DIY question: making vents for your bonnet

[nam.qhc]

has anyone made vents for their bonnet b4? i want some vents in my bonnet.. any tips on "DIY." thanks in advance

[cheapdouchebag]

the vents for it to look stylish? or for cooling?

my 2cents: if its for cooling, could always do the hood mod which raises the hood up on a angle from the windscreenwipers side of the hood.

EDIT: and thats cheap cheap too!

[nam.qhc]

yeah its for cooling.. im sorry bro.. but "raises the hood up on a angle from the windscreenwipers side of the hood." doesnt make sense to me >< sorry.

[cheapdouchebag]

http://www.activeboard.com/forum.spark?aBID=43793&p=3&topicID=6594654
see how its raiseda bit? costs about $1-$20 bucks to do

[nam.qhc]

ah yeah.. simple and cheap.. but not good to the eye bro. thanks for the suggestion tho xD

[cheapdouchebag]

imo, it looks good, especially on drift cars :)

[dynasty]

sorry but what kind of vent looks good on an eg civic? dont tell me you're going to double side tape some autobarn vents to your hood?

[xntrik]

ah yeah.. simple and cheap.. but not good to the eye bro. thanks for the suggestion tho xD

so its really not for cooling. :thumbdwn:

[cheapdouchebag]

might just go buy a new hood if u want a vent.
the onyl one ive seen that i rckn looks good on a eg whilist keeping it looking 100% jdm style is the one on a black eg hatcchie on the youtube vid FF squad at buttonwillow.
others imo, just cant stand it. also especially with fender vents.

[geeang]

If you want vents, grab an angle grinder, cut some big holes in your bonnet, then drive into a tree.

[redefine]

If you want vents, grab an angle grinder, cut some big holes in your bonnet, then drive into a tree.

goddamnit you watched me do that didnt you! stole my idea!! :wave:

but seriously. dont bother. vents are only gonna do something if you have 1. a top mount intercooler like a rexy (which i doubt you do) or 2. the vent is feeding cold air to your filter, and im sorry, but a vent in the middle of your bonnet isnt going to do that....

im not sure how you expect a single vent to cool it THAT much, you'd be better off raising the bonnet mounting.

[cheapdouchebag]

can i stress one more time, rasing the bonnet from the wiper end loks awesome haha. race looking!

[trism]

its also defectable.

[miss_motorsport]

i have a vent in my car only because the former owner thought that they would put a vent in a perfectly good crx bonnet... bad move, over time it has caused cracks in the bog & paint. not happy!

the cheapest part of this adventure is the "idea"

the vents may be cheap but the fitment and respraying the bonnet cost you $$$ i would allow a minimum of $500 for this mod

if you are doing this for asthetics and attempt a DIY with no pannel or paint experience you may not be 100% happy with the result.

the only way i could find the vent mod justifiable is if it will improve the performance of the car

good luck ;)

[EK1.6LCIV]

get some celica gt four import vents made to fit on your bonnet (the side vents it has not the middle intake), theyre metal of the same grade as your oem bonnet. Depending on how you attach them will depend on legality.

http://images.autoexposure.co.uk/AETA73180/AETV53362949_1b.jpg

Wouldn't use washers ethier, they're defectable as it raises the bonnets edges making a sharp surface if you hit a pedestrian (I really still don't understand the needs for sooo many laws in qld and other states when their roads are still very poorly designed, serious make good roads then make laws for cars...)

[redefine]

i would hardly call the edge of the bonnet sharp, especially when the edge is facing away from the front

[geeang]

i would hardly call the edge of the bonnet sharp, especially when the edge is facing away from the front

Regardless, it is still an edge.

If you had a head-on accident with the raised bonnet, it could potentially spear straight through the windscreen and cut you in half. :thumbsup:

[trism]

it could potentially spear straight through the windscreen and cut you in half. :thumbsup:

this is why spacing bonnets is illegal.

[curtis265]

I rkn you'd be better off trying to make some sort of grille or cut holes in bumper 'grilles' and get a CAI (or use that pipe trick where people run a pipe down to where the foglight goes)

I think hood spacers look like assss too. And you might get water in it

Seriously, looks like the hood doesn't sit properly, and the bodylines are all fuked up
http://gallery.8thcivic.com/albums/Exterior-Style-Mods/DSC_0025.jpg

[Alvis]

meh, I don't think bonnet vents don't really do anything too drastic - more for looks than anything IMHO - a raised bonnet however can look pretty good on a civic:

I'm not convinced on vents, maybe do some more homework and let us know... some pics for you anyway

http://img709.imageshack.us/img709/5413/dsc00553db4.jpg
By civica (http://profile.imageshack.us/user/civica) at 2010-05-01

http://img709.imageshack.us/img709/7585/dsc00558rt2.jpg
By civica (http://profile.imageshack.us/user/civica) at 2010-05-01

http://img594.imageshack.us/img594/968/dsc00559dt4.jpg
By civica (http://profile.imageshack.us/user/civica) at 2010-05-01

[redefine]

Regardless, it is still an edge.

