Bonnet Vents

Massive

Torque Master
Points
72
Location
Weir
Car
Clio 172 Cup
ok a few questions ive found some vents i like, also ive found a few bonnets with vents already on them!

but how easy are vents to fit, without showing the lines where you have cut, is it a pro job?

also im lookin at a carbon fibre bonnet, yes its expensive :s but would look good in my opinion with the colour of the car, but can you put vents into carbon firbre bonnets, or would they look stupid if they were not carbon as well?
 

Massive

Torque Master
Points
72
Location
Weir
Car
Clio 172 Cup
so if i get a a carbon firbre bonnet i would be best to get carbon fibre vents, think i might look for a carbon bonnet with vents already in, or if not see what a body shop can do for me *gulp*
 

Loz

Torque King
Points
252
Location
Wolverhampton, U.K.
Car
MX-5
In my mind it's not the cutting that would be the hard part, it would be the positioning of the vents making sure they are straight & symmetrical. I think buying a bonnet with the vents in would be bestist :amuse:

Lets have some pic's then Massive, what's on your shopping list :bigsmile::bigsmile::bigsmile:

**If you do get a carbon bonnet & you plan to fit the vents yourself, make sure you wear a breathing mask when cutting. Some Carbon fibre parts contain 'Carbon Nano-tubes' which add to the strength of the part, but may (it's not 100% certain yet) damage lungs in much the same way as asbestos if breathed in.**
 

Massive

Torque Master
Points
72
Location
Weir
Car
Clio 172 Cup
dont think ill be doin any cutting ill probably make a mess of it, sorry ill have to get some pics up been busy, my rover cost me 600 quid :s has had a full engine rebuild after the head gasket

it needs the mot now, needs 3 new tyres and rear susp bushes :s
 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
Car
Passat 2.0 TDi
I've actually been considering bonnet vents to funnel some air down the back of the engine bay to where the turbo is (hidden away, out of the air stream!!)

What's the likely cost to get this done professionally?
 

turbonutter69

TC ModFather
Moderator
Points
652
Location
Alone in the dark.
Car
Insignia SRI.
I've been thinking of cuttin some holes for vents in my bonnet as my engine runs very hot. But my question is. What about the water that it lets through? What happens to it? Would I need to place a tray under the vent all the way to the front?
 

turbonutter69

TC ModFather
Moderator
Points
652
Location
Alone in the dark.
Car
Insignia SRI.
I was just worried bout the air filter an the electrics? Would I need to put vents in or could I cut the holes and put mesh behind it? Would that let too much water through? What about when the car is stood an it's raining?
 

gendox

Track Warrior
Points
67
Location
Corby, Nortants
Car
Pug 206 LX
err i would imagin unless the angle your filter is at ie facing down or level it should be ok i mean if you had a vent on the bonnet the filter would no normally sit right in it normally behind it. so its all about position but i would put a strong grille if its larger like a scooby vent or evo vent but i would put some mesh if its just small
 

turbonutter69

TC ModFather
Moderator
Points
652
Location
Alone in the dark.
Car
Insignia SRI.
I was thinkin of having 3. 1 between the radiator and the engine. It would be about the manifold. And 1 either side around where the airfilter sits. It's a mod that will have to wait cause if I do, do it then I want to make sure it looks right...
 

gendox

Track Warrior
Points
67
Location
Corby, Nortants
Car
Pug 206 LX
ok so the radiator one i would imagin to be a hole like an evo and the other two aswell im sure cold water on the radiator would not be a prob plus the manifold will sort that out because of the heat where does the air filter sit do you have a pic of your bonnet
 

gendox

Track Warrior
Points
67
Location
Corby, Nortants
Car
Pug 206 LX
it will take time but mostly common sense lol its shouldnt be too difficult why even see ive there is already bonnents for your car and see where they are positioned
 

turbonutter69

TC ModFather
Moderator
Points
652
Location
Alone in the dark.
Car
Insignia SRI.
it will take time but mostly common sense lol its shouldnt be too difficult why even see ive there is already bonnents for your car and see where they are positioned

I had thought about this but if I do it I want it to be individual and of my own thought. It will take a lot of time and thought to do this mod I think.
 

old-git

Moderator
Points
627
Location
Essex
Car
Elan & Robin Hood
ok a few questions ive found some vents i like, also ive found a few bonnets with vents already on them!

but how easy are vents to fit, without showing the lines where you have cut, is it a pro job?

also im lookin at a carbon fibre bonnet, yes its expensive :s but would look good in my opinion with the colour of the car, but can you put vents into carbon firbre bonnets, or would they look stupid if they were not carbon as well?

