Wind coming from the handbrake tunnel?

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My 10-year-old VS (normal body) has always done this, and I've never been certain just why it does, either.

There's an access port at the front of the tunnel for removing/replacing the long front-to-back shift rod, but that should be covered with a metal plate, and it is on my car.

So, where does this air pressure come from?

It does tend to corroborate the theory that the shape of our cars creates positive pressure underneath when they're in motion. And the fact that the front end also gets 'light' at speed is another supposed 'proof' of that. But I've never seen any wind tunnel tests or serious science that confirms this specifically for our cars.

In theory, the tunnel should be sealed at the back with various rubber bits where sundry tubes and cables exit, but my car has none of those, so if there is generally positive pressure under the car it could enter there.

On my car, the temperature of the air jet at the handbrake does warm up as the engine does, and I'd think if the air were just ambient air from under the car that that wouldn't happen.

So, while I may have lots of semi-educated guesses, I probably don't really know why this happens either.

I'll bet Don Herbert would have known.

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I don’t have a handbrake, but air has always flowed into the shifter in my Spyder, from the hole in the firewall. In temps like this, it gets so hot to the touch that it’s burnie.

@Sacto Mitch posted:

It does tend to corroborate the theory that the shape of our cars creates positive pressure underneath when they're in motion. And the fact that the front end also gets 'light' at speed is another supposed 'proof' of that. But I've never seen any wind tunnel tests or serious science that confirms this specifically for our cars.

I'm just a shophead schlub from Flyover, USA, but I was a solid B- student at THS (and that included exactly one year of biology, which is as far as slacker HS kids needed to go in the sciences during the '70s). But one wonders exactly how much science is needed to confirm what you see and experience? I'd think Jr. High Practical Science would suffice.

The thing looks exactly like a wing in profile, is nearly perfectly flat on the bottom, and gets light in the front as speed increases. The lower you drop it, the less pronounced the lift becomes.

If it walks like a duck, etc.

I, too, get a small amount of air out of the handbrake boot on my pan-based Speedster. I have not noticed an increase in temperature over time, but I’ll check that out on the next drive.  
I have the proper cover and rubber gasket on the cover at the front of the frame, and I have both rubber boots installed on the cables at the rear of the pan.  Given all that…….  There is still an air leak there that I have never found the source of.

I thought of stuffing a piece of closed cell foam in the opening of the e-brake on the tunnel, but haven’t taken the time to figure out how to do that yet.

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@Stan Galat posted:

...If it walks like a duck, etc...

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OK, maybe it flies like a duck, too.

Further thought leads me to believe there's no gasket or air-tight seal where the tranny nosecone enters the tunnel, is there? And while the tranny probably warms up slower than the engine, it does eventually get pretty hot. So maybe that's where my handbrake ventilation is coming from?

I'm really surprised the VW engineers didn't use this source of pressurized air to power the windshield washers.

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Listen, I know you guys are farting and blaming the hot air on the the e-beake...

If that front plate is affixed to the tunnel, the air is mostly coming from the gap around the transaxle nose cone. There is a rubber grommet/gasket that could fit there, but making it tight is not always a builder's highest priority. Might be other grommets on the e-brake lines, fuel line and the clutch tube.

The air in the area around these is at high pressure when the car is underway.

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With the Berg 5 nosecone and some custom, uh, 'clearancing' to accommodate it, I may have more of a gap there than most folks do.

But I definitely don't have any of the other mentioned rubber grommets, so I guess you could say I have a full-flow tunnel.

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y'all are not alone...my 2018 JPS does that as well...i have just been to lazy to investigate it any further..it's one of those "it is what is is" things i reckon...i have only driven in proper rain only a couple times (not by choice)  and i know where rain enters...drivers side wheel well where wiring loom enters firewall near fuse block...not a rain car , but i probably should address that...but not today...it's summer here at the moment ...perhaps a addition to the Dr. JEKYLL discussion...but upon initial delivery in 2018..Mr. Hyde improperly installed (shocking, i know) the rubber washers on my windshield wipers and it MONSOONED like a waterfall inside my car the 1st night i had it....another painfull memory flashback i try to forget....go figure