How do Hood Scoops and Bonnet Vents Work?

Getting back to aerodynamics, today I explain how hood scoops and bonnet vents work for road and track. I explain the basics of how the airflow works around them, where it goes to, and what this airflow can be used for.

[@lamia197]

I have a friend with a 2005 Subaru hood scoop backwards as a vent, he needed cooling in traffic. He says its helps alot.

[@lamia197]

​@@Russell_and_Rosko Its a itasha, so.... but it works so meh.

[@itswizardgaming3487]

Wanted to do the opposite with vents for a scoop because I don't want a massive hoodscoop wondering if that will work

[@brandonturner3943]

I got the autozone scoop I put it on with mesh facing forward. O made my temp hotter. I was thinking about turning it backwards. Orrr cut some vent holes and put vent covers on it not sure

[@Mattys91gt]

could u get any pics of it under the hood I have a mustang but I'm trying to do the samething

[@JoeOvercoat]

6:00 When you’ve been driving 80 miles an hour on the interstate on a hot day and then you come to a near but not quite halt in bumper-to-bumper traffic, for an extended duration, venting the engine compartment is highly desirable. So yes to what you said, but that’s the case that comes to mind.

[@alphachingon6920]

Thanks for This video! This should be played on a big screen on ricers meetings worldwide.

[@holdXtoshoot]

I came here looking for a ways to improve my off-roders cabin airflow with ramscoop. Was not disappointed and now I want to have a really fast car for my next project. Thanks for making all of this understandable for even a foreigner. Subscribed.

[@VictorChaninitialvic3]

Love your vids! These videos should deserve more views i swear

[@phantom6653]

10 seconds in, and you earned a like. hood scoops, and vents used by both legitimate cars, and ricers.💯

[@maristoldboys5466]

🤣😂😂 same here all said with a dry expression

[@galant310]

hey keep up the good work brother! I wish you all the best for 2016 and that you prosper in your field cause you do an awesome job. very intelligent reviews and information

[@KYLEENGINEERS]

+kishon Palmer Thanks for the compliments!

[@galant310]

+KYLE.DRIVES you're welcome

[@oneferrdek3346]

@@KYLEENGINEERS hi Kyle i from Poland , and want reduced drag my Infiniti FX 45 . Please show me what i can do? On my car. Big hood drag car is good or not? Thanks you very munch. And wait for video . Maximum low drag

[@mieszkooracz7370]

This was what I was searchig for! Thank You!! :-)

[@worawitthmaguro1110]

Great explanation hit on the spot really worth watching this thx a lot.

[@tlr_automotive]

Great video, very informational

[@tashriqc8704]

Very informative thanks man

[@mohammadersi5241]

Awesome😍😍😍thanks for the great vid

[@palmjc3872]

very good information👍

[@leviledbetter]

I love ordering parts without understanding the science and then seeing that I wasn't dumb with my decision. I have a 4.7 v8 2nd gen dodge dakota. Shes got a top mounted dual cold air intake with about half an inch clearance to the hood. Gonna cut holes and add a scoop over each intake. So I think I've made a good choice.

[@carlosduenas8000]

You look like Ryan Gosling little bro lol your show should be called drive lmao

[@gordonramsey7186]

This aged well since it’s a meme now lol

[@povilaslondon]

For the rear engined cars it's even more important to have hood vents. It eliminates front lift at high speeds because high pressure air builds under the frunk/bonnet. Plus radiators are usually at the front so it gives the same benefit as for front engined cars.

[@rorymcdaniel26]

Dig your videos, They have answered many detailed questions, And provided unique insights. You shine as a teacher.

[@SWF1127]

Most informative! Tku

[@LeaveNoTrashBehind]

Getting a carbon air ram hood for my Firebird. It's a must!

[@DD-sq3mr]

the wheel well vents is a pretty clever idea.

[@officialyungtwizted3858]

I just like the way they look. Makes the car look cool lol.

[@jamestubebristow]

I fully agree with venting the front wheel arch as shown in the video. What about the rear wheel arch being vented also? If the rear vents are located near the rear wing will this disturb the flow under the rear wing in anyway?

