The BMW S55 engine has become a modern legend among performance enthusiasts. Found in the F80 M3, F82 M4, and related models, this 3.0-liter twin-turbo inline-six combines German engineering precision with astonishing tuning headroom. While the factory turbos are impressive, many owners quickly discover that upgrading to aftermarket units like those from Pure Turbos unlocks another level of power. Gains of up to 150 wheel horsepower are not only possible but repeatable with a proper setup. This article provides a deep dive into what Pure Turbos offer for the S55, realistic performance expectations, installation costs, supporting modifications, and everything else you need to know before making the leap.

Why the S55 Engine Responds So Well to Turbo Upgrades

The S55 is a closed-deck, direct-injected engine with forged steel crankshaft and sintered connecting rods. Its factory twin-turbo setup uses small, low-inertia turbos that spool quickly but choke off flow at higher RPMs. This design prioritizes responsive low-end torque—excellent for daily driving but limiting for enthusiasts chasing 600+ wheel horsepower. The engine block itself is robust; with proper fueling and tuning, it can handle well over 700 whp. The weak link is the stock turbochargers. Replacing them with larger, more efficient units like Pure Turbos addresses that bottleneck directly.

Pure Turbos specializes in bolt-on turbo upgrades for BMW applications. Their turbos use larger compressor and turbine wheels, revised housings, and upgraded internals to flow more air while maintaining factory-like spool characteristics. For the S55, their Stage 1 and Stage 2 kits are the most popular. Let’s break down what each offers.

Pure Turbo Offerings for the S55: Stage 1 vs. Stage 2

Pure Stage 1

The Stage 1 upgrade uses a larger compressor wheel and a billet compressor wheel design while retaining the factory turbine housing and exhaust manifold. This makes installation relatively straightforward. Power gains range from 80 to 120 whp over stock with a conservative tune. Many owners see 580–620 whp on 91-93 octane and over 650 whp with E85. Spool is nearly identical to stock, with peak torque arriving around 3,200 RPM.

Pure Stage 2

The Stage 2 kit goes further with a larger turbine wheel and a revised turbine housing. This increases flow capacity significantly but comes at the cost of slightly delayed spool (full boost around 3,600–3,800 RPM). With Stage 2, 650–700 whp on pump gas is common, and 750+ whp is achievable with E85 and upgraded fueling. The gain over Stage 1 is roughly 50–80 whp depending on supporting mods and tuning.

Both kits are direct bolt-ons—no custom fabrication required. Pure Turbos also offers hybrid options (Stage 2+ and Stage 2.5) for those chasing 800+ whp, but those require more extensive supporting modifications.

Realistic Power Gains: How 150 HP Happens

The claim of “150 horsepower gains” is often based on peak wheel horsepower increases compared to a stock, healthy S55. But how is that achieved? Let’s look at the factors.

  • Increased airflow: Larger compressor wheels move more air per revolution. Combined with higher boost pressure, the engine ingests a significantly greater mass of air.
  • Improved efficiency: Pure Turbos’ billet wheels and improved aerodynamics reduce intake air temperatures and backpressure. Cooler, denser air means more oxygen for combustion.
  • Higher boost ceiling: Stock turbos are limited to roughly 18–20 psi before heat becomes an issue. Pure Stage 2 turbos can safely run 25–28 psi with proper intercooling.
  • Optimized tuning: A custom tune (via flash or piggyback) adjusts fuel, timing, and boost curves to exploit the turbo’s flow capacity. E85 blends further unlock power by allowing more aggressive timing and higher boost without knock.

On a dynojet, a stock F80 M3 typically puts down 380–400 whp. A car with Pure Stage 2 turbos, downpipes, an upgraded intercooler, and an E85 tune can see 580–630 whp. That’s a gain of 200+ whp in the best cases—well above 150 hp at the crank. Even a conservative Stage 1 setup with 93 octane and no other modifications will net 100–130 whp gains.

