At what restriction should I change the filter

[ZeeOSix]

Originally Posted By: Colt45ws
An interesting test would be to take it to the track one weekend with a new Motorcraft filter and the plugged Amsoil. Run as back-to-back as possible 2 or 3 runs of each and see what 20" of restriction means for WOT power.
1" of H20 = .036PSI. So at 20" you are losing .72PSI across the filter.


You'd be losing 3~4% power at WOT on a N/A engine.

 

[rrounds]

I can say I don't feel any difference in the power of the car(S2000) even if I go from have filter that has 12 to 15" H2O on the filter to a new filter.

ROD

 

[Colt45ws]

Originally Posted By: ZeeOSix
Originally Posted By: Colt45ws
An interesting test would be to take it to the track one weekend with a new Motorcraft filter and the plugged Amsoil. Run as back-to-back as possible 2 or 3 runs of each and see what 20" of restriction means for WOT power.
1" of H20 = .036PSI. So at 20" you are losing .72PSI across the filter.


You'd be losing 3~4% power at WOT on a N/A engine.

That'd be about 9HP for me. Interesting.

 

[Jim Allen]

The gas engine restriction spec is commonly 15" unless the engine mfr. says different.

 

[gaijinnv]

Originally Posted By: mitsuman47
I've had my wix restriction gauge for a few years now. I changed one air filter at 80k miles because the gauge never budged, and I thought that my restriction gauge may not read a low enough amount of pressure for my little 1.7L, low power engine to register on it. I've seen a recommendation for gasoline engines to change at about 20 inches of h2o, but figured that the reference engine is considerably larger than mine. So, what do you guys think is a good amount of restriction for me to change the filter in my 1.7L honda?


I first installed a Wix Filter Guard on my Toyota 5.7l V8 which indicated 8-25 inches H2O:

It never budged - even with a WOT test.

I soon replaced it with a K&N Filter Minder which reads a maximum of 10 inches of H20:

This more sensitive K&N gauge reads 50% (approx. 5 inches of H2O) after a WOT test with a new OEM paper filter. It is available for a good price here: K&N Filter Minder on Amazon

At least now I know I am "on the gauge" and reasonably sure any additional filter/intake restriction will be quickly picked up by the gauge.

HTH

 

[mitsuman47]

Do both gauges require the same size hole to be drilled?

 

[gaijinnv]

Originally Posted By: mitsuman47
Do both gauges require the same size hole to be drilled?


Yes. Both gauges are exactly the same dimensions. If you don't like one, just pull it out and plug in the other one.

HTH