Front NACA ducts - cutting out

Does anyone have any close-up pics of the three NACA ducts on the front clam that have been cut-out, ie opened up.

My GTD (like many others) hasn't been done & I feel it looks wrong. Also I'd like to use the ducts as they were originally intended, ie the centre dust into the cockpit & the side ducts to the brakes.

Before I attack the front clam I'd be interested & grateful to see a close up picture.

TIA

Julian, Take a look in the "Any real GT40 owners out there lurking ?" thread. There are some really good pictures of the nose section of an original. While the center duct does go to the demister, it doesn't appear that the two side ducts do go to the brakes. - Lynn

Lynn,

Just had a look at that thread, but he pictures don't show & the web link mentioned doesn't work.

Re the side ducts, I can't see where else they would go if they don't serve the brakes? AFAIK The intake duct will only take in air if it has a matching exit duct.

I figured the side NACA's take air to the back's of the front wheels which is then drawn thru the wheels, cooling the discs en-route.

For the centre NACA I assumed the air would be drawn out thru the vents in the side windows.

WDYT?

Julian,

Go to the post by Duane Hart on Jan 5.
there is a link to his site(Sporting Images). It has photos of a yellow and red DRB with what looks like brake ducts that align with the NACA ducts on the front clip. They look like factory built parts. Perhaps they might fit, or perhaps be adapted to fit your GTD?

Bill

I thought the side fender ducts fed the side fresh air vents inside the cockpit. Aren't the brakes fed from the two holes on either side of the radiator opening on the front?

Bill, thanks for the pointer. in this image http://www.sportingimages.com.au/weekly-motorsports/gt40photos/IMG_3864.JPG

It looks as tho the side NACA's are indeed ducted to the cockpit. Mark's post makes sense regarding the intakes either side of the radiator intake feeding the brakes.

Julian,

Somewhere, I saw photos of the brake ducts on #1075. They were from the front alongside the radiator aperture to the inside of the rotors.
I'm sure you could modify something to suit your purpose.
How about some of the other GTD guys out there or GT Developments themselves?
Best of luck.

Bill

FYI, check ERA's website
http://www.erareplicas.com/gt/gt.htm

They duct the 3 nose ducts to the cockpit (and
AC if ordered), and the scoops on the side of
the radiator to the front brakes.

I believe there used to be some pix of
the ducting to the cockpit.

Ian

On the Sabre we purchase a Super Space Saver unit from Vintage Air and then dismantle it and rehouse the components to fit. I used one of the vacuum servos and dampers to control the entry of fresh air from the two side ducts into the cockpit. A solenoid contols the servo's supply of vacuum so I have a toggle for fresh air on the console with the other A/C controls. - Lynn

OK, thanks guys. TBH I had concerns regarding cutting the fiberglass, but since my earlier posts & some prep last night I've cut & filed the centre vent & am V pleased with the result, didn't even mark the paint!

I did the basic cutting with a Dremel & then tidied up with sandpaper & got a nice smooth edge.

If nothing else I think it dramatically improves the look of the front of the car.

Julian

Can you post a picture. Would be interested in seeing the result.

Martin

Julian
I have a GTD and I have opened up the two outer ducts. I glassed in a tunnel from each and ran them up to the bulkhead then through flexible tube to the eyeball vents in the dash. They give a good blast of fresh air when on the move and I have some small fans in the pipework for when the car is stationary. Who needs aircon?
Brian.

Hi all

Here's a photo of Ian Braker's open NACA ducts on his GTD

My Roaring Forties GT40 turnkey has open ducts. A visit to their website and a look at the magazine article in Unique Cars has a good photo of the front. The black Mk11 also has all ducts cut out. These small details really do add to the overall look. regards

[ March 05, 2002: Message edited by: norman falkiner ]

Martin, unfortunatley I don't have a digital camera at the mo so pictures take a while!

Got fully carried away last night & finished the three NACA ducts & then set about the rather ugly flange around the radiator intake. Again a huge improvement to looks & airflow. Poor old Dremel earned it's keep last night! The nostrils are next!

As to connecting the vents to the cockpit, the centre one wil be fairly easy, by cutting the bulkhead & fabricating a small ally scoop... it'll simply vent into the footwell.

As for the side NACA's I hope to make up a setup similar to Brian's, however I need to decide whether to keep the air-con. I want to keep things simple & avoid fitting extra flaps, switches fans etc.

I also need to work out a way of keeping the rain out. Possibly a hole in the floor will do!!

Looking at a test on Colvilles genuine GT40 in an old copy of C&SC, it has a row of slots in the back of the roof. Presumably these are to aid airflow in the cockpit. Nice idea, but I won't be cutting holes in my roof!

Hi Julian

Two warnings about what you are doing.

One, rain may come in the centre duct into the footwell. You have already thought a little about this by the looks of it. Rain comes through the duct and even if you haven't made a route into the cabin, it then trickles down the front of the centre section and come in around the footwell opening panel. This lands on your legs when driving. It takes some thought to seal this from water and still keep it totally useable. The foam backed tape doesn't make a very good water seal. Once at Silverstone it rained very hard and I had pushed my camera and other stuff out of view down the footwell and came back to find everything quite wet. Gtd's are not really watertight!

Secondly, if you cut off all the webbing around every opening you will get the effects you want, but also possibly open yourself up to cracking in the paint work as the vibrations etc transmit through the body. This may take a little time to show itself. However let me know what happens as I have thought about what you are doing myself but been apprehensive about doing it for real. Don't forget to seal any newly exposed edges with paint as water may damage the fibre glass, making it unsightly.

Malcolm

Malcolm,

Thanks for the warnings. Being that this is first car I've had with a roof, I'm not that bothered about a little water. Racing my Westfield I watched with great amusement as other drivers went to extraordinary lengths to stay dry, none of which worked! so I just think 'sod it' & get wet. Wouldn't be the first time!

A quick temporary solution would be some duct tape on the inside of the vents! Every race car features duct tape, *somewhere*!

It seems to me the fiberglass GTD mouldings are about three times as thick as they need to be! So I'm not concerned about cracking at the moment!

I hope to bring the car to yours on the 23rd if it's still convenient, prolly give silverstone a miss if there's no GT40's racing...

cheers!

Julian

If you want to see how I have overcome the problem of water ingress into the car through the ducts, my car will be at the GT40 Enthusiasts Club AGM at Gaydon this Saturday. It's much easier to have a look rather than me try to explain.


Brian.

Thanks Brian, Unfortunatley I won't be at the meeting.. I'd be interested to see your car another time tho....

I believe that the two ducts on top of the guards originaly channeled air to the famous cool air outlets in the seats. They proved not to be too effective, so the ducts may have been since used for other purposes. Can anyone else confirm this?