phoenix7

stick with an Aluminum hood for now.

Do you have a turbo?

CarzArKoo1

No sir hehe. but the scoop looks nicer on the car.

phoenix7

dial8

iTrader: (4)

Haha!

Red_Rabbit86

i personly am not a fan of ebay, altho i have never shoped at ebay so i have a bi'est opinion. most good shops can get you the hood for you, even though they are not a direct dealer.

gopher_6_9

[QUOTE=boostedfc3s;7628841]If the cars cooling system is operating properly you will not see a differance in temps, the thermastat is what controls water temp and it will open and close to maintain that temp.

Now when I put the ram air hood on the ranger, I noticed a differnce in how long it to to get warm if you started driving without letting it warm up, I noticed a huge differance in underhood temps.

RacerXtreme7

iTrader: (2)

NZConvertible caught it. Its marketing bullshit. Yeah sure the front vents actually VENT, but the rears near the windshield is going to have air going into those vents, not hot air comming out. Guys, just buy the hood style you like, be it smooth n/a stock, stock TII, or some other chopped up creation. What matters is you like the style.


~Mike.........

Tofuman FC3S

iTrader: (1)

Yeah, like he said ^^ Ofc, the front of the windshield is a high pressure area, but if you were to duct the front big vents, so it would strictly vent the intercooler (on a VMIC), I could see that ~maybe~ the pressure in the enginebay could built up, and be bigger than the outside pressure (front of windshield). It would work then, possebly only at higher speeds. But those are if's and when's, what's important and fact is that it's not a very good place to vent you enginebay.

Riz.

CarzArKoo1

Since we are now discussing about areodynamics, any clues that having a hood scoop will create a lot pressure pushing the hood up. Since the air goes in to the hood, any comment or actually the wind are pushing it down on to the hood with pressure as we drive our FC or FD, and is it faster we go the pressure tends to push down harder on the hood instead of pushing it up, might sound stupid but really want to know base on the car design already

dial8

iTrader: (4)

So far as I know, the only two hoods on the planet that offer great aero for FCs are the RE-A GTC hood, and the Sexy Style hood. RE-A is expensive and hard to come by, and Sexy was discontinued...I think. RacerXtreme7 called it best, style is king, and while I like the one Phoenix tossed out I'm more of a fan of R-Magic.

phoenix7

going back on the diagram:

some people complain about hoods LIFTING at high speeds due the hood's angle. That same lifting effect should LIFT and PULL the hot air our of those vents right??

When air goes over the openings it should create a vaccuum and pull the air out. You and NZ are right, I'm not a fluid dynamic engineer but i just don't see how air couldn't be sucked out. If you can clear this up then you get 1million forum bux.

2gTURBOrx45

Seibon make good hoods for a good price

Tofuman FC3S

iTrader: (1)

You are 100% right sir. The place of the vent is a natural low pressure area anyways, and the shape of the vent increases this effect. However for it to work, and (hot) air to migrate you need a higher pressure area as well. Because of that big hole in the front of you bumper the engine bay will get more pressurised as you speed up. Like I said: the difference of presure above and below makes the air wanna move through the vents, taking the heath with it.

But you already knew this...

Riz.

CarzArKoo1

I believe they don't make cf hood for FC.

NZConvertible

What that article proves is that a massive hole at the front of the hood (a low pressure area) will allow some of the hot air that's passed through the radiator to be sucked out, reducing the underbonnet temp. That's no surprise. It doesn't prove that air is able to ignore the laws of aerodynamics and flow in the direction of higher pressure, as their marketing animation incorrectly shows.

Forcing outside air into the engine bay may lower the measured underbonnet temp, but it doesn't help with engine cooling. A hood scoop will always increase the average air pressure in the engine bay (when the car's moving), and increasing the pressure behind the radiator will always reduce the amount of air flowing through it. This is an inescapable fact. In terms of engine cooling, airflow through the radiator is many times more important that airflow over the outside of the engine. IMO anyone upgrading to a FMIC should blank off the hood scoop to reduce engine bay pressure.

Hot air rises, no surprise there. But airflow management when the car's moving is far more important than what happens when it's stationary. Vent's at the rear of the hood will result in outside air flowing into the engine bay when you're driving, exacerbating the problem described above. If those vents were further forward where the presure above the hood is lower than ambient, they'll aid cooling by sucking air out.

Not necessarily. If there's a small lip at the leading edge of the vent then a low pressure area is formed behind the lip, i.e. over the vent. Without the lip air will just go straight over the top of it. But if the vent is located at the front of the hood, there's already a low pressure zone there caused by the car's shape. There's always a pressure build-up under the hood from air being forced in through the front of the nose, so by placing an opening where there's a pressure difference, air will flow through it. Since the pressure is higher below the vent than above it, air flows upwards and out of the engine bay. This lowers the pressure in the engine bay, increasing the airflow through the radiator.

