thoughts on a diy louvre type bonnet scoop 4runner/79 series

turtl3tim
Here and there
Posts: 59
Joined: February 10th, 2014, 9:10 pm
Location: Bunbury, WA

thoughts on a diy louvre type bonnet scoop 4runner/79 series

Unread post by turtl3tim » May 4th, 2016, 11:34 pm

hi all, as the title says, im toying with the idea of hacking up my bonnet. the 4runner has a nice little buldge at the front which i can see working very well at being converted into a scoop, so it will look like a bit of a spin off from a 79 series bonnet.

ive gone to the extreme effort of editing a picture in paint, because i dont have photoshop, nor would i know how to use it lol. i would need to have a good look at the bracing structure on the underside of the bonnet before going ahead, but im just chasing thoughts and opinions atm (btw if anyone does have photoshop, and would be interested in having a proper go at this for me, then hit me up and i will take a better, front on picture for u to play around with)

enjoy :petrified:

Image
Last edited by turtl3tim on May 5th, 2016, 11:46 am, edited 1 time in total.
92' 4runner, 3.0Loser manual. Custom DIYPVC snorkel. ISR mod. Hurricane headers with 2.5" exhaust, stainless 200cpsi cat and turbo muffler. TJM bullbar with hella spotties, LED indicators. 2" body lift. 15x10's 0 offset chromies, 31x10.5 a/t's. FlameThrower injectors, 7mge vafm upgrade with modified cressida airbox for snorkel, 7mge coil upgrade. Plugs gapped to 7mge specs (1.1mm). Eagle 7mm spark leads. Aftermarket a-pillar oil pressure and water temp gauges, rear Aussie Lokka

Peter Aawen
Admin
Posts: 20778
Joined: June 17th, 2005, 8:01 pm

Re: thoughts on a diy louver type bonnet scoop 4runner/79 se

Unread post by Peter Aawen » May 5th, 2016, 9:42 am

Poorly planned siting of bonnet scoops can kill the ability of your cooling system to cope with the heat load under the bonnet!!

I can't see your pic, (did you load it as an attachment or via a link?) but if you are planning on putting an 'inlet' scoop of any sort on there, especially towards the front, you could be about to stuff your cooling system!! And if you are putting an 'outlet' scoop too close to the rear, you might well be doing the same!!

If you want to avoid over-heating problems, you need to really understand what the OE designed airflow under the bonnet is meant to do before you even dream of fitting a scoop or even just raising the rear of the bonnet a little bit!! They might look 'tuff', but many 'poorly planned' aftermarket scoop fittings/positions are just crap & only serve to tell the informed world how little the owner/fitter really knows about what goes on under their bonnet!! And they usually complain about all their over-heating problems too! :rolleyes:
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

turtl3tim
Here and there
Posts: 59
Joined: February 10th, 2014, 9:10 pm
Location: Bunbury, WA

Re: thoughts on a diy louvre type bonnet scoop 4runner/79 se

Unread post by turtl3tim » May 5th, 2016, 11:59 am

well i dont have any overheating problems...or access to a wind tunnel to work out exactly where to mount them lol, but i am aware that the 3vzes can run warm and produce alot of under bonnet heat, i have seen a couple of photos of people fitting xkr vents (not scoops) to their bonnets.

i was just planning on having something a little different, i certainly dont want to impede on the cooling systems ability, but any added cooling/heat dissipation effects would be great. I was also toying with the idea of getting one of the new hilux scoops (4 sectioned as opposed to the old 3 sectioned ones)
Image
and some of these if they dont end up looking too overkill (i would cut the louvered sections to make them functional)
Image

where would u plan on mounting a scoop and vent? most people normally just whack the scoops at the back of the bonnet in the centre. and the vents are more towards the middle of the bonnet on the sides of the raised lip.

