Do exhaust cutouts increase horsepower?

By: Kristen Hall-Geisler  | 

The Ram 392 Quick Silver has a 470 horsepower, 392 HEMI V-8 from the SRT lineup. For additional performance, it's equipped with a cold-air intake kit and headers featuring an electronic exhaust cutout for maximum power and sound at the track.
The Ram 392 Quick Silver has a 470 horsepower, 392 HEMI V-8 from the SRT lineup. For additional performance, it's equipped with a cold-air intake kit and headers featuring an electronic exhaust cutout for maximum power and sound at the track.
(Courtesy of Chrysler Group LLC)

In the beginning, there was the engine, and lo, it did require fuel and air in its cylinders, which would combust when a spark was introduced. But alas, there was verily always some leftover stuff in the cylinder that needed to be cleared out via the exhaust system. The faster the exhaust could be pushed out of the engine, the faster the combustion process could start over -- which giveth more horsepower. And so, we must taketh away the exhaust as quickly as possible.

This could come to pass if the twists and turns and mufflers that run along the bottom of the car could be eliminated. But again, alas, they cannot. They are required by those on high to keepeth our streets noise free and our air breathable.

Advertisement

But what if we promiseth to only bypass the exhaust system while we race safely on the track? Why, then we may installeth a Y-shaped exhaust cutout. It shall be inserted into the exhaust system between the engine and the muffler, with "the slant" (as the short pipe shall be known), facing downward and toward the back of the car. When extra horsepower hath been shown to be required, a flange or block plate in the cutout can be moved into place manually or electronically to allow the exhaust gases to escape the labyrinth of exhaust system with haste. Whilst on the streets of the town, the cutout can be cut off, allowing the exhaust to travel the full extent of the system, through catalyst and muffler alike.

Yea, verily, clearing out the exhaust more quickly doth impart more horsepower. But, lest ye forget, bypassing the muffler doth make for a noisy car -- one that yon policemen might pull over for violations.

Originally Published: May 31, 2013

Advertisement

Exhaust Cutouts FAQ

Do exhaust cutouts increase horsepower?
Clearing out the exhaust more quickly does impart more horsepower. But, don't forget, bypassing the muffler makes for a noisy car.
What is the point of exhaust cutouts?
When extra horsepower is required, a flange or block plate in the cutout can be moved into place manually or electronically to allow the exhaust gases to escape the labyrinth of exhaust system quickly.
How much does it cost to install exhaust cutouts?
The price of exhaust cutouts will ultimately depend on the type you choose. Manual cutouts are usually cheaper and installation fees will vary among mechanics. You should get quotes from several places to see where you can get the best price.
What is an exhaust cutoff?
An exhaust cutoff is Y-shaped. It's inserted into the exhaust system between the engine and the muffler, with "the slant" (as the short pipe shall be known), facing downward and toward the back of the car.
Are exhaust cutouts legal?
That depends on where you live. Most states allow an objective method of measuring exhaust noise, whereas some prohibit mufflers that emit excessive noise and modification to vehicles if it causes the muffler to emit more noise than the original.

Lots More Information

Author's Note: Do exhaust cutouts increase horsepower?

I had heard of exhaust cutouts in my car-loving life, but I'd never seen one, and I'd never really wondered much about them. I was happy to learn that such a simple, straightforward piece of automotive equipment could do so much for a car's power. Happy enough to run out and buy myself a cutout? Not quite. I'm saving up for a turbocharger, myself. Besides, an unmuffled Subaru Baja on the drag strip just seems silly, right? Whereas everyone knows Subarus love turbo on dirt roads -- and so do I.

Related Articles

  • Engine Basics. "Electronic Exhaust Cutout Basics." (May 15, 2013) http://www.quicktimeperformance.com/QTEC/
  • InstallUniversity.com. "Exhaust Cutout Explanation." May 29, 2000. (May 15, 2013) http://www.installuniversity.com/install_university/installu_pages/freshman_year/exhaust_cutout_explanation.htm
  • Quick Time Performance. "The QTP Electric Cutout." (May 15, 2013) http://www.quicktimeperformance.com/QTEC/