Bonnet Vents?

[scWirral]

Any ideas about the technical advantages of venting the bonnent above the air intake. A mate of mine who has a tiger kit car suggest that although the cold air is probably scooped up pretty well by the big holes in the front of the car, venting further up the bonnet could help let the hot air out and so reduce the charge temperature.

What experience do you guys have of the difference when one of these Apexi type boxes are fitted? Do they make a noticable difference?

I know that the best solution will always be a feckin big intercooler / chargecooler, but I probably need some paintwork attention and the cost of a vent would be pretty low.

Not really that bothered about the looks of the thing, although a nice carbon bonnet would still make me drool!

[Driftin Ste]

:nod: Your mate speaks the truth especialy with the 200sx a vent by the induction box works wonders but a vent at the top of the bonnet releases alot of unwanted heat,or altering the bonnet to be drift style(packing the top of the bonnet off the hinges so its slightly higher than the wings,thus venting the heat from rear and sides). :eek:
I have just ditched my HKS super blower kit to install an Apexi filter and cold air box and the running temp has dropped and my car runs alot sweeter with the cool air being taken in. :clap:
ive also fitted a HYBRID intercooler kit which has even further reduced running tempritures, :thumbs: :notworthy i fitted them all myself on my drive so its easy affordable cooling plus all those shiney things under your bonnet makes you proud to drive a 200sx :whip:

i got all my mods from apex they have a thread on this site Bren will help
and if you require a carbon bonnet they also supply those too :Plug:

hope thats helped you mate :wave:

ste :wack: :confused: :eek:

driftin my way through life
live life sideways

[Jammers]

I have a vent directly in front of my air filter to ram cold air into it and a vent further up above the manifold to let the hot air out.
Under testing it revealed a 15 degree difference in before and after and made a difference in the hot weather :thumbs:
Pictures to follow ....

James

[Jammers]

Pictures ...

http://www.palmer.f9.co.uk/front4.jpg


http://www.palmer.f9.co.uk/front3.jpg

[hadyn]

i've got two vents at the back of my bonnet, the one sits above the manifold and is functional and the other sits above the plenum not doing much :)

http://www.sxoc.com/images/dynamic/memberimgs/lores/20049261752346.jpg

http://www.sxoc.com/images/dynamic/memberimgs/lores/20049261752314.jpg

as said above the S14 gets a nice air feed in and doesnt really need that much air, advantages can be gained by letting hot air out........i can say that the car definately feels more responsive at the top end after venting the hot air out above the manifold...

will be fitting a non vented carbon bonnet soon, so will be able to tell you if the vents make a truly noticable difference..

a quick fix you can do is to remove the big rubber strip at the back of the engine bay, as this will squeeze a tiny bit of hot air out of the bay :)

[PhilMorrison]

I've got 10 vents in my bonnet :wack:

http://www.sxoc.co.uk/images/dynamic/memberimgs/lores/20043162017443.jpg

[Hates_]

I've got 10 vents in my bonnet :wack:Show off :p

[Matt_T]

phil, what did you do to the ribs under the bonnet? cut around, through or remove? I need a BIG hole for a v mount :nod:

[PhilMorrison]

CUTCUTCUTCUTCUT :D the vents themselves actually provide the structure that was lost by cutting the under brace out..

[king_j]

can we buy a bonnet like yours phill or is it a one off.. its a lovely lookign car too.

[PhilMorrison]

I made it mate, but I'll be selling carbon fibre copies of it very soon :)

[king_j]

ohhhhhhhhhhhh...yay...

[SX Sam]

Is your mates a Tiger Z1 with the two kawazaki Z1 engines and a split gear stick?? If it is these are awsome cars 0-60 in 2.7 i think there was one on top gear ages ago getting in the guiness book of records for fastest 0-60 of a car!

[Jammers]

To be quite honest i would rather like the vent to be over to the middle of the bonnet more, but that means its directly over the manifold and rain water dropping onto a red hot manifold is courting disaster really ..... :nod:
I have also removed the rubber strip.
All in all, a worthwhile mod and distinctive ..... although i think Phil's bonnet is taking the p1ss!!!!!!!! :D ;)

[Bart]

I've got 10 vents in my bonnet :wack:

http://www.sxoc.co.uk/images/dynamic/memberimgs/lores/20043162017443.jpg
:thumbs:

[Lenagh]

i've got two vents at the back of my bonnet, the one sits above the manifold and is functional and the other sits above the plenum not doing much :)

Haydn did brutus help you out and if so is he still doing work ?

