While it is a big impedance to airflow my thinking is that it's not the bottleneck in the flow through the engine compartment which is the cause of the cooling problems. Otherwise the Koyo radiators would show bigger improvements over the stock radiator. The problem is the flow through the radiator and consequently the pressure at the front of the radiator is being dictated by how well the air is being evacuated from the engine bay. The total flow area into the engine bay is greater than the flow area out of the engine bay causing the higher pressure under the hood and making the Cp under the hood very close to the front of the grill and higher than the base of the windshield.

 

Interesting. The propped up area of the hood on my car is quite warm. And the only way for it to get warm is if air is escaping there... I have a heat sensor, and I'll check the temp when I get home.

 

MAc11 and Rotor (or prober if you will)
Last I remember when I started this tread its purpose was to find a simpler way to get the car cooled off, and to reduce under hood temps. Well I actually knew what needs to be done, the question remained HOW ,as I wanted to keep the OEM hood unmodified? Thanks to the man who you just called an idiot, and a fool, that solution was discovered quickly and painlessly. By now numerous folks had implemented this mod and reported positive results.

I don't remember in any of my original posts seeking to improve the air dynamics of the car. But hey, this thread has proven to be loads of fun thanks to you two.
Especially I love how you both start insulting people when you are cornered and have nothing else to say.
And please don't try telling us here that you in fact did know what that diagram represented. And if color does represent the pressure, then look carefully at the color right at the grill or (inside of it) and compare it with the color at the cowl.

With that said, I'll wait until Jeff posts his reply, which I am sure will be embarrassing enough for both of you to leave this forum for another few days, and will make it yet again a great entertainment for the rest of us.

 

Hmmm...not really sure, more just reporting what I've observed. That written, I think that maybe you are getting heat there because of being in stop and go traffic? Also, if a radiator - for example - as a heat exchanger doesn't do a 100% job of removing heat. Likewise, maybe this applies to the "propped up area" you are referring to...or is it hotter than it used to be? It may be more efficient, but not 100% by any means in getting rid of that radiant heat.

I'd suggest taping some thin streamers along the windshield/hood and see where the air is going in person.

 

1) no one said the mod didn't work. Just that you have no idea why it works

2) that is a surface graph. There is nothing about under hood (or post radiator) airflow or pressure so I'm not sure where you get "inside the grill" color. Nor car you make any assumption as to what the under hood pressure is to compare it to the cowl pressure to say which way air is moving to/from the cowl area.

3) Thanks for showing that you need to quit acting like you know what you are talking about by admitting you are riding MM's coat tails.

 

I don't pretend. I either know, or I don't. And I have no trouble admitting one or the other.
And yes I do have a great degree of respect for MM, and tent to stand by him in cases where my opinion matches his.
Also he is funny as hell, when making fun of you and the stubborn likes of you.

Oh and as far as at or inside the grill (I'll let myself be a little rude, just for the fun of it)...

Look closer dumb ***.

 

rude or not, you're wrong. its surface. The red area you are referring to is still only pre-radiator and shows nothing of under hood pressure or airflow. try again.

 

Ahh. I got nuthin...
I'm used to being called an idiot. That is what happens when you are willing to tape your ***** to the cowl and see what happens.

I like angry/frustrated people - they give my day perspective. That's why I thank my lucky stars for folks like TeamRX8!
When Mac11 and pr0bed reach that kind of fever pitch I'll get back to you.

 

As per

But you can keep on trying...

Who said anything about the radiator?

 

thank you for illustrating that you have no data from post radiator - under the hood.

 

Data that I was interested is the temp readings of the coolant, not the underhood pressure. And there is plenty of reports on that.

 

Then why are you referencing a airflow/pressure picture/response?


As for this line of discussion, please find me where I said that this does not work and we can end this.

 

Guys - who cares? Really?
If you want to have a discussion on fluid dynamics, then do it with relevant data (from the target vehicle) and proper math, not "feely" stuff.

Otherwise, the empirical data stands alone.

 

I concur.

 

So, let it go.

 

oh look, another rocket scientist commenting on something he is clueless on... i would have never guessed

 

So tell me if air goes IN and not OUT of the hood, how is that improving the radiator efficiency as you had stated earlier? Why is it now suddenly your avoiding the whole subject on how this modification works or doesn't work.

 

it was hotter on the ride home today. And even through I was boosting around traffic, the coolant was still in the 180-190 F range. I was only able to get it to go to 200 F by driving in 3rd at 5000-6000 rpm for a while.


Also, by the time I parked the car, the hood vented area read 103 F. Not conclusive though, since there was about 8 minutes of slow driving as I cooled down the car.

 

Nothing increases "radiator efficiency". "Cooling efficiency" is affected by, among other things, air flow.
If you create a greater pressure differential between the front (grille) side of the rad and the back (engine) side, the flow will be higher and so will the heat rejection.
If you create an additional path for air to remove itself from the engine compartment, it will flow from an area of higher pressure to an area of (relatively) lower pressure.
As I pointed out, even if the venturi effect across the cowl raises the pressure there at the cowl, it will still be net lower pressure then that of the grille. Flow will occur because there is a pressure differential.

Air goes OUT of the hood. There is a pressure differential.
Air goes OUT of the hood. There is a pressure differential.
Air goes OUT of the hood. There is a pressure differential.

Now, how would you like me to restate that the next time you claim I am being unclear?

 

How about with an actual test of airflow? Thermometers do not test airflow. And to quote someone whos statements you may take stock in:

 

no matter what you guys do and say here, this thread will never be as awesome as the thread that argued if water cooled better than glycol.

 

why you gotta kill a brothahs dreams?

 

I'm hoping he'll see the light. You too.
The theory makes no difference whatsoever.
Air leaves the engine bay at a greater rate with the strip gone. Who really cares how or why other than you two?

 

That really doesn't sound like it matches with your typical attitude.

I know what is going on with the airflow, I'm not at all concerned about the theory or the graphs of a volvo. I think its fun to see you say you don't care about the theory, yet that is all you have to base you conclusions on - theory and big words.

 

I base my conclusion on one thing and one thing only - my car (as well as others) doesn't overheat after performing this mod under conditions in which it otherwise would.
Obviously, you do not know what is going on with air flow any more than those that have experience with it.

My typical "attitude" is the same, but after a while I lose my interested in stupid people with insipid arguments.
Get a dictionary.