Detailed Installation Costs: What You Actually Pay

The original article gave a broad cost range. Let’s expand that with real-world pricing as of 2025. Prices vary by vendor, but these are typical:

ComponentCost Range
Pure Stage 1 turbos (pair)$2,500 – $3,000
Pure Stage 2 turbos (pair)$3,200 – $3,800
Installation labor$1,200 – $2,000 (8–12 hours at $150–$180/hr)
Tuning (custom remote or dyno)$600 – $1,200
Supporting parts (intercooler, charge pipes, intakes, spark plugs, etc.)$1,000 – $2,500
Fuel system upgrade (port injection or HPFP for E85)$1,500 – $3,500
Clutch or torque converter upgrade (if manual or DCT)$1,500 – $3,000

Total budget range: For a reliable 600+ whp setup with Stage 2 turbos, expect to spend between $7,000 and $12,000 including all parts, labor, and tuning. That figure can climb if you choose a top-tier shop, upgraded cooling, or a built transmission.

It’s tempting to cut corners—avoiding an upgraded intercooler or using a mail-order tune—but the S55 is sensitive to heat and knock. A proper intercooler and a quality custom tune are non-negotiable for reliability at these power levels.

Installation Process: Step-by-Step Overview

Installing Pure Turbos on an S55 is not a beginner job. The engine bay is tight, and many ancillary components must be removed to access the turbos. Here’s a high-level outline of what a professional shop will do:

  1. Disconnect battery and drain coolant/oil.
  2. Remove air intake system, charge pipes, and intercooler.
  3. Remove exhaust manifolds and downpipes. On the S55, the turbos are integrated into the exhaust manifold, so this step requires removing the entire hot side.
  4. Disconnect oil and coolant lines from the stock turbos.
  5. Extract the factory turbochargers. This may require removing the engine mount or using special subframe clearance tools.
  6. Install new Pure Turbos with fresh gaskets, seals, and hardware. Ensure proper turbo clocking for oil drain alignment.
  7. Reconnect oil and coolant lines, install new exhaust manifold gaskets, and torque everything to spec.
  8. Reinstall downpipes, charge pipes, intercooler, intake, and all accessories.
  9. Prime the oil system (crank without fuel injectors) to avoid dry start.
  10. Refill fluids, perform any necessary leak checks, and begin the tuning process.

Most professional shops complete the job in 8–14 hours. DIY installation is possible but requires specialized tools (e.g., E8/E10 torx sockets, turbo line wrenches) and a lift. Expect a full weekend if you have experience.

Supporting Modifications You Cannot Ignore

Pure Turbos alone won’t give you 150+ whp. They need a supporting cast. Here are the essentials:

Fuel System Upgrades

Factory high-pressure fuel pump (HPFP) and low-pressure fuel system are limited. Beyond around 580–600 whp on E85, fuel pressure drops. Solutions include upgraded HPFPs (often from Dorch or Precision Raceworks) and port injection (PI) with a secondary controller. If you stay on pump gas, stock fueling is adequate up to Stage 2 levels, but E85 requires an upgrade to safely reach 650+ whp.

Intercooling

The stock S55 intercooler is adequate for 400 whp. With Pure Turbos, intake air temperatures skyrocket without a larger intercooler (e.g., Wagner Tuning or CSF). An upgraded intercooler reduces IATs by 20–40°F, allowing consistent power and protecting the engine from detonation.

Exhaust Restrictions

Factory downpipes have restrictive catalytic converters. Swapping to catted or catless downpipes reduces backpressure and spool time. Many owners also upgrade the midpipe and axel-back to reduce sound restriction, but those are less critical for power.

Engine Management and Tuning

A standalone ECM or flash tune (via Bootmod3, MHD, or custom RomCal) is mandatory. The stock DME can’t handle the higher airflow and boost. Custom tuning compensates for fueling, ignition timing, cam timing, and knock control.

