No, this isn't another thread asking about that square rubber block that goes at the top of the firewall and often found laying in the frunk...


I've wondered this for years now but never bothered to ask anyone. What are these holes for under the left and right fenders which are on the outside of each side member? There is literally nothing inside these side members. They lead to a dead end towards the cabin (I've even snaked them with a camera). The front of these cavities are where the bumper bar's impact absorbers mount. Aside from that, nothing going on with these side members and these certainly don't appear to be ducts that direct air anywhere (again, lead to a dead end).

Anyone know this mystery? Hold over from older 911's? If so, what was the purpose originally?

I just cant live with this mystery any longer.

 

Mounting point for a jig on the assembly line?

 

I don't think they're on every car

 

It's on the fender side of every car, not the frunk side. They're under the fender liner.

 

I had contemplated that as a possibility but have never come across any real evidence or mention of such, so I've been wondering for years.

While we're on that path, I've always wondered the same about those large holes on the floor pan of the interior and frunk which have large metal discs inserted and seam sealed. There's a number of those that are about 3 to 4" in diameter or so.

 

The holes in the front fender wells are the cabin air outlets to the atmosphere. It comes from the side rails next to the rear seats and near the seatbelt reel mounts. There is a flapper check valve that lets air out but none in.
I was concerned about mice getting into the channel so I put some course stainless steel wool in the outlets.

I was told the large holes in the floor pan are for draining after the body was dipped. Don't know if this is accurate

 

Thanks Mike.

I'm aware of the vents/flapper by the rear seats. I believe these are to let air escape from the cabin when you swing the door shut.

I don't see how these are interconnected. I've snaked a camera down hole pictured above and it lead to a dead end. Will give it another look and see what I find.

 

Also, regarding the floor pan holes, that is as plausible as anything, so I'll believe it.

 

Did you go in from vent hole end to inspect? The vent air has to go out somewhere. The vent uses the chassis rocker box structure, that the cabin heat pipe is inside of, and continues past the point where the heat pipe exists into the interior by the dead pedal. It then continues forward to the exit holes you show in the outside of the front end side box structure. The factory fender liners specifically allow this opening to be exposed.

 

I went into the hole in question again and hit what seemed like a dead end again right by the firewall area.

I then removed the trap door located at the lower rearward corner of the front wheel well/fender. When I snaked the camera that way, I was able to easily get it right to the hole in question (or at least see the day light shining into it). Looks like I was hitting a false passage when going the other way.



Soooo... I'm going to go with Mike's theory that it allows that whole channel to vent all the way along the side sills, including those cabin air pressure flappers hidden behind the side panels at the B pillar.