Background:
A recent comparison of the modified GTI intake versus aftermarket showed that the GTI intake performs similarly at the 500 whp level with a hybrid-turbocharger.
My modifications to the GTI intake include using a BMC panel air filter. I wondered how well a stock air filter would perform instead of the BMC.
I obtained a new Mann air filter to test with.
Test Process:
Two tests will be performed, one using a flow bench and the second with the intake installed on the Mk7 GTI.
The test with the flow bench includes the intake, turbo inlet hose, turbo inlet elbow, and an adapter simulating a hybrid turbocharger. The flow rate through the intake will be measured at 28″ of H2O.
The second test will involve installing the intake on the GTI and recording OBD2 data using each air filter during a full-throttle 4th gear pull.
Test Results:
The flow rate through the intake with the BMC panel filter is 486 CFM @ 28″ of H2O.
The flow rate through the intake with the Mann filter is slightly lower at 474 CFM @ 28″ of H2O.
These results are shown on the following chart:
Conditions during the data collection are similar; the outside air temperature is 78°F for each test case.
The intake air temperature during the test with the BMC filter is slightly higher. This isn’t a product of the filter, but the temperature of components during the test.
Boost pressure level using each filter is unchanged.
The turbocharger wastegate duty cycle (WGDC) is also unchanged.
The estimated peak wheel horsepower is very similar for each test case.
Conclusions:
A modified Mk7 GTI stock intake system was tested using an aftermarket BMC panel air filter and a Mann ‘stock’ panel filter.
Flow testing with a flow bench and street data with a hybrid turbo-equipped GTI was collected for comparison.
The BMC filter flows slightly more than the Mann filter, but the difference is insignificant when installed on the GTI.
Operating at a boost pressure of 32-34 psi, the Mk7 GTI’s performance using the BMC and Mann filters was not significantly changed.
Interesting result! Not what I would have expected given the different filter materials. What do you think causes the filters to be so similar?
Are there any good resources rigorously testing the filtration capabilities between various filter materials and manufacturers?
I don’t know much about the particulars of air filter design. I haven’t seen any tests of filters available for the Mk7.