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Dyno Test Results — C190 Build Series
AMG GT C
PTG Turbos + ARM Downpipes
The C190 build program takes its biggest step yet. PTG turbos paired with ARM Downpipes on the M178, three pulls, 734 WHP and 600 WTQ on the best runs, and a power curve that is still climbing at 7,000 RPM.
Overview
Where This Build Started and What Changed
Where This Build Started and What Changed
If you have been following this build from the beginning, you know where we started. In our stock dyno session, a completely unmodified 2020 Mercedes AMG GT C produced 556 WHP and 567 WTQ on a Mustang Dynamometer. Clean numbers, strong baseline, and the foundation every future test on this car references. If you haven't read that post, start there.
The GT C was chosen deliberately as ARM's C190 build platform. As detailed in our C190 trim level breakdown, the GT C is uniquely positioned in the lineup: it carries the GT R's larger turbocharger specification from the factory, paired with standard M178 cylinder heads and a calibration that leaves significant power on the table relative to the hardware already in the car. The gap between what the GT C is doing from the factory and what its hardware can support is exactly the story this build is designed to tell.
This session adds the two most significant hardware changes yet: PTG aftermarket turbos replacing the factory units, and ARM C190 Downpipes freeing up the exhaust restriction directly at the turbocharger outlets. Stock intake was retained for this test to isolate the contribution of the turbo and downpipe combination.
Test vehicle: 2020 Mercedes AMG GT C (C190)
Engine: M178 4.0L V8 Biturbo
Dyno: Dynojet
Fuel: 93 Octane Pump Gas
Hardware: PTG Turbos + ARM C190 Downpipes + Stock Intake
Total runs: 3
Note on dyno comparison: The stock baseline was recorded on a Mustang Dynamometer. This session was conducted on a Dynojet. These are different dynamometers with different correction methodologies, which means the numbers are not directly apples-to-apples. We are presenting both for reference, but the meaningful comparison is the delta across sessions rather than a direct number-to-number subtraction.
The Numbers
Best Run Results
Best WHP — Run 3
734
wheel horsepower
Best WTQ — Run 1
600
wheel torque (ft-lbs)
Peak WHP RPM
7,230
still climbing at redline
Peak WTQ RPM
4,990
arrives early, holds strong
Run Spread (WHP)
27
across all 3 runs
Run by Run
Full Dyno Data
| Run | Configuration | WHP | WTQ | Peak WHP RPM |
|---|---|---|---|---|
| , | Stock (Mustang Dyno — reference) | 556 | 567 | ~5,500 |
| 1 | PTG Turbos + ARM Downpipes | 707 | 600 | 6,880 |
| 2 | PTG Turbos + ARM Downpipes | 719 | 597 | 6,870 |
| 3 | PTG Turbos + ARM Downpipes ★ Best | 734 | 595 | 7,230 |
Three pulls, 27 WHP separating the lowest from the highest. The torque numbers are even tighter, all three runs landing within 5 WTQ of each other across the entire session. That consistency is a strong signal that the hardware combination is settled and repeatable under load.
Curve Analysis
What the Dyno Chart Shows
Torque builds quickly from 2,000 RPM and arrives at its peak of approximately 600 WTQ around 4,500 RPM. That early torque delivery is a characteristic of the PTG turbos spinning up fast despite being larger and making boost efficiently in the mid-range. All three runs track the torque curve closely throughout the entire pull, with the spread between them staying within 5 WTQ from bottom to top.
The power curve is where the PTG turbo combination really distinguishes itself from the stock M178 configuration. On the stock GT C, peak power arrived in the 5,400 to 5,600 RPM range and rolled off progressively toward the 7,000 RPM redline. On this setup, power does not peak in that window. It keeps climbing through 6,000 RPM, through 6,500 RPM, and on Run 3 it is still pulling hard at 7,230 RPM when the run ends. That extended top-end climb is what the PTG turbo hardware enables, and it is visible across all three pulls on the chart.
The fact that Run 3 extends furthest in RPM and produces the highest peak number is notable. It suggests the combination may not have fully shown its ceiling on the earlier runs. The power curve on Run 3 has not turned over by the end of the pull, which means 734 WHP is where the data ends, not necessarily where the power does.
The stock intake was retained for this test. The intake is the next variable in the build sequence, and keeping it stock here allows us to cleanly isolate what the PTG turbos and ARM Downpipes are contributing before adding another component. The next dyno session will add the intake to the equation.
This is one data point in a longer build sequence. The PTG turbos and ARM Downpipes have shown what this platform is capable of when the primary hardware constraints are removed. Next up: upgraded intakes. The stock intake was retained for this test intentionally, keeping one variable isolated so the turbo and downpipe contribution is clear in the data. Adding higher-flow intakes to this combination is the next step, and we will be back on the Dynojet to document exactly what they add. Stay tuned.
-The ARM Team