GeorgeNZ

I'm going to have a play around with some data logging at our next track day and was looking for drag coefficient and frontal area numbers - anybody??

TIA

NZ951

Drag = 0.30 (circa)

Daddio

Drag could be significantly lower with better aerodynamics at the nose, which is shaped a little too much like a brick.

NZ951

Its not bad frontal though... for the 80's it was very good really.

GeorgeNZ

I'd have thought it was the rear that needed to be cleaned up for a lower cd - its the big hole in the air left behind that is the problem.

any idea in frontal area?

Rich Sandor

For a stock 944 turbo, Cd has been published by various sources between 0.33 to 0.34 or 0.31 to 0.32 for lowered turbo cup cars with slightly smaller mirrors.

The problem is frontal area is measured slightly differently by different manufacterers, so you'll see slightly different Cd numbers. (Read "Race Car Aerodynamics" by Katz.)

peanut

easy way to improve things is to look at what the race guys do to their motors to improve Aerodynamics.
Lowering the car decreases lift reduces drag and presents a smaller frontal area (improved Aerodynamics) It also dramatically improves handling as well.
The next thing maybe to consider is reducing the amount of air going under the car.Also make the air flow smooth by putting some sheet grp/metal shrouding under there. Reduce the air flow under the sides of the car with sculpted skirts. Enclose the wheels better in the wheel wells. The under-bonnet area vents pretty well on a stock 944 anyway but look at ways at reducing the amount of air flow into the under bonnet area (lift and drag) without compromising engine cooling.

I have a good basic manual on Auto Aerodyamics by Geffrey Howard but I'm sure there are lots of much improved books out there now

awilson40

here ya go
http://www.teknett.com/pwp/drmayf/tbls.htm

Rich Sandor

Peanut: I don't think he's trying to change the aerodynamics, he just needs the numbers to input into the data logger.

Dilberto

The CD and frontal area numbers are among the best in the world for a production car. I believe it still is too.

Zach

peanut

It was pretty good in its day dilberto 0.39 (oops) cd I believe for the stock UK 944 but almost any modern car far supasses it especially the citroens Lets face it it is a bit of a brick compared with say aMitubishi or Mazda

tommye

Porsches published numbers: NA=0.35, S2/Turbo=0.33.
But, does anybody know about the convertible ? and the 968/968 convertible???
I've never seen anything from the factory for these models.

Tommy

GeorgeNZ

thanks guys - still after the frontal area number if anyone comes across it - yeah, its numbers to load into the data logger

I'll try and calculate something from a digital photo and gridding it - at least it should be in the ballpark

azmi951

SAE says (heightXwidth)*0.8 measured from the tips of the mirrors and from the ground to the tallest point on the roof.

That powertrain class is sure paying off.

Waterguy

The values I have are Cd = 0.33 (turbo), 0.35 (NA). Frontal area (A) is 20.3 sq. ft., 1.89 sq. m. I can't remember the source, but I think it was R&T. There was something about the 951 having the lowest CdA of any production car when it was released in 1986.