Discover the Most Effective Methods for Turbocharging Your E36/Z3

 

Discover the Most Effective Methods for Turbocharging Your E36/Z3
both on a budget and balling out.

Turbocharging an E36 or Z3 is one of the most rewarding ways to breathe new life into your classic BMW. Whether you're chasing high horsepower numbers or just want to boost performance while keeping the car street-friendly, there’s a lot to consider before diving in. This guide outlines everything you need, along with options to save or splurge based on your goals and budget.

 

The Basics of Turbocharging

Turbocharging fundamentally changes the dynamics of your engine by forcing more air into the combustion chamber, allowing it to burn more fuel and create more power. For your E36/Z3, proper planning and quality execution are critical to ensure reliability and performance. We will be going over the core components with some added Poverty Built tips to help you decide correctly.

Core Components for Turbocharging Your E36/Z3

1. Turbocharger

  • What It Does: Compresses air to increase the engine's power potential.
  • Options:
    • Budget: Used OEM turbos (e.g., Holset HX35). Affordable but may have wear and tear.
    • Mid-Range: Chinese-made turbos (like eBay specials). Hit or miss, so inspect thoroughly. We have not had a problem with maxpeedingrods turbos.
    • Premium: Garrett, BorgWarner, or Precision turbos. Reliable, efficient, and offer excellent performance for serious builds.
    • Can You Cheap Out? Yes, if you're willing to risk durability or replace it later.

Turbo Sizing Recommendations by Power Goals

Below is a table to help guide you in selecting a turbo based on horsepower goals:

Horsepower Goal Recommended Turbo Size Popular Turbos
250–350hp T3/T4 hybrid, ~50mm inducer Garrett GT28, Holset HX30/HX35, eBay equivalent 
350–500hp Mid-sized, ~57-60mm inducer Garrett GT35, BorgWarner S257, Precision 5858, eBay equivalent
500–700hp Large frame, ~62-67mm inducer Garrett GTX3582R, BorgWarner S366, Precision 6266
700hp+ Extra-large, 70mm+ inducer BorgWarner S400 series, Precision 6766

Key Sizing Factors to Consider

  1. Compressor Map Matching: Ensure the turbo’s efficiency range matches your desired horsepower. A poorly matched turbo may result in surge or poor spool.
  2. AR Ratio: The exhaust housing (AR) size affects spool time and power band. A smaller AR spools faster but may choke at high RPM; a larger AR supports more power but with slower response.
  3. Boost Levels: Higher boost doesn’t always mean more power. Ensure your turbo operates efficiently within your desired boost range (e.g., 8-15 psi for stock engines, 15+ psi for built engines).

2. Exhaust Manifold

  • What It Does: Routes exhaust gases to the turbo.
  • Options:
    • Budget: Log-style cast iron manifolds. Durable but not optimal for high flow.
    • Mid-Range: eBay tubular manifolds. Often hit-or-miss quality; consider reinforcing welds. This is the same for CXRacing and all of the Chinese manifolds.
    • Premium: Custom or brand-name tubular manifolds (e.g., RSI, 5150). Better flow, higher reliability.
  • Can You Cheap Out? You could. the eBay log-style cast manifolds are a pain to deal with but with a lot of planning you can get them to function right. Mid-Range Manifolds will need welds reinforced as they commonly crack.

3. Intercooler and Piping

  • What It Does: Cools compressed air from the turbo, improving performance and reducing engine knock.
  • Options:
    • Budget: Universal intercoolers and DIY piping kits. Effective if sized correctly. 
    • Mid-Range: Kits from brands like CX Racing. Pre-designed for your platform but not top-shelf materials. Normally require a bit of user-required modification to work correctly.
    • Premium: High-performance intercoolers from Mishimoto or Treadstone. Best for high-horsepower builds.
  • Can You Cheap Out? Yes, but improper sizing can result in heat soak and power loss. Budget intercoolers normally have pretty bad efficiency and have big boost loss.

