Introduction

The Berk Technologies A90 Supra Downpipe is one of the most impactful bolt-on modifications you can make to your Toyota GR Supra. Designed for the B58 engine platform, this downpipe replaces the factory unit’s restrictive catalytic converter with a high-flow alternative, freeing up exhaust flow and allowing the turbocharger to spool more efficiently. Enthusiasts typically see gains of 20–40 horsepower and similar torque increases, depending on supporting modifications and fuel.

However, a downpipe swap is not a simple plug-and-play affair. The factory components often refuse to cooperate due to corrosion, tight clearances, and stubborn fasteners. Without careful technique, you risk stripped bolts, exhaust leaks, or even damage to the oxygen sensors. This guide provides detailed, step-by-step instructions and pro tips to ensure your Berk downpipe fits perfectly the first time.

Why Upgrade to the Berk Technologies A90 Supra Downpipe?

Before diving into the installation, it’s worth understanding what makes this downpipe a top choice for Supra owners. Berk Technologies has built a reputation for precision TIG-welded stainless steel construction, mandrel-bent tubing for unrestricted flow, and a design that retains the factory O2 sensor bungs and mounting points. The downpipe is available in catted and catless versions. The catted option uses a high-flow GESI catalyst that keeps the check engine light off with a tune, while the catless version is intended for off-road or race-only use.

Beyond raw power gains, the Berk downpipe also produces a deeper, more aggressive exhaust note. The turbo whistle becomes more pronounced, and the overall sound profile is transformed without being obnoxious. For owners planning further modifications like a bigger intercooler or ECU tune, this downpipe is an essential building block.

Tools and Materials Needed

Proper preparation eliminates frustration. Gather the following items before you lift the car:

  • Socket set (metric, 10mm–18mm) – Include deep sockets for the downpipe-to-turbo bolts.
  • Torque wrench (1/2″ drive) – Critical for tightening bolts to spec without stripping.
  • Breaker bar or impact wrench – For stubborn factory bolts.
  • Flathead screwdriver or trim tool – For disconnecting electrical connectors.
  • Oxygen sensor socket (22mm) – Needed to transfer sensors from the stock downpipe.
  • Penetrating oil (e.g., WD-40 Specialist or Liquid Wrench) – Apply a day before to loosen seized fasteners.
  • New OEM gaskets – Downpipe-to-turbo gasket and downpipe-to-midpipe gasket. Do not reuse old ones.
  • Anti-seize compound – For O2 sensor threads.
  • Jack and two jack stands – Used for safe lifting and stabilization.
  • Safety glasses and mechanic’s gloves – Protect from debris and hot surfaces.
  • Ramps (optional) – Some owners prefer ramps for additional clearance, but jack stands are safer for extended work.

Consider having a small pick set and a flashlight handy to inspect hard-to-reach areas.

Preparation and Safety

Working underneath a vehicle carries inherent risks. Park the Supra on a level concrete surface, engage the parking brake, and chock the rear wheels. Lift the front of the car using the factory jacking points, then place jack stands under the designated lift points on the frame rails. Never rely solely on a hydraulic jack.

Allow the exhaust system to cool completely if the car has been driven recently. Burns from hot exhaust components are one of the most common injuries during downpipe installations. Once cool, disconnect the negative battery terminal to prevent any electrical shorts or accidental airbag deployment while working near the engine bay.

Step-by-Step Installation Guide

Step 1: Safely Lift and Secure the Vehicle

Using the jack, raise the front of the Supra until you have adequate clearance to work underneath (approximately 18–24 inches). Place jack stands at the four reinforced lift points – two on each side – and lower the car gently onto them. Give the car a gentle shake to confirm stability before proceeding.

Step 2: Remove the Under Engine Cover

The Supra has a plastic undercover that protects the engine bay. Use a 10mm socket to remove the fasteners holding it in place. Set the cover aside along with all hardware in a labeled container.

Step 3: Locate and Disconnect the Downpipe

From underneath the car, identify the downpipe connecting the turbocharger outlet to the midpipe. The stock unit is heavily shielded and includes a large catalytic converter. You may need to remove a small heat shield near the firewall to access the top-downpipe-to-turbo bolts. Use a 13mm or 14mm socket for these.

Pro tip: Before removing anything, spray penetrating oil onto the three downpipe-to-turbo bolts and the two bolts at the midpipe connection. Wait 10–15 minutes for the oil to soak in.

Step 4: Unplug the Oxygen Sensors

There are two oxygen sensors: one upstream of the catalytic converter (before the turbo) and one downstream (after the cat). Disconnect the wiring connectors carefully by pressing the locking tabs. Use a 22mm O2 sensor socket to unscrew both sensors from the stock downpipe. Be gentle – the ceramic element inside is fragile if handled roughly.

Step 5: Remove the Stock Downpipe

With the oxygen sensors removed, undo the three bolts at the turbo flange using a combination of a wrench and socket. The bolts may be very tight; use a breaker bar if needed. Next, remove the two bolts (or V-band clamp) connecting the downpipe to the midpipe. Carefully lower the stock downpipe out from the bottom of the car. You may need to rotate it to clear the subframe and steering shaft.

Common challenge: On some A90 Supras, the top bolt at the turbo flange is nearly inaccessible. A wobble extension or flex-head ratchet can help. If a bolt strips, use a bolt extractor or replace it with a high-quality aftermarket bolt from an auto parts store.

