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Vented bonnet

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silviac

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Do those bonnets with vent really helps for any reason?

I know lifted bonnet hinges doesn't work but I heard that reverse vent in the middle helps the temperature down.

Any legit source?

What about vents on sides? One facing front and the other reverse vent?
 

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Reversed vents will definitely work. The air flow over the top produces negative pressure which sucks the hot air out of the engine bay.

And, yes you're right, lifting the back of the bonnet does absolutely nothing. That's been tested by attaching strands of wool in the gap at the edge of the bonnet. They didn't move.
 
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silviac

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if you were to have vented bonnet, then you would right? rather than factory one.
 

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I wouldn't. There are downsides. The main one being as soon as you're parked-up and it rains. You may as well have the bonnet up...

I wouldn't mind a small vent over the mani, but get water flowing onto a cooked mani and...
 
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rofl, unless you can get a evo vent modifed somehow into the s15 bonnet.... the evo design is quite smart in reducing water entering the engine bay :D
 
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silviac

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A'PEXi said:
rofl, unless you can get a evo vent modifed somehow into the s15 bonnet.... the evo design is quite smart in reducing water entering the engine bay :D
do you know how they are designed?
 
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Sic15

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Hi from NZ.

I run a carbon fibre vented bonnet and the cover is off the coil packs as aids to cooling / airflow management.

Running an S14 radiator PFL ( around 20 + mm thick) - only the last 2 days, getting a 600 X 300 X 76 intercooler to replace the Evo one, plus have a plate under the front bumper assembly ( still standard - no body kit) . Expect to fit an air control plate - aluminium - at the top - just between the headlights to help control air flow later this week.

Car ran a little warm on dyno a couple of weeks back with the STD radiator (no bonnet fitted as it would be damaged by running open - from the force of air from the fan at the dyno place). Strategy to improve cooling so far - fitting of the PFL unit, + air deflector + bigger intercooler.

For context the engine puts out 220 + kw on a dynapack hub dyno and torque is around 390 nm so there is a bit of heat to manage.

Anyway yesterday it poured down while driving back from Palmerston North to Wellington - a journey of 100 odd Kms.

The engine did not suffer any problems with water in the wrong places. Water from the bonnett vent hits the shroud over the viscous fan if I leave the car parked in heavy rain.
 
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