Good info on these web sites

[Alfred1]

http://www.teknett.com/pwp/drmayf/porsche.htm

http://www.gtechprosupport.com/support/AeroDragCalc.htm


I got these results for a 1980 911 SC

------

Gtech Aero Drag Calculator Results
Calculated HP loss due to aero drag is: 9.4 horsepower.

Drag Coefficient (Cd) : 0.34

Frontal area : 19.30 sq. ft.

Speed : 60 mph


and


Gtech Aero Drag Calculator Results
Calculated HP loss due to aero drag is: 26.9 horsepower.

Drag Coefficient (Cd) : 0.34

Frontal area : 19.30 sq. ft.

Speed : 85 mph


The 911 requires 17.5 more hp to overcome the drag at 85 mph than at it does at 60 mph.

[ruddyboys]

Alfred you have way too much time on your hands.

[Alfred1]

That information is relevant to the discussion some of us had about fuel mileage in a now locked thread. The loss of power due to drag is also not insignificant when comparing the hp that a G-Tech measures compared to a chassis dyno.

[BigD9146gt]

First of all, remember the old saying, "Don't kill the messenger". That being said...

Alfred, even though you have some very good points, from what i've seen, you've started out alittle too head strong, so now nobody cares about anything you have to say and writes it all off as you being psycho.

Just a thought...

[sean_V8_914]

most people dont realize that wind resistance is non linear. run the numbers in 5 mph increments and this becomes clear. what is CD for a 914?

[Alfred1]

Originally posted by sean_V8_914
most people dont realize that wind resistance is non linear. run the numbers in 5 mph increments and this becomes clear. what is CD for a 914?

I used to have that number somewhere but now I can't find it. I think it was 0.37 (it was under 0.4).

[Alfred1]

Originally posted by BigD9146gt
First of all, remember the old saying, "Don't kill the messenger". That being said...

Alfred, even though you have some very good points, from what i've seen, you've started out alittle too head strong, so now nobody cares about anything you have to say and writes it all off as you being psycho.

Just a thought...

Yeah, don't take this wrong either but the more technical training people have (no I don't mean vocational school) the more they can relate to what I'm saying.

[Acox914]

.37? whats a 911 or a 928?

alfred, neat info: what do you do for a living?

[Alfred1]

Originally posted by sean_V8_914
most people dont realize that wind resistance is non linear. run the numbers in 5 mph increments and this becomes clear. what is CD for a 914?

Found it.

J P Stein
Senior Member

Registered: Mar 1999
Location: Vancouver,Wa.
Posts: 1728

Here's more than you probably want to know.

1)top on,windows up,&headlights shut CD .363
2)Headlights up CD.380
3)headlights up, windows open CD .381
4)same as above but roof off CD.484
From UP Fixen vol.5 pg 314

[Alfred1]

Originally posted by Acox914
.37? whats a 911 or a 928?

alfred, neat info: what do you do for a living?

I tutor in math and I'm always taking more math courses at 'school'.

[BigD9146gt]

I remember reading somewhere that the 914's headlights, when up, created about 15lbs of resistance at 65mph. Thats pretty cool about the numbers for when the top is removed...

[schosh]

The numbers between top on and top off pretty much reflect my experience ...but the grin factor goes down..

[Conrad W Peden]

914 CD's

1)top on,windows up,&headlights shut CD .363
2)Headlights up CD.380
3)headlights up, windows open CD .381
4)same as above but roof off CD.484

[Bleyseng]

Conrad, you ever hook up with Alfred?? He lives in Vancouver,BC..

Geoff

[sean_V8_914]

if you open the headlights at 85 you can actually feel the drag. this effect was even more pronounced in my Miata. I wonder if the 916 nose improves this number.

[Conrad W Peden]

No Geoff, I like it on my rock and dont leave too often. Maybe once every couple years.