[@johnkim3858]

Kyle really deserves more views on his videos.

[@izzoArtistry]

How about the aero of hood spacers, slight opening from the back of the hood towards the windshield. Would love to see a breakdown of that!

[@matthewszostek1819]

You missed the cowl induction hood

[@dizkoteck]

most important useful video of youtube

[@tonybailey89]

Useful information but I think there was a huge missed opportunity not discussing the venturi effect and pressure differentials that hood vents introduce to help pull hot air from inside the engine bay especially when your moving

[@onetoris]

Great job explaining the exact question I had...

[@MichaelJohnson-tf8so]

Are the currently popular louvered vents (rivet on type) any more effective than simply drilling several rows of 1" holes in the top of the hood? If the goal is to extract high pressure air from under the hood to fill low pressure on the top of the hood, would holes cause aerodynamic drag? For context, I'm only considering race car / track car applications.

[@lovethesmellofracefuelinth7374]

I've got fresh air induction through the headlights on my Challenger and was thinking about getting a demon hood in order to move air into the engine bay, so what is your opinion on that and will it help build more power ?

[@jamaisvu2664]

On the NB miata I found CFDs that map the location of high and low pressure areas over the hood in order to place the hood vents in a better location to pull hot air out at speed. Is this mode effective than simply allowing heat to escape while at a standstill?

[@PhillyDee215]

Great info 👍 now with the hoods vent or bonnet vents.....how does that work when it rains 🌧 🤔I've been wanting bonnet vents on my hood for years🤦‍♂️

[@ProjectAnubisUSA]

So the LANCER EVOLVE HOOD is best since it's recessed into the hood then tapers up towards the windshield. Good informative videos bro

[@mosesfernandes1499]

wRITING A DISSERTATION on bonnet vents and aerodynamics, any suggestion on good citations I can use

[@mr.smalllegs5725]

Nice im going tu use everything i learnt here on my stock bmw

[@cortana324]

Will adding vents by itself help release backpressure from the wheels if the wheel area is already vented? or do i need to connect it. Also, how on earth do you connect it?

[@galihargo6997]

Hey man i have a question, my stock undertray for the underside of my engine bay is broken and i want to make a full undertray but i dont want to cut holes on the hood whats going to happen will my under tray or hood gonna blow because of little airflow in the engine bay???

[@2391jessie]

Can u pls look at the aero on the FK8-CTR venting engine bay heat thru the trailing edge of wheel arch extension?

[@aidan5720]

will this be useful on a focus ST 2007? im thinking of getting better headers/exhaust with better ventilation to improve performance

[@fox10169]

great expiation, i really learned quite a bit ! what are your thoughts on hood spacers??

[@elibruhim2102]

?

[@sambo92]

If you're not going fast they work, if the car sees over 100+ mph, not a good idea

[@MyLonewolf25]

They only work at low speed

[@camlobesvtec]

I plan to make a hood intake for a turbo charged application. I'm wondering if you can help me with a type of shape for the hood scoop please. My plan is to not allow any air from the hood intake to enter the engine bay. My filtered intake will be capturing as much air as possible. Any input would greatly help

[@EWOverland]

Hi, I am looking for some basics for designing air induction to the intercooler for Pajero that is positioned fery low in the front of the vehicle. Allthoughs I have also a bash plate that is restricting the flow to the intercooler

[@stupidme12114]

i have 3sge engine (FWD) i wanted to install vent near the radiator and vent near the headers (Replaced Stock). Will that work in cooling the under hood temps?

[@SolidariusLive]

The Getz with the scoop. Amen.

[@Cyge240sx]

Are top and side mount intercoolers still in use? i was under the impression they were dangerous?

[@basslover8863]

On my 2003 wrx with the top vents installed when the car was still it felt like a hairdryer with all the hot air coming out so it definitely should work in traffic depending on how hot your engine runs

[@spankeyfish]

re: the tyre rotation pressurising the wheel well, could that be why some Fords feed the air box from a grill at the front of the (usually left) wheel well?

[@benjaminbec]

My car overheats it’s only a v6 would you recommend a hood scope to help with overheating ? Or is there another route I can go to help with this ?