RacerXtreme7

iTrader: (2)

Your not reading it through, or your reading comprehension sucks. Maybe I'm just being a *****? The front vents near the front of the car, YES will extract/vent/pull hot air out. The vents near the rear of the hood were the wndshield meets, NO wont pull NO air out. If anything, air will enter those rear vents. Its a high pressure zone were the front of the hood is low pressure. Don't believe me? Ever heard of a "cowl hood vent"? You know, the big redneck reverse hood scoops/ vents that have the opening near the windshield? Those pull air INTO the engine bay. NASCAR (uhhg) uses vents right at the windshield base and run air boxes around their CARBS (carbs, wow, 1900's tech) to aid in induction (yes, its higher pressure then ambient air, but they wont see positive boost, at least near immesurable). You don't need a windtunnel to know this (BTW I work at NASA were we have over 10 wind tunnels). Now as for hoods lifting, pulling etc. your over thinking this. Dude, its a HOOD, buy the style you like. Aero effect other then pulling hot air out are trivial as I don't suspect you'll be doing speeds over 120 MPH or your in serious racing and need that .000001% advantage that a true aero hood provides. Stop over thinking this, get a hood you like. 90% of even FAST high power street Rx7's run in high load situations dont even warrent thinking of all this aero crap. If your stuckmon frontal downforce, its in the lip spoiler, not the hood. And those stupid canard thinggies ricers like to use aren''t for downforce either. They creat a vortex so the air traveling down the SIDE of the car pull air from under it.

~Mike.........

phoenix7

You can argue that the angle of the windshield plays a role in the "vortex" you mentioned but the same principle applies. The hot air will still get sucked out.


The main problem here is that most people want a vented hood to lower car temps, look cool or just to have something not stock. In reality you want the hot engine bay to expel the heat so your sensors and your wires don't get all brittle and cause any possible problems due to broken wires. I'm looking for other examples and I invite you to do the same. I think this is important and we should come to a bonafide conclusion so we all at least know what IS and ISN'T GOOD.

We really need someone who has taken fluid dynamics engineering in here to settle this.

CarzArKoo1

how about the turbo 2 hood? where does those arrows go

phoenix7

i'm guessing into the Intercooler. haha, i haven't seen any diagrams. I can give it a good layman's guess but gotta figure it out.

mike_merryguy

iTrader: (8)

well, I would say about that Illegal hood comment... I do belive the law is a MINIMUM of two hood latches, I really don't think they care if you "over secure" your hood to your car by adding hood pins, the hood pin is to keep the hood from flying open while you drive, i personally have never heard of anyone getting a ticket for a modded hood with extra pins
after rereading your post..
now if what you mean by your comment is that the user will only install hood pins, I don't think that the pins were desinged to be used as a stand alone, I havn't seen any CF hoods that don't have a latch, I think that every hood I have looked at still has stock latch support, if it does not then I woudn't buy it, I belive the reason for the hood pins is that becuase of the weak nature of the CF vs steel or alum, the air may get under the lip of the hood and raise it up with such force that it will break the stock latch system, while with a steel or alum welded hood latch will not move with such force, the pins are required to keep this force from pulling the hood to the point of fracture.

with that being said, if the manufactur says that the hood doesn't require pins, then you are buying a good hood and if it breaks then i am sure they will fix ur ****..

if they say you need hood pins, either they are smart or they make poor quality CF, I would most likly go with the company being smart, it just makes more sense to use pins with a hood that is so much weaker than stock, its a pretty serious event to have a hood fly open, havn't you guys seen Tommy Boy??? LOL

magus2222

iTrader: (22)

"belive the reason for the hood pins is that becuase of the weak nature of the CF vs steel or alum"

WOAH, thats news to me. i didnt know that................
basically what you just said is sooooo counter intuitive, it blew my mind out of my ear.
are you joking me, cf is by far one of the strongest man made materials. if it werent as strong as it is, why would super cars be made of it, why would lemans cars be running shells and BRAKE ROTORS made out of it, why would drag boats be using cf or even carbon-kevlar instead of aluminum or steel.....................
let me see, if i do remember right, i do believe that CF has something like 15x the tensile strength of steel, 10x that of aluminum, oh and weighs 1/100th that of steel, and 1/50th that of aluminum.
if that were the case mike_merryguy, then why would the pagani zonda be made of carbon-kevlar and aeronotic aluminum? same as the farrari enzo, lamborghini mercialago lp640, and the bugati veyron?
god damn, facts man, facts.

peace

p.s. no, you cant get in trouble for having hood pins, only gives cops more reasonable suspicion of having a modded engine.

phoenix7

the real CF ****, not the CF LAYER, FG, POS you get these days.

RETed

Whoever made that animated GIF is an idiot.

Here's the official FC aero graph straight from Mazda...



Now can you see why you don't want the vent at the base of the windshield?


-Ted

RETed

Actually, it's the two-stage locking mechanism that's required.
I dunno if it's a federal law that covers all vehicles in the USA, or if it's a local (i.e. state) law, but down here they will nail you for just hood pins...no matter how many you have on your car.
The two-stage locking mechanism is to prevent you from accidently knocking the hood release and causing the hood to fly off the car during vehicle movement.
Hood pins cannot do this.


-Ted

phoenix7

wouldn't the larger vent and the angle change the way the air flows when compared to an NA hood?