4. Fuel System Upgrades

  • What It Does: Supplies the engine with the extra fuel needed for boost.
  • Components: High-flow fuel injectors, upgraded fuel pump, and a rising rate fuel pressure regulator.
  • Options:
    • Budget: Used injectors and Walbro 255 fuel pump. Functional for mild builds. Junkyard injectors such as the Bosch Green Giants, and some Ford fuel injectors work great on a budget. Just make sure you get them flow matched.
    • Premium: New, flow-tested injectors from Siemens/Deatchwerks/FI and Aeromotive/Deatchwerks fuel pumps.
  • Can You Cheap Out? No, as insufficient fueling can lead to catastrophic engine damage.

Injector Sizing Chart by Power Goals

Use this chart to determine the minimum injector size for your build based on horsepower goals and fuel type.

Horsepower Goal Gasoline (CC/Min) E85 (CC/Min) Popular Injector Options
250hp 270–330cc 400–450cc Bosch 0280155968 (EV6 315cc), OEM Green Giants
350hp 440–500cc 650–750cc Bosch EV14 440cc, DeatschWerks 550cc
450hp 550–630cc 800–950cc DeatschWerks 750cc, Bosch EV14 630cc
600hp 750–850cc 1,150–1,300cc FIC 850cc, Injector Dynamics ID1050x
700hp+ 1,000cc+ 1,500cc+ Injector Dynamics ID1300x, FIC 1200cc

Key Considerations When Choosing Injectors

  1. Fuel Pump Capacity: Ensure your fuel pump can handle the flow rate of your injectors, especially if running E85.
  2. Tuning Support: Larger injectors may require advanced ECU tuning to achieve smooth drivability.
  3. Future Upgrades: Consider sizing injectors slightly larger than your current power goal to leave room for future modifications.

5. MAF Sensor Options

What It Does: Measures the air entering the engine, allowing the ECU to calculate the necessary fuel and ignition adjustments for optimal performance.

Components: MAF sensor, proper housing, and wiring adaptations where necessary.

Options:

  • Budget: Nissan 350Z MAF sensor (part number: 22680-7S000) combined with a 2.2k ohm resistor installed inline with the signal wire. This setup is affordable and suitable for mild turbo builds up to ~450hp. Junkyard-sourced 350Z sensors can reduce costs, but ensure they’re tested and functional.
  • Premium:
    • Audi RS4 MAF: Reliable for power levels up to ~550hp, offering OEM quality and precision. Works well for moderate builds with balanced cost and performance.
    • HPX MAF: Supports up to ~750hp. This option provides excellent precision and reliability, suited for higher boost levels.
    • HPX-E MAF: Capable of handling 1000hp+, this sensor is ideal for extreme builds where airflow and accuracy are critical. It's a professional-grade solution for high-performance setups.

MAF Sensor Options for Turbocharged E36/E46

MAF Option Max Power Supported Special Considerations Ideal Setup
Nissan 350Z MAF Up to ~450hp Requires a 2.2k ohm resistor installed inline with the signal wire. Use part number 22680-7S000 for proper calibration. Works best with mild to moderate turbo setups.
Audi RS4 MAF Up to ~550hp Known for durability and wide calibration potential. Requires correct housing size and ECU tuning. Ideal for setups with moderate boost levels, maintaining OEM-like MAF reliability.
HPX MAF Up to ~750hp A versatile, high-power option. Requires proper scaling in ECU tuning. Best suited for setups pushing higher boost levels, or for proper headroom.
HPX-E MAF 1000hp+ Designed for extreme power levels. Offers excellent precision for high-boost setups. Perfect for high-performance builds targeting 1000hp+, or for proper headroom.

Key Considerations for Choosing a MAF

  • Power Goals: Select a MAF that aligns with your target horsepower to avoid sensor limitations.
  • Housing Size: Ensure the MAF housing matches the airflow characteristics of your setup. This can directly impact sensor accuracy.
  • Reliability: High-power setups may benefit from upgrading to aftermarket options like the HPX series for better precision and durability.