[@aesopm9200]

given pressure is high in the wheel well, i'm unclear on how to do brake ducting and cooling. is it high but lower than at the very front of the car so the classic approach works? if it's high would i be better off with the ducting going to an exit at a low pressure area? the wheels aren't solid is air getting sucked out through the spokes sufficiently for our purposes? anyway that's a request for a video, or if you are busy, a comment would be great.

[@BoostedPastime]

So essentially hood spacers/risers will help then? Due to cowl induction while moving and acting as a vent at idle?

[@septembrrr]

This is more educational than school

[@sikrip]

Nice video. What I am missing the location where the air should be vented on the hood. Should it be close to the windscreen or close to the front of the car?

[@DiscoR53]

Cars with a top mount inter cooler; is it better to use a scoop placed at the high pressure area on the bonnet , or use a vent in a low pressure area.

[@heitorbernardes7977]

Can i vent out a ducted radiator under the car, with a flat floor? Using something like a caved in scoop or louvers, is it a good idea or just do it through the bonnet?

[@izack367]

what about when its raining ist it gonna cause any trouble if the water gets sucked into the engine through air intake ?

[@vinceking7878]

I guess that the hot air from the radiators can warm up the engine bay alot, so is a bonnet vent alone sufficient when running an undertray?

[@JarikTentsu]

Hi mate, Can you do a video discussing hood vent placement and design in more detail? Eg, at the sides of the bonnet vs middle, front vs back. Also how does this affect aero over and around the car. Was told by an aero engineer to a vent right above the v mount intercooler would ruin airflow over the top of the car, so interested to understand this better. Would also be good to see your take on something like under Suzuki's bonnet, which seems to have had a lot of thought go into it.

[@Dr_Xyzt]

Draw a line from the leading edge of the hood to the top of the cab. If you add fins that stick up to that line, you're doing way too much. The top of the first fin needs to be higher than the edge of the rear-most opening. That should help you size things. -- Something you should consider is how the air hits the windshield. I put a vented hood on my truck, and now the water droplets don't blow away the way they used to. The eddies that hit the windshield make the droplets do all kinds of stuff. In my case, I was lucky because my vision isn't obstructed, but it's in the way of a low mounted dash cam.

[@shawnwieser7101]

What is the advantage in running or not running wheel well, in a road race car versus a drag car?

[@BadAssEngineering]

Please make a video on improving Pickup Truck AeroDynamics :) I know its silly, but it would be interesting to see how Tailgate/No tailgate, Tonneau Covers, etc can help and so on

[@JerseyMikeP]

Tonneau cover is MUCH better...I'm going to make my own with a Sculpted profile. Actually seen Drag info showing a Cap is better than a Open tailgate up pickup.

[@GokuInstinct1]

Dumb question but if its raining, will it ruin the engine if I have a vented hood?

[@paniki_man2512]

So, with underbody panel installed, does hood louver is still useless?

[@Mattys91gt]

I have a 91 mustang gt with a reverse hood scoop I'm trying to use it for heat to excapse I'm not sure how big to make the hole if I could send u pics u might be able to tell me or look at the 82 mustang gt hood scoop going on a foxbody mustang 91 mustang gt

[@mileswatkins6472]

Whats the diffrences between a cowl hood and hood scoops ?

[@Sunsetwithlotion]

I learned more from this than a whole year in school

[@Papucho257]

"street" knowledge will always be better than a school

[@Papucho257]

I can guarantee you that from a surveying field.

[@muhdelyas-abgyas562]

I have a scoop to help prevent overheating

[@SoI_Badguy]

No, you have a hood scoop because you picked it off of an autozone isle.

[@devjk1]

@@SoI_Badguy obviously you've never seen a WRX/STI or an Evo. But neither of those prevent overheating, they just keep air cooler after being compressed in the turbo so op is still wrong.

[@SoI_Badguy]

@@devjk1 Look at his liked videos and tell me he owns a WRX my dude.

[@devjk1]

@@SoI_Badguy he could just be lame as fuck and own a WRX, who knows 😂

[@thatvolvoguy6565]

@@SoI_Badguy how can liked videos define what car a guy drives

[@watrousmark401]

Is it possible that with fender vents causing high pressure air to exit the wheelwell you could get more airflow over your brakes?

