Study (model) of various aeromods affecting a Porsche 914

[wyatt]

I found a web-page people may be interested in. Way at the bottom are the results of several CAD flow model tests and the corresponding effects to the vehicle's performance. I am personally more concerned with the Cd reduction and Horsepower Gained (or less horsepower used) than the down force, but interesting none the less.

[MetroMPG]

Hey Wyatt - good find!

Hope you don't mind I moved it into its own thread. Definitely a threadworthy post.

I don't understand the difference between "rear wheels blocked" and "rear wheels blocked flush with car", but there's a significant difference between the two.

[mar5ka]

I frequent this web site often, it means when you cover the wheels make it smooth, dont interfer the the vehicles lines, but the most interesting thing is when covering the rear wheels, notice the rear window he has two different shapes and notchback and a fastback shape, the 914 uses less HP with the notchback shape then with fastback.........

[wyatt]

Thanks! Definitely don't mind, the reason I posted it was so it would get seen. I noticed that between the "notchback and fastback" shape says that one has rear wheels blocked, and the other says rear wheels blocked flush with car. Even though the pictures look like they have identical wheel blocks, I wonder if that's how it was run. Either way, we can get a good idea in CAD, but we have to prove in the real world.

[Hasbro]

Originally Posted by MetroMPG

Hey Wyatt - good find!

Hope you don't mind I moved it into its own thread. Definitely a threadworthy post.

I don't understand the difference between "rear wheels blocked" and "rear wheels blocked flush with car", but there's a significant difference between the two.

Perhaps the non flush test was to simulate a flared situation comparable to a 914-6 body fender flare.

[some_other_dave]

I take it you mean the "GT fender flare", as the 914-6 had the same fender lines as the four-cylinder 914s.

If you're curious about the details, there is an email link at the bottom of the page with the results. I'm sure he'd be happy to talk about them with you.

It would be prudent to write him anyway and ask if you can post the image here; he very explicitly states that you must have permission to use the data on the page...

-soD

[aerohead]

Good score! !Muchas gracias!

[Hasbro]

Yes, thanks, the GT Flares. Hard to believe that a stock 914 weighed almost 2900 lbs.!

[some_other_dave]

It didn't. The early four-cylinder cars weighed closer to 1900 lbs., the six-cylinders about 2100 lbs, and the later four-cylinders about 2200 lbs. Not sure where the 2900 lbs figure comes from--the current Boxster is right around there...

-soD

[Hasbro]

You know, being such a gearhead, I shouldn't have just accepted the stats below even if it is from a PCA page. I knew better. V

http://vista.pca.org/stl/index.htm
Specifications for the 1970-76 914-4

Engine:

Horizontally opposed flat-4 cylinder, mid-mounted 1.7, 1.8, or 2.0L engine
Bore and Stroke: 90x66mm; 93x66mm; 94x71mm
Displacement:1.7L (1679cc); 1.8L (1795cc); 2.0L (1971cc)
Horsepower: 80 (1.7L), 79 (1.8L), 95 (2.0L)*
Compression ratio: 8.2:1 ; 7.3:1 ; 7.6:1
Cd:
Fuel system:
Drivetrain:

5 speed manual transmission



Suspension:

Independent front with lower control arms, spring struts, anti-roll bar
Independent rear, with semi-trailing arms, transverse torsion bars, anti-roll bar



Dimensions:

Curb weight: 2,892 lbs
Wheelbase: 94.5"
Length: 170.9"
Width: 68.3"
Height: 50.2"
Track front/rear: 58.2"/57.1"
Ground clearance: 4.9"