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Understanding the M133 Engine and Dinan’s Role
The Mercedes-Benz M133 engine, found in models like the A45 AMG, CLA45 AMG, and GLA45 AMG, is a turbocharged 2.0‑liter four‑cylinder that punches well above its displacement. Factory outputs of 355–375 hp and 332 lb‑ft of torque redefined what a small‑displacement engine could achieve. However, the aftermarket community quickly realized that with the right hardware and calibration, the M133 had substantial untapped potential. Among tuners, Dinan has earned a reputation for producing reliable, CARB‑compliant performance packages that preserve daily‑driveability while unlocking serious power gains. The Dinan Stage 2 Kit is one of their most popular offerings, designed specifically for the M133 to push it to the next level without sacrificing longevity or drivability.
What’s Included in the Dinan Stage 2 Kit
The Dinan Stage 2 Kit is far more than a simple ECU tune. It is a comprehensive hardware‑plus‑software package engineered to work as a system. Here is a detailed breakdown of each component and its role in the performance upgrade:
High‑Flow Intercooler
The stock intercooler on the M133 is sufficient for factory power levels, but under sustained boost it quickly becomes heat‑soaked, leading to timing retard and power loss. Dinan’s high‑flow intercooler features a larger core and optimized end‑tank design to reduce intake air temperatures by 30–40 °F under heavy load. Lower intake temperatures allow the ECU to maintain aggressive timing and boost targets, resulting in consistent power delivery during track sessions or repeated acceleration runs.
Upgraded Turbocharger Assembly
While the M133’s factory turbocharger is a twin‑scroll unit that spools quickly, it runs out of steam at higher rpm when boost is turned up. Dinan includes a re‑worked turbo with a billet compressor wheel and a larger turbine housing. This modification increases flow capacity by roughly 15 % while retaining the factory’s quick spool characteristics. The upgraded turbo is balanced and calibrated to work with the included software, producing more boost at the mid‑range and holding it longer toward redline.
Performance Software Tuning
At the heart of the kit is Dinan’s proprietary ECU calibration. Unlike off‑the‑shelf “flash” tunes that blindly increase boost, Dinan’s software adjusts fueling, timing, boost pressure, throttle mapping, and vanos (variable valve timing) curves using data gathered from extensive dyno testing. The tune also disables many factory safety limits that would otherwise pull power when the upgraded hardware is installed. Importantly, Dinan’s software is emissions‑legal in all 50 states (CARB eligible) and can be updated via OBD‑II.
Enhanced Exhaust System
To reduce backpressure and help the turbo breathe, the kit includes a high‑flow downpipe and a cat‑back exhaust section. The downpipe replaces the restrictive factory catalytic converter with a less restrictive unit (still emissions‑legal) that improves exhaust flow by 25 %. The cat‑back uses mandrel‑bent tubing and a straight‑through muffler design to reduce restriction without excessive drone. The result is a deeper, more aggressive exhaust note and a solid 8–10 hp gain at the wheels.
Installation Process: What to Expect
Installing the Dinan Stage 2 Kit requires intermediate to advanced mechanical skills, a well‑equipped garage, and roughly 8–12 hours of labor for the first‑timer. If you are not comfortable working on turbo systems and ECU flashing, professional installation is strongly recommended. Below is a more detailed guide than the standard bullet list, including critical nuances that can make the difference between a smooth install and a frustrating weekend.
Tools and Prep Work
Beyond basic hand tools, you will need:
- A quality torque wrench (ft‑lb and in‑lb ranges)
- Flathead and Phillips screwdrivers
- Pliers (including snap‑ring pliers)
- Engine oil and coolant (for top‑off after removing components)
- Dinan‑provided OBD‑flash cable and laptop with their software
- A helper for lifting the intercooler and turbo into place
Step‑by‑Step (Expanded)
1. Battery Disconnection and System Drain. Disconnect the negative battery terminal and let the car sit for 10 minutes to discharge the ECU capacitors. Drain the engine coolant to below the level of the turbo lines (using a drain plug or loosening a lower hose). Have a catch pan ready.
2. Remove the Factory Intercooler. The intercooler sits in front of the radiator and is held by four bolts and two hose clamps. Carefully disconnect the charge pipes and lift it out. Clean the mounting area; the new Dinan unit should fit with no modifications. Torque the bolts to Dinan’s spec (usually 18 lb‑ft).
3. Turbocharger Removal. This is the most complex step. Unbolt the heat shields, unhook the O₂ sensor connectors, and disconnect the oil feed and return lines (have new crush washers ready). Remove the turbo‑to‑downpipe bolts. The turbo is heavy; support it while loosening the manifold bolts (seven bolts on an M133). Slide the turbo out from underneath the car. Install the Dinan turbo using new gaskets and torque all fasteners to factory specs.
4. Exhaust System Swap. Unbolt the factory downpipe from the turbine housing and remove the mid‑pipe section. The Dinan downpipe and cat‑back bolt directly in place. Use high‑temperature anti‑seize on the studs to ease future removal. Do not tighten the exhaust clamps fully until the entire system is aligned, then torque to spec.
5. ECU Flash. With the hardware installed, reconnect the battery and plug the OBD‑flash cable into the diagnostic port. Dinan’s software will guide you through a 15‑minute flash process. Do not interrupt the flash or turn off the ignition. Once complete, the software will verify the new calibration and clear any fault codes.
