Functional Use For Rear Vents?

[ballin280z]

Does anyone know the purpose of the S30 vent holes in the rear quarter panels? I tried searching for a purpose for them but found nothing, so if anyone knows I'd love the input.

[RTz]

The simple version... when you turn on the HVAC fan, the air must have a place to go. No place to go=no flow.

[Bartman]

240Z’s had a somewhat revolutionary (for the time) flow-through ventilation system integrated into the design. The intake vents are below the dash on either side and are individually operated with push and pull type knobs. One of the problems was that the exit vents on the hatch tended to suck in the exhaust fumes. On later models the exit vents were move to the sides (underneath the emblems), but the exhaust fume problem remained.

[getoffmyinternet]

The air intake is under the emblems?

[RTz]

The air intake is under the emblems?

 

Nope, air exit.

 

Think of the vents as relief air.

 

Re-read Bartman's post.

[getoffmyinternet]

Duh to me. I was still caught up with the exhaust entering, but I guess that's mostly just when it's off.

 

Seems that when it is on cabin air, no air needs to exit, But on vent air from the front of the car, well there you go.

[twoeightyzx]

Not to thread highjack but I've seen a few people who have welded over these side vents for a cleaner lookand would eventually like to do the same. Will welding them closed cause a problem in later use?

[Careless]

Someone also posted at some point in time (I'm not gonna dig the thread up!), that after welding shut those holes, it became noticeably hard to close the doors, or it would require a bit more force, as there was no place for air to go upon closing them.

 

I'm not sure how much truth there is to that post, as I'm sure in a 30 year old car, a grommet or two is going to find itself to pieces and be enough to let air out. But judging by the size of the air vents I'd say it's highly possible that it could not be a large enough escape for cabin air if the vents were welded and a failing grommet you've never seen are the only things you're relying on to relieve cabin pressure.

[theghosttanker]

If you close those vents up, your defroster will will work even worse, unless you crack open your windows or open the footwell vents. And, as you may have noticed, if you open your windows, the exhaust fumes get even worse in the car. And driving with your footwell vents open in cold weather kinda sux too, and once you get up to any good speed, they will also overpower your blower fan, once again making the defroster even worse.

It depends in part on when and where you drive. Here in CT, I would leave the vents open.Instead of welding them shut, you might want to figure out some kind of trick cover that blends in better, maybe juust some kind of subtle louver work that is painted to match the body.

[Tony D]

Ghosttanker nails their function & issue, it's defrost and airflow. The relocation to the quarters was to give a place to allow for a larger vent without being obtrusive. The original small rectangular hatch placement vents on the early cars weren't functioning that well, and had issues with water leakage to the interior more than any perceived issue with 'fumes'. When new, 'fumes' was not really an issue with either position. Drive a Z without a rear hatch, and you will notice the defroster works really well, and there is no fume issue at all.

 

With the 34 degree mornings finally getting me frost on the windshield, the lower vents blowing cold air onto my legs is kind of sucky, as the heater is on 'high, fan position 3' to keep the interior at 70mph whilst going 80mph down the 60 freeway in the morning.

 

In the FSM the show the 'flow through' fucntion of design to the heater system, as well.