A while back we set out to answer a simple question: how much power is the M177 intercooler system really giving up when it heat-soaks, and how much of that can be recovered with better radiators?
Short version: in 90–95°F ambient, the stock system gains 8–14°F of intake temp every 60–130 run. By the fourth pull our car was pulling so much timing we abandoned the fifth run entirely. That's not a worst case — that's a stock C63 doing what stock C63s do in summer. Below is the full test data, so you can judge it for yourself.
How we tested
- 2016+ W205 C63 S, hybrid turbos at 27+ PSI of boost — deliberately a high heat load
- Back-to-back 60–130 mph runs, roughly 60 seconds apart
- 90–95°F ambient, Texas summer, ~4,000 ft density altitude
- All data starts at Run 2. Run 1 was thrown out for every configuration so each system starts equally pre-stressed — no cherry-picking cold runs.
We went through five-plus core concepts — varying core thickness, fin and tube sizing, water routing and end tank design — before settling on the final configuration. The core was co-developed with PWR, and the design converts the main radiator from single-pass to triple-pass.
How much do M177 intake temps rise on back-to-back pulls?
Average intake air temperature above ambient, per run:
| Configuration | Run 2 | Run 3 | Run 4 | Run 5 |
|---|---|---|---|---|
| Stock | 35°F | 48°F | 55°F | Abandoned — excessive timing pull |
| MW Stage 1 (main radiator) | 23°F | 26°F | 25°F | 30°F |
| MW Stage 1.5 (main + auxiliary) | 19°F | 25°F | 26°F | 26°F |
The stock line only goes one direction. The upgraded systems essentially plateau — by the fifth pull, Stage 1.5 average IATs were about 30°F cooler than where stock gave up, a 45% reduction.
Peak intake temps — what actually makes your tune pull timing
Peak intake air temperature above ambient, per run:
| Configuration | Run 2 | Run 3 | Run 4 | Run 5 |
|---|---|---|---|---|
| Stock | 43°F | 53°F | 61°F | Abandoned |
| MW Stage 1 | 33°F | 35°F | 37°F | 39°F |
| MW Stage 1.5 | 30°F | 33°F | 35°F | 34°F |
Stock peaked 61°F over ambient by run four and quit. Stage 1.5 never broke 40°F over ambient — and the car kept making full power on pull five. Peak reductions worked out to 54% and 30°F versus the stock system's trajectory.
The part nobody talks about: engine coolant temps
Our auxiliary coolers are reversible and mount to either side of the vehicle. On the right-hand side, the auxiliary cooler acts as an additional engine radiator. With the full three-piece system (Stage 2), peak engine coolant temps ran 9–12°F cooler than stock, pull after pull:
| Peak ECT above ambient | Run 2 | Run 3 | Run 4 | Run 5 |
|---|---|---|---|---|
| Stock | 108°F | 117°F | 119°F | 121°F |
| MW Stage 2 | 99°F | 106°F | 109°F | 109°F |
FAQ
Which stage should I get?
If you street-drive and want the single biggest improvement, the Stage 1 main radiator gets you most of the way — 45% lower average IATs. If you run back-to-back pulls, roll race, or tune aggressively, the auxiliary radiator's peak-temp control is worth it. The Stage 2 kit replaces all three front radiators and adds the engine coolant benefit — and saves $190 versus buying the pieces separately.
What cars does this fit?
2015–2021 Mercedes-AMG C63 and C63 S (W205). The auxiliary radiator is reversible and mounts on either side of the vehicle.
Will this help a stock car, or only tuned cars?
We tested on a hybrid-turbo car at 27+ PSI deliberately, because it's the highest heat load. A stock or Stage 1/2 tuned car generates less heat, so it holds out longer — but the stock heat exchangers still soak in hot weather, and the failure mode is the same: rising IATs, pulled timing, lost power. The relative improvement carries over.
Do I need anything special to install it?
Vacuum filling per the official Mercedes work instructions, done by a reputable mechanic with the proper tools. Failure to properly install will lead to inferior results.
Where are these made?
Designed and made in the USA, with a core co-developed with PWR.
Questions about the methodology or the logging setup? Get in touch — happy to talk through it.