Mod for interior airflow?

[RH77]

Originally Posted by markweatherill

On a hot day, DIY brackets that allow a hatchback to be securely cracked/propped open a little would possibly help..? Maybe it would aid in finding the ideal rear roofline angle as an aside.

Has anyone tried this? I'd be curious to give it a shot...

RH77

[Frank Lee]

Of course somebody's tried it. And they dang near got asphyxiated by exhaust fumes.

[RH77]

Originally Posted by Frank Lee

Of course somebody's tried it. And they dang near got asphyxiated by exhaust fumes.

I transported a treadmill a few Winters back and had the hatch open about 6" -- all I remember was that it was COLD. Makes sense that the undercar flow forces the exhaust into the cabin. Buggah.

[jamesqf]

Originally Posted by Frank Lee

And they dang near got asphyxiated by exhaust fumes.

Well, that's one way to test your emissions control system :-)

[Xringer]

Originally Posted by RH77

Has anyone tried this? I'd be curious to give it a shot...

RH77

I've driven around town with my rear hatch window wide open and
never smelled anything. But, I did have my side windows down a bit..
Gave me great ventilation. The pneumatic(?) lifters hold it up pretty well.

Maybe I should tilt it up and lock it down at the tear-drop angle,
and do a highway speed test..?.

[aerohead]

Originally Posted by RH77

Has anyone tried this? I'd be curious to give it a shot...

RH77

In the recent past,this would net you carbon monoxide poisoning.With newer,cleaner engines this may not be as big an issue,however,you would still be inviting the the outdoors in and from the direction of your own exhaust pipe.I have carried large items in a hatchback which necessitated propping the hatch open,and I suffered every mile 'til I got to my destination.The reason the cowl is used for a ventilation inlet is that it is at a relatively high static pressure ( NASCAR teams breathe their engines from here ) and the air source is away from the tailpipes of the car in front of you.Engineers try to cite the air outlet such that a relatively constant pressure differential is present across the cabin,rather than building into a hurricane draft,as speed increases.They're thinking air changes more than evaporative cooling.I've used auxiliary electric fans to increase air velocity across me.The proliferation of air conditioning has turned ventilation design away from passive,to forced air systems.Kinda hard to modify.

[RH77]

Originally Posted by aerohead

In the recent past,this would net you carbon monoxide poisoning.With newer,cleaner engines this may not be as big an issue,however,you would still be inviting the the outdoors in and from the direction of your own exhaust pipe.I have carried large items in a hatchback which necessitated propping the hatch open,and I suffered every mile 'til I got to my destination.The reason the cowl is used for a ventilation inlet is that it is at a relatively high static pressure ( NASCAR teams breathe their engines from here ) and the air source is away from the tailpipes of the car in front of you.Engineers try to cite the air outlet such that a relatively constant pressure differential is present across the cabin,rather than building into a hurricane draft,as speed increases.They're thinking air changes more than evaporative cooling.I've used auxiliary electric fans to increase air velocity across me.The proliferation of air conditioning has turned ventilation design away from passive,to forced air systems.Kinda hard to modify.

That has been the problem -- the rubber seal between the engine and vent inlet has deteriorated over time and draws-in hot air. When the valve cover gasket was oozing oil and toasted on the block and header, the "aroma" wasn't the best Since that's fixed, my next project may be to repair the seal and invest in a fan.

If I crack the passenger window and turn the air on recirc, I can get some decent air movement. Even with the recirc off, at highway speeds there's plenty of air movement -- even with the blower in the "off" position -- but it's hot air.

But alas, it's A/C season for a while unless I'm not doing work-related stuff.

RH77

[craig5_12]

I have a long commute (60 miles 1 way) and in the summer it's over 100 a lot of the time. I don't have A/C...something wrong with the compressor...so I drive with the windows down. It's ridiculously hot and I need to go buy some beaded seat covers I suppose. I'm suffering for now though.
Wondering:
1) If I drive with my rear seat folded flat and open up some sort of duct to the outside through my trunk, this could help alleviate the reduced drag from the open windows as well as improve the wake...right?
2) What affect does having the sunroof open along with both windows have on MPG? (car specific I'm sure...I need a scanguage...)