What are you trying to achieve; air in, air out or just posing?
 

claymore

The Torque Meister
Points
447
Location
Shrewsbury
Car
T-10k,




 

HDi fun

TC ModFather
Points
637
Location
Buckinghamshire UK
Car
Passat 2.0 TDi
What sort of duct are you thinking of HDI, something like a NACA duct?

I don't know, that's the problem. All I want to do is scoop some air down the back of the engine compartment without making the car look silly or become noisy. There's a lot of control gear at the back of the engine bay - all the turbo control vacuum valves are located there so space is very tight.

The car already has an oil/water heat exchanger as standard so perhaps an additional oil cooler mounted at the front would be better that vents. Same problem though - where the heck do I put it?

I'm open to suggestions on this one
 

old-git

Moderator
Points
627
Location
Essex
Car
Elan & Robin Hood
I want air in/ out so I can cool the engine abit...

Air flowing over the engine will do BA in the cooling department, that is what the radiator is for. If the engine is overheating (and timing etc is correct) you need to improve the efficiency of the heat exchanger. This can be done in various ways.

Make sure that ALL of the air entering the intakes is channelled through the radiator (ie none of it escapes around the edges).

Make sure that there sufficient pressure differential between the two faces of the radiator in order to achieve an efficient flow through it. If the air can't get out once it has passed though the radiator it will severely restrict flow and therefore heat removal. There is no point in putting more intake scoops on if the extra air can't get out! You may well find that the fitting of an air OUTLET has more effect than in inlet as it allows the existing radiator to work more efficiently.

Look into fitting a more efficient radiator. Even one the same size can be better if a more efficient core is utilised.

Positioning of intakes and outlets is VERY important if they are to perform properly. Intakes need to be located in areas of high pressure (relative to where the air is going) and outlets in low-pressure areas, otherwise you are wasting your time and money. A scoop placed at the front of the bonnet will not flow more air into the engine bay if the pressure under the bonnet is higher than that outside, no matter how fast you are going.

If you are only interested in aesthetics, then ignore the above :) Bear in mind, however, that a badly placed scoop could actually impair your cooling by messing up pressure differentials.
 

turbonutter69

TC ModFather
Moderator
Points
652
Location
Alone in the dark.
Car
Insignia SRI.
Thanks for the tips mate. The main idea is just to release some heat from the engine bay. When I open the bonnet after a good drive I get a massive wave of hot air thats been stuck under the bonnet I just wanna relieve that Tbh..... There will be a lot of thought going in to this before I decide where i'm gonna start cuttin with the grinder....:D
 

Loz

Torque King
Points
252
Location
Wolverhampton, U.K.
Car
MX-5
Look into fitting a more efficient radiator. Even one the same size can be better if a more efficient core is utilised.

A good article that Old-git :D

Am I right in thinking that a cheap(ish) route is to fit a radiator from an equivalent diesel model?

Here's a pic' of the bonnet that's on my car, the vent is positioned right over the exhaust manifold. **Edited this is my car!!!**

 
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old-git

Moderator
Points
627
Location
Essex
Car
Elan & Robin Hood
A good article that Old-git :D

Am I right in thinking that a cheap(ish) route is to fit a radiator from an equivalent diesel model?

Here's a pic' of the bonnet that's on my car, the vent is positioned right over the exhaust manifold. **Edited this is my car!!!**

Thank you, I try my best :)

I know nothing about diesel rads, perhaps HDi can help.

The vents by the windscreen are in an area that is usually a high pressure zone (that's why heater intakes are placed there) so air will tend to flow into engine bay. The front scoop is in an area of low pressure on cars with a relatively streamlined front end, so air may will try to flow out.

However, it is easy to check this. Attach a few short lengths (50mm) of string or wool to the bonnet just in front of the scoop (as close to the opening as possible but parallel to it) and on top of the rear grills. Go for a drive following a couple of friends in another car. The passenger will be able to ascertain whether air is flowing in or out of the scoop and vents (photos will help).
 
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gendox

Track Warrior
Points
67
Location
Corby, Nortants
Car
Pug 206 LX
Thank you, I try my best :)

I know nothing about diesel rads, perhaps HDi can help.

The vents by the windscreen are in an area that is usually a high pressure zone (that's why heater intakes are placed there) so air will tend to flow into engine bay. The front scoop is in an area of low pressure on cars with a relatively streamlined front end, so air may will try to flow out.

However, it is easy to check this. Attach a few short lengths (50mm) of string or wool to the bonnet just in front of the scoop (as close to the opening as possible but parallel to it) and on top of the rear grills. Go for a drive following a couple of friends in another car. The passenger will be able to ascertain whether air is flowing in or out of the scoop and vents (photos will help).

Or buy a wind tunnel :D
 

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