Your car may have a louder voice than you've heard from it. Here's what changes when the exhaust valves open, why the difference shows up most at the times you'd least expect, and clips of what it sounds like across different engines. Turn it up.
Key takeaways
- An open exhaust valve gives you your car's loudest factory setting: deeper, fuller and more present than the same car with the valves shut.
- With the valve closed, exhaust gas takes a longer, more muffled path. Open, it gets a more direct route out, so less of the sound is soaked up on the way.
- Depending on the model, the difference often shows up most at idle, low revs and on overrun, because that's where the factory logic tends to close the valves.
- Opening the valves doesn't push your exhaust past its maximum sound volume under full load, it lets you hear the full sound possible at all times.
01The short answer
Open exhaust valves unlock your exhaust's full sound: deeper, fuller and more present, with more of the engine's character coming through all the time, not only some of the time.
With the valves closed, the same car can sound flat and polite. Open, it can sound like the car it was meant to be.
How big the change is depends on the car and exhaust setup. On some it's a more subtle step up. On others the difference is night and day. The clips below give a feel for the range.
02Why an open valve sounds different
A valved exhaust has two ways out. With the valve closed, gas is pushed through the longer path, through baffles and chambers built to absorb sound. Open the valve and the gas gets a more direct route to the tailpipes, so less of the sound is soaked up before it reaches you.
A flap inside the exhaust, usually near the muffler, moved by an electric valve actuator on command from the ECU. Closed, it sends exhaust gas through the quieter path. Open, it gives the gas a more direct route out, for the most sound from the exhaust.
The ECU decides when to open it, based on drive mode, revs, load and throttle. The full logic is in how OEM exhaust valves work, and the bigger picture of why new cars got quieter is in why modern performance cars sound so muted.
03What changes when the valves open
Where you'll hear the biggest change can be surprising. Many cars already open the valves at high revs or full throttle, especially in sport modes. The gap is often widest at idle, lower revs, on overrun and steady cruising, because that's where the factory logic tends to close the valves. That's also where you spend most of your driving.
Sport mode may open the valves more, but it does not keep them open all the way and all the time. It varies from car to car. The car decides when the valves open, not you.
04What it sounds like
Every engine layout has its own voice, and opening the valves lets more of it out. A few of the most common:
Inline six (BMW M3, Toyota Supra)
Smooth and rising, building into a howl as the revs climb. With the valves open, the low rev burble can fill out and the top end can get noticeably more raw. See the BMW 3 Series / M3 range and the GR Supra.
Five cylinder (Audi RS3)
The famous offbeat warble. Open valves can bring out more of that uneven, slightly off kilter rhythm that makes the five cylinder so recognisable. See the RS3 range.
V8 (Ford Mustang GT, Audi RS6)
A deep burble at idle and a heavy, rolling note under load. This is where open valves can make the biggest difference at low revs. See the Mustang range and the RS6 range.
Turbo four cylinder (VW Golf R, Mercedes-AMG A45)
A sharper rasp, with more crackle on gear changes on some cars. Small engines can surprise people with how much voice they have with the valves open. See the Golf range and the A-Class / A45 range.
05How to unlock your car's sound on demand
A controller is the simplest way.
A plug and play device that intercepts the signal to your factory electric exhaust valves and lets you override it, so you can hold the valves open on demand and then hand control back to normal factory behaviour. It allows for maximum exhaust flow for the most sound from the exhaust.
With a wireless controller like 11MODE, ON keeps the valves fully open in any drive mode and OFF hands full control back to the car. It plugs in at the valve actuator in minutes with no tools, no control box and no cables to route. It fits 1,000+ make, model and year combinations across 25+ brands, on petrol cars with factory electric exhaust valves. Every method for opening the valves, including the cheaper and messier ones, is in how to open your exhaust valves on any car, and the wider options are in how to make your car louder.
06What an open valve won't do
- It won't increase the maximum volume under full load. You'll hear more volume for the times the valves are normally closed, even in sport modes.
- It won't add power. Power stays the same.
- It can bring drone on some cars. Open valves at a steady highway cruise can hum through the cabin, which is why having an off button and handing control back to the car matters.
A controller will unlock your exhaust sound and keep the valves fully open. Loud for the drive you've been looking forward to, factory quiet for the early start and the long highway run. The valves are already there. The only question is who decides when they open.
Noise regulations vary by country and state, and these products are sold for off-road and track use, so check the rules where you drive before running your valves open on the street.
07Frequently asked questions
What does an open exhaust valve sound like?
A deeper, fuller and more present sound, with more of the engine's character coming through all the time, not only some of the time. How big the change is depends on the car and the engine layout.
Is an exhaust louder with the valve open?
Yes. An open valve gives the gas a more direct route out, so less sound is absorbed. It's the exhaust's own loud setting, not louder than that.
Why do my valves seem closed when I'm cruising?
On many cars the factory logic is conservative and can close the valves at low revs, less throttle and steady speeds. It varies by car and drive mode, so the car decides, not you.
Does an open exhaust valve cause drone?
It can on some cars, mostly at a steady highway cruise. That's why having an off button matters: OFF hands the valves back to the car for the long runs.
Does opening the exhaust valve add horsepower?
Not exactly. Opening the valves changes how your car sounds, and power stays the same.
Can I have the open valve sound and still keep the quiet?
Yes, with a controller. ON keeps the valves open, and OFF returns full factory control, so quiet is one button away.
Is it legal to drive with the valves open?
Noise regulations vary by country and state, and these products are sold for off-road and track use, so check the rules where you drive before running your valves open on the street.
08The bottom line
Your car with its exhaust valves open is your car's real voice, the one the factory often keeps hidden. Listen to the clips, try a cold start on your own car, and if you like what you hear, check your car and turn it to 11.
