The Toyota Supra equipped with the BMW-engineered B46 powerplant has quickly become a favorite among enthusiasts looking for a balance of efficiency and unexpected tuning potential. Among the most impactful upgrades owners choose, the b46 supra downpipe stands out as a modification that dramatically transforms the car’s performance, driving feel, and exhaust tone. Whether you’re a daily driver seeking quicker throttle response or a performance enthusiast chasing higher horsepower, a quality downpipe upgrade is a must-have for maximizing the B46 engine’s capabilities.
What Is a B46 Supra Downpipe and Why Does It Matter?
The downpipe is one of the most crucial components in a turbocharged system. It channels exhaust gases from the turbocharger to the rest of the exhaust system. The factory B46 downpipe includes restrictive catalytic converters designed for emissions compliance but not optimized for performance.
A b46 supra downpipe replaces the restrictive OEM unit with a freer-flowing design (either high-flow catted or catless), allowing the turbo to breathe more efficiently. This upgrade reduces backpressure, improves turbo spool, increases power output, and enhances overall engine efficiency.
Performance Benefits of Upgrading to a B46 Supra Downpipe
1. Increased Horsepower and Torque
One of the most appealing benefits of installing a b46 supra downpipe is the noticeable boost in power. By improving exhaust flow, the turbocharger doesn’t have to work as hard to push exhaust gases out, enabling quicker spool and higher efficiency. Gains of 20–40+ horsepower are common, especially when paired with proper tuning.
2. Faster Turbo Spool and Sharper Throttle Response
Reduced backpressure means that the turbo reaches peak boost quicker. This results in a sharper, more responsive driving experience, especially in the mid-range where the B46 engine already shines. You’ll feel a more immediate surge of power when accelerating, making the car livelier and more engaging.
3. Dramatically Improved Exhaust Sound
Many enthusiasts upgrade their b46 supra downpipe simply for the sound difference. The restrictive stock catalytic converter muffles much of the turbo’s character.
With an upgraded downpipe, you get:
A deeper and more aggressive exhaust tone
Louder cold starts
Enhanced turbo whistle and spool
Sharper pops and burbles (depending on tune)
Catless downpipes offer the loudest and rawest sound, while high-flow catted versions balance performance with a more refined tone.
4. Lower Exhaust Temperatures
Better exhaust flow helps the engine maintain lower exhaust gas temperatures (EGTs). This not only protects engine components but also allows the vehicle to sustain higher performance levels during spirited driving.
B46 Supra Downpipe Options: Catted vs. Catless
High-Flow Catted Downpipe
A high-flow catted b46 supra downpipe is ideal for those who want performance while maintaining a cleaner exhaust and reducing odor. These downpipes use performance-grade catalytic converters designed to improve flow without compromising drivability.
Pros:
Reduced smell
Less chance of CEL (check engine light)
Better for daily driving
Cons:
Slightly less peak power than catless
Higher cost
Catless Downpipe
For maximum performance and sound, a catless b46 supra downpipe is the best option. With zero restrictions, the turbocharger performs at its most efficient level.
Pros:
Maximum horsepower gains
Loudest and most aggressive sound
Fastest turbo spool
Cons:
Strong exhaust smell
CEL almost guaranteed without a tune or CEL fix
Not emissions compliant in many regions
Best Materials and Build Quality Features to Look For
When choosing the right b46 supra downpipe, consider:
304 stainless steel construction for durability
Mandrel-bent piping for smooth airflow
Precision TIG welding for reliability
OEM-style flanges for perfect fitment
Heat shielding or thermal wrapping for lower engine bay temps
A well-designed downpipe not only performs better but also lasts longer and ensures a perfect fit.
Do You Need a Tune After Installing a Downpipe?
While a tune isn’t mandatory for some high-flow catted downpipes, tuning is highly recommended. A proper ECU tune optimizes boost levels, air-fuel ratios, and ignition timing to fully utilize the improved airflow.
With a tune, the b46 supra downpipe unlocks its full power potential and helps prevent CEL warnings.
Final Thoughts
Upgrading to a b46 supra downpipe is one of the most effective ways to increase power, improve throttle response, and unleash a more exciting exhaust note from your B46-powered Supra. With the right build quality, proper installation, and optional tuning, this single upgrade transforms the Supra into an even more dynamic and powerful machine.