If you had a head-on accident with the raised bonnet, it could potentially spear straight through the windscreen and cut you in half. :thumbsup:

im sorry...but are the 4 mounting bolts, 2 on each side, designed to support much more then the weight of the bonnet itself...going to shear off and fail before the designed crumple points collapse??
on a stock bonnet it wont make a difference. and wont be any more likely then a bonnet with no washers
it only holds where you have a carbon bonnet...and even then, if you have designed weak points, its likely to shatter before it comes through the windshield. cf is not stronger then steel per volume...its only stronger per weight.

and the raised bonnet is less of an edge then an actual scoop which is legal providing that it follows guidelines (that is, if a 165mm disc is rolled up the bonnet, the point of contact with the scoop is on the lower half of the disc)

[curtis265]

The shear force won't be acting on a 'plane' anymore, the bolts are more likely to bendinto an 's' shape, and pull such that the bolt will be in tension. I dont know if bolts are stronger in shear or tension, but my bet is that the plates taht the bolts go through will crush/tear before bolts break

I reckon the bolts will hold, and the bonnet will just crease like so
http://3.bp.blogspot.com/_ytmmefaB3q4/SQA9x95NCrI/AAAAAAAAATk/TGin65zjnA4/s400/ferrari+car+crash+3.jpg

Carbon will shatter into sharp pieces.. and spear you

[MrMcGinty]

simple fact is that any small car or hatchback looks SOOOO ricey with hood scoops. your better off cutting holes in your bumper where it looks less obvious.

[redefine]

The shear force won't be acting on a 'plane' anymore, the bolts are more likely to bendinto an 's' shape, and pull such that the bolt will be in tension. I dont know if bolts are stronger in shear or tension, but my bet is that the plates taht the bolts go through will crush/tear before bolts break

I reckon the bolts will hold, and the bonnet will just crease like so
http://3.bp.blogspot.com/_ytmmefaB3q4/SQA9x95NCrI/AAAAAAAAATk/TGin65zjnA4/s400/ferrari+car+crash+3.jpg

Carbon will shatter into sharp pieces.. and spear you

this pic is what WILL happen. raised bonnet or no.
if im correct the bolts will be stronger in tension, being steel, and a shear force is a combination of tension compression. steel is actually quite weak in compression (which is why we use concrete, and not steel for foundations, its the combined tensile strength of steel and compressive strength of concrete that makes reinforced concrete so good, but thats another point)

if the bolts were to shear off you would need an EXTREMELY rigid bonnet. like insanely rigid. considering the length of the bonnet, the cross-sectional area, and the compressive strength

and i rekon the carbon shards would have a better chance of scratching and getting in the eyes of bystanders then spearing you in any way. the firewall/windscreen do a great job of protecting you from shards of material

[curtis265]

this pic is what WILL happen. raised bonnet or no.
if im correct the bolts will be stronger in tension, being steel, and a shear force is a combination of tension compression. steel is actually quite weak in compression (which is why we use concrete, and not steel for foundations, its the combined tensile strength of steel and compressive strength of concrete that makes reinforced concrete so good, but thats another point)

if the bolts were to shear off you would need an EXTREMELY rigid bonnet. like insanely rigid. considering the length of the bonnet, the cross-sectional area, and the compressive strength

and i rekon the carbon shards would have a better chance of scratching and getting in the eyes of bystanders then spearing you in any way. the firewall/windscreen do a great job of protecting you from shards of material

Well actually... I'm still not sure about bolts being stronger in tension than shear, but shear is not a combination of tension and compression, it's just shear... and steel is equally strong in tension and compression, the issue is that if a steel member (say in a roof truss) is subject to compression without either having lateral restraint or being suitably 'stocky' it will buckle under the loading.

Concrete is used for building foundations because it can take on a large area whilst being relatively cheap compared to steel.


and yes, in order for the bonnet to spear you, you'd need to be very rigid so it won't buckle... but that means it'd be thick, and also heavy... I suppose that's undesirable isn't it

Hows that for a civil engineer's nerd-out!

[redefine]

whoops forgot about that :p your right about shear. i was thinking of a bending moment.

depends what you meant by strength. in both compression and tension it has the same modulus of elasticity, but the yield strength is much lower in compression. THATS what i was talking about. i shoulda been more specific.

i honestly dont see what people are afraid of about bonnets. even if the bolts do shear off, AND the bonnet is capable of piercing the glass windscreen, the angles that its at, the bonnet is likely to glance off and cover the windscreen then actually pass through it.

[StrawberryFace]

If you want vents, grab an angle grinder, cut some big holes in your bonnet, then drive into a tree.


maybe he juss wants vents but hes too scared to say because of people like this that say dumb shit!!! not your car mate soo keep shit comments to urself.

[curtis265]

^ i bet you have vents, lol

[kira_ti]

consider something like this http://www.hondatuningmagazine.com/features/htup_0903_1991_honda_crx_jdm/photo_25.html ? I think it would look ok and help feeding the air for your short ram or itb though