Background:
As part of my testing with the Shuenk IS48 turbocharger, I have been working with Russell Road & Racing to make ECU tune revisions to increase boost pressure and see how much I can get from the turbocharger.
With the finalized boost pressure curve as shown in the chart below, I decided to install a Blaze ATOM Race and MGM7 intake on the GTI to see how the turbocharger wastegate duty cycle would respond.
The baseline intake system I have been using during ECU tuning consists of the Racingline R600 intake, the Racingline cotton filter, and the Shuenk IS48 ported shroud turbo inlet hose.
Products under test:
In addition to the Racingline intake serving as the baseline, I have two other “high performance” intake options on hand for testing: the popular Blaze ATOM Race and the MGM7 intake I have been developing.
In bench tests, the Racingline and Blaze ATOM Race were nearly indistinguishable, as shown in the chart below.
Note: The small increase in flow rate of the Blaze ATOM over the R600 during this test could be attributed to the exclusion of the Blaze air duct tray, which fits inside the air filter opening.
The MGM7 intake and elbow have a significant advantage over the two commercial intakes in the bench test. The question is if the performance level is past the point of diminishing returns, where a significant comparative benefit of isolated components corresponds with differences in turbocharger performance.
Blaze adapter:
The Blaze intake silicone hose does not fit directly to the Shuenk IS48 compressor housing, and the Shuenk silicone inlet hose does not fit with the Blaze air filter housing, forcing me to develop an alternative solution.
I made an adapter that would fit at the end of the Blaze silicone hose and seal over the compressor inlet of the Shuenk IS48. This adapter allows for a smooth transition from the Blaze silicone hose to the larger Shuenk compressor housing.
Test setup:
The power level the GTI is operating at with this boost pressure curve makes logging data at full throttle in third gear infeasible, and logging in fourth gear is constrained to one suitable location, where I can get a single run before I have to reset. From a practical standpoint, one pull of WGDC is enough to get a rough idea of how the intakes compare.
The different intakes are installed in the GTI and logged on the street to collect wastegate duty-cycle data for comparison.
Test results:
The Racingline R600 and MGM7 comparison is shown in the chart below. Consistent with the bench testing, the wastegate duty cycle (WGDC) with the MGM7 components is lower than with the Racingline and Shuenk components.
The Blaze ATOM results are similar to the R600, with the MGM7 showing a 5-6% WGDC advantage at 6500 RPM. This is also consistent with the flow testing.
Conclusions:
The Blaze ATOM Race intake and Racingline R600 intakes were compared with the MGM7 intake setup on an IS48 equipped Mk7 GTI.
Using a high-boost-pressure ECU tune, the turbocharger wastegate duty cycle was lower with the MGM7 intake than with the commercial Blaze and Racingline intakes, showing a 5-6% advantage in wastegate duty cycle around 6,500 RPM during a fourth-gear full-throttle pull.
The results of the street logging correlate well with flow bench testing performed on these intakes.