Selecting
long tube headers can be an intimidating task and does require some technical knowledge, but it isn’t the voodoo some make it out to be. In this post I will try to arm you with as much information as I can to help you decide on the best option for you and your ride. Below I will provide some technical info and lay out some of the options available at
APEX Motorsports. If you have any questions feel free to give us a call at (502)930-APEX or
CLICK HERE send an email to one of our team members.
Which Manufacturer Should I Go With?
The good news here is that this is hard to get wrong. Ask around on the forums and you will hear some of the same brand names over and over again. The 3 brands that we currently carry that meet the criteria below are
Kooks,
ARH,
Pfadt,
Stainless Works, and
Stainless Power. From a performance stand point all of them are pretty close, no one has a secret that makes one brand produce substantially better results than any of the others. It’s mostly a question of quality and, again, most of them are pretty close in this area as well. There are a couple of things to pay close attention to though.
Pay attention to what they are made from. Stainless steel (particularly 304) is what you will want to look for. 304 stainless steel will not rust or discolor from exposure to the atmosphere like the cheaper 400 series stainless steel. Unlike aluminized steel, it will not rust from the inside out due to the corrosive fluids produced during combustion. 304 can discolor slightly from getting extremely hot or if you spill engine oil on them but another attribute is that it isn’t permanent.
Pay attention to how they are made. CNC mandrel bending is the best manufacturing method for producing exhaust systems and headers that flow and fit well. When this process is used in conjunction with the 304 stainless steel it allows for the use of a thinner wall tubing that will weigh less than other headers. Those weight savings will be lost, however, if you opt for the ceramic coating some manufacturer promote. With stainless steel the coating isn’t needed for corrosion resistance purposes (ceramic coating is often pushed because the manufacture is using inferior metal) and I have never seen the claimed reductions in under hood temperature demonstrated in hard numbers.
What Primary Diameter Should I Go With?
This is the area that seems to cause the most confusion but it is fairly straight forward. Header manufacturers usually offer two or three options when is comes to primary diameters for a specific vehicle. For example, for the Camaro SS most manufacturers are offering 1 3/4 inch, 1 7/8 inch, and 2 inch primaries. Here are the results of some recent back-to-back testing on an otherwise stock SS:
Stock: 372 RWHP 376 RWTQ
1 3/4 headers with high flow cats: 401 RWHP 404 RWTQ
1 7/8 headers with high flow cats: 408 RWHP 409 RWTQ
2 headers with high flow cats: 413 RWHP 410 RWTQ
As you can see, simply switching from the restrictive stock manifolds to 1 3/4 long tube headers is worth approximately 30 RWHP and 30 RWTQ on a bone stock Camaro SS. The larger the primary diameter gets the more air the headers will flow and the further up the RPM range the power band is moved. The impact of the larger primary diameters is amplified the more powerful the engine is, especially when you introduce forced induction. This means that generally the more power you make or the more race oriented your application is the bigger primary diameter you need, the closer to stock or the more street oriented the smaller primary diameter you need.
In the specific example of the 2010+ Camaro SS, we have found that the 1 7/8 long tube headers are the best all around header for the typical bolt on modified car that is driven regularly and occasionally taken to the track. They offer a tremendous improvement over stock with room to grow as owners modify their car further. The 2 inch headers offer very similar numbers to the 1 7/8 headers up to 5000 RPM where the 2 inch headers pull ahead. They are ideal for those running forced induction or for race applications.
Tri-Y Headers
Pfadt recently announced that they are releasing Tri-Y headers for the 5th Gen Camaro and since then we have been inundated with questions about this type of design. Traditional 4-into-1 long tube headers merge all four primary tubes into a single collector similar to the one pictured below.
Tri-Y headers utilize a different approach. These headers feature three Y-pipes that merge the runners in pairs. Because of this they are sometimes also referred to as 4-into-2-into-1 headers. The Pfadt Tri-Ys are very elegant and because of that the differences are difficult to see in photos so below is a very rudimentary set of Tri-Y headers and a set of traditional 4-into-1 style long tube headers below that for a direct comparison. You can see that there are three separate events rather than one as is the case with a traditional 4-into-1 long tube headers.
Now that you know what Tri-Y header are, the question is what is the difference from a performance perspective. The commonly accepted theory is that 4-into-1 long tube headers offer stronger peak horsepower gains, while the Tri-Y headers produce stronger low and mid-range torque gains (ideal for street performance).
High Flow Cats or Cat Delete (Off Road Pipe)
With modern high flow cats there is essentially no performance advantage to a cat delete. They flow 99.9% as well as straight pipe. On a dyno you might see 1-3 rwhp in the mid RPM range. Going with a cat delete does cost less but the biggest draw back for street driven cars in my opinion is the rotten egg smell of running without cats. The other is the potential legal issues. For track cars neither of these are a concern so save the money and apply it elsewhere.