Chimney under the scoop

[MR2NortE]

after spending some time looking under the bonnet of my GT, i noticed that the air that the bonnet scoop collects feeds it down a chimney that sits directly on top of the turbo and internal wastegate. now what is the point of that? cos before i have this subbie i always thought the scoop was to feed cold air to the top mounted intercooler but in the case with my ride, the intercooler is water cooled and therefore enclsoed in a box. i am confused.

also how do i know when to top up the water for the intercooler i.e how full should it be? and do i have to use distilled water? cheers.

[DTSJR]

The chimney does two things. When teh car is sitting still, it allows hot air coming off the turbo to vent out the hood scoop. And when driving, it takes air from the hood scoop and blows it down onto the turbo to cool it.

[MR2NortE]

i see so the sole purpose is to keep the under bonnet temp down? in that case why don't other car manufactures do it?

[DTSJR]

Well its just to keep the turbo cool on our cars. Other cars use other methods.

[Subtle]

Not wishing to be controversial, but a the plate in the shroud above the chimney seems to be a baffle that constrains the flow down the chimney.

I think the flat-lying baffle is to keep the rain out, but allows heat to vent when parked.

Because of the fmic I've reversed the scoop on the twgn, and kept the chimney to vent the high heat from the turbo. The forward part of the shroud has holes to vent airflow when moving.

[DTSJR]

I wont argue with anything you said as it is true, but Im pretty sure some air does get forced down there while driving. Im not saying its a lot though. Its a pretty small scoop, and I know that the scoop on the RS doesnt take in much air, so I can only guess how little the legacy scoop takes in. I havent had a chance to take a good look at the setup, but thats what it looks like from a glance. Lets heat out, takes in cool air while moving, and keeps rain out.

[MR2NortE]

thanks for all the input:) much appreciated. while still on the subject, how does the factory legacy scoop fixed on the bonnet? is there any screws or bolts or nuts? thinking of fitting a larger scoop to catch more cold air in.

[Subtle]

A few bolts, but with a water i/c you wont physically need a bigger scoop.

[DTSJR]

It would probably be cheaper and more effective to just get a water i/c liek Subtle said then to have a bigger scoop fabricated.

[MR2NortE]

i see... so how do i know how much water it should be in that water to air intercooler tank that's attached to the TB? is it supposed to be only filled with purified/mineral water? cheers

[555BCTurbo]

It would probably be cheaper and more effective to just get a water i/c liek Subtle said then to have a bigger scoop fabricated.

It's a Legacy GT (ej20g), so it has an AWIC factory...