Civic Si / Integra / Accord 1.5T Downpipe | Two Step Performance

Two Step Performance High Efficiency Downpipe, TSP-HC11-HEDP

The factory downpipe on your 1.5T is the single biggest restriction on the hot side of the engine. Two Step Performance built this downpipe specifically for the 2022+ Honda Civic 1.5T (including the Civic Si), the 2023+ Acura Integra 1.5T, and the 2018+ Honda Accord 1.5T to fix that. It uses a genuine GESi G-Sport 400 CPSI catalytic converter with a 4.5-inch OD cat body, it runs on a completely stock ECU without triggering a check engine light, and it bolts directly to your factory exhaust or most aftermarket front pipes with no adapter needed.

Not for sale or shipment to California. This product is not CARB legal.

EPA Compliant, No Tune, No CEL

Here is what separates this from a race pipe. The GESi G-Sport cat at the core of this downpipe is EPA compliant and rated for use up to 850 horsepower. On a 1.5T, you will never need a bigger cat. It is also formulated for small displacement direct injection engines, which matters more than people give it credit for: a cat that is not matched to a small DI engine is where you get sulfur smell and weird part-throttle drivability issues. This one does not have those problems.

You can bolt this onto a completely stock ECU, drive away, and never see a CEL. No tune required, no codes to clear, no limp mode. If you want to add a tune later and get everything the downpipe has to offer, that is an option, but you do not need one to run it.

How It Is Built

Two Step Performance uses 304 stainless steel investment cast ends on both the inlet and outlet. Those ends are CNC pocketed for a clean transition into the 4.5-inch OD cat body, so exhaust gas moves through without hitting a sharp step or a rough weld transition. The cast outlet blends smoothly into your front pipe on the other end.

Construction quality on a downpipe matters because this part lives in sustained heat, constant thermal cycling, and real exhaust pressure. The 304 stainless construction is what keeps it from failing under those conditions over time.

Plug-and-Play Fitment

This downpipe is compatible with your factory exhaust and most aftermarket front pipes. No adapter is necessary. It also fits all variant models on the supported platforms, including RHD and international cars, so if you are running a non-US Civic, Integra, or Accord 1.5T, you are covered.

It does not fit 2.0T models. The Civic Type R (FK8, FL5) and the Integra Type S (DE5) use a different Two Step Performance downpipe with a 5.0-inch OD cat. If you are on a 2.0T, this is not your part.

Common Questions

Does this fit the 11th gen Civic Si? Yes. The 2022+ Civic Si is a 1.5T car, so this is the right downpipe for it, same fitment as any other 2022+ Civic 1.5T.

Do I need a tune? No. It runs on a stock ECU with no check engine light. A tune will get you more out of it, but it is not required to install and drive.

Will it fit the Civic Type R or Integra Type S? No. Those are 2.0T engines and use a separate Two Step downpipe with a larger 5.0-inch OD cat.

Is it catless? No. It runs a 400 CPSI GESi G-Sport EPA-compliant cat rated to 850 hp, so your emissions equipment stays intact.

What is in the box? The downpipe, gaskets, and stainless hardware.

Can I order this if I am in California? No. This product is not CARB legal and cannot be sold or shipped to California.

Fits These Cars

• 2022, 2023, 2024 Honda Civic 1.5T, including the Civic Si
• 2023, 2024 Acura Integra 1.5T
• 2018, 2019, 2020, 2021, 2022 Honda Accord 1.5T
• Fits all variant models including RHD and international
• Does NOT fit 2.0T models: Civic Type R FK8/FL5, Integra Type S DE5

Manufacturer part number: TSP-HC11-HEDP. Not for sale or shipment to California.