Performance Metrics: What to Expect on the Road

Numbers aside, the driving experience transforms. Here are quantifiable improvements reported by owners after Pure Turbo Stage 2 installation:

  • 0–60 mph: Drops from ~3.8 seconds stock to 3.0–3.2 seconds on street tires (Michelin PS4S). With drag radial and proper traction, 2.7–2.8 seconds is possible.
  • 1/4-mile: Stock M4 runs ~11.8 @ 118 mph. Stage 2 Pure Turbo cars trap 125–130 mph and run 10.7–11.0 seconds depending on traction.
  • 60–130 mph: A common metric for highway pulls. Stock: ~9.5 seconds. Stage 2 with E85: ~5.8–6.5 seconds.
  • Throttle response: Even with larger turbos, Pure Turbos spool quickly. In-gear acceleration from 3,000 RPM pulls hard, with no significant lag below 3,500 RPM.

These numbers are repeatable on a well-maintained car with proper cooling. The S55’s robust bottom end means these power levels are reliable for many tens of thousands of miles if oil changes are kept on a short interval and heat is managed.

Reliability Considerations After the Upgrade

While the S55 engine itself is tough, pushing it to 150+ HP over stock increases stress on several components:

  • Clutch / Transmission: The manual Getrag 6-speed (GS6-45BZ) holds up to about 600 wtq. Beyond that, a clutch upgrade (e.g., Clutch Masters FX850 or South Bend Stage 3) is essential. DCT (7-speed) is stronger but can develop slip at 650+ whp; upgraded clutches and valve body work are recommended.
  • Crank hub: The infamous S55 crank hub issue. At high power, the hub can spin, causing catastrophic valve damage. An aftermarket captured crank hub (from Maximum PSI, Gintani, etc.) is a wise upgrade for Stage 2 power levels. Budget $2,000-$3,000 for the part and labor.
  • Oil heat: Sustained high-speed driving or track use can push oil temps past 260°F. An oil cooler upgrade is recommended for track duty.

Despite these caveats, thousands of S55 owners daily-drive cars with Pure Turbos without issues. The key is meticulous maintenance, proper cooling, and conservative tuning that respects the engine’s limits.

Real Owner Testimonials and Dyno Results

To ground this article in real-world data, we reached out to known performance shops and forums. For example, Pure Turbos’ official website showcases a Stage 2 S55 making 680 whp and 610 lb-ft on 93 octane with stock fueling and port injection. Another well-documented build by BMW M3 Blog demonstrates a Pure Stage 1 M4 running 10.8@128 mph in the quarter mile. These results align with the power gains we’ve discussed.

If you’re on the fence, consider reading build threads on BMW POST or M3Cutters to see real owners’ experiences with installation, tuning, and long-term reliability.

Comparison with Other Turbo Upgrades

Pure Turbos isn’t the only player. Competitors include Vargas Oil Cooler (VTT), RB Turbo, and Dinan. How do they stack up?

  • VTT Stage 2: Similar power potential, slightly lower cost. Some owners report spool characteristics that are a bit later than Pure. Pure turbos tend to retain better low-end response.
  • RB Turbo: Known for high-end power but often require more supporting modifications (inlet pipes, larger wastegates). Spool is slower but top-end flow is excellent.
  • Dinan turbo upgrades: More conservative, CARB-compliant, but expensive and limited to ~580 whp.

For the balance of power, response, and ease of installation, Pure Turbos remains the top choice for most S55 owners aiming for 600–750 whp. Their customer support and extensive tuning data make them a safe bet.

Conclusion: Is the Investment Worth It?

Boosting the S55 with Pure Turbos is one of the most effective modifications for transforming the M3 or M4 into a true performance machine. Gains of 150 horsepower are achievable with Stage 1 and easily exceeded with Stage 2 and proper supporting mods. The total cost—ranging from $7,000 to $12,000—is significant, but comparable to buying a faster car outright. When you factor in the reliability of the S55 engine and the comprehensive aftermarket support, the investment makes sense for anyone who values acceleration, track capability, or simply the thrill of driving a high-horsepower German sports car.

Before you commit, research thoroughly, choose a reputable shop, and budget for the supporting parts you’ll inevitably need. With the right approach, a Pure Turbo S55 becomes a daily-drivable 600+ horsepower weapon that can hang with far more expensive exotics. The smile per dollar ratio is off the charts.