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ed_ma61
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legalalities of hood vents??	Sun, 28 December 2003 11:56

i want to mount a single, reward facing cosworth style, air extraction vent in my bonnet. it will be on the drivers side, up towards the windshield, and shouldnt require any bonnet structural supports to be cut through to install it. it will be reasonably flush with the bonnet. i seem to remember there being issues re bonnet vents and engine fires - disallowing the use of reward vents etc, but cant find nada in writing about it. ? maybe im mistaken... does anyone know the official (ie legal) ins and outs of mounting bonnet vents that are relevant here? cheers ed [Updated on: Sun, 28 December 2003 11:58] [Report message to a moderator]

STR8 2.8
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Re: legalalities of hood vents??	Sun, 28 December 2003 12:11

have u tried contacting the rta (u prob have) the email enquiry thing has been most helpful to me regarding legalities of mods [Report message to a moderator]

wiso
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Re: legalalities of hood vents??	Sun, 28 December 2003 12:25

I don't think there are many problems with fitting hood vents, I had a gt4 style vent fitted to my ST162 bonnet, thing is because it is such a large scoop the main centre of the bonnet bracing got cut out, which left it pretty weak. The later on when I had to get the new engine engineered, the guy did the whole car, which included the scoop. he didn't pass it first because the bracing had come loose and with the centre cut out it didn't pass as structurally strong enough . To fix this he told me to use a urethane bonding agent (the little beads that hold the skin to the frame is this same stuff) and a bit of fibre glassing, but also the top side has to be a neat fit with no sharp edges that could injure anybody (not like someone falling on your bonnet isn't going to injure them ) or cause further injury. The RTA seemed pretty happy with this setup that I had. but this wasn't a rearward facing one. well thats my little story I hope it helped a bit. [Updated on: Sun, 28 December 2003 12:34] [Report message to a moderator]

Grega
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Re: legalalities of hood vents??	Sun, 28 December 2003 19:07

ed - also have a look at the turbo diesel patrols (the new ones) they have bonnet vents and cost very little new (also i've got a mate who works at nissan who might be able to get it cheap) [Report message to a moderator]

7M-Brisbane
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November 2002

Re: legalalities of hood vents??	Sun, 28 December 2003 23:06

In QLD there's a funny rule where they get a circle and roll it up your bonnet. If at any point the center line of the circle is below a point on the bonnet vent then the bonnet vent is illegal - otherwise it's a free-for-all. Unsure of the diameter of the circle, however. Just contact your local RTA an they can tell you, or else they'll put you onto an engineer that can give you the info you need. Vents in QLD I believe are not allowed to point backwards in the manner that your are describing - in the event of a hose springing loose you may get p/s fluid or oil on the windscreen. That's their line of thinking anyway. Also, in QLD fitting a bonnet vent to your car makes you gay, you may wish to check this out locally too [Report message to a moderator]

midnight
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Sydney
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November 2003

Re: legalalities of hood vents??	Mon, 29 December 2003 02:09

there was a phat wrx in a street tuner mag that had its scoop backward... well it makes sense if youve got a front-mount... [Report message to a moderator]

clancey
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Brisbane
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July 2002

Re: legalalities of hood vents??	Mon, 29 December 2003 02:20

Fully sic Maaaatteee!!! [Report message to a moderator]

clancey
Regular

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Brisbane
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July 2002

Re: legalalities of hood vents??	Mon, 29 December 2003 02:22

If only bonnet scoops didn't look so gay, i really need something on mine as the paint is starting to bubble near the turbo [Report message to a moderator]

pro_ke
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adelaide
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April 2003

Re: legalalities of hood vents??	Mon, 29 December 2003 02:52

theres a very detailed explanation of this including diagrams on the transport SA website unfortunately this does not apply to you ed [Report message to a moderator]

StuC
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Melbourne
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December 2003

Re: legalalities of hood vents??	Mon, 29 December 2003 03:02

Heres a link to the VicRoads rules n reg-it mentions something bout the circle measuring thing. It might give u an idea of what u can do http://www.vicroads.vic.gov.au/vrne/vrninte.nsf/Li nkView/DB1081513CC4D2E7CA256B5F007AE7F3A0E6B550C59 A6444204A171BCD2A5F8F Hope it helps [Report message to a moderator]

ed_ma61
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Re: legalalities of hood vents??	Mon, 29 December 2003 03:25

oh, so we're clear - i dont want a scoop!! lol - how ghey would that look on a supra! just a flush mounted extraction vent so i can stir up some airflow around the back of the engine bay - get some air out from around the back of the extractors. rta info line it is then (those guys are hopeless!) [Report message to a moderator]

onejayzed
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Perth
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September 2003

