Why Upgrade Your W213 E63 to 800 Horsepower?

The Mercedes-AMG E63 in its W213 generation already delivers a formidable 603 horsepower from its hand-built 4.0‑liter twin‑turbo V8. Yet for serious enthusiasts, stock power is just the beginning. Reaching the 800‑horsepower threshold transforms the E63 into a true super‑sedan that can rival purpose‑built exotics. This article breaks down an $8,000 investment using Posa turbochargers—a proven path to reliable four‑digit crank output. We will examine each cost, the supporting hardware required, and the real‑world performance gains you can expect.

The Core Upgrade: Posa Turbocharger Kit – $5,000

What the Posa Kit Includes

The heart of this build is the Posa Turbocharger kit designed specifically for the M177 engine. At approximately $5,000, the kit provides billet compressor wheels, upgraded turbine housings, reinforced wastegate actuators, and all necessary gaskets and hardware. Posa’s engineering focuses on maintaining spool characteristics while increasing flow capacity enough to support 800 horsepower without exceeding the engine’s fuel system limits when paired with E85.

Why Choose Posa Over Other Brands?

Posa has established a reputation in the Mercedes performance community for drop‑in compatibility and consistent quality. Unlike some budget alternatives, Posa’s turbochargers use factory‑flange designs, meaning no custom fabrication is required. The company also offers direct technical support and calibration guidance, which reduces installation headaches. For a street‑driven car that also sees track days, Posa strikes a strong balance between cost and durability.

Installation Labor – $1,500

Skill Requirements and Time Investment

Installing upgraded turbochargers on a W213 E63 is not a weekend driveway job. The factory turbos sit tightly against the engine block, requiring removal of the intake system, exhaust manifolds, heat shields, and sometimes the front coolant radiator for access. A qualified performance shop will typically quote 14–20 hours of labor. The $1,500 estimate assumes $100–$125 per hour, a common rate for specialized European tuning facilities.

What to Look for in a Shop

Choose a shop with proven experience on Mercedes M177/M178 engines. Improper torque on turbo oil lines or incorrect wastegate preload can lead to oil starvation or boost spikes. Reputable builders often include a post‑installation inspection on a dyno to verify oil pressure and boost response. This labor cost also covers replacing consumables such as oil, coolant, and gaskets that cannot be reused.

Supporting Modifications – $1,000

The $1,000 allocated for “supporting mods” is a baseline. In practice, many owners say this figure is conservative, but it covers the essential upgrades needed to let the Posa turbos perform safely.

Intercooler Upgrade – $400–$600

The factory intercooler system, while adequate for stock levels, becomes a bottleneck at higher boost. Upgrading to a larger air‑to‑water intercooler core, such as a CSF or Wagner unit, reduces intake air temperatures (IATs) by 30–40°F. Lower IATs mean the ECU does not have to pull timing, allowing the 800‑horsepower target to be sustained without detonation. A quality intercooler typically costs $400–$600 and can be installed alongside the turbo swap.

Exhaust Downpipes – $300–$500

Freeing up exhaust flow is critical. Catted downpipes with larger inner diameter (e.g., 3.0‑inch) reduce backpressure and improve turbo spool. Many 800‑hp builds use high‑flow catalytic converters to keep emissions legal while still gaining 15–25 horsepower. A set of quality downpipes runs roughly $300–$500. Combined with the stock rear exhaust (which is already free‑flowing), the engine can breathe properly.

Additional Items That May Exceed the $1,000 Estimate

If your budget allows, consider an upgraded heat exchanger for the intercooler system or a cold‑air intake. However, the stock airbox flows well until about 850 horsepower, so the $1,000 budget as stated is sufficient for the essential supporting mods.

Tuning and Calibration – $500

Why Tuning Is Non‑Negotiable

Simply bolting on larger turbos without recalibrating the engine management system will not only leave power on the table but also risk engine damage. The $500 tuning cost typically covers a remote or in‑shop session with a custom ECU map. The tuner will adjust fuel timing, boost pressure targets, wastegate duty cycles, and throttle mapping to match the new turbochargers.

Fuel Type Considerations

To reach 800 horsepower reliably, 93 octane pump gas is usually sufficient, but many tuners recommend ethanol blends (E50 or E85) for added knock resistance and cooling. If you plan to use ethanol, factor in an additional $200–$400 for a flex‑fuel sensor and ethanol content analyzer. The $500 estimate in the cost breakdown assumes pump gas tuning only.

