Understanding the 700 HP Target for the E63

The Mercedes-AMG E63, particularly the M157 and M177 twin-turbo V8 platforms, responds exceptionally well to turbo upgrades. Reaching 700 wheel horsepower requires a systematic approach: selecting the right turbocharger, matching it with a capable wastegate, and dialing in boost pressure and air-fuel ratio (AFR) through professional calibration. The ETS and Tial wastegates are two proven options for precise boost control in this power range. This article provides a detailed roadmap for adjusting boost and AFR to safely and reliably achieve 700 hp with these wastegates.

Turbocharger Selection and Upgrade Options

A 700 hp goal on a stock-bottom-end E63 is aggressive but achievable with proper fueling and tuning. The factory turbos on the M157 (E63 2012-2013) and M177 (2014+) can support roughly 580-620 whp on pump gas with a tune and downpipes. To cross the 700 hp threshold, you need larger compressor wheels, upgraded bearings, or a full hybrid turbo kit. Popular options include:

  • Hybrid stock-frame turbos – Use larger billet compressor wheels (e.g., 68mm or 72mm) that fit the stock housings. Companies like Pure Turbos, VTT, or custom builds from reputable shops offer these.
  • High-flow drop-in cartridges – Replace the internals while reusing the stock turbine housing. Cheaper than full turbos but limited on flow.
  • Big-turbo kits – For serious power above 700 whp, a single-scroll or divided T4/T6 setup with custom manifolds is necessary, but this article focuses on the more common hybrid route.

Key Considerations for Turbo Choice

  • Compressor maps must support the air mass required for 700 hp (approximately 65-75 lb/min at 20-24 psi).
  • Turbine side should spool well under 4,000 rpm on a 6.2L or 4.0L V8. A .82 A/R housing is typical.
  • Oil and coolant lines: upgrade to braided stainless lines to prevent failures at higher heat loads.

The Role of Wastegates in Boost Control

The wastegate regulates exhaust flow bypassing the turbine, directly controlling boost pressure. For a 700 hp E63, the wastegate must hold boost steady at high exhaust backpressure without creeping. Both ETS and Tial offer external wastegates with different characteristics.

ETS Wastegates

ETS (Extreme Turbo Systems) produces a compact Tial-style 38mm and 45mm gate with a forged 304 stainless steel body and a billet actuator. They are known for consistent operation under high heat and maintain a stable spring curve. The ETS unit uses a dual diaphragm design that reduces internal leakage common in older designs.

  • Spring rates: 5-15 psi (single spring) up to 25+ psi with dual springs.
  • Adjustablity: all ETS gates come with a spring preload adjustment screw, allowing fine-tuning of boost level by ±2 psi.
  • Recommended for: daily-driven applications where consistent boost over long pulls is important.

Tial Wastegates

Tial is the gold standard for external wastegates. The MV-R (38mm) and MV-S (44mm) models feature a v-band inlet/outlet, an open dump tube, and a spring-loaded diaphragm. Tial uses a viton diaphragm that resists heat and pressure cycling. The main advantage is the precise spring selection and excellent cracking repeatability.

  • Spring color codes: green (7.25 psi), red (11.6 psi), blue (14.5 psi), and so on. Mixing springs allows custom boost pressures.
  • The anodized billet body resists corrosion and thermal expansion better than cast iron alternatives.
  • Tial gates are preferred for high-boost race setups (20+ psi) where the gate must see minimal hysteresis.

Wastegate Integration for the E63

On twin-turbo E63s, wastegates are typically mounted on the exhaust manifold or downpipe. Hybrid turbos often come with an integrated wastegate port, but if you are using a custom kit, you will need a wastegate of the correct flange type (Tial 38mm V-band or 45mm V-band for larger flows). Ensure the wastegate position allows for a short dump tube to avoid backpressure issues.

Boost Adjustment Strategy

Setting boost for 700 hp involves balancing spool, peak torque, and turbine speed limits. The wastegate controls maximum boost by opening at a predetermined pressure; the ECU’s boost solenoid duty cycle can raise boost above the wastegate spring setting by regulating the reference pressure signal.