Re: legalalities of hood vents??	Mon, 29 December 2003 03:27

that circle from memory is 125mmØ - and cutting the webbing under your bonnet is a big no-no in ANY state. your bonnet provides a large amount of protection in a front on collision and will fold like a wet paper bag without those members intact. you will require an eng cert if you cut those members. that said, there really is no need to cut the members, regardless if the vent is over one, if it's a rear facing vent. the members aren't directly welded to the bonnet, so there is space between the metals. if it's air extaction you want (instead of forcing air in) then just cutting the 'panel' and not the webbing should suffice. [Report message to a moderator]

ed_ma61
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Re: legalalities of hood vents??	Mon, 29 December 2003 03:35

this is what i was thinking (nowhere near as big tho)... vanes pointed backwards... [Report message to a moderator]

punkdefender
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Dandenong/VIC
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May 2002

Re: legalalities of hood vents??	Mon, 29 December 2003 03:47

who does these? how much is it? Update - dont worry found the web site from the link to the image above [Updated on: Mon, 29 December 2003 03:54] [Report message to a moderator]

onejayzed
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Perth
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September 2003

Re: legalalities of hood vents??	Mon, 29 December 2003 05:32

if you don't cut the bonnet member i see no reason why that wouldn't be legal. i mean, XR falcons and sierras have them... [Report message to a moderator]

speakafreaka
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March 2003

Re: legalalities of hood vents??

Mon, 29 December 2003 07:08

/www.performancestylingcentre.com.au

ie you have to cut a hole in the bonnet to fit this vent

Anti rice clause Laughing

[Report message to a moderator]

speakafreaka
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March 2003

Re: legalalities of hood vents??	Mon, 29 December 2003 07:27

i would love a vent like that [Report message to a moderator]

Toobs
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I Supported Toymods

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December 2002

Re: legalalities of hood vents??	Mon, 29 December 2003 07:48

I would describe that as a smallish vent... depending on how physically big it is (looks pretty small). The Group A's have two vents pointing back towards the windscreen... I don't know whether you are doing much different to that. As for the pic you have put up speakafreaka the vent there looks like a fully sik custom job... Armed with little more than an angle grinder, a few bits of MDF and some hot glue Ahmed and Tran decided to rice up their fully sik Toyota and came out with that! [Report message to a moderator]

speakafreaka
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March 2003

Re: legalalities of hood vents??	Mon, 29 December 2003 08:34

http://www.kidsheart.co.jp/top.htm cough [Report message to a moderator]

Norbie
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Re: legalalities of hood vents??	Tue, 30 December 2003 01:57

If you just want to get some hot air out of your engine bay, have you considered shimming the bonnet hinges and removing the rubber seal at the back of the engine bay? This allows a fairly large volume of hot air to escape past your windscreen, and in my experience it's been extremely effective - it basically solved the overheating problems I'd been having after my 2JZ install. Sure it looks a little bodgy, but that's a compromise I'm willing to make. [Report message to a moderator]

Allan
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Re: legalalities of hood vents??	Tue, 30 December 2003 02:15

ricer [Report message to a moderator]

Norbie
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Re: legalalities of hood vents??	Tue, 30 December 2003 02:18

Yeah, but my rice-mobile is faster than your rice-mobile. And it doesn't overheat either. [Report message to a moderator]

Allan
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Melbourne
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Re: legalalities of hood vents??	Tue, 30 December 2003 03:06

Well yes yours is faster but mine dosent overheat with the bonnet on properly Allan [Report message to a moderator]

Classique71
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Colac, Victoria
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May 2002