Reputable tuners for the M177 platform include Weistec Engineering, Eurocharged, and RENNtech. These companies have extensive experience with Posa turbochargers and can provide base maps that are safe for street driving.

Total Investment and Real Costs – $8,000 (Before Extras)

Summing the components: $5,000 (turbos) + $1,500 (labor) + $1,000 (supporting mods) + $500 (tuning) = $8,000. This is the headline figure. In practice, most owners spend between $8,000 and $10,000 because of incidental costs like new oil lines, gaskets, fluids, and possibly an upgraded intercooler heat exchanger. But for a budget‑minded enthusiast, $8,000 is achievable by sourcing parts during sales and using a competitive independent shop.

Performance Gains: What 800 Horsepower Feels Like

With this configuration, the W213 E63 can accelerate from 0–60 mph in the low 2.7‑second range on street tires and achieve trap speeds above 140 mph in the quarter‑mile. More importantly, the power delivery is linear—the upgraded turbos spool only slightly later than stock, yet they pull hard all the way to redline. On the highway, passing power becomes effortless; a 60–130 mph time under seven seconds is realistic with proper traction.

Reliability and Maintenance Considerations

Engine Bottom‑End Strength

The M177 engine features a forged steel crank and forged connecting rods, making it robust enough for 800 horsepower on a conservative tune. However, high‑mileage engines (over 60,000 miles) may benefit from upgraded valve springs and a crankcase breather system to reduce blow‑by. Posa turbos are designed to run at 18–22 psi of boost, which is well within the stock fuel system’s capacity as long as you use quality fuel and proper oil change intervals.

Oil and Cooling Upgrades

At 800 horsepower, heat management becomes critical. Upgrading to a larger oil cooler and auxiliary transmission cooler (if equipped with the AMG Speedshift MCT 9‑speed) adds another $800–$1,200 to the budget. For street driving, the stock cooling system is adequate, but track sessions will require these additions to prevent oil temperature exceeding 270°F.

Comparing Alternatives to Posa Turbos

Other turbo options exist in the $5,000 price range. For example, Pure Turbos offers a Stage 2+ kit for the M177 that also supports 800‑plus horsepower. Pure turbochargers are known for their billet wheels and unique bearing designs, but they can cost $1,000–$1,500 more than Posa. The Posa kit remains the price‑to‑performance leader for owners who want to stay near the $8,000 total figure.

Another option is to retain the factory turbos and add a methanol injection system plus a tune, which yields about 700 horsepower for around $2,500. But for a clean 800‑horsepower build, the turbo swap is the most dependable route.

Should You DIY to Save Money?

Some experienced home mechanics attempt the installation themselves. The job requires a lift, specialty tools (like turbo inlet removal tools), and a solid understanding of engine vacuum lines. A DIY install can save $1,500 in labor but adds considerable risk. If the turbos are not properly clocked or oil feed lines are kinked, expensive engine damage can occur. For most owners, paying a professional shop is money well spent.

Long‑Term Value and Resale

An 800‑horsepower W213 E63 with Posa turbos and proper supporting mods is a desirable build in the used car market. While you will not recoup the full $8,000 at sale, a documented, clean installation can add $3,000–$5,000 to the car’s value over a stock example. Keep all receipts and dyno sheets to prove the quality of the work. If the car is returned to stock, the turbos can be sold separately for $2,500–$3,000, further offsetting costs.

Insider Tips from the Community

In the Posa Turbo Instagram community and dedicated Mercedes forums, owners consistently recommend these additional steps:

  • Upgrade motor mounts – The extra torque can cause factory mounts to collapse under hard acceleration. Solid or polyurethane mounts cost about $250.
  • Install a boost gauge – Monitor actual boost pressure to verify tune safety. A quality P3 gauge integrates into the vent.
  • Use a dedicated can of race gas or ethanol for dyno runs – This ensures consistent numbers and protects the engine during the tuning session.

Final Recommendations

For the W213 E63 owner who wants a serious power increase without stepping into full race-car territory, the Posa turbocharger upgrade at an $8,000 total investment offers an exceptional value proposition. The key to success lies in not cutting corners on labor and supporting mods. Invest in a quality intercooler, use a reputable tuner, and budget an extra $1,000–$2,000 for unforeseen expenses. The result is a daily‑drivable 800‑horsepower sedan that will humble almost anything on the road—including many dedicated sports cars. Do your research, select a qualified shop, and enjoy the thrill of a properly built M177 monster.