Suttner ST-167 Bypass Soap Injector with 3/8" Quick Connects
The Suttner ST-167 is a stainless steel bypass downstream injector, the same injector we build into our Premium Single Soap Wash System, now sold on its own. Flip the lever to soap mode and it draws chemical straight from your pail, drum, or tote at a consistent dilution. Flip it to bypass and water routes around the injector, so you rinse at full pressure with no pressure lost through the injector.
It comes as pictured, ready to install with 3/8" quick connects, a wall mounting bracket, and a braided chemical inlet line with barb. It's built for fleet washers, truck washes, wash bays, and detailers who want soap and full rinse power from any lance.
Why Choose the ST-167 Bypass Injector?
- Full rinse pressure: a standard injector costs you some pressure even when rinsing. The ST-167's bypass sends water around the injector, so your rinse hits at full power.
- Soap and rinse from one lever: switch modes at the injector without changing nozzles or disconnecting anything
- Works with any lance: because the injector does the switching, you can soap through a standard high-pressure wand, foam lance, or hi-lo wand
- Keeps chemicals out of your pump: downstream injection adds soap after the pump
- Stainless steel, built for pros: rated 1,000 to 5,000 PSI and up to 212°F by Suttner
- Ready to install: quick connects, wall bracket, and chemical inlet line come on the injector
Specifications
| Model | Suttner ST-167 bypass downstream injector |
| Modes | Soap (injector) and bypass (full-pressure rinse), selected by lever |
| Water connections | 3/8" quick connects, installed (3/8" female ports) |
| Chemical inlet | Braided chemical line with hose barb |
| Metering | Replaceable injector nozzle; size must match your PSI and GPM |
| Operating pressure | 1,000 to 5,000 PSI / 350 bar (manufacturer rating) |
| Flow range | 1 to 18 GPM (manufacturer rating); 2.5 GPM minimum recommended |
| Maximum temperature | 212°F (100°C); best foam at 130°F or less |
| Material | Stainless steel |
| Mounting | Wall mounting bracket, included |
| SKU | IWP13690 |
How a Bypass Injector Works
A downstream injector uses the Venturi effect: water speeds up through a narrow nozzle, creating suction that pulls soap through your pickup tube and mixes it into the stream. A standard injector sits in the water path all the time, which means some pressure is lost even when you rinse.
The ST-167 has two paths, chosen with its lever:
- Soap mode: water flows through the injection chamber and draws chemical at the set dilution.
- Bypass mode: water flows through bypass bores alongside the injector. No chemical is drawn and no rinse pressure is lost.
Want the full breakdown? Read our Downstream Chemical Injectors: The Complete Guide.
How to Install and Use
- Mount the injector to a wall with the included bracket, near your pressure washer and soap container.
- Turn off the pressure washer and release pressure from the gun.
- Connect your pressure washer hose to the injector inlet and your wash hose to the outlet using the 3/8" quick connects. Follow the flow arrow on the injector.
- Push your pickup tubing onto the chemical line barb and place the strainer end in your soap container.
- Set the lever to soap mode and apply soap from the bottom up.
- Flip the lever to bypass and rinse from the top down at full pressure.
- After washing, draw clean water through the pickup tube to flush the injector.
Frequently Asked Questions
What is the Suttner ST-167?
The ST-167 is a stainless steel bypass downstream injector from Suttner. It draws one soap or chemical into the water line after your pump, and a lever switches it to a bypass mode for full-pressure rinsing.
What's the difference between the ST-167 and the ST-160?
Both are single-chemical downstream injectors. The ST-160 draws soap when your lance is in low-pressure mode, and water always passes through the injector. The ST-167 adds a bypass lever, so you choose soap or rinse at the injector and get full rinse pressure.
Is this the same injector used in the Premium Single Soap Wash System?
Yes. It's the injector from our Premium Single Soap Wash System, sold by itself for customers who already have a lance, hose, and draw tube.
What's included?
The ST-167 injector as pictured: 3/8" quick connects installed, a wall mounting bracket, and a braided chemical inlet line with barb. A lance, pickup tubing, draw tube, and metering tips are not included; those come in our complete soap systems.
Does the nozzle size need to match my pressure washer?
Yes. The injector nozzle has to match your machine's flow and pressure to draw soap correctly. Call us at 616-777-7175 with your PSI and GPM and we'll confirm the right size.
Why isn't my injector drawing soap?
Check that the lever is in soap mode, the pickup tube and strainer are clear, there's no air leak at the barb, the soap isn't too thick, and the pickup tube isn't too long. Flush the injector with clean water after every use.
Can I run two soaps?
The ST-167 draws one chemical at a time. For two-step touchless soaps, see the Dual Soap Wash System with the Suttner ST-164.
Complete Your Setup
- Premium Single Soap Wash System with the ST-167 and Foaminator lance
- Premium Single Barrel Hi-Lo Wand
- Touchless 1 & 2 truck wash soap