Re: legalalities of hood vents??	Tue, 30 December 2003 10:51

face it - youve both got scoop envy Ed - you see plenty of cars about with the cosworth style vents -though id try norbies idea first before chopping up your bonnet. Seems to be a common theme no matter what motor you have in an ma61 - they run hot - not much air getting thru etc .. I dont thing the full dorifto monstervent setup would look all that crash hot if the rest of the cars basically stock looking externally . my gt4 has tho vents in it - like the cosworth style - only smaller - they dont seem to do much - though youc an visially see heat rising from the vents when standing still - plus thru the monster scoop on the top ( hence mega heatsoak to the top mounted a to a intercooler ) The group A's mesh version though dissipates rising heat ALOT better - thanks to a bloody big hole directly over the manifold/turbo . id say a reduction in at least 10 - 15 degrees after comparing mine - then with a group a with the feel test .. ( one reason i chose to use the group a bonnet - as the gt4 has inherited chronic underbonnet heat from the factory ) [Updated on: Tue, 30 December 2003 10:55] [Report message to a moderator]

rob_RA40
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c'town, NSW
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Re: legalalities of hood vents??	Tue, 30 December 2003 10:58

Ed, considered cutting the bonnet and folding up gills? [Report message to a moderator]

ed_ma61
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Re: legalalities of hood vents??

Tue, 30 December 2003 12:04

rob_RA40 wrote on Tue, 30 December 2003 21:58

Ed, considered cutting the bonnet and folding up gills?

um, no?

(damn, we *just* threw out a perfetly goo bonnet too!...)

i think ill try shimming the back of the hood... level 2 drift bonnet spec. ive seen it done before, and it did look a tad 'ghey' but if it helps the heat exit (ive already removed the rubber strip)

cheers
ed

[Report message to a moderator]

feral4mr2
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Re: legalalities of hood vents??	Tue, 30 December 2003 12:15

surely building an extraction scoop you can leave the factory underside bracing of the bonnet in tack keeping bonnet strength/rigidity. you would only need to cut out the top skin of the bonnet where the scoop will reside as 'onejayzed' mentioned. being an extraction scoop it wouldnt need to stick up much at all if not level with the bonnet, so the sphere test would be an easy pass. though a small raised edge on the leading lip of the scoop would aid in creating a vacum above the opening when the air passes over it. i have read somewhere about what '7M-Brisbane' said about the oil/coolant etc. that 'can possibly' be sprayed onto the windscreen. i say boo hoo so what.. if you want an extraction scoop do it.. sika flex is great stuff for keeping the top skin to the bracing. [Report message to a moderator]

Norbie
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Re: legalalities of hood vents??	Tue, 30 December 2003 12:16

A while ago I found a fibreglass replacement for the front panel between the headlights (whatever that's called) which had nostril-like vents built into it. I think that would be quite effective at increasing airflow through the engine bay. It does look pretty ghey, but it's worth considering if you get a bit desperate. I know for a fact that removing the panel entirely makes a HUGE difference - for example, my car was overheating badly on the freeway while towing a big dual-axle trailer full of crap on a hot day, but as soon as I removed that panel the temperature went back to normal and stayed there. That's the whole problem with MA61's - the design of the front end makes it bloody hard to get air through them. [Report message to a moderator]

ae86drift
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Re: legalalities of hood vents??	Tue, 30 December 2003 12:22

what about a drop vent? [Report message to a moderator]

ed_ma61
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Re: legalalities of hood vents??	Tue, 30 December 2003 12:32

wtf is a drop vent? and i whole heartedly agree with you there norbie... the front of the supra looks cool, but is fuckin useless to get air to flow through... cheers ed [Report message to a moderator]

ae86drift
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Re: legalalities of hood vents??	Tue, 30 December 2003 12:43

drop vent here [Report message to a moderator]

ed_ma61
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Re: legalalities of hood vents??	Tue, 30 December 2003 12:50

that vent is soley designed to increase flow through the radiator - a problem im not having... the issue is clearing hot air from the back of the engine bay - which that vent, i suspect, would actually make worse [Report message to a moderator]

oldcorollas
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Re: legalalities of hood vents??	Tue, 30 December 2003 13:51

just another thought to consider is the air pressure at the places you want to put a vent. the very front of the car is obviously high pressure, but the base of the windscreen (where all of the air that is going over the car, is suddenly squished by the windscreen), is also a high pressure area... i vaguely remember reading about having cold air intakes from there for this reason... similar to whichever commondore it is that has a rearward facing intake scoop...... anyhoo, another thing to think about.... have to have a pressure drop to have airflow when you are at speed. Cya, Stewart [Report message to a moderator]

ae86drift
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Re: legalalities of hood vents??	Tue, 30 December 2003 13:56

true its designed to pull mre through the radiator also it works in a vacumn way to suck more air through the engine bay at speed i imagine it also would contribute to a general overall drop in engine bay heat maybe you could raise your hood up at the rear about 1 cm maybe for the meantime? [Report message to a moderator]

ae86drift
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Re: legalalities of hood vents??	Tue, 30 December 2003 14:00

