Drag efficiency of the A2 and how to improve it.

A2Steve

Member
Came across a good bit of information today. Fuel efficiency is a big factor in many people buying an A2 TDI and so the folloiwng information may be interesting. It shows what items make up the A2's drag and the effect that modifications can have in both a positive and negative context.

Parts Percentage of Total Drag

Cooling package (including radiator, intercooler, oil cooler, etc) 33.4%

Exterior 31.7%

Front wheels 13.1%

Rear wheels 6.9%

Floor 6.9%

Rear Axle 3.1%

Engine 3.1%

Front Suspension 1.4%

Exhaust 0.7%





Modification % Change


Lowering the vehicle by 30mm approx. -5

Smooth wheel covers -1 to -3

Wide tires +2 to +4

Windows flush with exterior approx. -1

Sealing body gaps -2 to -5

Underbody panels -1 to -7

Concealed headlamps +3 to +10

Outside rearview mirrors +2 to +5

Airflow into the engine compartment +4 to +14

Brake cooling devices +2 to +5

Interior ventilation approx. +1

Open windows approx. +5

Open sunroof approx. +2

Roof-mounted rack approx. +40
 

A2Dreamer

A2OC Donor
Yes, I've seen this before and am really interested in trying to reduce drag (had a couple of gen 1 insights and, surprisingly, there are are significant improvements that can be made on them!).

This guy has a good youtube channel, mostly just touting his books, but useful and interesting nonetheless.

 

4markowen

A2OC Donor
I popped it in the weight loss thread, but I was toying with replacing the wing mirrors with cameras, as you see on EVs and Lorries. Not that the A2's wing mirrors are especially large, but enough to make a difference.

Cheap £30-40 reversing camera with a decent night performance and 3D print the outside casing.

Also was thinking about a spat over the rear wheel to minimise turbulence around that area. Although don't think I can bring myself to due to aesthetics :)

And also deflectors in front of the front wheels.

Slowly working towards an EV conversion so also toying with a completely flat underside front to back, and reducing the air intake up front to just the slit under the service flap.

Also, in some way want to direct air flow over the front wheels to create a boundary layer and reduce drag there. So directing air to just behind the wheel arch liner and directing it out of there. (redesigned fog lamp holders? drop the fog lamps for an intake?)

and finally, creating flush door handles.
 

A2Dreamer

A2OC Donor
Not quite got the colour right, but I don't think it's too bad...!!

Need to get back to work..!!

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mtl

A2OC Donor
I got chills when I saw these photos. There should be a warning before opening this post :)
 

audifan

A2OC Donor
Someone’s already way ahead of us

View attachment 96339
Well just imagine the tail gate gas struts trying to cope with that lot! Nice way to turn poor rear visibility almost impossible especially as the door mirrors are also removed, not to mention the PITA it would be to check tyre pressures or change a tyre. Curious just how the covers on the front arches would move to enable you to steer the car. Bet it Cd is higher than a standard car.

At least the car from i-robot was "semi believable" a film that had several Audis playing important roles...

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