Background:
Following a disappointing experience trying the cp-e engine and transmission mounts I purchased a set of Black Forest Industries Stage 1 mounts as replacements for the 034 Street Density mounts that had been on my GTI.
The noise and vibration level with the BFI mounts was much less than the cp-e mounts but still seemed slightly greater than the 034 Mounts.
I decided to try and quantify the differences in vibration level of the 034 Street Density mounts and BFI Stage 1 mounts.
Test Procedure:
Using an iPhone and an Accelerometer app the phone is placed in the center of the dashboard to measure the vibrations picked up by the phone.
The App records x, y , and z-axis accelerations and generates a total acceleration value measured in meters per second squared (m/sec^2).
Only the total acceleration value is used in the comparisons.
Test vehicles are a Mk7 Golf R with the 034 Motorsport Street Density Engine and DSG Transmission mounts and a Mk7 GTI with the Black Forest Industries (BFI) Stage 1 Engine and DSG Transmission mounts.
Data recording with each vehicle begins with the engine off. The vehicle is started and the acceleration values are logged for approximately one and two minutes.
The Golf R engine was warm enough at the start to immediately settle into a low idle rpm. The GTI operates slightly longer to allow the engine idle to decrease.
Assumptions:
Comparing the measurements made on two vehicles introduces the possibility of other variables contributing to the response in a significant way.
The GTI is equipped with 034 Motorsport Street Density subframe bushings and 034’s upper and lower dogbone inserts. It also uses an Aluminum MQB subframe and TyrolSport deadset kit.
The Golf R has an unknown brand set of subframe bushings, potentially also 034 Street density since the motor and transmission mounts are from 034. It also uses a CTS lower dogbone insert. It is unknown if there is an upper insert installed. The Golf R does not use a deadset kit.
Test Results:
Shown first is the Golf R on 034 Street Density mounts.
The spike is at engine start.
The next chart is of the GTI on BFI Stage 1 mounts.
Again, the spike is when the engine is started.
Comparing the phone’s acceleration values for each mount over approximately 30 seconds:
Comparing a summary of data over 5 seconds just before halting the data recording.
The mean acceleration value with the BFI mounts is 321% greater than the mean acceleration with the 034 Street Density mounts.
Conclusion:
The 034 Motorsport Street Density and BFI Stage 1 mounts were compared by measuring the total acceleration of an iPhone placed on the dashboard of a Mk7 GTI and Mk7 Golf R.
The acceleration values (vibrations) were greater on the GTI with BFI mounts than on the Golf R with 034 Mounts.
Amazing! FINALLY someone puts data to NVH from mods instead of the pure subjectivity that’s out there. Would love to see more of this.
Thanks.
I’d have liked to have made a cleaner comparison on one car, but the diagnosis was my GTI was shaking badly due to a failing subframe mount and that would have been a terrible before and after comparison.