Does removing the blanking plates to the two vents on the front of the bonnet make any difference to cooling, engine noise etc. or does it just allow water to enter the engine bay?

I presume the vent grills are there for homologation purposes only. Has anyboby removed theirs - if so, to what effect?

you'll find that the noise will increase from the engine bay, but the problem could be that there are some wiring that passes by close to the vents and this may cause a problem!!!!

I have removed the metal pieces. I think the hot air can escape faster and if a small hood is made, then more cold air can get to the open air filter. As u know the Subaru engine heats up very fast. sO i guess the vents help in cooling down the engine bay.

I asked this question ages ago and was told that the reason the vents are there is because the rally cars need the vents and the homologation (back when it was required) necessitated the road cars using the same bonnet as the WRC cars. However, since the bits which needed cooling (don't know what - somebody else will tell, no doubt) aren't there or don't exist on the road car, opening the vents will just allow engine noise out and water in. Which, as is pointed out above, could be bad considering that there's various electrics just there.

I imagine that if the vents were really required or of any use they would be open on an STi; since they're sealed on my Type-R and other STis I've seen I can only conclude that the vents are unecessary unless you're running a WRC car.

Which I'm not. :-(

The bonnet vents are dummy and serve no purpose other than looking decorative !!

I guess it depends how hot it is and how hard the car is being driven, but I have found that huge amounts of hot air come out of the vents (with the backing removed).

Of course I have only noticed this when the car is stopped - but I imagine that the air coming in through the radiator would be able to pass through more freely now that it has an easier exit. The air can only flow into the engine bay at the same speed it is allowed to escape. Pretty obvious I know http://bbs.sidc.co.uk/smile.gif

On my 97 hatch there are wires under the RHS vent but they have been unaffected so far.

Also just because Subaru leaves the backing in on their STI version is not an indication that it is the best thing to do. Sorry subaru http://bbs.sidc.co.uk/smile.gif hehe!

Jon

PS If you are driving mostly in traffic in cold weather removing the vents is probably a waste of time. But living in average temp of 30 degrees C with lots of open roads - I can say it is definitly worth it!!

I doubt water entry is a particular problem. The standard vents have holes that drain the water into the engine bay anyway, and they're not sited to avoid wires, as far as I can tell.