Study (model) of various aeromods affecting a Porsche 914

[orange4boy]

Found this chart on 914 world

I found a report in two french magazines of 1970 and 1973.
Test was made on the Monthlery oval track. They mesured fuel consumption at various speed. The car was always on 5th gear. I converted the values from Liter/100 km to MPG.
They made the test in 1970 with a 1.7 and in 1973 with a 2.0 ...

914/6 also on chart.



With a microscopic frontal area of 17.2, a Cd of .36 and CdA of 6.19, the 914 is a prime ecomodding target. WANT!!1!

[orange4boy]

Porsche 914 mileage Ad:

29 mpg claimed.

http://www.youtube.com/watch?feature...&v=muRuHA-MREs

Nice stache.

[some_other_dave]

Originally Posted by orange4boy

I find it hard to believe that the drag is greater with the fastback but we don't know the angle so perhaps it is more than the ideal of ~12-15 degrees

I don't know about the angle, but there are other considerations. For instance, at speed there is air flow going forward along the rear deck. I guess this is where the cooling and induction air come from? I have seen a number of photos and even a video or two of tuft testing done on 914s over the years that show this. It's pretty counterintuitive, but the tufts clearly showed rear-to-front air flow.

The water-cooled conversions don't have that problem, but they generally have air flow coming in through the front panel and exiting either under the front or out of the front wheel wells. None of which is that good for the car's aero.


EDIT:

Oh, and I averaged about 34 MPG two weekends ago. Over about 600 miles, at freeway speeds, including some mountain climbing. (I-80 from SF to SLC.)

-soD

[aerohead]

Bill Bernstruch,one of the videographers who has attended Bonneville and El Mirage events put a VHS together long ago which included a 914 at El Mirage.
As the car makes it's pass you can clearly see the dust from the lakebed coming up and forward over the rear deck,completely filling the void all the way to the roofline,and within it,you can see a tranverse vortex circulating above the cooling inlet slamming dirt through the hole.
A K&N wouldn't last 2-seconds inside there.
I suspect that this could be witnessed on any Beetle,Ghia,912,and 911,and it's an intentional design criteria for the air-cooled engines.

[orange4boy]

Resurrecting this thread as I am considering buying a slightly rough-around-the-edges 914 as a grocery-getter/middle age crisis project.

It's red, just the right colour for a crisis car. But that will have to change. I hate red cars. It's interior is quite good considering and it has remarkably little rust for a wet coast car but it's had some dodgy bodywork done. Original EFI is missing. It has a single carb.

If I can get it for ~$2000, I might just go for it. Can't go down in value and it's "moddable" and considering the condition, I won't feel like I'm committing vehicular blasphemy. HMMMM.

[some_other_dave]

The three main things to look for in a 914:
- Rust
- Rust
- Rust

Go to the 914world website and do a search on "hell hole" to see some of what can happen.

-soD

[kach22i]

I posted this a while ago, nesting it here for future reference.

Driving with the top down?
http://ecomodder.com/forum/showthrea...tml#post374311

Originally Posted by kach22i

Ever wonder what taking your Targa top off does to your aerodynamics?

Vehicle aerodynamics


Spiffy Cd calculator at the site above too.

Yep, those are numbers for a Porsche 914, lamps (headlights) up and down too.

[freebeard]

Originally Posted by orange4boy

With a microscopic frontal area of 17.2, a Cd of .36 and CdA of 6.19, the 914 is a prime ecomodding target. WANT!!1!

They're also a prime candidate for an electric conversion. I went looking for the Cd/CDa of a Beetle (0.46/19.3) and I found this:
1947 VW Beetle-Based V2 Sagitta is More Aerodynamic than New Golf, Mercedes CLA!

It turns out that the V2 Sagitta has a drag coefficient (Cd) of 0.217 corresponding to a frontal area of 2.10 square meters.

This means the car is two times more aerodynamic than the VW Beetle it was based on, which had a Cd of 0,46 and a frontal area of 1.80 square meters. While that is not surprising, it’s only when comparing the V2 Sagitta’s results with those of modern cars that we get a true sense of Volkhart’s work.

The 1947 car is more aerodynamic than Volkswagen’s Golf Mk7, which has a drag coefficient of 0.27 and a frontal area of 2.19 square meters. Not only that, but it also beats the most aerodynamic production car of the moment, the Mercedes-Benz CLA, which has a Cd of 0.22!

Volkhart’s car also stands up really well against its modern-day equivalent - the Volkswagen XL1. At 0.189 and a frontal area of 1.50, the XL1 beats the V2 Sagitta, but not by an overwhelming margin.

Originally Posted by orange4boy

I am considering buying a slightly rough-around-the-edges 914 as a grocery-getter/middle age crisis project.

It's red, just the right colour for a crisis car. But that will have to change. I hate red cars. It's interior is quite good considering and it has remarkably little rust for a wet coast car but it's had some dodgy bodywork done. Original EFI is missing. It has a single carb.

If I can get it for ~$2000, I might just go for it.

I see what you did there. As for the colour, go to YouTube and search on "Plastidip whole car". What's the single carb, a side-draft Weber?