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Discussion Starter · #1 ·
So, nowadays, people are always going on about hot the stock filter is just as good as aftermarket filters. That wasn't the prevailing sentiment back in 2004 though, when we were scrambling to get anything else. I remember thinking I felt a difference when I first installed my BMC, even started a thread about it. But since I reset my ECU at the same time, I couldn't really be sure.

At any rate, an hour ago I decided with a little ingenuity, a Dyson, and a manometer, I could measure how well the stock filter flows versus my BMC (which is pretty dirty and needs to be cleaned soon). I cut out a piece of cardboard and sealed up the open end of the filter with some duct tape, created a small hole for the manometer tube, and voila, a sealed vacuum/filter environment to measure.

Tested it out five times on each, running it for at least 10 seconds.

At any rate, what I found was the dirty BMC produced HALF the vaccum as the stock filter. Within 3 seconds, the mostly clean stock was at -.10, the dirty BMC never broke -.05.





I even hooked the foam sock back up to see if it affected the stock flow, but it registered the same -.10


No idea how the vacuum created by the Dyson DC17 compares to the inside of the airbox at full boost, but even dirty, the BMC did definitely flowed more air. So I guess that's settled.
 

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What you just proved is that the stock filter flows as well as the aftermarket filter.

There is a 0.05 inches of water difference between the two...which equates to 0.001806 psi.

In other words....negligible.
 

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So I guess in the end, this test was a good try. I bet there is a better way to test his that will yield better results.
No, it's a good test. It shows two things:

1. At whatever flow rate that Dyson is pulling (pretty stout, I'd have to believe) neither filter is causing much pressure drop. Less than two thousandths of a PSI, which is a loss of .012% compared to atmospheric.

2. The stock filter is flowing at the same rate as the aftermarket, for all intents and purposes.

So certainly not a waste of time.
 

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Discussion Starter · #8 ·
Most dyson's flow between 50-70 CFM, while an R at 5000 RPM will be flowing 200+ CFM.
So, if there is a MEASURABLE difference (twice as much) in flow rate at 50-70 CFM, it likely follows that there is even more difference at 200+ CFM?
 

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So, if there is a MEASURABLE difference (twice as much) in flow rate at 50-70 CFM, it likely follows that there is even more difference at 200+ CFM?
With a dirty filter too. That's just what I was thinking, R.
 

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So, if there is a MEASURABLE difference (twice as much) in flow rate at 50-70 CFM, it likely follows that there is even more difference at 200+ CFM?
at very least 4x the flow means 4x the difference, nevermind the extra suction from the turbo under boost, positive pressure from the CAIs, and also positive pressure air from the factory snorkel.
 

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Now get a second vacuum in there to add more air flow.
 

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Um.

Its just a filter.

....

Just sayin'
 

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First of all, R Kelly rocks and if it weren't for all his haRd work and multitude of tests, trials, reports, pictures, videos, gtech data, related to all kinds of mods such as intakes (developed and marketed the most popular CAI), exhausts, lighting, tires, wheels, suspension, audio, etc, etc, etc, this R forum would be far behind where it is today. A big thanks to guys like him, Jim Lill, JRL, Needsdecaf (to name just the first few that come to mind from way back in the early R forum days of 2003-2006).

Here's what I know about P2 R filters: Under stock boost I have measured similar and nearly identical peak MAF gm/sec reading between my BMC and stock/OEM paper filters (with each test topping out in 3rd gear under similar load, temps, etc).

LTA
 

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Discussion Starter · #17 ·
Here's what I know about P2 R filters: Under stock boost I have measured similar and nearly identical peak MAF gm/sec reading between my BMC and stock/OEM paper filters (with each test topping out in 3rd gear under similar load, temps, etc).

LTA
That is NOT nearly as much fun as conducting a home science experiment with your 4 and 7 year old helping you hook up the "noo-noo" to the yellow filter and the red filter. And per my 7 year old, the red filter clearly "won".

:)
 

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First of all, R Kelly rocks and if it weren't for all his haRd work and multitude of tests, trials, reports, pictures, videos, gtech data, related to all kinds of mods such as intakes (developed and marketed the most popular CAI), exhausts, lighting, tires, wheels, suspension, audio, etc, etc, etc, this R forum would be far behind where it is today. A big thanks to guys like him, Jim Lill, JRL, Needsdecaf (to name just the first few that come to mind from way back in the early R forum days of 2003-2006).
Brown nose award of the year, right there :p

At least the Dyson didn't loose suction between the two tests, due to its unique cyclone technology. As for the tests themselves, this goes to show you, AEM is best.
 

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Discussion Starter · #19 ·
Brown nose award of the year, right there :p

At least the Dyson didn't loose suction between the two tests, due to its unique cyclone technology. As for the tests themselves, this goes to show you, AEM is best.
Joe, let's not talk about brown streaks, ok? :p

Besides, that was not nearly as bad the whole threads that people have started to thank me for stuff, that was REALLY embarassing.

And LTA, thank you for the sentiment, but you forgot the R Mugs. ;)
 

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Don't get me wrong this is an excellent thread!!

Though next time to get more suction you should use something like this (your kids would approve)



:p
 
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