : the CSL has the same tank with the M3 E46.

Alex, the cardboard does not have 80kg of downforce on it, that's measured at the wheels. What is does is modify the airflow resulting in greater pressure differential above and below the car, that's where the force comes from.

Plus when manufactures quote downforce in kg then this can only be at a specific speed, and it's normally 280kph or so on!

Anyway this is a tried and tested technique, it's how we modify shapes in the wind tunnel and then try early testing on track. The rear spoiler is not elegant but I was simply proving to Al how effective aero could be. The standard CSL still generates lift so there are large gains to be found with the right aero.

[alexk]

Fair enough guys.

Here is the wind tunnel for the CSL @ 200km/h



It's not bad, but it cannot be compared to the values cars like the 997 GT3 RS produce, that have these racing spoilers.

[northernjim]

Nice to see your car on here al


I'm surprised at all the bits falling apart after this last trip tho! I wonder if a 9.5" wheel would have been more robust? Were you losing air out of the tyres?


Neil- Al's engine and exhaust are standard

Originally Posted by alexk

My point has to do with the use of cardboard.

When I see/hear a downfore of 80, 100, 120 kg, I expect that if you put 80kg of weight on this cardboard flap it's going to hold it.
Because if it cannot hold this weight when it's static, it will not have 80kg of downforce.
I don't underestimate what a flap, extension etc can do, but it's critical for it to be properly attached to the car and do not flex whatsoever.

Try out the front flaps of a CSL to see how much weight they can hold.

Alex this isn't the same cardboard that your cereal comes in.....

Coupled with the fact that the down force is measured on the wheels rather than along the 5cm piece of high tech cardboard- I suspect that you would be surprised at its strength when wrapped in that tape.

[alexk]

BTW, what front camber are you running ?
It seems massive


EDIT : also, have you weighted the front carbon wings ?

[Pooky]

Originally Posted by shimmy

also to bare in mind is for the Ring the cars have to remain TUF ( i thinki thats what its called) and with big wings you get puuled and thrown off. Happened to SamT last year.

I persoanlly would love to take the CSL aero a step further. I bought my spare front and rear bumper for just that purpose. Im sure a good aero package would add to grip levels.

Plan is to develop a CSL aero package and normal M3 separate. Large potential in aero gains on both cars but we want to do it without a big rear wing but with extension of the boot lid somehow. This cant be the most efficient for drag but will give better lift properties.

Working on a way of getting my CSL in the tunnel for a quick test...

[Rutkowski]

Originally Posted by alexk

Fair enough guys.

Here is the wind tunnel for the CSL @ 200km/h



It's not bad, but it cannot be compared to the values cars like the 997 GT3 RS produce, that have these racing spoilers.

i really thought, CSL would create better downforce.... @ 250km/h + the lift would be even worse, much worse.

[Neil M]

Time to call it quits?:

[alclark]

Absolutely badass , and absolutely hideous at the same time.

Silly as it sounds, I'd like to keep it looking like a road car that goes well on the track, rather than a racing car that will never race.

'Tis amazing though - bet it runs well.

[alclark]

Originally Posted by alexk

BTW, what front camber are you running ?
It seems massive


EDIT : also, have you weighted the front carbon wings ?

Around 4 degrees at the front - the carbon wings weighed around a kilo and a bit each if I recall, less than a third of the weight of the steel wings.