Basic Boost Control Using Wastegate Spring

  1. Select a spring that gives you a baseline boost 4-6 psi below your target. Example: target 22 psi → use a 14.5 psi spring (Tial blue) as base. This leaves room for the solenoid to add boost without exceeding wastegate capacity.
  2. Install the wastegate with the spring in the correct orientation. Preload the spring to the manufacturer’s spec (usually 0.020" gap for Tial).
  3. Connect the wastegate top port to boost source (from compressor outlet) and bottom port to atmosphere or to a boost solenoid. For a basic high-boost system, the top port receives positive pressure, pushing the valve closed for higher boost.

Using ETS Wastegate Adjustment

  • Turn the preload screw clockwise to increase boost by 1-2 psi. Counterclockwise decreases. Do not exceed 3 psi of adjustment to avoid damaging the diaphragm.
  • Upon first start, monitor boost gauge. If boost creeps above target, the gate is too small or the spring is too stiff. If boost falls off after spool, the gate may be too large or the spring preload is too low.

Using Tial Wastegate Tuning

  • Tial gates are not user-adjustable via preload screw (only water level adjustment on some models). You change spring packs. To increase boost, add a shim that reduces travel? Actually, Tial offers a "J" spring for adjustable base pressure, but most just swap to a higher-rated spring set.
  • For 22 psi target, combine a 14.5 psi spring (blue) with a 7.25 psi spring (green) to achieve approximately 21.75 psi. Adding a 0.020" shim can add 0.5-1 psi.

Electronic Boost Control

To fine-tune boost for 700 hp on the street vs. track, use a 3-port MAC valve or OEM-style boost solenoid controlled by ECU tuning software (ECUtek, Cobb, etc.). The solenoid modulates vacuum/boost to the wastegate, allowing higher boost at lower rpm and tapering at redline. A typical map: start at 15 psi wastegate base, ramp to 24 psi by 3500 rpm, then taper to 20 psi at 7000 rpm to protect the turbine.

Air-Fuel Ratio Tuning for 700 HP

AFR directly affects power output and engine safety. For a pump-gas E63 running 93 octane, the ideal lambda is 0.78-0.82 (AFR 11.5-12.0 on gasoline scale) at full boost. On E85 you can run richer (0.70-0.75 lambda, AFR 10.3-11.0) for additional cooling and knock margin.

Fuel System Requirements

Stock fuel injectors (2.5-3.0 mm nozzles) max out around 600 whp. For 700 hp you need at least 1000 cc/min injectors (e.g., Bosch EV14 1000cc, Injector Dynamics ID1050x). Upgrade the high-pressure fuel pump (HPFP) to a Dorch Stage 2 or 3, and install a low-pressure fuel pump (Lift pump) from Holley or Radium. Fuel lines should be -8 AN from tank to rail.

AFR Adjustment Methods

  • Increase fuel injector pulse width in mapping (fuel tables).
  • Adjust fuel pressure regulator (if using return-style system). Stock is pressure referenced, but for high flow you might need a purpose-built regulator.
  • Tuning wideband O2 sensor correction factors. The ECU uses closed-loop at part throttle, but at WOT it runs open-loop with the tune.

Target AFR Values

FuelLambdaAFR (Gasoline Scale)Notes
93 octane pump0.8011.76Safe for 20+ psi
E850.7611.18Better cooling, more timing
Methanol injection0.82-0.8512.06-12.50Must monitor IATs

Complete Tuning Procedure

Below is the step-by-step process to dial in boost and AFR for a 700 hp E63 with ETS or Tial wastegates.

Safety Preparations

  • Install a wideband O2 sensor in the downpipe (Driven Racing Power or AEM).
  • Boost gauge (P3 or AIM) to read actual manifold pressure.
  • Data logging system (MHD, ECUtek, or standalone) to capture boost, AFR, fuel pressure, knock, and IAT.
  • Check intercooler capacity: stock water-to-air intercoolers can heat soak. Upgrade to a larger heat exchanger (e.g., CSR) or run a killer chiller.

