• Registered: 2009-06-25
  • Posts: 554

Topic: Luggage rack controversy

I know there are more than a few opinions about installing a luggage carrier on Ghias and early Porsches. Some feel like it completes the vintage look. Some are like, "why bother, not gonna use it anyway". More than a few have expressed disapproval stating that it interferes with engine cooling.

Me? I doubt if I would ever actually carry luggage on one unless it was on a road trip or tour. Otherwise, it would serve no purpose other than looks in a normal install.

As far as cooling, I don't think it's as bad as some claim because the tube design of most racks flows more air than the stock engine cover louvers. And, even with a suitcase strapped on, it's far less restrictive than the stock rain guard (which I removed in mine). However, I can see a problem if the rack has less than 3 inches clearance from the decklid, and you have luggage strapped on.

Now, you might ask why I would even be considering a luggage rack, when I don’t plan on using it for luggage? The answer is: I can’t find a good hood scoop.

Huh?

Yes. I want a way to get more air into the engine compartment. Scoops are ugly. Raising the edge of the decklid is ugly. Luggage racks look nice.
The solution for both looks and cooling issues would be to use a luggage rack with a clear diverter to direct air into the decklid air inlet. You get air scoop functionality, hidden by a luggage rack, that provides much more cool air than stock.

Any thought or comments?


Paul

  • From: Canada
  • Registered: 2004-03-27
  • Posts: 630

Re: Luggage rack controversy

Sounds like it's worth a try.  As far as aesthetics go, as long as you as owner of the car likes the look, who gives a rip what others think?

Without the diverter, I'd be curious how the airflow over the air inlets are altered by both unladen and loaded luggage racks.  Would a loaded rack cause something of a vacuum resulting in reduced airflow?

1979 Type 1 Convertible                                       1976 Scirocco (For Sale!)
1971 Type 1 Semi-Automatic Super                       1968 Type 1 Sedan
1961 Type 1 Sedan
1957 Type 1 Sunroof

Der Bugmeister's Website

  • From: City of Roses
  • Registered: 2004-03-29
  • Posts: 793

Re: Luggage rack controversy

Hiya Paul,

Hmmmmmm..............just what car (and year) are we talking about here?

Mike

1970 AS Bug
1970 Bus - The Ruptured Duck
  • Registered: 2009-06-25
  • Posts: 554

Re: Luggage rack controversy

Bookwus wrote:

Hiya Paul,

Hmmmmmm..............just what car (and year) are we talking about here?

'92 honda civic with a green plastic body kit.



Just kidding!

1970 Karmann Ghia coupe, engine size is between 1600 and 1776. I did not check actual displacement when I had it out, but the engine is a late model with VW/Audi heads.

  • From: City of Roses
  • Registered: 2004-03-29
  • Posts: 793

Re: Luggage rack controversy

Hiya Paul,

Oh ho!

Might it possible to "louver" the rear decklid to allow more airflow?

Just a thought borrowed from old school hot rodding.

Mike

1970 AS Bug
1970 Bus - The Ruptured Duck
  • Registered: 2009-06-25
  • Posts: 554

Re: Luggage rack controversy

Bookwus wrote:

Might it possible to "louver" the rear decklid to allow more airflow?

Yeah Mike, the decklid could be punched. The most effective way would be for the louvers to be sticking up and facing forward, but I'm not sure I would like the resulting look and it's not all that subtle if they are sticking up. Having them punched inward and facing forward would be the next best thing, but with either way, you have an odd combination of the louvers and the OEM vents mixing things up, unless I have the OEM vents eliminated with clean metal and punch the whole surface.

Of course, the louvers would look cool if done right, but would tip people off that something non-stock is going on under that hood. I prefer sleepers  wink

  • Registered: 2009-06-25
  • Posts: 554

Re: Luggage rack controversy

Der Bugmeister wrote:

Without the diverter, I'd be curious how the airflow over the air inlets are altered by both unladen and loaded luggage racks.  Would a loaded rack cause something of a vacuum resulting in reduced airflow?

An all-tube rack installed normally with no luggage will have little to no measureable effect, with the exception of blocking two cooling slots on models that do not require drilling. For the ones with wooden slats, there is a higher possibility of affecting cooling because the design is not as "open" as an all-tube rack.

Now, load the racks up and the difference between wooden slats and tubes becomes moot: no airflow through the rack itself.
When loaded, the airflow is determined by the space between the rack and the decklid, and the angle of the rack in relation to the mounting surface.

If the rack is at the same angle as the deck lid, then that's a problem because there will be a laminar airflow between the lid and the bottom of the rack, and the engine has to pull all it needs out of that airflow. That may make it harder for the engine to breathe or maybe no difference because there is a slight vacuum on the decklid anyways (Ghia bodies generate lift in front and back).

Now if the rack is closer in front than back, it will be a definite problem because there will be a significant increase in vacuum under the rack which will make the engine fight for air.

The model I'm looking at is slanted the opposite way so that it is higher in front than back, so it would slightly improve airflow to the engine when loaded because the angle will trap air and increase pressure under the rack when loaded. Adding a clear diverter will force a pressure increase to the engine vents regardless of suitcases or not.

I plan on going back to the old days and doing some aerodynamic flow testing in the next week or so to see where the bow wave from the windshield and roof rejoins the body. As it is, I can cruise for hours at normal speeds with no heat increase, but if I bump it up to 80MPH or so (which this car does quite easily), the airflow over the decklid generates more vacuum the faster you go, making it more difficult for the engine to draw air in, and the bow wave re-join point will move farther back, past the louvers. So the engine needs more air because of the higher RPM and power required, but has less available air. I'll let you guys know what I find out...

