Lan Man

Question

I have a 99 UK Imprezza, when u open the bonnet the two extra air vent in the bonnet are covered.

Are these covers supposed to stay on, would you not get better cooling with them off?
or are they like the old directable air box's, - on in the winter off in the summer?

and also, just quickly while I'm here
If i hold the car at about 3-3500 rpm, under slight throttle, just at the sort of revs when u would normally floor it or change gear, i hear what sounds like pinking, but i dont get it if i try the old "slowly up hill in 4th with open throttle trick".

Any thoughts would be appreciated

Lan Man

dhorwich

I had the same question when i first got my scoob.... it turned out that with the vents off the under bonnet temps seemed to get higher..!

I didnt take loads of temp measurments, but with the vents off my induction kit (blitz sus) felt hot after a run, and with the vents on the kit was alot less hot..!

I think what might of been happening was the the air passing under the car was being drawn up into the engine bay and out the vents, and passing the hot exhaust manifold on its way...

Dan

R.B

If you want more cool air intake for the engine i would advise you to get a mini scoop because the removal of the plate could lead to problems with the engine from the rain.

siwrx

had mine off in the rain once and it soaked my blitz induction kit and made the car want to stall. never again its a summer only thing

hypoluxa

I'd be wary of removing the passenger side vent above the battery. Makes the car a little easier to steal unfortunatly.

hades

Re: the noise. At those revs on light throttles, could be wastegate flutter: AFAIK, the wastegate is pulsed at fairly rapidly in that kind of situation. Do you also get a similar noise if you're on say 1/4 throttle, just before the turbo spools up properly?

With turbo engines, you're unlikely to induce pinking by going slowly up a hill in 4th. Low static compression ratio means you are much more likely to get it when you are on full boost. Similarly at a steady 3k on very light throttle, I don't think you would be making enough boost to make it det.

I'm no expert by any means, but that would be my thoughts.

Imprezive

Hi guys,
IIRC, the bonnet vents have a cover underneath, with a hole yes?
if that's what your talking about, then i have Read that removal of these is NOT a good thing . They serve a purpose, being that they simulate a chimney.
In the same way wind passing over a chimney pot, sucks the smoke from a fire upwards.
Air passing over the bonnet and vents suck the internal heat out of the engine bay, so my guess would be that removal would increase interal tepm.
Removal might help if sitting in traffic a lot,

Cheers,
B.

mista weava

mine has covers and is an import, so aside from all the other comments, i feel that if the car was running around in Japan with them on, given that their climate is hotter, i would say leave them on.
this is purely a common sense view i took, but what the others say must be true also.
weava

i might also add that the bugeye lost the vents al together as does the model appearing in feb/march next year

[Edited by mista weava - 11/27/2002 11:26:24 AM]

Lan Man

Thanks for the feedback guys, Looks like I be leaving them on.

Hades, cheers for the advice, think I might get it listened too, as I have a HKS full decat, and can still hear it.
I know it had its original ecu put back in when i bought it, after running a Tek2 for a while, don't know if that could have confused it possibly.

Lan Man