[cfg83]

jamesqf -

Here's my idea. Crack the rear passenger window down maybe 2 inches. Get something like a half-circle pipe. Aim one end just barely into the airflow. Aim the other end at the back of the driver's head.

My idea is that you will lose some aero, but you may get the best "bang for the buck" because you should be getting pretty fast air flowing onto the back of your head (as opposed to your face, which would make your eyes water).

You could test this by having someone hold the "half-pipe" to the window while aiming it at the back of your head.

PS - Maybe the pipe should be conical, large intake to small outlet.

PPS - It might be more efficient to have the pipe cut in half like a Jai-Alai glove so that you capture more incoming air through the window, as opposed to the diameter of the pipe :

The Cesta


CarloSW2

[Frank Lee]

You may find that a duct in that region brings exhaust gasses into the passenger compartment.

[cfg83]

Frank Lee -

Originally Posted by Frank Lee

You may find that a duct in that region brings exhaust gasses into the passenger compartment.

Darnit, I just can't win! At first I thought you meant from other cars. It could be the front passenger window instead. I am already opening the window for "fresh" (freeway pollution) air anyway.

It's easy to try. Ha ha, I just realized I can use the CO alarm for my gas furnace to test for carbon monoxide (there's a sad commentary there somewhere).

CarloSW2

[Frank Lee]

NO! I'm sorry, I meant to respond to this:

1) If I drive with my rear seat folded flat and open up some sort of duct to the outside through my trunk, this could help alleviate the reduced drag from the open windows as well as improve the wake...right?

[Xringer]

Unless the air intake is back near the rear end, near the exhaust pipe,
it's normally not a problem for most cars.

There are millions of people who rode around in the station wagons with the
rear window open, who lived to tell the tale..


I used to have a plain old smoke detector in my garage, but it went off
almost every time I started up an ICE..

[vtec-e]

The airflow in the civic is ok most of the time with the fan off but if its wet out, the car steams up. So i glued a small plastic scoop over the intake for the ventilation and it helped a lot. The airflow was like the fan was on the one or two setting. The scoop was only above the edge of the hood by half an inch and was only about 5 or 6 inches wide. It worked well, until i turned on the wipers! I had misjudged how far the wiper arm moves and it promptly removed my air scoop! But until then, it certainly worked well. I might re-install another one now that winter is approaching and steamy windows beckon.

ollie

[Tony Raine]

here is what i do as far as airflow

i'll start with a pic to reference off of

i also have a sunroof (the kind that retracts INTO the body)

if its really bright outside, i leave the sunroof closed (it has a solid sliding cover on the inside), and open the side windows and the "wing" windows that are right behind the door windows.

yeah, the wings probably aren't to good for aero, but i don't go over 50-55 very much (if i do i close them).

if its dark/cloudy, i open just the sunroof and wings (leave door windows up). i've found that if i leave the wings closed with windows down, stuff in the back (my back seats are folded down 95% of the time) blows all over the place. if i open the wings, i can have loose paper back there, and it hardly moves.

my favorite setup is door windows closed, sunroof and wings open. there is very little wind noise, and temps stay pretty comfortable (even with leather seats).

on the highway, just sunroof open is very comfortable. not a lot of air blows in (i have to stick my hand out of the rig to feel a breeze), but its enough unless its over 90 degrees.

of course, i have no real way to to judge mpg gains/losses yet



heres a thought. ever seen those ducts on the rear quarter windows on nascar? nothing sticks out, its basically a window with a hole in it. duct that to a convenient area.

[craig5_12]

Thats not a bad idea, I hate the foggy windows...steamy windows are much better...anyhow...I'm thinking a thin attachment for a vacuum cleaner the long skinny one, might be sufficient to allow enough air in, a small enough crack in the window, and still remain fairly aerodynamic if put lengthwise on the A-Pillar...hmm...