[@JerseyMikeP]

Yes. Behind the fender flare is a GOOD low pressure area...race cars are better doing it on the top of the fender like the 1969 Dodge Daytona.

[@tilepusher]

Just wondering.... I live in Las Vegas, Nevada where it rarely gets below freezing, but over half the year we experience temps over 100F. So this is a cooling question. What would be the negatives of getting longer hood bolts & fender washers/spacers, raising the hood over the hood hinges, to make a gap at the back of the engine bay for hot air to escape?

[@griffturkltek9933]

Not worth it. Might help in slow speed traffic, but at highway speeds, will have a negative effect.

[@spudbmx6140]

You say the pressure on top of the wheel is vented upwards out of wheel vents, thus creating some downforce. But wouldnt this downforce already be there due to it being a reaction force against the tyre? I'd imagine the force would be between the tyre and wheel well without a vent, causing an net upward force on the body whilst a downward force on the tyre. Isnt this ideal? If this is correct, it would present a form of unsprung aero and a counter force (lifting) against the body to lessen sprung aero. Unless when you say it gives downforce your implying it lessens lift caused by what Ive guessed/explained in the wheel well.

[@SoulAss4ssin]

just got done watching this, looked out at my 59 apache.... i think non of this applies to me. made my head hurt. lead plates in the bed, more HP!

[@demonslayerx061]

What about the front fender side vents?

[@jkrigelman]

Don't see this question in the comments. But what about a cowl induction hood? This would change the flow pattern of the hood, but I would assume less obstructive than a big STI style scope.

[@tydztan]

Is it the same concept as you demonstrated with hood vents in cars that have two large hood vents? Examples of this would be ferrari 488 or f50. I've always wondered the reasoning behind those large vents that seem to face backwards. Its logical to me that the scoop is to force air in but the large hood vents are less intuitive. great videos by the way. super interesting.

[@chm1ata]

Late reply, but those cars have radiators in the front, but not an engine bay. It's simply to get air through the radiators, without having the air going under the car

[@jamesengland7461]

The scoop on vents with Kyle!

[@obtrunco]

Interesting video but I'm skeptical about your explanation of hood vent efficiency in a non-race car. How much engine heat can actually be evacuated from below the engine bay while the car is in motion? I doubt it's much since hot air has a tendency to want to rise up thus being mostly trapped without also having some top venting. Additionally the air that hits it from the front mostly benefits the radiator because there are so many obstacles in that area that air flow wouldn't be much once it gets through all that.

[@billtaylor3499]

Normal air turbulence at speed is probably an order of magnitude, or more, above the forces of hot air rising in a gravity field. Work on flow mass, let velocity deal with "Hot air rising", which is a factor in very slow urban traffic. But you Should have backed off the turbo well before pulling off a high speed section.

[@tabryis]

You're right. You actually the scoop facing the driver, not away. This way the air coming in from the front moves through the engine bay and the hot air pushed itself out naturally; far more efficient while moving. Thinking about it, air moves underneath the car at the same rate as its being pushed in through the front so that's not gonna push all that hot air out from the engine bay out of the bottom either. If anything You're better off with just a vent there with no scoop (if it's facing the wrong way) because that way at least you're not forcing that hot air to stay inside the engine bay

[@HalfChink]

What about cowl induction? Is there any positives to that configuration?

[@sambo92]

On a modern car, not really. Mainly just good for fitting a blower or a high rise manifold.

[@benignrabbit1882]

I am looking for what can help my 2017 camaro 2.0T. The engine bay gets really hot the turbo gets extreme hot and I find it necessary to make the engine bay cooler. What would be the best for such a bay? Yes it is stock but it gets really hot like it's a factory thing to be so hot and I want it to be cooler.

[@sambo92]

I'd look for an ss hood that has the vents.

[@GetYoJonesOn]

For the hood vents, doesn’t the air flowing over the hood create a high pressure zone and prevent (or reduce) air flow from the engine bay that is at lower pressure? (Air doesn’t flow from low to high pressure does it)?