Some cars actually have negative air pressure just in front of the windscreen (e.g. Minis, I think), so would try to suck air OUT at that point so lifting a bonnet up at the rear would work for little cost (edit) from club 4ag (www.club4ag.com) Back to my AE86, another significant part of the cooling process and drawing air positively from engine compartment, is additional top vents. One can achieve this ala Volkswagen trick by using nuts or washers and long screws to prop the hood up at the rear by half an inch or so. Cutting vent holes and ducts are very effective as well. When making holes in any rwd hood, you should always vent directly after the radiator. In the case of the AE86, it would be above and between the radiator and the timing belt cover. zing a better pic of my bonnet [Updated on: Tue, 30 December 2003 15:07] [Report message to a moderator]

onejayzed
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Perth
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September 2003

Re: legalalities of hood vents??	Wed, 31 December 2003 01:45

that 'lip on the leading edge' comment was almost on the money - the reason those radiator air extractor vents work so well is because they're under the line of the bonnet. hence there is a vacuum created and air gets sucked out. if you want decent air extraction, grafting something like reversed monaro guard flutes into your bonnet would do the trick - below the bonnet line. [Report message to a moderator]

ed_ma61
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Re: legalalities of hood vents??	Wed, 31 December 2003 04:17

well, its official - she overheats in traffic! i had to pull into the subburbs to get some speed up and clear the engine bay of all the damn heat soak! yeash! ill try the bonnet hinge trick first, as its not permanent... then yeah, a recessed vent might be the go ... bernoulli's principle (sp) cheers ed [Report message to a moderator]

Allan
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Melbourne
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Re: legalalities of hood vents??	Wed, 31 December 2003 07:56

What about some holes in the inner guard's not anywhere critical of course! Allan [Report message to a moderator]

7M-Brisbane
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Re: legalalities of hood vents??	Thu, 01 January 2004 00:34

It's not ideal, but consider water or even methanol injection if all else fails. With compression so high your engine is always goign to generate a lot of heat, even at low engine speeds. [Report message to a moderator]

V8_MA61
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Re: legalalities of hood vents??	Thu, 01 January 2004 01:14

Whilst taking the rubber bit of strip off the back of the engine bay is good for cooling, are you sure you want to be seeing fumes rise up and roll off your windscreen in traffic?? Only to go in your car if your windows are down... [Report message to a moderator]

CrUZsida
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Re: legalalities of hood vents??	Thu, 01 January 2004 04:59

or or [Report message to a moderator]

Norbie
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Re: legalalities of hood vents??	Thu, 01 January 2004 05:01

There shouldn't be any fumes to begin with... and if there are, you'll know straight away that something's up! Having said that, my atmo-venting BOV makes for a faint oil smell when it blows off at high boost/rpm. No big deal though. [Report message to a moderator]

CrUZsida
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Re: legalalities of hood vents??	Thu, 01 January 2004 05:08

Ed, have you tried running a cooler thermostat, or no thermostat just to test it? [Report message to a moderator]

Norbie
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Re: legalalities of hood vents??	Thu, 01 January 2004 05:13

It's pretty obvious Ed is having problems getting enough airflow... I doubt the thermostat is the problem here. [Report message to a moderator]

V8_MA61
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Re: legalalities of hood vents??	Thu, 01 January 2004 05:19

sorry..i didnt mean fumes...you know like the heat waves you see on a hot day rising off the road - go on correct me with the proper name someone [Report message to a moderator]

Purple_Beasty
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May 2002

Re: legalalities of hood vents??

Thu, 01 January 2004 05:46

ed_ma61 wrote on Wed, 31 December 2003 17:17

ill try the bonnet hinge trick first, as its not permanent...

cheers
ed

One thing to consider before jacking up the back of the bonnet, does it have those little tags that lock into the front of the hinges?

If so jacking the bonnet up may well be illegal (it is in NZ, not sure on Oz). Those tags prevent the bonnet going back through your windscreen and taking your head off in an accident.

