Outer Limits 4x4 Board

I was thinking of fitting a bonnet scoop to my v8 disco as it gets very hot. I have circuit breakers near tot he engine bay that keep tripping due to the heat coming out of there. Will be moving them regardless. The air is cold but not COLD, and the air con guy says it is related to how hot it is getting under the bonnet, a common problem with the rover V8's.
So i was thinking of a bonnet scoop to create some air flow, but then i got thinking about the deeper water crossings and how i think the bonnet scoop might prevent the retension of the air pocket under the bonnet and there for the electrics getting wet.
Just wondering what you guys think.
cheers

yes
it will help but vents would work better to draw the hot air out

Cooter, where would those vents you mentioned be available from?
I have seen them on rangies, on the side parts towards windscreen on bonnet.

Are they the same ones you are suggesting?

Where would you put them on a disco?

Do you have them?

Are they affective?

Do you know how much?

Sorry bout all the

An interesting observation I've made since fitting electric thermos is that the air con is now icy cold in slow speed and idling traffic (like I've never even felt the air con being this cold before except in winter!!). It got a good run yesterday in 37 degree heat on the way home and i had to re-direct the vents away from my hands it was that cold.

When you think about it there's heaps of space for the air to exit below the engine, problem being at idle, or low speeds, the engine driven fan wont push enough air through to keep the engine bay cooler.

Food for thought...

Cheers stuee mine doesn't overheat, the air is cold and i have thermos
But under any bonnet is plenty of heat and any little bit helps
Also I reckon they look sweet as on a Rangy
Can't quite picture it on a Disco though

If you need to do it to keep the engine cool...fine. But just dont put a GU patrol one on! They look pox and everyone goes for them. Look at something that might suit the style of the disco.

Angus

Cheers guys, but what about the deep water crossings, any opinions on that.

If you were to fit a scoop, then would it be 1 in the middle, 1 off set to 1 side and if so which side, or 2 scoops.

Can you get them with say a swinging flap inside to help maintain the cushion of air in a deep water crossing, but i suppose probably not much chop when a wave comes over the bonnet.??

It seems to me the more ventilation/air flow the more likely the engine bay will fill in a deep water crossing would you agree, would an apron negate this at all? Am thinking not much as the water will come from beneath and air will exit through scoop??

I would just want one or two vents, not a scoop. A scoop will look silly.

The shape of the disco hood makes me think (just my thoughts off-hand) that a single vent fairly close to the windscreen end, and wide rather than long (across the bonnet not front to back), would look the most acceptable.

This has the advantage of being the high point of the bonnet which is where heat will go.

If you were really concerned about the "air pocket" then maybe you could build in some kind of clips so you can put a piece of canvas or whatever across the vent, inside the bonnet, prior to a water crossing.

Or you could face the scoop backwards... This would prevent the water flowing straight in but you might on get as much of an air ram effect.

Angus

This one of Tuskers wasnt bad. I cant recall what it was off.... IIRC I think it may have been a WRX one, but I could be completely wrong there.

How about lifting the rear of bonnet with a couple of spaces on the hinges??? Would let the heat out like a scope but no cutting required????

I thought wrx were front facing with the opening
You wont get much air facing it that way
Will deflect straight over to cool windscreen

mcdisco wrote:Or you could face the scoop backwards... This would prevent the water flowing straight in but you might on get as much of an air ram effect.

Angus

You don't want an air ram effect. You want air to flow OUT of the bonnet scoop/vent/whatever, so it is easier for air to flow IN via the radiator.

luv4bee'n wrote:I thought wrx were front facing with the opening
You wont get much air facing it that way
Will deflect straight over to cool windscreen

not if you turn them around

as chimpboy said you want air to flow in through the front and out the back, your not cooling a intercooler under the scoop it is to vent the air out and get better air flow through the engine bay.

chimpboy wrote:

mcdisco wrote:Or you could face the scoop backwards... This would prevent the water flowing straight in but you might on get as much of an air ram effect.

Angus

You don't want an air ram effect. You want air to flow OUT of the bonnet scoop/vent/whatever, so it is easier for air to flow IN via the radiator.

yeah good point...

facing backwards would create a vacuum sort of effect and cause the air to be drawn out.

some good points there, but wouldn't you think that there is already lots of room through the vents at the base of the wind screen, am thinking that a rearward facing scoop wouldn't do much, it would be beneficial but wouldn't think it would be enough to be worth the trouble.
Am thinking a large forward facing scoop with side vents fitted to the guards would be the best way to circulate air through the engine bay. The amount of heat coming off the exhaust in these things is unbeleivable and probably best extracted through the bottom or the sides instead of being dragged up to the top and through the scoop.??
Still worried about those hard runs through deep water though.

As said, the rearward facing scoops drop the pressure under the bonnet so encourage more air to come in through the radiators. I can only assume that a forward facing scoop will reduce engine cooling as the pressure differential between the front and back of the radiator will be less and so the airflow through it (but there will probably be the capacity to absorb this), and the engine bay will be cooled more. Also, do the guard vents (gills???) vent all the way through to the engine bay or just the inner guards?

from my limited knowledge, its not only the direction that the scoop or vent is placed, but more importantly where it is placed.

i would do some wool pile testing before you go cutting holes in your car. you may be very surprised to see what the air is doing at different speeds.

Serg

the area at the base of your windscreen is a high pressure area with a roll effect if you fit a rear facing scoop that high pressure area will actually draw air from under the bonnet through the radiator
as stated above
i removed a section of my inner guard as outside the wheel well is another high pressure area but normally the low pressure air inside your wheel well is trapped in by the higher pressure air rolling the low pressure air inside the wheel well but by breaking the sealed section of your inner guard it will allow the air rammed into the engine bay leak into your inner wheel well equalizing the pressure and allow it to be drawn out by passing air

hope that makes sense to every 1 else as it made sense in my head

i had a lil over heating issue on my rangie, it wasn't gettin massively hot, but warmer then i would have liked it too.
i've been eyein off those vents on the side of the bonnet as well.
there on ebay by the way, 15bux each.
i decided to try and make my own.
i used some sheet steel and cut the sorround out, then used speaker mesh for the inside. cost me nothin.


would have used same color red but meh, they work too. ive noticed the temp gauge stayin a lil lower in situations where it would be higher.

i think u'd get alot better air flow with a less retrictive material. still good for a freebie, and better then nothing.

ive also seen rangie classic rear c pillar to cab vents used at the rear sides of the bonnet. I'm running twin davis craig 12in fans and a booster pump, standard pump, no thermostat. works great till you get a cold morning and you cant get the heater warm, you cant win!

def90 wrote:i think u'd get alot better air flow with a less retrictive material. still good for a freebie, and better then nothing.

was better then a freebie, i was at work clocked on when i made em, so i got paid to make em
yeah would be better with different material, but they do work and as you said, better then nothing.