Date: Thu, 02 Nov 2006 21:45:28 +0000 From: Colin Stamp <col.dustbinnospamp.plus.com> Subject: Re: Cold Air Intake
On Thu, 02 Nov 2006 14:32:51 -0500, Fred W <Malt_Houndnospamm-me-not*yahoo.com> wrote: >I fail to see how the boost would vary with temperature, considering >that the ECU can run the charge up as high as it can until it begins to >detonate. That would be the "hard limit" on boost. When you have that >musch intake pressure going on, it isn't going to make a diddly bit of >difference how free flowing the intake is UNTIL you reach massive flow >rates, at which point you could lose pressure due to the restriction. I have to say, I disagree a bit here too. Like you say, the boost *pressure* won't change, but if the air is cooler, then the mass will be greater for the same pressure. I agree though, that any increase in peak power due to just fitting a CAI will be pretty marginal. > >I don't have any specs or scientific evidence, but considering how small >the engine displacemnet is, and how low rps these things spin, I still >say any cold air intake, or other fiddling with the intake to "improve >flow" would not net any tangible difference. If you can do something to the intake that genuinely increases flow, then it's still worthwhile, even though the boost pressure is limited. It might not increase peak power, but IME, it really can help off-boost where the boost limit doesn't apply. I've got no figures, but I recently changed my air filter for a new standard one. The old one had done 60K miles. My bum tells me that the 9-3 is now slightly faster off boost, has a slightly lower boost threshold and shows a bit less lag. It could all be in my mind, I suppose... Cheers, Colin.
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