Something to think about.

Callum

[Report message to a moderator]

Classique71
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Re: legalalities of hood vents??

Thu, 01 January 2004 06:12

Norbie wrote on Thu, 01 January 2004 16:01

Having said that, my atmo-venting BOV makes for a faint oil smell when it blows off at high boost/rpm. No big deal though.

taking a stab in the dak here - norbie do you run a oil catch can - for the oil vapor ?

Im going to be looking at this for the gt4 - to stop that oil vapor getting into the induction/new intercooler setup .
In your norbiful wisdom - is there benefits in doing this that you know of ?

Guessing that thats what the smell is .

Also for those three pics - the first looks too " cordia " for me - second looks like a cheap bug catcher - third - looks like a " work in progress "

I still think eiuther jacking it up a little like norbie said would be the first avenue - then after that - the cosworth vents ..

compared to the three pics above - the vents wouldnt look wrong

[Updated on: Thu, 01 January 2004 06:25]

[Report message to a moderator]

Norbie
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Re: legalalities of hood vents??	Thu, 01 January 2004 08:33

No I don't run an oil catch can, and yes it is a good idea. I've just been too cheap/lazy to do it yet. [Report message to a moderator]

Classique71
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Re: legalalities of hood vents??	Thu, 01 January 2004 08:35

goodo - ta for the answer - might look at getting one soon [Report message to a moderator]

BlackSupra
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Re: legalalities of hood vents??	Thu, 01 January 2004 11:36

A personal fav [Report message to a moderator]

V8_MA61
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Re: legalalities of hood vents??	Thu, 01 January 2004 12:07

that two tone and wing is sooo fugly! [Report message to a moderator]

Allan
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Re: legalalities of hood vents??	Thu, 01 January 2004 12:21

geeee combine that with norbies fully sik shim'ed bonnet and ya got serious rice! [Report message to a moderator]

Norbie
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Re: legalalities of hood vents??	Fri, 02 January 2004 04:56

My eyes! It burns!! [Report message to a moderator]

ed_ma61
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Re: legalalities of hood vents??	Fri, 02 January 2004 14:15

yeah, there is NO thermostat installed at the moment (i dred putting one in presently!)... water injection is a DEFINITE at the present time. ive got all the hardware (spare a misting jet - which im just waiting for the place to reopen so i can buy it). im also trying to sort out the final touches of a MAP/RPM switch to run it. will let me leanout the hell-rich top end mixes and gain some power, whilst still supressing detonation. plus it will cool the cyls significantly, and help prevent issues elsewhere in the rpm/load range. its all good!...however, i REALLY should be running aftermarket management on this. its getting quite obvious that this is the case... ahh well.. we'll make do. ive just been reading the merits of ethanol fuel too... sounds like a decent fuel additive... http://www.mct.gov.br/clima/ingles/comunic_old/alc ohol3.htm did i mention the heat soak has started causing pinging!! arrghh! i love engines! ed [Report message to a moderator]

chrisss
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melb
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Re: legalalities of hood vents??	Sat, 03 January 2004 02:04

just a little info about thermostats in case you didnt know. removing the thermostat can actually cause your car to overheat. - the termostat causes a restriction in the cooling system which helps raise the boiling point - ie higher pressure = higher boiling point. imagine that the thermostat actually helps to keep the water in contact with the walls of cooling passages - any of this making sense?? so ed put that thermo back in!!! so I can quickly see three things contributing to your overheat prob. 1. extractors - put the orig exhaust mani back on, if you havnt sold it!! 2. high comp ratio - dont know if that would affect it much tho? never considered it - but if your timing is out and your getting knocking than that will, so adjust your timing waaay back and see what that does. 3. the afforementioned thermostat. [Report message to a moderator]

ed_ma61
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Re: legalalities of hood vents??	Sat, 03 January 2004 02:18

thermostats do exceptionally little to the coolant system pressure and thus boiling point etc... what they DO do is slow the flow of coolant through the system thus allowing more time for heat transfer out of the radiator. experience with these motors has shown me, though, that despite high coolant flow rates, the energy transfer through the radiator is sufficient to prevent overheating. ive already discounted this event from contributing to the issues im having. there are several more conspicuous problems which need adressing first cheers ed [Report message to a moderator]

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