HKS Super Turbo Muffler – Toyota GR Supra 3.0 A90/A91

OVERVIEW

HKS makes two exhausts for the 3.0 GR Supra with two different goals, and the Super Turbo Muffler is the one built for power and comfort. Its full straight layout removes the narrow points in the factory system to improve exhaust flow, giving a moderately sporty sound without the unpleasant drone, and it meets Japan's noise regulations. The 110 mm tips use HKS's slotted inner design for extra sound control, with a titanium gradation finish sized to suit the bumper cut-outs.

Both versions reuse the factory exhaust valve control and actuator, so the valve can still be switched from the cockpit and the car keeps its Normal and Sport sound modes.

Two versions are offered. 31029-AT003 replaces the exhaust from the first mid pipe back and is for cars without an OPF (gasoline particulate filter); HKS states that 31029-AT003, AT007 and AT008 are the same physical product, so it also covers later 3.0 automatic and 6-speed manual cars. 31029-AT004 is the main muffler only: it connects to the factory mid pipe, works with or without an OPF, and is EU certified.

SPECS

• 31029-AT003: Super Turbo Muffler (SSR), SUS304, 110 mm tips L&R, center pipe 85 → 70 mm × 2
• 31029-AT003: proximity noise 87 dB (stock 85 dB), idle 61 dB (stock 58 dB)
• 31029-AT003: minimum ground clearance 111 mm, weight 24.7 kg (stock 26.7 kg), certification JARI10200001P
• 31029-AT004: main muffler only, SUS304L, 110 mm tips L&R, center pipe 80 → 70 mm × 2
• 31029-AT004: proximity noise 87 dB (stock 85 dB), ground clearance 125 mm, weight 23.9 kg
• 31029-AT004: works with and without OPF; EU certified
• Both: reuse the factory exhaust valve control and actuator; Normal / Sport switching retained
• Made in Japan

PARTS INCLUDED

• 31029-AT003: HKS Super Turbo Muffler system from the first mid pipe back, with twin tips and hardware
• 31029-AT004: HKS Super Turbo Muffler main muffler with twin tips and hardware; the factory mid pipe is retained

TECH RESOURCES

• Required extras: none. The factory exhaust valve actuator is transferred to the HKS system.
• Recommended: fresh exhaust flange gaskets and nuts, as the factory hardware is often damaged on removal.
• Installation manual, 31029-AT004 (HKS): 31029-AT004 Super Turbo Muffler installation manual (PDF)
• 31029-AT004 install note: HKS has the factory muffler cut at the mid-pipe service separation point, and the HKS muffler connects there. Professional installation recommended.
• 31029-AT003 installation notes: HKS does not publish a manual for this part. Raise and support the car, unbolt the factory system from the first mid pipe back, transfer the exhaust valve actuator, then hang the HKS system on the OEM rubber mounts and align the tips before final torque.
• Which one? No OPF and want the full system → 31029-AT003. Car has an OPF, or you want to keep the factory mid pipe → 31029-AT004.
• Want it louder? See the HKS Dual Muffler for the GR Supra 3.0. 2.0 B48 car? See the HKS Super Turbo Muffler for the GR Supra 2.0.
• No CARB EO is published for 31029-AT003 — off-road / competition use only in California.
• Price is for the item selected only; labor is not included.

PART NUMBER

• 31029-AT003 — HKS Super Turbo Muffler, GR Supra 3.0 B58, non-OPF (same product as 31029-AT007 / 31029-AT008)
• 31029-AT004 — HKS Super Turbo Muffler main muffler, GR Supra 3.0 B58, with or without OPF

VEHICLE APPLICATIONS