Suggest: A good vent design?

gryphoon81

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61
Location
Putrajaya, Malaysia
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Perodua Viva 1.0
Hi and welcome, its been a while since my last posted.

Right now i would need suggestion of a good vent design for my kei car/compact car. A vent design on a bonnet makes provision for both cold air to get in and a route for the hot air to exit.

Please provide with link or picture/image of a good design vent. I hope i can do it DIY.

Here i share picture/image of my ride. That duct on the hood only a dummy.



 

obi_waynne

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A3 1.4 TFSI 150 COD
I prefer to see vents like this in pairs, symettrically placed on the bonnet. When you have just one vent on one side it looks unbalanced.

I think for practical purposes to allow hot air out and cold air in you need a Mitsubishi EVO style vent near to the front radiator - perhaps a third of the way down.
 

sar1f

Wrench Pro
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16
Location
United States/Kansas City
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VW Corrado g60
I would say lifting the center of the hood at the windscreen end or porting toward the back of the bonnet would be best to give the air a chance to get through the whole bay and the air behind the motor a chance to be removed. The tricky part about gettig the air to circulate isn't the porting its the compact nature of all the components in the bay already. Compact car= compact fitement= minimul breathing room= super-creative thinking.

I'm very ancsious to see where this goes and what type of mods are settled on. Another thing that might sway the votes would be how your ba itself is setup. Such as is it stock and your workingaround those larger internals or have you swapped out pieces like the intake filter box for a cone filter thus freeing up more area for the air to flo one way verses another?
 

gryphoon81

New member
Points
61
Location
Putrajaya, Malaysia
Car
Perodua Viva 1.0
I prefer to see vents like this in pairs, symettrically placed on the bonnet. When you have just one vent on one side it looks unbalanced.

I think for practical purposes to allow hot air out and cold air in you need a Mitsubishi EVO style vent near to the front radiator - perhaps a third of the way down.

If you don't mind showing me a picture of Mitsubishi EVO that you mention. TQ.
 

gryphoon81

New member
Points
61
Location
Putrajaya, Malaysia
Car
Perodua Viva 1.0
I would say lifting the center of the hood at the windscreen end or porting toward the back of the bonnet would be best to give the air a chance to get through the whole bay and the air behind the motor a chance to be removed. The tricky part about gettig the air to circulate isn't the porting its the compact nature of all the components in the bay already. Compact car= compact fitement= minimul breathing room= super-creative thinking.

I'm very ancsious to see where this goes and what type of mods are settled on. Another thing that might sway the votes would be how your ba itself is setup. Such as is it stock and your workingaround those larger internals or have you swapped out pieces like the intake filter box for a cone filter thus freeing up more area for the air to flo one way verses another?

Right now i already lift end of the hood a little bit but already test it not sufficient enough to let hot air out. I also already take out intake filter box and add open air/filter pod and i would say it give the engine more pickup and more save space. Later i will post of my engine bay if i have a chances. Thanks.. really want to creative thinking.
 

jarrus

Pro Tuner
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West Midlands, UK
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Suzuki Swift Sport
This is a difficult one really.

The reason for that is that in order to get more cold air in, you need to get the hot air out...

Think of it like this, as your car is driving along at a speed of 56 mph (or about 80kmh i believe) The rate of air that is coming in contact with the open part of the body like the grill which let air in the engine bay is increased than if you were doing a speed of 20 mph. At which eventually the outside air pressure is greater than the air pressure inside the engine bay so the air flows into the engine bay...
But... you also need to expel the air entering your engine bay because if the pressure difference is 0 (or there is no difference) then no air will enter the engine bay because the air pressure on the outside is equal to that on the inside.

So... adding a vent to allow the air to flow out of the engine is a far more effective way of removing hot air in the engine bay with cool outside air. The idea is to keep inside of the engine bay at a lower air pressure than the outside of the engine bay thus the high pressure of air hitting the front of the car will then pass though into the engine rather than being force around the car. Adding bonnet vents can acutally increase the efficiencey of radiators and intercoolers (on a forced inducted car) just because the air is now able to flow though them absorbing heat from the intake/coolant system,and flowing into the engine bay and out of the new bonnet vents rather than them acting as a static radiator.

I hope this makes sence. Feel free to ask any questions...
 

sar1f

Wrench Pro
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16
Location
United States/Kansas City
Car
VW Corrado g60
I think I'm stuck with the fact that there just isn't much bonnet, or bay for that matter to port from and not much space on which to mount the port. Would it be possible to run electric fan(s) to force the air through? I know the front ports have the intake fan or fans behind the radiator but is it possible to run say the EVO bonnet in question and install a exhaust directed fan under it? Or would the flow be to far off for effectiveness?
 

obi_waynne

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Something like the Mitsubishi EVO V shape should do the job and will look nice. (Thanks for the update, you'l have to post us up some pics as well when you get to 10 posts.)
 

droponikz

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Wiley Colorado
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Chevy Colbalt SS
Well what if you put a relatively large front hood vent, then ,maybe a vent on each side, wouldnt that give sorta an airflow path for the cool air to come in and the hot air out.:blink:
 

old-git

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Essex
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Elan & Robin Hood
Depends on whether the vents are located in high or low pressure areas. Place them badly and they could work back to front :)
 
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