Paul

Last edited by Altema (2010-05-27 09:58:23)

  • From: Greenville NC
  • Registered: 2007-03-10
  • Posts: 209

Re: Luggage rack controversy

Sometimes I wonder if we "over-think" things when it comes to our cars.

I have a luggage rack on my car...not even a VW one, but very unique.  It is a 70's era "universal" square rack.  I found it in a barn belonging to an old guy who used to work on VW's.  It was something a customer left with him years before.  Whether on the car, off the car, or loaded with suitcases, I've never seen a difference in engine temperature according to the VDO gauge.

BTW, I got the rack, a wooden Dick Pope slalom ski, a Hazet wrench, a under-dash A/C unit, and a couple of other odds and ends, for $45.00.

1974 Beetle- Red Bug
1971 Beetle--in pieces, will be finished someday.
1978 Westfalia--workin' on it.
1979 Triple White convertible--rusty hulk, but can't bring myself to part it out.
  • Registered: 2009-06-25
  • Posts: 554

Re: Luggage rack controversy

shutterbug wrote:

BTW, I got the rack, a wooden Dick Pope slalom ski, a Hazet wrench, a under-dash A/C unit, and a couple of other odds and ends, for $45.00.

Now that's a steal!

Paul

  • From: Greenville NC
  • Registered: 2007-03-10
  • Posts: 209

Re: Luggage rack controversy

Altema wrote:
shutterbug wrote:

BTW, I got the rack, a wooden Dick Pope slalom ski, a Hazet wrench, a under-dash A/C unit, and a couple of other odds and ends, for $45.00.

Now that's a steal!

Paul


Well, I forgot I also threw in an old desk chair and the $45.  Still, I was quite happy with the deal.

1974 Beetle- Red Bug
1971 Beetle--in pieces, will be finished someday.
1978 Westfalia--workin' on it.
1979 Triple White convertible--rusty hulk, but can't bring myself to part it out.
  • Registered: 2009-06-25
  • Posts: 554

Re: Luggage rack controversy

shutterbug wrote:

Whether on the car, off the car, or loaded with suitcases, I've never seen a difference in engine temperature according to the VDO gauge.

By the way, thanks for the valuable information; I think that would qualify as a very good test. What type of temperature are you reading; cylinder head or oil? The results are just as valid with either type, but I'm just curious.

Paul

  • From: Greenville NC
  • Registered: 2007-03-10
  • Posts: 209

Re: Luggage rack controversy

Oil temperature.

1974 Beetle- Red Bug
1971 Beetle--in pieces, will be finished someday.
1978 Westfalia--workin' on it.
1979 Triple White convertible--rusty hulk, but can't bring myself to part it out.
  • Registered: 2009-06-25
  • Posts: 554

Re: Luggage rack controversy

Altema wrote:

Yes. I want a way to get more air into the engine compartment. Scoops are ugly.

I stand corrected... You guys didn't mention the Judson scoop! Looks good when painted body color, and very functional when facing forward. The "traditional" direction is rear facing, but that has no cooling benefit, I'm looking to mount ine the opposite way. Now I have to find a knock-off because I don't want to waste a genuine artice when I can't use the Judson supercharger anyways, and the "official" reproduction is 451 US dollars.

Paul

  • Registered: 2009-06-25
  • Posts: 554

Re: Luggage rack controversy

By the way, here's a photo of an un-painted one installed the "traditional" way...

Paul

http://karmannghias.org/Judson36hp_files/Judsonscoopinst4.JPG

Last edited by Altema (2010-06-23 01:33:44)

  • Registered: 2009-06-25
  • Posts: 554

Re: Luggage rack controversy

Update: I've been doing some experiments with a scoop I fabricated for testing purposes. It is similar in size to the Judson scoop and minus the curves, but with a larger "mouth" to grab more air. I did the testing to see how much of a difference in engine cooling it would make, and to gauge public reaction.

Did it make the car run cooler? Definetly. After a hard drive in 80 degree F weather, the dipstick is more comfortable to the touch, air cleaner is cold, carb is cool, intake above the heat risers is cool, generator is cool enough to rest your hand on comfortably (normally too hot to touch for more than a second).

Public reaction? Mixed. People who did not know what a Ghia was were curious about the scoop. Those familar with the KG reacted with confusion or offence. Reactions from hotrodders depended on the circumstance: If you blow by them on the freeway they thought the scoop was cool. If you are puttering around town, they think it's absurd.

Now, I COULD get a Judson reproduction, or make one similar. That looks a bit more subtle, but the only change in reaction would be from the ones familar with the KG, and of course purists would still scorn it for being on backwards, even if the traditional way is non-functional from a cooling perspective.

The conclusion is that the scoop as an add-on is very functional, and I would certainly use one on a trip, but I would never pull into a place where other vintage cars were hanging out without removing it first. So, I'm back to having the same functionality with the luggage rack and the hidden deflector. I'd get similar results, not everyone would even notice it, and I don't think those who did see it and figured out it's purpose could claim I ruined the lines of the car.

Anyway, it was fun playing around with the scoop in the meantime, and I'll have it in standby for really hot days, and for when I feel like thumbing my nose at purists, lol

The scoop actually did not take long to make, except for the paint. And not only does it work better than a wrong-way Judson scoop, there is zero damage done to the car. It attaches via thumbscrews through the existing openings, and can be installed in a minute or removed in seconds. A few pictures are below for the curious, and maybe I'll make a better looking one until I get the luggage rack  wink

Paul


http://i235.photobucket.com/albums/ee288/altema/Misc%20tech%20photos/Ghiascoop01.jpg


http://i235.photobucket.com/albums/ee288/altema/Misc%20tech%20photos/Ghiascoop02.jpg


http://i235.photobucket.com/albums/ee288/altema/Misc%20tech%20photos/Ghiascoop03.jpg