Air Filter size important on Turbo engine? Yes!
http://www.r2cperformance.com/black-...l-filters.aspx
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these filters allowed Camaro Andreas's car to go 6.3 at over 220mph. Says he tried without the filters and it made no difference.
So I'd find it very hard...in fact impossible to believe changing an air filter caused 2 full AFR points difference at idle, considering how relatively little air the engine would be consuming at idle.
Unless previously you had the most ridiculous piece of **** air filter possible. Pictures would speak a thousand words as to what you had before and have now though
By all means use the biggest and best quality filter you can, that's just common sense. But unless it's very bad to start with, I cant see it making a huge difference. And if there was a difference, it would mostly only be when the restriction is there. ie at high loads.
Here it is next to the old AFE filter. Wish the new one had the additional filter cone on top.

Last edited by Monte4ever; Oct 13, 2015 at 02:27 AM.
http://www.ebay.com/itm/Filter-Minder-Dash-Panel-Gauge-168501-00225-Air-Filter-Restriction-Monitoring-/321870077347?hash=item4af0f39da3&vxp=mtr
Hope to get back to the track this weekend.
Something like this would be ok. No need to use fancy names for gauges.
It can tell you if there is a pressure drop, which is to say, there is a slight restriction. If we decrease air filter size gradually, there will be more and more pressure drop (restriction) after the filter, until a full laboratory vacuum is established and there is no net movement of air molecules. Naturally, if we go the other direction, by increasing the size of the filter, the pressure will increase until it hits atmospheric, and then stabilizing around there, as it will tend to fluctuate on a running engine and even in the ambient air. Achieving this state is to say that the filter is "non-existent" or therefore "as if it was not there" which would be an nearly ideal situation, since it is as far opposite of the full vacuum, zero flow situation I have just had the honor of mentioning you are able to attain without exotic means at atmospheric pressure.
In other words, you would be able to establish and record any improvement, or gains as you put it, with this method, which is also to say that you are incorrect in your reasoning; you seem to be dismissing the difference between negligible "gains" (it is common for inlet plumbing to present a vacuum for the sake of PCV and the factory indeed adjusts the pressure in this location for this very reason using carefully planned restriction fittings) and whether there has been any improvement whatsoever.
Last edited by kingtal0n; Oct 13, 2015 at 08:25 PM.
Something like this would be ok. No need to use fancy names for gauges.
It can tell you if there is a pressure drop, which is to say, there is a slight restriction. If we decrease air filter size gradually, there will be more and more pressure drop (restriction) after the filter, until a full laboratory vacuum is established and there is no net movement of air molecules. Naturally, if we go the other direction, by increasing the size of the filter, the pressure will increase until it hits atmospheric, and then stabilizing around there, as it will tend to fluctuate on a running engine and even in the ambient air. Achieving this state is to say that the filter is "non-existent" or therefore "as if it was not there" which would be an nearly ideal situation, since it is as far opposite of the full vacuum, zero flow situation I have just had the honor of mentioning you are able to attain without exotic means at atmospheric pressure.
In other words, you would be able to establish and record any improvement, or gains as you put it, with this method, which is also to say that you are incorrect in your reasoning; you seem to be dismissing the difference between negligible "gains" (it is common for inlet plumbing to present a vacuum for the sake of PCV and the factory indeed adjusts the pressure in this location for this very reason using carefully planned restriction fittings) and whether there has been any improvement whatsoever.
A straight edged intake from say a turbo or supercharger inlet with no filter my represent zero restriction. However if you then add a properly designed bellmouth/velocity stack, you could see improvements in power. Yet pressure difference has not changed.
Smooth airflow will always work better here than turbulent airflow, and often a filter can help to smooth airflow. So it would be preferable to have a good filter with perhaps a very small restriction in terms of water pressure measurement vs no filter, no restriction but highly turbulent airflow.
And as for negligible gains, until you're into the realms of 20, 50, 100hp etc...anything sub that level is negligible especially when we're talking mostly about boosted builds probably in the region of 800+ HP
If you had say 1000hp and there was an indicated gain of even 20hp...that really is negligible and could simply be any number of dyno variations.
Of course the manometer would be a useful tool in monitoring the health of any filter or intake setup to alert the driver of any issues which is perhaps a better use of such a thing here.
"Modern engines universally have tuned intake tract volumes and associated resonance frequencies, designed to provide higher than atmospheric intake air pressure while the intake valves are open"
-https://en.wikipedia.org/wiki/Velocity_stack
If you had say 1000hp and there was an indicated gain of even 20hp...that really is negligible and could simply be any number of dyno variations.








