mac11

iTrader: (1)

It's funny that you started this thread and now act like an authority on this subject 24 hours after someone clued you in on this mod when you have done absolutely nothing to figure out how and why this would give any results of any kind.

mac11

iTrader: (1)

Oh I forgot, you pointed an infrared gun out a windshield on a sunny day in arizona to determine airflow.

MazdaManiac

iTrader: (3)

Oh yeah, I forgot that I was measuring the surface of the sun. My bad.
Are you really such a complete fool?
All temperatures are relative and the thermometer wasn't inside the cabin.. Just stop, please.

mac11

iTrader: (1)

You were driving from your roof?

r0tor

iTrader: (1)

especially when said person posts his temperature findings which correlated to a classic description of a circulating vortex in a stagnant high pressure area

oh and someone tell those damn raindrops that hit the rotor indention in the hood and actually run down the hood to collect with its little buddies at the bottom that they should be going the otherway because of all the airflow there

olddragger

iTrader: (3)

I did the same as you MM but I found some really good heavy duty felt at the home depo store. It also has self adhesive. works great.
I am always looking to see if things can be done "better". Most of the time they cant! But, this w/e I am going to look and see if a very small cut in the underneath surface of the hood, at the cowl sealing section, the little rise part, may increase the space for ventilating. may even be overkill--I just like to look.
Great idea.
olddragger

shaunv74

I think the problem is in our 8's that's not the case. There should be a low pressure zone in our engine bay if we had proper air evacuation but we don't seem to hence some of the cooling problems and success people are seeing with this mod.

I think your idea of putting a few pieces of yarn in the gap between the hood and windshield would prove out which direction the air is moving pretty solidly.

MM or Rotorrocks would either of you have time in your schedule to videotape such an event?

r0tor

iTrader: (1)

i can't wait till a coroner finds that someone died while sitting in traffic because they did a worthless mod to a car that had an exhaust leak at the headers...

mac11

iTrader: (1)

It was more than an idea.

rotorocks

I had no doubt in my mind that it will work, because instead of taping ribbons on my hood and then as MM would put it "spinning around and spitting", I use some common sense. Air goes in, it has to come out. It does come out under the car, but not before it fills the entire engine compartment and creates positive pressure in there.

I am just curious if it ever occurred to you that the reason the ribbons did not get blown away was because of the turbulence that occurs in that area? In my opinion it is caused by the fact that there is deepening at the base of the window and it may well have negative pressure in there. if that is true, then it may in fact help with the extraction of the hot air.

Oh and by the way, I started this tread because I was looking for input on how to better implement this, without changing the stock look of the car. Not asking whether it will or will not work.

MazdaManiac

iTrader: (3)

OK, Corky, let me see if I can simplify this for you.

Picture #1 is a remote sensing infrared thermometer.

It measures temperature by comparing a calibrated value to the amount of radiant energy it detects using a infrared opto-transistor. It has an accuracy of one inch per foot.
It indicates its measurement area by use of a "laser beam" that is not attached to a sharks head. Look at picture #2.

Wherever the beam is, that is the temperature of that surface in an area proscribed by the above referenced accuracy ratio (12:1).
On the sides of your car there are relatively large panes of glass that are mounted to movable rails that are actuated by a set of gear motors mounted inside the door frame. Observe picture #3.

By toggling a switch mounted in the passenger compartment on the inside door trim, you can move these panes of glass downward into a recess in the door, allowing for access to the outside world while still seated in the passenger compartment. It is quite refreshing!

Once access to the outside space is acquired, it is a relatively simple act to point the laser beam at different things and measure their temperature. Note picture #4.

The thermometer doesn't read the temperature of the air. It reads the temperature of the surface that the air is passing over.
It doesn't care how the air is flowing - it just looks at its net effect on the area over which it flows.

Kane

iTrader: (1)

LMAO, Sarcasm is great!

Jax_RX8

MM is correct - and this is different to the traditional theory and why the heated debate - let me explain why.

At idle, I think we all agree heat rises up and out of the gap - no issues here - as you have "positive" pressure from the engine bay from the heat and thus airflow is out from under the hood through the gap.

With vehicle movement, you now have two competing pressures - this is important - two competing pressures:

- the pressure from airflow into the engine bay trying to escape, and

- the positive pressure created at the cowl area (base of the windshield) from the windshield angle and air flow across the hood/windshield.

The real question is, does the positive pressure from the cowl ever get high enough to overcome the pressure from the engine bay air trying to escape? I think the answer is either no, or not until you reach very, very high speeds.

Here is my rational - for positive pressure to be formed at the cowl at all, you need some angle between the windshield and hood. 180 degrees, or flat, would never produce any positive pressure no matter how fast air flows - there has to be a bend before positive pressure can be achieved - and the more the bend, the more pressure is produced at a specific airflow.

The 8 has almost no angle - looks like maybe 160 degrees or so - which means mucho airflow would be required to produce any positive pressure at all - much less be enough to overcome the pressure entering the engine bay and trying to escape.

So, I don't think the engine bay pressure at speed is ever overcome by the cowl area pressure because the windshield angle is not great enough to produce enough positive pressure. Thus, I think there is almost always airflow out of the cowl area for the 8.

Now you could argue at some real high speed, enough cowl pressure may be produced to shift the balance, but not at anywhere near normal operating speeds.

You see, NASCAR does this, but they have very high speeds and more windshield angle (although not as much as they used too) to product the pressure they see into the engine intakes. They also have the cowl area sealed up to not allow engine air to escape from there - it must go under the car. If they did open up the cowl to allow engine air to escape, they would likely not have much, if any, pressure there either.

My two cents - argue away.

mac11

iTrader: (1)

so really then you are making unqualified statements about how you theorize the air to be moving based on readings you took that have very little to do with directional airflow and have not actually observed said airflow. Thats terrific. I can almost hear mazda calling now with that job offer

Brettus

iTrader: (2)

Yes - MM is definately the master of sarcasim .
I wonder if this mod is as good as putting a bigger radiator in ?

MazdaManiac

iTrader: (3)

You are really grasping straws.
Do you want to explain the delta in temps across this region and the difference with and without the weatherstrip? Go ahead. I can wait.

Well, its different.
The bigger rad did nothing to alleviate my overheating, but it does pull back from the threshold of overheating much faster than the stock radiator. That is its benefit - a quicker return to balance than OE.

The cowl weatherstrip delete actually provided an immediate, measurable drop in under-hood temperatures and engine operating temperatures. I imagine that together, you get the fastest return to normal than just one or the other alone.
Bigger fans are next for me.

mac11

iTrader: (1)

While stopped or at speed?

MazdaManiac

iTrader: (3)

Just STFU.

Trekk

+1

XDEEDUBBX

yea no shyt moron, I was simply stating it, sue me for not reading every thread out there. I wouldn't even consider that idea nor the washers, just simply stating what i've seen.

shaunv74

Also the obvious difference in a cowl induction intake from what we are talking about is that your intake will be at a much lower pressure than the windsheild or engine compartment due to the vaccum effect of the motor ingesting air.

rotorocks

And why are you calling me a moron?
I believe I politely explained to you th reason why I did not want to insert the washers. And yes I did state it earlier. I had no beef with you..

You are not a very nice person are you?

rotorocks

MM
PM sent

MazdaManiac

iTrader: (3)

PM received. Great idea.

XDEEDUBBX

sorry dude, my mistake , I thought you called me an old record player...