Hi, I'm new here and my cD is .37, can you help me get a .30?

[NeilBlanchard]

The reason there is a spoiler (like the Audi TT Coupe) is that there is lift in the back.

[AutoDeutchland]

I fixed the image link in my last post.

[Cd]

A trip strip is a small strip of something added to the car body in an area where there is too much curvature to maintain attached flow.

Here is a strip added on the roof of a car. I'm guessing it is a bit to low to 'snag' the air past the boundary layer. A tuft test would reveal how effective it would be.



To get a good idea of what the airflow around your car is doing, it would be very helpful to do a tuft test on your car.

AutoSpeed - Aero Testing - Part 1

Once you see where the problem areas are, you can begin to address them.

[Ecky]

The point of the trip strip is what, to cause clean separation?

[freebeard]

difusser—This suggests ~3° is optimum:



The air those fans could suck out of the interior would be a drop in the bucket compared to the air flowing over the outside. And it would make your ears pop.

A trip strip is a strake or flap that is small in scale but affects air flow locally. https://en.wikipedia.org/wiki/Gurney_flap

[Cd]

Originally Posted by Ecky

The point of the trip strip is what, to cause clean separation?

Correct.

Here is an excellent example that was just posted : http://ecomodder.com/forum/showthrea...ars-30990.html

[AutoDeutchland]

So 3 degrees means it will look very subtle, almost flat underneath. My car is 159.8" long. About where do I want that 3 degree bend and does the optimum angle and position change with the ride height and amount of air I let or don't let under the car?

[aerohead]

The Porsche 911 Carrera had Cd 0.39-0.32.
All the difference was in refinements to inlets and smoothing the belly.
This is the range of drag reduction you're interested in.So perhaps an optimized,air-tight cooling inlet/grille-block,and belly-panning/diffuser could do it,without really altering the 'look.'

That rear spoiler would be very beneficial.

[jeff88]

aerohead, are you saying that a grill block and belly pan were good for 7 "points" for the Porsche? Do you think that can equate across the board to 7 points for the Crossfire?

[AutoDeutchland]

I will definitively do those things. My modding skills are very extensive and radiator relocation would not be out of the question. I can seal the front of that car tight. My question is: before I finish and paint the front bumper, do I want a splitter to keep air from under the car? Remember to account for an imminent 2" suspension drop. Also, is it better to port the exhaust out the sides right behind the front tires or directly underneath the headers into the underside. I'd like to make my aero and my engines exhaling mutually beneficial to each other. i.e. low pressure sucks exhaust gas out improving exhaust flow.