Some are common misconceptions we hear from customers. Others are outright falsehoods we see propagated on forums, videos, and Facebook groups.

They’re performance myths—and they could be keeping your vehicle from reaching its potential. Specifically, we’re talking about three automotive myths that could be costing your engine power and performance.

Myth 1: Engine Airflow–Bigger is Better

Bigger engine components mean more power, right?

The simple fact is bigger is NOT always better. And bigger does not always equal better performance. This goes for carburetors, cylinder heads, headers, and other components.

Let’s start by looking at the carburetor.

Larger barrels mean that the incoming air does not have to move as quickly. If the barrels are too big, the loss of air velocity means the cylinder will not fill to its full capacity. For that reason bigger CFM is not necessarily the way to go…and a carb that is too big will actually put out less torque and horsepower. 

The same principle applies when choosing cylinder heads, too.  Find out how by watching the video.

Myth 2: Advertised Cam Duration

How important is advertised camshaft duration?

When shopping for an aftermarket cam, you’ll notice many camshaft manufacturers will list two duration values—advertised and duration at .050-inch lift.

You’ll want to downplay the role of advertised duration when choosing a camshaft…and the video will tell you why.

Myth 3: Backpressure is Good

Is exhaust backpressure really needed?

Actually, no.

The goal of your exhaust system is to get rid of spent gases as quickly as possible, and backpressure makes it harder to do this. So why do some people say backpressure in exhaust is good?

Much of it can be attributed to confusion between backpressure and exhaust scavenging. Exhaust scavenging occurs as a pulse of exhaust gas runs through the exhaust pipe and a little area of vacuum, or low pressure, is created behind it. This vacuum or low pressure area helps to pull along the next exhaust pulse behind it and can actually help better exhaust gas from your combustion chambers. 

So where does the confusion between scavenging and backpressure come in? Watch the video to learn more.

Three myths debunked in one video!

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Author: David Fuller

David Fuller is OnAllCylinders' managing editor. During his 20-year career in the auto industry, he has covered a variety of races, shows, and industry events and has authored articles for multiple magazines. He has also partnered with mainstream and trade publications on a wide range of editorial projects. In 2012, he helped establish OnAllCylinders, where he enjoys covering all facets of hot rodding and racing.