So exhaust fumes aside...do we think this would help the wake?
1) If I drive with my rear seat folded flat and open up some sort of duct to the outside through my trunk, this could help alleviate the reduced drag from the open windows as well as improve the wake...right?

On a side note I have about 375 miles on this tank and I'm not even at 3/4 mark yet! No scangauge though so it'll have to wait until fill-up to check MPG...

[SuperTrooper]

Originally Posted by Tony Raine

here is what i do as far as airflow

i'll start with a pic to reference off of

i also have a sunroof (the kind that retracts INTO the body)

if its really bright outside, i leave the sunroof closed (it has a solid sliding cover on the inside), and open the side windows and the "wing" windows that are right behind the door windows.

yeah, the wings probably aren't to good for aero, but i don't go over 50-55 very much (if i do i close them).

if its dark/cloudy, i open just the sunroof and wings (leave door windows up). i've found that if i leave the wings closed with windows down, stuff in the back (my back seats are folded down 95% of the time) blows all over the place. if i open the wings, i can have loose paper back there, and it hardly moves.

my favorite setup is door windows closed, sunroof and wings open. there is very little wind noise, and temps stay pretty comfortable (even with leather seats).

on the highway, just sunroof open is very comfortable. not a lot of air blows in (i have to stick my hand out of the rig to feel a breeze), but its enough unless its over 90 degrees.

of course, i have no real way to to judge mpg gains/losses yet



heres a thought. ever seen those ducts on the rear quarter windows on nascar? nothing sticks out, its basically a window with a hole in it. duct that to a convenient area.

Tony, have you thought about lowering your Sport? It is cheap and super easy for your generation Exploder:

http://stlouismtb.tripod.com/loweringwriteup.html

Lowering seems to produce good returns for fuel economy gains. I'm trying to talk my wife into lowering hers, the "Green Monster".

[Tony Raine]

Originally Posted by SuperTrooper

Tony, have you thought about lowering your Sport? It is cheap and super easy for your generation Exploder:

http://stlouismtb.tripod.com/loweringwriteup.html

Lowering seems to produce good returns for fuel economy gains. I'm trying to talk my wife into lowering hers, the "Green Monster".

yup, thats the next step (after removing the lift). gonna drop the front as much as i can without slapping the bumpstops all the time, and then block the rear down a little for a slight rake so i don't nose-up when towing. then switch to 28" tall street tires.

but first i gotta sell my other 2 sets of mud tires (the ones for my bronco). then this set you see here (which is almost new) will go on the bronco. that money will help offset the costs of the tires, lowering blocks, and alignment.

[superchow]

Originally Posted by aerohead

Baron Reinhard von Fachsenfeld's "Aerodynamiks des Kraftfahrtzeugs" ( sp? )

Aerodynamik des Kraftfahrzeugs - very close! (I'm German, if anyone wishes to inquire as to my qualifications on the German spelling issue. )

On the airflow issue - I enjoy tilting the sunroof and cracking either the rear passenger or rear driver side windows. The air flowing over the car sucks the air out the sunroof which in turn is supplied by the rear cracked windows. Another plus is that if my wife isn't hot at all, she won't even feel the breeze when I open the passenger side window. Conversely, the opposite is true for the driver side rear window. Very low noise and highly effective.

The effect is reduced when opening both rear windows. Must have to do with turbulence...

[jamesqf]

Originally Posted by cfg83

Here's my idea. Crack the rear passenger window down maybe 2 inches.

Duh, what's a rear passenger window? (Says driver of Honda Insight, the latest in a series of two-seaters going back to an Austin-Healey Sprite.)

But yes, something like the "cool Scoop" I used on the Cherokee (airplane windows don't roll down, and there's just a small flap about the size of my hand that opens) would work. I was hoping for something more aerodynamic, as in if you can take some high-pressure air from the front, run it through the car for cooling, then exhaust it into a low-pressure area at the rear, you've reduced drag in addition to getting a nice cool breeze.