examples
Image
this images is from the ih8mud forum and the poster, posted this-
red= hi pressure
yellow=streaking (turbulence, but movement)
green=no air movement - low pressure/neg pressure
Image
Image
92' 4runner, 3.0Loser manual. Custom DIYPVC snorkel. ISR mod. Hurricane headers with 2.5" exhaust, stainless 200cpsi cat and turbo muffler. TJM bullbar with hella spotties, LED indicators. 2" body lift. 15x10's 0 offset chromies, 31x10.5 a/t's. FlameThrower injectors, 7mge vafm upgrade with modified cressida airbox for snorkel, 7mge coil upgrade. Plugs gapped to 7mge specs (1.1mm). Eagle 7mm spark leads. Aftermarket a-pillar oil pressure and water temp gauges, rear Aussie Lokka

Peter Aawen
Admin
Posts: 20778
Joined: June 17th, 2005, 8:01 pm

Re: thoughts on a diy louvre type bonnet scoop 4runner/79 se

Unread post by Peter Aawen » May 5th, 2016, 2:07 pm

turtl3tim wrote:well i dont have any overheating problems...


Maybe you don't just yet, but whacking either scoops or vents on somewhere WITHOUT access to a wind tunnel; or copying something that HAS had said access; or at least doing some rudimentary investigation into the air flow & pressure areas under the bonnet & there's a good chance you will have over heating problems!! And not necessarily just over-heating the cooling system either!! Did you realise that the airflow under your bonnet doesn't just cool by passing thru the radiator?? It also cools the coolant by flowing past the coolant reservoir; cools the battery by flowing past it; cools the oil by swirling around the oil filter & in some cases the metal plate covering the oil cooler that's inserted into the side of the block; and it even cools underbody components as it flows out underneath the vehicle!!
..... most people normally just whack the scoops at the back of the bonnet in the centre. and the vents are more towards the middle of the bonnet on the sides of the raised lip.....
^^ That's exactly the wrong way to go about it!! Vehicle manufacturers have generally put MILLIONS of $$ into testing & designing, & in doing so have worked out the high pressure/low pressure areas & probably even modified the inner guards & under bonnet/under body areas just to get the most benefit they can out of the air flow thru the front of the car, along the sides of the engine passing & cooling it a little as well as the oil filter/cooler, battery, & coolant reservoir as it goes by, and then collecting up the back of the engine bay where (most often these days) it creates a little bit of a high pressure pocket of relatively dead air that forces the rest of the cooling flow of air DOWN & OUT UNDERNEATH the vehicle, where it passes the transmission & transfer case, the diff & shocks, & even the fuel tank - all things that need cooling & that you stuffing around with poorly planned bonnet scoops or vents will be helping to cook!!

IF there happens to be bonnet on that model vehicle with that or a similar shaped engine mounted in the engine bay that the manufacturer has actually put a scoop or vent on to, then at least try to identify the position & design of the cut-out & scoop so that you can even vaguely mimic &/or benefit from the millions of dollars that the manufacturer spent rather than just whacking one on somewhere else & hoping!! Or failing finding a manufacturers bonnet to base the placement/design of your scoop/vent on (& it's gotta be the same model vehicle & a similar engine btw, cos EVERYTHING under the bonnet & covered by the inner guards & under bonnet as well as under the body will impact on the air flow path) then you could try sticking a heap of 2-3" long lengths of coloured wool all over the components under the bonnet/body, fixing a Go-pro or similar camera under there & then driving at various speeds & with the camera in various positions so that you can see what those coloured wool 'tell-tales' do in the air-flow - that way you'll get a bit of an idea of where the air path is & what it passes & cools as it flows thru, & you might even be able to work out where adding some air being forced in by a scoop or sucked out via a vent might help...

But sticking a scoop or vent on just cos it makes your vehicle look 'different' - that's a real 'newb' mistake that is only advertising the owner/driver's ignorance to the world :crazy:

If you need to do it, then make the effort, do the homework, and do it RIGHT!! :thumb:
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

typhoeus
Need to get out more
Posts: 2058
Joined: February 6th, 2011, 8:25 pm

Re: thoughts on a diy louvre type bonnet scoop 4runner/79 se

Unread post by typhoeus » May 5th, 2016, 8:31 pm

Pick up a spare bonnet to play with. if you cut holes in the wrong spot, pop rivet a patch over it & try a different spot. when you have it worked out & not overheating etc, then cut your good bonnet!!

Return to “Body and Barwork”