What Are Straight Pipes | Muffler Delete, Glass Packs & Side Pipes

Do Straight Pipes Add Horsepower? The answer here is yes and no, and it depends entirely on how it’s done. But the most important part of the answer is that simply hacking the muffler off any car is not a guarantee of more horsepower. The only guarantee is more noise.

Generally speaking, it’s true that mufflers tend to create backpressure, and backpressure in an exhaust system robs horsepower. How much is a function of the engine, exhaust and mufflers in question. A large displacement engine and/or one with a big cam and high flowing heads will be more affected by restrictions in the exhaust. Similarly, not all mufflers are created equal. Typically, the muffler or mufflers that the manufacturer hung underneath your car at the factory were designed with maximum sound reduction as a priority. As such, stock mufflers will usually create more backpressure than a muffler designed with maximum performance in mind.

That’s an important thing to consider as we talk about straight pipes, noise, and horsepower. Simple logic may state that “mufflers are restrictive, so I should cut mine off to eliminate the restriction.” However, it’s worth noting that in many cases, a high-performance muffler and exhaust system will yield a huge increase in performance while still offering some reduction in sound. In fact, many well-designed performance exhaust systems and mufflers will sound better than a system where the muffler was simply removed. Instead of abrasive cackles and screeches, the exhaust note will be more of a powerful rumble.

How Much do Straight Pipes Cost? As with most everything automotive, there’s a right way and a wrong way to “straight piping” a car and there are pros and cons of a straight pipe exhaust. Obviously, the appeal of the straight pipe or muffler delete solution is that it’s generally reductive and therefore cheaper than adding fancy components. Simply cutting the muffler off and replacing it with a section of exhaust tubing and some clamps will be fairly cheap. On the other end of the spectrum, the sky’s the limit on a custom straight pipe exhaust system tailored to your car and built out of stainless.

If you’re targeting the budget end of the straight pipe cost spectrum, consider the extent of the surgery required. Modern cars generally have complex exhaust systems with multiple catalytic converters, mufflers, and resonators to deal with. Also consider the cost of the performance tune to the engine’s computer that will be necessary to make the most of the backpressure reduction and may even be required just to get the car to run properly.

Are Straight Pipes Legal? Straight pipes are always going to be dicey in the eyes of the law. Are straight pipes illegal? It’s going to be different depending on where you live, but just about every town, city, or state will have rules about how loud a car can be before the red and blue lights come on in your mirror. The obvious general rule is to check in on what your local laws are before you do any work on your exhaust.

And don’t forget emissions. Many cars, especially late models, have complex emissions systems in place on the exhaust system. Removing these pieces will generally make the car louder and will potentially reduce backpressure, but can create some serious legal issues as well. Additionally, this can cause a major problem in states where emissions are tested and may even lead to those pieces being reinstalled to get past the sniffer.

Best Glass Pack Mufflers Most glass packs will have a straight-through design with a perforated tube in the center and fiberglass in the small diameter case. Speedway Motors features several different brands of glass packs to fit just about anything. Here’s a quick look at some of the major considerations.

Most old-school hot rod glass packs will have a mild steel case, often painted a signature color like the light metallic blue of “Smithy’s” mufflers, the purple of “Purple Hornies,” or bright red to evoke the old “cherry bomb” mufflers. For the ultimate in durability and a little extra bling, Speedway Motors also offers a stainless glasspack in either raw or polished.

While the most common glass pack design will simply use round inlet and outlet tubes that can be clamped or welded to the rest of the exhaust system, some actually have a flange on the inlet and turnouts on the other end. Commonly called “header mufflers,” this design is meant to forego the rest of the exhaust system and simply bolt to the header flange, then dump under the floor. Needless to say, the glasspack sound of these is plenty aggressive, especially inside the car where the exhaust uses the floorboards as a giant bass drum. Simply because of their configuration, this style will likely be the loudest glasspack muffler.

Glass packs are not the only choice when it comes to selecting the best performance muffler for your car. Chamber mufflers and “turbo” mufflers are also great alternatives that will generally offer a more mellow sound profile while still flowing enough to support some real horsepower. Often, these mufflers are included in an exhaust kit that can be tailored to perfectly fit your car.

What about open headers vs straight pipe? Now we’re talking about the straightest of straight pipes. This is a common setup on racecars that run in places where noise is not an issue. And it’s almost a must to take the newly engine-swapped hot rod out for a rip with open headers before heading back into the shop to build the rest of the exhaust. Theoretically, open headers offer the ultimate in performance potential, but will be seriously loud and always illegal. To understand more, check out our deep dive into how much horsepower do headers add.

Exhaust cutouts are a “best of both worlds” solution. Similar to the old lake pipes, these will add a “Y” to the exhaust pipe, one branch of which goes through the mufflers, and the other ends in a capped flange. When the cap is removed, exhaust follows the path of least resistance out of the open flange, bypassing the mufflers and making a bunch of racket. The ultimate version of this is the electric cutout that can go from mild to wild with the flip of a switch inside the car.

Ultimately, the best exhaust system for your car is going to be the one that does everything you want it to do while still being legal and safe. In most cases, just removing the muffler will simply create a loud car that the neighbors will hate and honestly, you will too after a little time out on the road. (Trust us.) As we’ve discussed, a well thought out exhaust with the right mufflers and exhaust pipe size can do it all, and options like cutouts or lake pipes can offer pure, un-muffled chaos when you need it, but can then be capped for daily use without accumulating a stack of fix-it tickets.