[James]

a vent at the top of the bonnet releases alot of unwanted heat,or altering the bonnet to be drift style(packing the top of the bonnet off the hinges so its slightly higher than the wings,thus venting the heat from rear and sides). :eek:

If you check out the autospeed article on vents and airflow on the front of the car, the air pressure right at the back of the bonnet near the windscreen is quite a lot higher than that inside the engine bay, so if you have vents at the back of the bonnet, you will likely be sucking air in rather than letting the heat out. I had the bonnet on my drift car jacked up at the back and put it back to standard after reading that article..........

[Giblets]

I was thinking about venting above the air filter, but when it rains does it suck water into the air intake? :confused:

[Bart]

I was thinking about venting above the air filter, but when it rains does it suck water into the air intake? :confused:
:thumbs:

[James]

If you're truly interested in what works, what doesn't and why, have a look here (http://www.autospeed.com/cms/A_2159/article.html)

You may need to sign up to read the whole article (it's in 3 parts) but it's well worth it. There's also a load of other excellent articles there. It's the best aource of tuning info I think I've ever found. All factual and technical, but written in a way that makes it simple and easy to understand :thumbs:

[Tricky-Ricky]

Quite happy with my classic style vent! :)

[hadyn]

Haydn did brutus help you out and if so is he still doing work ?

yep, hes still doing work you can find him at the styling section on the forum at www.gt4oc.com :thumbs:

[hadyn]

http://www.sxoc.com/vbb/attachment.php?attachmentid=12440

looks awesome :)

[dan_t]

heres mine...
http://www.sxoc.co.uk/images/dynamic/memberimgs/lores/20049241619235.jpg

[hadyn]

de-brick and de-grille asap dan t to make your S14 look spot on!! :)

[Enigma]

I have also been told about the low pressure at the base of the windscreen sucking air in which seems counter-intuative but I have noted that several 70s yank tanks actually have their air intakes on "backwards" to take advantage of this phenomena.
However if this is the case why do subaru put their vent on the conventional way around?
Keeping all this in mind where is the best place to vent the bonnet to let the heat out?
Appologies if all this is explained in the aformentioned article but I am to tight to pay to read it ;)

[dan_t]

I have de-bricked now, wheres the best (cheapest) place to suss a new grill?

[hadyn]

leave the grille out and mesh, looks top notch on an s14...

or you could use the standard grille and cut a hole where the grille is, which also looks good - theres a few threads about doing this so have a search...

now get it debricked and put a square or small plate on NOW!! that really does sort the front end out :)

[hadyn]

Keeping all this in mind where is the best place to vent the bonnet to let the heat out?
;)

above the manifold is where the biggest build up of heat is, so i think venting above there is the best thing to do with a style of vent that forces air out whilst moving, simply leaving a hole above will vent air when stationary but wont be as effective when you're moving

[dan_t]

lol read above... :nod: :D i HAVE de-bricked!! lol :P just not in this picture :D

I gotta change a headlight bulb later, so i expect the grill will be coming out, might see what it looks like :)

[scWirral]

Thanks for all the suggestions, guys. The debate about whether a rear facing top of the bonnet vent would suck or blow ;) is an interesting one. I saw a tv programme years ago where a guy was developing the aerodynamics of his race car by taping little wool tails all over the thing, a bit like they have on the sails of a dinghy. Maybe one of you double vent guys could perform a little experiment and let us know how you get on?

Also, although I said I wasn't too bothered about what the car looks like, some of those mods look v smart. Repect due, fellas!

[hadyn]

...so i expect the grill will be coming out, might see what it looks like

a bit like this :

http://img.photobucket.com/albums/v55/hadyn/wheelz_00331.jpg

[dan_t]

that is an improvement for sure!

is that meshed? or just left open? Is meshing necesery?

[hadyn]

i think meshing just stops any chavvy type hands from possibly getting their fingers under your bonnet latch and opening it up...

meshed or unmeshed it still looks rock hard...

lose the fogs too, completely sorts the s14 front end out then :)

[hadyn]

more rear vents on an S14:

http://www.kamiennagora.org/~nissan/biggal/wypasione/obrazki/s14_day1_n03.jpg

[Iain s14]

Here's my bonnet vent :)
http://www.imagestation.com/picture/sraid138/pdb750a2423237d23714502fdda501551/f71c20c6.jpg

[TomM]

...the best thing to do have a style of vent that forces air out whilst moving, simply leaving a hole above will vent air when stationary but won't be as effective when you're moving :confused: How can a vent force the air out from under the bonnet while moving? Do you mean fit an inverted scoop? Also, a hole above a hot area will be more effective while moving, as the flow of air over the bonnet creates a lower pressure than under the bonnet, so the hot air flows out.