[@gkman815]

The opposite actually, it creates a vacuum pulling hot air out of the engine bay

[@flamingronin]

My bonnet scoop is ducted to the back of my rad to generate a high pressure zone and thus thrust. I am able to hit ~350km/h with a NA 1.3L engine.

[@KYLEENGINEERS]

+Daniel Luong May I suggest that you turn your wing upside down as well then? The lift will reduce the force on your tyres, therefore decreasing the mass of your car, and as F=MA, this means you will accelerate significantly faster.

[@flamingronin]

+KYLE.DRIVES Don't be ridiculous, I can't decrease the mass of my car. Don't you know anything about the conservation of mass? Duh. You're onto something with the inverted wings though. Negative downforce will reduce the normal force on the wheels and thus friction so I can go even faster.

[@ernestoperez717]

lmaoooo. truuuu (not tru,I do not agree to this haha)

[@flamingronin]

+ernesto perez Trust me, I'm an engineer- I know what I'm saying.

[@ernestoperez717]

+Daniel Luong your radiator fans are most likely a large contributing factor to your thrust.

[@benedictroberts678]

So a Formula 3 type air scoop would be over kill on a toyota aygo? Got it

[@ernestoperez717]

do wheel vents behind the wheels like on the mitsubishi evo X have the same effect as the "hood" vents where the vents are above the wheels? improve downforce, reduce drag?. I can see the "hood" vent style for the wheels providing more air for the rear wing.is this true?

[@KYLEENGINEERS]

+ernesto perez Vents behind the rear wheels do help a bit in a similar way to the vents above (however obviously aren't as effective at improving downforce), but mainly what they do is help control the venting of the wheel wake and limit any jetting out the back of the wheel arch, which will improve drag and clean up the air alongside the car. I would not expect the effects of the wheel vents to propagate enough into the freestream to have a significant effect on the rear wing aerodynamics though

[@OrengoMotors]

+KYLE.DRIVES A lot of cars on time attack have vents behind the wheel, but more extreme than the evo x ones, like Nemo evo and under suzuki s15. Does these vents reduce drag? or does this " big open space" behind the wheel create more turbulence and drag? so they reduce drag and lift or only reduce lift?

[@KYLEENGINEERS]

+OrengoMotors Those vents are all about flow management, and function in exactly the same way as listed above, only better as they are more extreme. They are also present on LMP cars and various other forms of motorsport. It's largely about managing that wheel wake, stopping jetting out the side, reducing drag and improving downforce through the combination of venting the wheel arch and providing better airflow to the rear aerodynamic elements. It also will assist in preventing the tyre wake from being ingested into the undertray.

[@OrengoMotors]

+KYLE.DRIVES Thank you for your explanation!

[@jengal259]

KYLE.ENGINEERS cooling brakes?

[@mondo_stunts27]

Can you do a video on how bad aerodynamically a lifted 4x4 with metal bumpers is. Just for fun

[@redneckracing01]

Hi had some problems some years back after fitting a bonnet scoop. The added air flow into the engine bay stalled flow through the radiator, until the scoop was sealed to the cold air inlet.

[@KYLEENGINEERS]

+redneckracing01 Yep that is somewhat consistent with what I'm saying at 3:08 onwards, as the pressure inside the engine bay is increased unless there are sufficient outlet vents, thus making the pressure differential across the radiator worse. It's not so much "stalling" the radiator as it is dramatically reducing the airflow through it due to the adverse pressure differential.

[@redneckracing01]

+KYLE.DRIVES We had made an under tray to reduce dirty air from the engine bay to the under side of the car and to smooth out the bottom some .With this and the added air from the unsealed scoop we didn't have enough exiting airflow. Can you maybe give some insight on NASA ducts for exiting air .What advantages if any over other means?. Very informative videos please keep making them.

[@n8rad3]

Thanks for the video. Is it best to put the hood vents towards the front of the bonnet or further back? Or does it matter?

[@DubstepMetalcore]

it sucks he hasn't answered your question yet but I would say further towards the back because there's more time for pressure build-up on the hood. there is more surface area towards the front for pressure to build up before going into the scoop. if you put it at the front there's less directed air and more turbulent air so there's less focused air going into the scoop.

