One of the most common questions we have been asked over the years is what is the difference between a stock manifold and extractors/headers? Although technically they perform the same function, channelling exhaust gases from the cylinder head into the exhaust system, they have different qualities that may be beneficial, depending on your needs.
With extractors, all applications are different, so the results vary from car to car. You’re not going turn a 1.6 litre into a V8 by making this change, however, even though the results vary, we are yet to see an unhappy customer that has invested in a manifold replacement.
The decision to change this part of your car can come from a whole raft of different scenarios. As extractors are technically a performance product, they are associated with performance upgrades and really are an essential when you want to achieve optimum performance from your exhaust system.
Most manifolds are made from thick cast iron, clunky and generic, they create a large amount of back pressure and therefore exhaust gases escape less efficiently.
Introduce the smooth workings of extractors, which are a tubular design made of either mild steel or stainless steel. The tubes from each cylinder are generally fairly equal in length and smooth, meeting at a collector. Gases reach the collector at the same time from different points resulting in less back pressure.
Pros and Cons
The benefits of extractors in our opinion outweigh the cons. Although design in manifolds vary and some are better than most, the design of extractors simply allow for the exhaust gases to be more free flowing. Performance gains, better fuel economy, better exhaust note, are all benefits of extractors. The gain depends on the type of car they are installed on and the way in which you drive the vehicle. They run at their most optimum when coupled with a high flow catalytic converter and sports exhaust as these two elements are also designed to free flow and achieve a better ‘exhaust note’. A true header will not just provide a good path for exhaust to escape, they will also help draw the spent gases out of the combustion chamber.
The cons however are that cast iron is more robust than mild steel or stainless tube and manifolds are quieter, but extractors can vary depending on the quality of the tube and joins. It is essential that when you purchase extractors or headers, you search for quality and good design, not price. They are definitely one of those items where you get what you pay for and beware of being tempted by the cheap Ebay sets. You are more likely to be disappointed when they arrive.
In addition to performance applications, they are considered a very normal replacement for cars where manifolds are prone to cracking. We see cars that are notorious for cracked manifolds and we can pretty well diagnose the problem before it hits the hoist. In this respect, extractors are really the only way to go, there’s a high chance that stock replacement will simply fail again.
Another thing to consider when replacing a stock manifold is what type of extractors you will purchase – Tri Ys or 4 into 1s. The most accepted theory is 4 in 1 offer more top end power while Tri Ys are designed to increase midrange torque. It is best to talk to your local exhaust shop to discuss the best option for your vehicle.
For the extractor enthusiasts, there are premium upgrades to this product. Because of the heat cars generate, it is essential that extractors are strong and durable and a good upgrade to a standard set is a ceramic coating.
At Kirrawee Mufflers, we stock quality brands such as Advance, Pacemaker Redback and X Force. We also custom make headers for unique applications.
Over the past 20 years, there’s barely an exhaust we haven’t seen. Not only designing headers for a large exhaust brand we love building custom made systems for restorations shops, classic car dealerships and, what we are most well known for, working direct with the customer to ensure that what we build them makes them leave with a smile on their face.