6. Check for Leaks and Test. Refill coolant, start the engine, and let it idle for 5 minutes. Inspect all hose connections and turbo oil lines for leaks. Take a short test drive, watching boost pressure and temperature gauges. After 50 miles, re‑torque the turbo bolts and intercooler clamps.
Common Pitfalls: M133 turbo oil lines can be stubborn; use a line wrench to avoid rounding the nuts. The intercooler charge pipe may need a slight trim if the fitment is tight. If the car throws a lean code after the flash, the fuel pump may need upgrading—Dinan includes fuel map adjustments for stock pumps, but high‑mileage pumps may struggle.
Costs and Value Analysis
The Dinan Stage 2 Kit is not the cheapest option on the market, but its value lies in the integration and warranty support. Here is a realistic cost breakdown:
| Component | Estimated Price |
| Dinan Stage 2 Kit (full hardware + software) | $4,200 – $4,800 |
| Professional installation (8‑12 hours @ $125/hr) | $1,000 – $1,500 |
| Coolant and oil | $50 – $100 |
| Miscellaneous gaskets/hardware | $50 – $100 |
| Total | $5,300 – $6,500 |
Compare this to a simple piggyback tune (e.g., JB4) that costs under $600 but offers only moderate gains and no hardware. Dinan’s package includes a 2‑year/24,000‑mile warranty on parts and labor, which adds significant peace of mind. The intercooler and turbocharger alone are worth roughly $2,500 if purchased separately from other manufacturers, so the complete kit pricing is competitive when you factor in the R&D and calibration work.
Labor costs can be reduced if you perform the installation yourself. However, the turbo replacement is time‑sensitive: expect at least 10 hours if you have experience with German turbo cars. First‑time DIYers might need 15–18 hours. Considering the risks (overtightened bolts, leaks), many owners prefer professional installation.
Real‑World Performance Gains and Data
Dinan publishes conservative numbers, but independent dyno tests and owner reports consistently show impressive results. On a dynojet with SAE correction, a stock M133 (CLA45 AMG) typically puts down 330–340 whp and 320–330 wtq. After installing the Dinan Stage 2 Kit, the same car produces 390–405 whp and 380–400 wtq, depending on fuel quality and ambient conditions. That is an increase of roughly 60 whp and 65 wtq—figures that translate to a solid 11‑second quarter‑mile and a 0‑60 mph time of around 3.6 seconds with proper traction.
Beyond peak numbers, the driving experience changes dramatically. Boost builds earlier (full spool by 2,500 rpm instead of 3,200) and holds steady to redline. The improved intercooler means power does not degrade on hot days—a common complaint with the factory setup. Owners report the car pulls harder in fourth and fifth gear, and the exhaust note transforms from a muted drone to a snarling, aggressive sound under load. Throttle response in Sport+ mode becomes razor‑sharp, eliminating the slight lag between pedal input and boost arrival.
For real‑world data, Dinan’s official product page includes dyno graphs and videos. Independent forums such as MBWorld have extensive owner threads with track times and before/after logs. One user on MBWorld documented a 0.5‑second improvement in the 60‑130 mph time, going from 10.8 seconds stock to 10.3 seconds after Stage 2—a noticeable gain on the highway.
Maintenance and Reliability Considerations
Any engine upgrade carries the risk of increased wear, but the M133 is known for its robust internals. The forged steel crankshaft, reinforced aluminum block, and sodium‑filled exhaust valves can handle 400 whp reliably. However, the stage 2 kit places greater demand on the cooling system and fuel delivery. Dinan recommends upgrading the engine oil cooler for track use (their kit does not include one, but it is available separately).
Oil change intervals should be shortened to every 5,000 miles (instead of 10,000) because the higher heat load accelerates oil breakdown. Use a high‑quality full synthetic that meets MB‑229.5. The spark plugs should be replaced every 30,000 miles with a step‑colder plug (Dinan recommends NGK 97506 or equivalent). The upgraded turbo’s journal bearings are slightly less tolerant of oil starvation; ensure the oil level is always at the full mark and avoid hard driving until the engine reaches normal operating temperature.
One hidden issue: the Dinan software re‑enables some safety limits that the factory tune uses, but it also raises the boost target to around 26 psi (up from 21 psi). This can cause fuel pump fatigue on older cars. If you see fuel pressure drops above 5,500 rpm, consider a high‑pressure fuel pump upgrade (e.g., from Pure Turbos or XDI) as a complementary mod. The pump is not included in the kit, but many owners add it for sustained high‑rpm power.
Final Verdict
The Dinan Stage 2 Kit delivers on its promise: noticeable, reliable power gains that transform an already impressive M133 engine into a truly potent powerplant. The holistic approach (intercooler + turbo + exhaust + tune) ensures all supporting systems are addressed, unlike piecemeal upgrades that leave weak points. While the price tag may seem steep, the included warranty, CARB compliance, and Dinan’s reputation for durability make it a smart investment for owners who plan to keep their car for the long term.
If you are looking for a bolt‑on package that produces consistent 60‑plus wheel horsepower and enhanced drivability without the headaches of custom tuning or incompatible parts, the Dinan Stage 2 Kit is one of the best options available for the M133. Just budget accordingly and follow the maintenance guidelines—you will enjoy a car that’s both faster and more engaging to drive every day.
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