Step 6: Prepare the Berk Technologies Downpipe

Inspect the new downpipe for any shipping damage or debris inside the tubing. Thread the oxygen sensors back in, applying a small amount of anti-seize to the threads to prevent seizure in the future. Install the new gaskets on both flanges of the Berk downpipe. The gasket between the turbo and downpipe should be the graphite OEM style – do not use cheap paper gaskets.

Step 7: Install the Berk Downpipe

Slide the downpipe up from underneath, aligning the turbo flange first. It may help to have an assistant guide the downpipe while you manipulate the top bolts. Start all three bolts at the turbo flange by hand to ensure correct threading. Then loosely install the two bolts at the midpipe connection. This allows some movement for final alignment.

Fitment tip: The Berk downpipe is designed to be a direct bolt-on, but you may need to gently rotate the downpipe to avoid contact with the subframe or heat shield. Check for at least 1/4″ clearance around all points.

Step 8: Tighten All Fasteners to Specification

Using a torque wrench, tighten the downpipe-to-turbo bolts to 30–35 ft-lbs (refer to your vehicle’s service manual for exact specs). Tighten the midpipe bolts to 25 ft-lbs. Do not overtighten, as the aluminum threads in the turbo housing can strip easily. Reconnect the oxygen sensors and route the wiring away from hot surfaces.

Step 9: Reinstall Heat Shields and Under Cover

Replace any heat shields you removed. Ensure they do not rattle against the downpipe – add heat wrap or zip ties if necessary. Reinstall the under-engine cover using the original fasteners.

Post-Installation Checks and Testing

Before lowering the car completely, perform a careful inspection. Start the engine and listen for exhaust leaks, which sound like ticking or hissing near the flanges. Use a shop rag to block the tailpipe temporarily – any leak will become more audible. If you hear a leak, shut off the engine and re-tighten the bolts.

Check for any codes by plugging in an OBD2 scanner. A P0420 or P0430 catalyst efficiency code may appear after a catless downpipe installation even without a tune; this is normal and can be addressed with a tune or spacer. For catted versions, a code is less likely but still possible on some model years.

Take the car for a short test drive, varying engine speeds. Listen for rattles, check for any warning lights, and confirm that the vehicle spools the turbo smoothly. Re-check the downpipe bolts after the first heat cycle – they often require a small re-torque as the gaskets compress.

Tuning and ECU Considerations

Installing a high-flow downpipe changes the backpressure and exhaust flow characteristics. To fully utilize the improved flow, an ECU tune is highly recommended. A tune can adjust air-fuel ratios, ignition timing, and boost targets to extract the maximum horsepower while maintaining reliability. Tuning also eliminates the check engine light for catless downpipes and can disable the oxygen sensor monitors for emissions testing in some regions.

Many tuners offer off-the-shelf maps for downpipe-equipped Supras, or you can opt for a custom dyno tune. Popular tuning platforms include Bootmod3 and MHD Flasher. If you live in an area with strict emissions regulations, consider a catted downpipe and a tune that retains catalyst monitoring functionality.

Note that adding a downpipe without a tune will still provide moderate gains (10–15 hp) due to reduced restriction, but the full potential is unlocked with software optimization.

Common Installation Issues and How to Avoid Them

Stripped turbo bolts: These bolts are known to be soft. Use a high-quality 12-point socket and apply steady, even pressure. If a bolt starts to feel mushy, stop and use a bolt extractor immediately. Always replace with ARP studs or OEM bolts.

Oxygen sensor wire routing: Ensure sensor wires do not contact the exhaust or moving parts. Zip-tie them securely to existing harnesses. A burned wire will trigger a check engine light and require replacement.

Leaks from the midpipe connection: The factory spring-loaded bolts can loosen over time. Replace them with new hardware if they appear corroded. Use a flange alignment tool if the midpipe is angled.

Milky or white exhaust smoke after startup: This is normal if the downpipe was oil-coated during manufacturing. It will burn off after 10–15 minutes of idle. If smoke persists, check for a coolant leak.

Frequently Asked Questions

Will a Berk downpipe cause a check engine light?

The catted version rarely triggers a CEL on a stock tune, but it is not guaranteed. The catless version almost always triggers P0420. A tune is the only permanent fix.

Can I install the downpipe without removing the front wheels?

Yes. Working from underneath is sufficient. However, removing the front passenger wheel can provide better access to the oxygen sensor connectors on some A90 models.

Do I need to upgrade the intercooler with a downpipe?

Not immediately, but combining a downpipe with a larger intercooler yields greater consistent power. The stock intercooler becomes a bottleneck once boost is increased.

How long does the installation typically take?

A first-timer should allow 3–5 hours. Experienced mechanics can complete the job in 1.5–2 hours including test drive.

Conclusion

The Berk Technologies A90 Supra Downpipe is a rewarding upgrade that transforms the driving experience of the Toyota GR Supra. With careful preparation, the right tools, and attention to torque specifications, you can achieve a leak-free, perfect fit that will last for years. Whether you pair it with a tune for maximum power or run it as a standalone mod, the sound and performance gains are immediately noticeable. Take your time, follow these steps, and enjoy the enhanced responsiveness of your Supra.

For more information on Berk Technologies and their product lineup, visit their official product page or consult the installation resources available on the Supra MKV forum community. Also refer to the BMW TIS service information for official torque values and procedures applicable to the B58 engine.