Type 65 Aero Vents & Airflow

[Chopper]

Hi all,

I'm in the early stages of planning a possible gen 3 coupe build, and as a result I'm overthinking every detail. Today's ramble is regarding the Aero vents. I know some people like them, some don't...to each their own. My personal preference is to include them, I like that race car look. Aesthetics aside, my question boils down to functionality. I would like to do a car with windows and AC, but, I also think it would be nice to remove the windows, and drive with venting on a cool day.

Now, I do know that modifications will be required to make the aero vents functional as what is provided is more of a cosmetic piece. Assuming that could be done, I think in a perfect world one would build some mechanism that would allow the vents to be opened or closed. Whether this is a manually installed block before driving, or something that you could operate from the cockpit remains to be seen.

My biggest question about these is, when operating with aero vents, or simply without windows, wouldn't it be desirable to have some sort of vent on the back of the car? The originals have a vent cut in to the back of the spoiler to vent air out. I know when I drive my truck, if I open the little center rear window when the front windows are down, the air flow is a lot less turbulent. I assume that same principle would apply here.

In addition, how much air do the scoops on the rear side windows pick up? Is that an area that gets a lot of airflow, or does the shape of the body force air out and around those? I read somewhere that the original coupes also had wind deflectors on the A pillar to force more air in into these scoops for rear brake cooling. I wasn't planning on the A pillar deflectors, but was curious how the FFR body behaves in this regard.

A modern photo of the real CSX2299, showing the vent in the spoiler (interesting aside, the vents in the tail are blocked off, but can be see open in historic period photos):

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I'm sure most are familiar with the A pillar wind deflectors, but for reference they can be seen here:

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-Brandon

[Bob Brandle]

Brandon,
Have you thought of having the two windshield cowl mounted scoops functional and directing air into the cockpit? Possible with open/close valves? Fresh cooling air entering the front of the cockpit might be more useful than air trying to enter the rear 3/4 window Plexiglass scoops, that I believe were intended for rear braking cooling, not cockpit airflow.

Also consider a cockpit outflow vent or vents in the cockpit interior rear panel, dumping air into the (low pressure?) cavity behind the fuel tank/in front of the rear kahm-back panel or being routed to that 64-65 racing used vent in the back of the ducktail spoiler.

I'm working on installing both of these features in my Gen 3 Coupe.

The period correct racer plexiglass window scoops could still be on the car, functional or not.

Bob

[John Dol]

The cowl scoops have been made functional before to drop air into the foot boxes with a manually operated valve gate.
The 1/4 scoops do help getting air into the cockpit. Many have added block off windows due to AC usage.
I have seen AC/Heat vents been put in the trunk side walls to evacuate air, as well as making the slot in the spoiler functional.

HTH,


John

[edwardb]

Disclaimer: These observations based on now approx 400 miles on our Gen 3 Coupe. But FWIW. I briefly considered making the rear Kammback vents functional to relieve air pressure in the cockpit with everything else closed up. Decided against that and plan B was to put some vents in the rear hatchback wall for the same reason. Didn't do that either. So far, no regrets. We've driven the Coupe almost exclusively with the windows and side scoop blocking pieces installed. In cool weather with heat (yesterday morning in the 40's) and a couple of times near 90 and high humidity. Both heat and A/C made things comfortable and at no time did I think ventilation was an issue. I was able to come up with decent seals for the doors and side windows. Used the Factory Five supplied seal for the hatchback glass. But I wouldn't consider any of that DD level to where everything is completely sealed. Seems to be letting enough air through to not be an issue so far. Nothing you do will hurt anything for sure. Just not sure there's a big return. At least that's what I've observed so far.

But the bigger issue for me is that in spite of my efforts for sealing, insulation, and slightly quieter Gas-N side pipes, the car is relatively noisy and having things closed up helps. Even having the door sliding windows open makes a difference in the sound. So I guess my point is don't leave that consideration out of your decision making. Riding around with the windows out, scoops working, etc. will no doubt allow adequate ventilation. But might be louder than you expect. I suspect most (maybe all...) or our driving will be with everything closed up.

[Chopper]

Thanks for all the thoughtful responses, I have a lot to consider here.

Paul - I have read in your build thread about noise. I know these type of cars are going to be noisy, so not delusions. Would you say the primary source of noise for you is engine/exhaust noise, wind noise, or both?

-Brandon

[edwardb]

Thanks for all the thoughtful responses, I have a lot to consider here.

Paul - I have read in your build thread about noise. I know these type of cars are going to be noisy, so not delusions. Would you say the primary source of noise for you is engine/exhaust noise, wind noise, or both?

-Brandon

Engine/exhaust noise almost entirely. Can also hear, to a much lessor extent, the transmission and diff gears just a bit. I've heard people say that's because the hatch area is open to the cockpit unlike the Roadster with the enclosed trunk. Makes sense I guess. Haven't noticed any wind noise at all.

[Chopper]

Paul,

Thanks, makes sense. I'll plan on doubling up insulation along the sidepipes. I was actually thinking about spaying some on the inside of the body along the exhaust tubes to supplement the in-cockpit insulation. I still expect it to be pretty load, which is fine. I always wear ear plugs when I drive my roadster.

-Brandon

[jkrueger]

10000 miles on my coupe. I two 4" holes into the back wall of the hatchback area to vent air out. I ran the sliders windows for a long time and had and had these little windows in the rear brake scoop area that you could open and close (I don't remember where I bought them from, but someone on here will know). Those vents windows moved a lot of air without the scoops or the A pillar deflector. I think the vents in rear help with that.

The side pipes are super loud inside the car. I don't have any sound deadening inside the car except the standard carpet, and it is way louder inside the car than outside.

JC