 

6. Engine Management System (ECU)

  • What It Does: Controls air/fuel ratios, timing, and boost.
  • Options:
    • Budget: Stock ecu tuning from Poverty Built, or DIY tuning.
    • Premium: Standalone systems like Haltech or Link ECU. Ultimate control for big builds. We recommend using Link ECU and purchasing a tune through us.
  • Who to choose? Do your research. Although we have very budget oriented pricing, we aren't looking to make a killing. We're looking to make a living and help enthusiasts in the process.

7. Supporting Mods

  • What They Do: Ensure the engine and drivetrain can handle the increased power.
  • Must-Haves:
    • Proper oiling and cooling to your turbo and wastegate are insanely important.
      • You can use the lines you would have used for your throttle body heating to supply your turbo/wastegate with coolant.
      • Oil Feed: You can either use a RallyRoad VANOS oil banjo bolt with an added -4an fitting, or using a distribution block which would go in the same spot.
      • Oil Return: You have two options. You can either run a scavenge pump (may be required for bottom mount turbo setups) and pump the oil into the dipstick ccv return tube, or weld a -10an bung in the oil pan and run the drain to there.
    • Head gasket and ARP head studs for higher boost.
      • It is only recommended to run a Cometic MLS gasket if both the head deck and block deck have been resurfaced. These are known to leak with just a little warpage. Another option is to use a spacer plate and two head gaskets. You can also use cut-ring gaskets. Machine shop recommended to make sure the installation is proper of those cut-ring gaskets.
    • Exhaust system upgrades to reduce backpressure.
      • You definitely don't want to run a stock exhaust unless you're running super low power. Consider at minimum a 2.5" exhaust with high flowing resonators and muffler.
    • Clutch and drivetrain upgrades to handle torque.
      • For the budget oriented, FX clutches on eBay are awesome. Drivetrain mount upgrades are definitely recommended, especially the differential bushings.
  • Can You Cheap Out? Not for critical components like the head gasket and studs, but you can delay some drivetrain upgrades if you plan to stay under 300whp. Stock clutches will slip with a little bit of added power.

    Camshaft Sizing Recommendations by Power Goals

    Horsepower Goal Recommended Duration (Intake/Exhaust) Lift Range Popular Options
    250–400hp 240°/240° or Stock ~9–10mm OEM M50/M52 cams, mild regrinds
    400–500hp 252°/256° ~10.5mm Schrick 252°/256°, Cat Cams Street Turbo Cams
    500–600hp 256°/260° ~11mm Schrick 260°/256°, VAC Stage 1 Turbo Cams
    600hp+ 272°/264° or Custom 11.5mm+ VAC Stage 2 Turbo Cams, Schrick 272°/264°

    Key Considerations for Turbo Camshafts

    1. Valve Springs and Retainers: Higher lift and aggressive profiles may require upgraded valve springs to avoid valve float.
    2. Tuning: Turbo cams often require advanced tuning to optimize boost and airflow dynamics.
    3. Spool vs. Power Band: Aggressive cams may sacrifice low-end response for top-end power, so match the cam profile to your turbo and driving style.

    Planning Your Turbo Build: How Much Should You Spend?

    • Under $2,000 Build: Ideal for 5-7 psi on a stock engine. Focus on used parts, universal kits, and budget tuning solutions.
    • $5,000 Build: Mid-range build for 300-400whp. Invest in new components, proper tuning, and basic engine reinforcement.
    • $10,000+ Build: Serious track or high-horsepower street builds. Go for premium components, standalone management, and full supporting mods.

    Final Thoughts

    Turbocharging your E36/Z3 is a thrilling project that can transform your car's personality. The key is balancing your budget with your goals. Some corners can be cut, but skimping on critical areas like tuning, fueling, or engine reinforcement can lead to disaster.

    At Poverty Built, we specialize in affordable, high-quality solutions for tuning enthusiasts. Whether you're looking for a basic tune or custom ECU calibrations, we’re here to help you make your turbo dream a reality.

    Ready to take the leap? Contact us today for expert advice and tuning services!

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