Initial Baseline

  1. Load a base tune from a reputable tuner (e.g., Eurocharged, Renntech, Weistec) that targets 650-670 whp. Do not exceed stock fuel limits.
  2. Record logs: look for boost consistency, fuel pressure drop, and knock events.
  3. Ensure wastegate opens correctly: with engine off, apply compressed air to the top port – the gate should crack at the rated spring pressure.

Boost Map Calibration

  1. Set wastegate duty cycle table to a moderate level (e.g., 30% duty at high rpm).
  2. Perform a 3rd gear pull on a dyno or safe road. Monitor boost vs target. Adjust duty cycle table to hit target boost without overshoot.
  3. If boost is too high at wastegate basis, increase preload on ETS gate or use a smaller spring in Tial. If boost is too low, verify vacuum lines and solenoid operation.

AFR Fine-Tuning

  1. With boost stable, adjust the fuel injection multiplier to achieve 11.5 AFR at peak torque (around 3500-4500 rpm).
  2. At higher rpm (6000+), target slightly leaner (12.0 AFR) to improve power without knock.
  3. Use lambda tables: set target lambda to 0.80 for most of the powerband, then taper to 0.82 near redline.
  4. Check fuel trims at partial throttle to ensure closed loop stays within +/-5%.

Ignition Timing Strategy

At 700 hp with premium fuel, start with conservative timing: 12-14 degrees at peak torque, advancing to 18-20 degrees near redline. Reduce timing by 2-3 degrees if knock occurs. Use multiple knock control strategies.

Testing and Validation

After initial calibration, proper testing confirms reliability.

Dyno Testing

A load-bearing dyno (Mustang or Dynojet) is preferred. Do back-to-back pulls with cool down intervals. Compare horsepower, torque, and boost curves. Verify that AFR does not lean out above 12.5 across the pull. That indicates fuel starvation.

On-Road Testing

Simulate real driving: highway merges, hill climbs, and repeated WOT accelerations. Monitor oil and coolant temperatures. If IAT exceeds 130°F, increase intercooler capacity or run a water-meth injection system.

Common Pitfalls

  • Boost creep: Wastegate is too small. Symptoms: boost keeps rising beyond target at high rpm. Solutions: port the wastegate seat, use a larger gate (45mm instead of 38mm), or add an external wastegate to each turbo.
  • Lean AFR at high rpm: Fuel pump cannot keep up. Verify fuel pressure drops below 60 psi. Upgrade injectors or pump.
  • Knock at part throttle: Fuel quality or insufficient octane. Use fuel additive or switch to E85.

To ensure the engine survives the power increase, address these supporting modifications:

  • Intercooler: Upgrade to a massive bar-and-plate unit (e.g., CSF or AMS). Stock charge air coolers can cause 20+ psi of pressure drop.
  • Exhaust: Full 3-inch downpipes and a cat-back exhaust to reduce backpressure. Consider a cutout for less restriction.
  • Engine internals: For sustained 700 hp, replace spark plugs with one-step colder (NGK 6510) and install a high-flow crankcase vent system.
  • Cooling system: Upgraded radiator and oil cooler (e.g., CSF or Setrab) prevent heat soak during extended pulls.

Conclusion

Successfully tuning an E63 to 700 hp requires a balanced approach: select a turbocharger that matches your power goal, install a reliable wastegate (ETS or Tial), and methodically adjust boost and AFR using proper tools. The wastegate is the linchpin of boost control – its spring rate, size, and plumbing determine how accurately you hit your target. With careful data analysis and incremental adjustments, the 700 hp threshold is not only achievable but also safe for daily driving. Always work with a professional tuner and invest in quality components to avoid mechanical failures.

For detailed wastegate spring charts and installation guides, visit Tial’s official site or ETS’s product pages. Community forums like MBWorld and Eurocharged offer real-world tuning logs for reference.