New DOB Article – 3v PD Blower Buyers Guide

[Department Of Boost]

So what you are saying is, a larger volume of air flow will slow the air velocity which hurts the radiators' ability to transfer heat?

No. I'm saying that opening the grill doesn't get you any more volume.

Without understanding Bernoulli's math formula, higher velocity means lower air pressure. Does this apply to the venturi effect on the CAI?

The principal I'm referring to is that pressure is always equal on all surfaces. The pressure on the front of the car (there is a "bubble" of air up there) is equal on all surfaces. As long as there is pressure (there is) it doesn't matter if the air has to make a few bends, it will still have the same pressure as everywhere else. That's as long as there isn't a big restriction thrown in, which there isn't. And you need one serious restriction to make it matter.

 

[eighty6gt]

Why did ford open up the grille on the 2013 GT500? Styling? To save $!

I don't have time to read through this but maybe its w.r.t. an increase in boost and not cooling. Just say yep.

 

[Department Of Boost]

Why did ford open up the grille on the 2013 GT500? Styling? To save $!

For more cooling. Which works because it has a hood vent. The debate is about non hood vent equipped setups.

You can't shove in more air if there isn't anywhere for it to go. Make somewhere for it to go and you can shove more air in.

 

[eighty6gt]

I hate vented hoods/etc so I'm thinking of putting the 2013 GT500 fan in, and having a switch and added relay to force it on when i'm bombing around town at low speed. More delta P.

But, probably a stupid idea. Melt relays/wires/battery/alternator/not do anything.

 

[Sky Render]

For more cooling. Which works because it has a hood vent. The debate is about non hood vent equipped setups.

You can't shove in more air if there isn't anywhere for it to go. Make somewhere for it to go and you can shove more air in.

Exactly. Go read Terry Fair's build thread and look at what he did for hood venting.

 

[Department Of Boost]

Exactly. Go read Terry Fair's build thread and look at what he did for hood venting.

I can't remember the numbers but my SVT friend was telling me about having the S550 GT and GT350 in the wind tunnel and how much more air moved through the coolers on the GT350 because of the hood vent. It was a SHOCKING improvement!!!! And that is with the little weenie vent that the GT350 ended up with because of the styling guys dragging their feet. The performance guys wanted a bigger on e that moved even more air.

Also reduced front end lift considerably.

The wind tunnel goes up to 180mph.

 

[Pentalab]

You have a data set of............................one. Which isn't data. Not with the elevindy billion other variables in play.



I will one again refer you to Bernoulli's principle. When applied to how aerodynamics at the front of a car actually work your theory doesn't stand up.

https://en.wikipedia.org/wiki/Bernoulli's_principle

Me and everybody else that replaced the useless oem upper grille with the 7 bar grille all noticed the same effect. It's not much, .5 psi.

 

[Pentalab]

For more cooling. Which works because it has a hood vent. The debate is about non hood vent equipped setups.

You can't shove in more air if there isn't anywhere for it to go. Make somewhere for it to go and you can shove more air in.

With no hood vents, it only has one way to come out.... out the bottom. Pressure goes up to the square of the velocity. 100 mph has quadruple the pressure of 50 mph. 150 mph has 9 times the pressure compared to 50 mph. The openings on both sides of the block, and in front of the block, is the only place for built up air pressure to egress.

Remove the restriction of the oem upper grille and you will get more air coming out the bottom. You would get even more air through the rads if egress was supplemented with hood vents. The hood vents provide for a parallel path to the bottom sides of the block.

You are making it out like the existing openings on both sides of the block, and in front of the block are some kind of massive restriction. They are..up to a point, but not enough that an unrestricted upper grille won't have an effect. Boss has no hood vents. They run cooler with their oem upper grille tossed.

 

[Sky Render]

Bro, do you even fluid dynamics?

 

[Department Of Boost]

Remove the restriction of the oem upper grille and you will get more air coming out the bottom.

It's negligible because on cars without a FUNCTIONAL splitter (that means about touching the deck) the air pressure under the car is very high. Sure, you can jam a little more air out of the bottom, it's not like it's sealed. I'm not dealing in absolutes. I'm saying that the gains are so small as to be insignificant.

Additionally if you chuck more air under the car you increase lift and drag.

You are making it out like the existing openings on both sides of the block, and in front of the block are some kind of massive restriction.

I don't have the wind tunnel data to show you. But I am best friends with the guy who does have it/has done the testing. They are a massive restriction. You're either going to believe it or not. I don't even know why I'm wasting my time arguing with you. After this post you're going back on ignore. Are you the replacement for Dub?

They are..up to a point, but not enough that an unrestricted upper grille won't have an effect. Boss has no hood vents. They run cooler with their oem upper grille tossed.

Says you^^^^

Yet when I'm hanging out at the track with fast guys that also happen to be engineers that run BOSS 302's and they tell me opening the grill up didn't do any good, I tend to believe them.

Most of the population falls victim to the placebo effect when it comes to performance gains. I see it every single day ad nauseam. Just yesterday I saw a guy making an incredibly hostile argument that sub frame connectors on S197's are a good mod and when he did them to his car he could feel the handling difference ON THE STREET!!!!

I know you're going to argue (which I won't see) that there is no placebo effect with a temp gauge. Which is true. But running a back to back test eliminating all variables, which there are a billion when it comes to cooling, is nearly impossible. You certainly aren't doing it with one temp reading.

Add incomplete data to placebo effect and you have urban legend.

Good day sir.

 

[Pentalab]

So explain why the Boss folks had their cars go into limp mode, on a hot day. Problem was resolved by either removing the oem grille..or replacing it with the 7 bar grille. Several of them posted their results on corner carvers. Are they all nuts. The HVAC folks at work have the test gear to measure velocity and also volume /cfm. I believe it's small enough to fit in there. If it does, tests could be run..and data collected. The 7 bar grille could be partially covered, to simulate the oem upper grille....then re-run the tests.

All I know is my underhood temps went down, and the boost increased .5 psi....and no hood vents....and those results are repeatable.

 

[eighty6gt]

My boost varies 1+ psi based merely on weather. My underhood temperatures are stratospheric.