An EVO friend and I did a little experiment at work today. We’re both engineers at a company that makes OEM automotive parts, including intake air systems. Utilizing the flow test equipment normally used to test OEM designs, we evaluated the stock EVO intake (w/a K&N drop-in panel filter) compared to the Buschur filter. Both setups had the stock MAF bolted on.

The stock intake was tested in three ways: normal, without ram air duct/scoop, and without any filter.

Both the K&N and the Buschur filters are used, but have been fairly recently cleaned.

Pressure drop is reported in inches of H2O.

Results:

Item...............inH2O@350cfm........inH2O@400cf m
Buschur....................5.26................... ......6.46
OEM........................13.36.................. .....17.22
OEM (no filter)........9.24.......................not tested
OEM (no scoop).......9.76.......................not tested

The Buschur filter shows a whopping 61%-62% reduction in pressure drop compared to a stock system w/K&N panel filter!

The stock system can flow almost as well w/out the scoop as it does with no filter at all! (a 27% improvement over stock) Of course, you would be sucking hotter air, but it definitely means that there is power to be gained by increasing the area of the scoop (add another scoop on the other side of the airbox, perhaps?).

The Buschur setup was very, very loud during the test (almost painfully so). The MAF itself was generating a high pitched whistle noise. The stock setup does a very good job dampening this whistle, which gets about twice as loud when you remove the scoop.

Anyway, we were hoping to finally put to bed the constant argument of the stock airbox being better than aftermarket units. Of course, there are other considerations (smooth airflow into the MAF to get stable mixture readings, hot air underhood, etc.), but in terms of overall flow, the stock system isn’t nearly as good as the Buschur unit.

Now Mr Buschur, feel free to send us a free part or two for objectively proving the quality of your parts. We were thinking a pair of LICP’s would be nice!

 

Very interesting.

 

Glad you stuck with the inferior setup?

 

Had to read it twice, my bad.

 

No prob, I had a similar moment yesterday regarding prices where I stuck my foot halfway down my throat. =D

 

Iam thinking, if there is really any difference between cone k&n with adapter,
and stock air box...

The only bad thing about it is K&N cone that is open and sucks in all heat.

 

We'll have to try the temp test next.

Good call on the LICP. I can use one of those.

 

How about a stock filter in the stock airbox? Works filter? Maybe I'm getting crazy here.

Good work tho... very cool when people do these types of tests

 

Sorry for the noobie question... so pressure drop on intake is good?

Im thinking of putting a couple of holes on the top of the intake box, do you think that would help increase the airflow and gain more power?

 

^ dont even bother.......

 

One other consideration is the "ram air" effect of the scoop on the stock airbox. The fact that the inlet of the scoop is in a high pressure area would have a significant effect on pressure inside the airbox.

-Paul

 

Since most on here use PSI, I've done the liberty of converting.

PSI conversion

Item...............PSI@350cfm........PSI@400cfm
Buschur....................0.19................... ......0.23
OEM..........................0.48................. ........0.62
OEM (no filter)........0.33.......................not tested
OEM (no scoop).......0.35.......................not tested

 

The higher the pressure drop the more restriction in the system. The more restriction the less airflow is in the system.

This was purely a pressure test. Like others have mentioned there are several other factors that may determine the efficiency of the intake/filter.

 

As MIevo8MR said, our next test is to compare intake air temps with the stock setup vs. the Buschur (using EvoScan). I will try an idle test and driving test with each filter on the same day to compare results. My Buschur filter should be here in the next week or so, so I'll just do it at the same time I'm doing the install.

 

Wow, very nice test. So you mean I haven't been lieing to the people here on EVOm as some recent people have accused me of in my testing of parts!! What shock, I AM NOT A LIAR!! haha

Thanks for posting the results.

If I sent you something for a positive test it would look like a payoff for doing it. I'll take care of that via. PM!! haha

Thanks for again for the test.