Camshafts and Headers

*** Disclaimer; Direct from ipd’s Tech Tip archive!  This tech tip contains information from previous publications.  Products mentioned may not be available or the information may not be accurate due to changes in supply, manufacturing, or part number association.  Please contact ipd Customer Support if you have further questions.

Camshafts and Headers

Every spring, we get calls from vintage Volvo owners who are interested in increasing the horsepower in there trusty relics. One of the most common question is “how do I get more power out of my Volvo without spending a fortune”?  There isn’t an easy answer to this.

The first step is to move away from the “it’s still running so ill leave it alone” mindset. Before upgrading anything, it’s critical to ensure that you are starting with a solid foundation.  Many people have installed more aggressive cams ,headers and large exhausts only to find that their Volvo don’t go ant faster than they did before they spent hundreds of dollars. For example, a performance oriented camshaft or exhaust headers won’t do much good in an engine that’s losing compression past worn rings.

The first thing to do is avoid temptation toward bigger is better. Instead consider the kind of driving you’re actually going to be doing. How often do you really rev to 6000rpms? Do you use the car for carrying heavy loads, pulling a trailer or camping?   Each of these factors plays a role.

IPD offers a variety of stock grind cams if you are interested in returning a tired engine back to its original configuration. However if you’d like to increase the power output, we also offer the street torque and street performance camshafts. The street Torque is the more “civilized” of the two and offers a strong power band in the low and mid range rpms while the street performance is stronger in the higher revs.

If you’re still looking for more power, consider an exhaust header and a larger exhaust system. Think of your engine as an air pump; the more air you can move through the engine the more horsepower it will provide (This is a rough analogy-it isn’t quite as simple as this). Like Camshafts, exhaust components should be chosen with care. A bit bigger can be a lot better nut a lot bigger can get worse. Pay no attention to those who claim that 3” exhaust will result in massive power increase – it’s basically true that as the exhaust diameter increases, high end horsepower will also increase. However, as the exhaust diameter increases, low-end torque will decrease, This doesn’t matter if you have a race car with a power band that ranges 4000rpms to 8000rps but makes for a very hard to drive car in real world traffic. Economy will suffer too.

We’ve found that either the street torque or the street performance cams, coupled with a header and a 2” exhaust system work nicely on otherwise stock B20 engines. If you’re building a2130cc big bore kit, you may find that 2.25”or even 2.5”is more suitable as the larger displacements will provide an increase in low end torque that compensates for a larger pipe diameter.

Confusing? Yes. Whether you’re building a complete engine rebuild or simply freshening up a worn engine, choosing the correct parts is critical – its easy to spend hundreds, even thousands of dollars on a perfectly balanced and expertly assembled engine that ends up offering less horsepower then a solid stock B18 or B20. This is exactly what we’d like to avoid.

If this opens up more question then it answers, please give us a call and we’ll be happy to share what information we’ve managed to collect over the years in order to ensure that the next engine you build or refresh will yield the results you want