[@DubstepMetalcore]

or vice versa Ford events there's more pressurized air build up to pull air from the engine bay

[@DubstepMetalcore]

For vents lol

[@n8rad3]

David Levy Thanks for the reply!

[@JarikTentsu]

I would have suggested further forward. If you look at CFD pressure maps across a bonnet, lowest pressure is on the edges around the middle/front depending on the car. This would provide the best extraction. Further back and you get higher pressure from the wind screen. Probably varies a bit between cars though.

[@BornToDrive1500E]

Is venting the air from the radiator underneth the car bad? Do you, by putting more air underneath the car, increase the pressure and create lift?

[@KYLEENGINEERS]

+BornToDrive1500E Venting the air under the car will be bad, as it means that A. You aren't running a flat floor through your engine bay B. You will be inducing dirty air into the underfloor and C. You will not be working your front splitter as hard so your centre of pressure will shift rearwards. You can compensate for the increased total volume of air under the car by running a larger rear diffuser. Does that help?

[@BornToDrive1500E]

KYLE.DRIVES Yeah, that helped. Thanks for the answer! I am curently in the proces figuring out how to put a radiator on the front of fiat 600.

[@eagle_gr]

So from what you are saying , we should better create a "collector" just behind the radiator fans and duct all the hot air from a vent at the top of the bonnet? wouldnt that create a disturbance since some air will be duct from the top of the car and some from the bottom? because I was going to put a collector like borntodrive1500 said and send all the hot air to the bottom but your answer made me rethink that

[@prooxy1234]

I have a stock 01 tibby that tends to run a little hot, the radiators pretty new, water pumps solid, ive been looking at maybe putting vents or a scoop on it to increase air cooling. Any advice? this video made me doubt it would do anything lol

[@aflo661]

prooxy1234 Have you thought about running an oil cooler? Might be a ineffective for daily driving but if your talking track days it might be a good idea?

[@prooxy1234]

nah nothing crazy, just runs too hot on sunny florida days when im driving for a bit water pumps pretty new, hoses and radiator are pretty new.

[@illuviium]

Does anyone know what those hoops are? On the thumbnail of this video, he has some hoops at the front of his engine hood. Looks to be mainly for appearance but I’d like to know the name. Makes your car look like it has piercings

[@Dragunov302]

I’m hoping my aftermarket hood scoop that I put on my sti that’s located closer to the front of the car that it will grab more air

[@yjfoo23]

What if rain water gets through the scoops and vents? Would water affect the engine and belts and electronics?

[@StephenHarristnt]

The engine components get splashed with water from below in normal driving. The electrical boxes are sealed to protect against splashes also. Would have to really deluge the injectors and electronics to cause problems. As such, have to strategically choose where the vents are placed, and should be okay.

[@zains3990]

what do you recommend for an 01 integra type r i want the engine to be cooler...a vent or scoop?? please

[@pascha4527]

just use hood spacer. its cheaper.

[@MyLonewolf25]

@@pascha4527 those don’t do shit at speed

[@adrianmoyes2856]

I just got soooooo educated

[@TheSol115]

Hola hood raisers work ?

[@JasperSkallow]

what about ram air?

[@billashe2108]

Kyle, in your video I missed an explanation about Cowl Induction Hood Scoops.

[@MyBacon92]

I like the explanation, the reason I searched hood scoops and how do they work is because WATER. Where does the water go when you wash your car, or when it rains? Does the water soak up the whole engine bay? I am a noob, sorry...

[@Yakushi0Mikatsu]

What about roof scoops?

[@dylanschmidt4607]

What about rain getting in?

[@bobmotherfuckinsmith3089]

Cowl induction scoops are great for aero.

[@death2yourtruth]

Just add locking hood latch and drive with hood open

[@XeroFailGames]

Yea not gonna lie I looked this up to see if putting a vented hood and an intercooler on my Si will really keep it cooler shit heat soaks so bad in 90 degree weather

[@chaseshort7331]

So scoops make your whip quicker?

[@bradleyfarve]

Chase Short yes

[@JerseyMikeP]

You Forgot the Fender vents behind teh front wheels to help with high pressure, ETC.