Shorty headers are better than most stock collectors, although they also offer short runners as a variety, they do not converge (in rows) into a single plenum/log as a variety. The Shorty header uses the same finishing style as a long-tube header – the collector. So why not just use a long tube header? We are aware that headers help generate more power and torque on almost any motor when the standard cast manifold is upgraded. This thinking should continue, because electricity generation is a matter of airflow, right? As we have discovered, yes and no. In fact, it is more about optimizing the way exhaust gases are removed from the engine`s combustion chamber. More on that in a minute. Once the JBA short circuit strips were tightly tightened and our new PerTronix/JBA connector wires were firm, we moved to the back of the exhaust. As the standard exhaust was simply too quiet for our taste, we opted for JBA`s Performance exhaust system (PN 40-3051), which would replace the exhaust south of the catalytic converter. Again, the key is to leave the storage catalyst alone and in the storage location to achieve CARB compliance. We decided to contact the professionals at Pertronix (maker of JBA headers, Doug headers and Patriot headers) and Holley Performance Parts (parent company of Hooker Headers) to find out what benefits can be achieved by installing a « shorty » header on a modern muscle car and how CARB/EPA legality plays a role in header selection.
Clockwise from the upper left corner, Cat4Ward JBA headers feature 3/8-inch thick CNC laser flanges, oversized exhaust outlets, and factory-style exhaust gas cleaning connectors. We removed the intake manifold and plug-in wires to create additional installation space on the driver`s side. We were a little impatient when we ripped off the plug wires, and after 60,000 miles, the old OEM plug-in wires in our hands collapsed. No problem. We ordered a set of new PerTronix plugwires and hit these babies once both headers were fully installed. According to Don, « The short header will not be a limiting factor in revs, especially on a late-road car equipped with a catalytic converter. Engine design, cam specifications, cylinder heads, intake, and the cats themselves will all affect the rpm range before the short header affects performance. We`ve all heard that short headers are suitable for anything below a certain engine speed and that long-tube headers should be taken into account when rotating above a certain speed. According to Evan, « There is no speed limit for a header, just a bottleneck in the airflow or unoptimized cleaning. These can generate diminishing returns above a certain speed point.
This point will be entirely based on the application of the engine. « This leads to design issues, both because of the space available to build a four-pipe manifold and because of the lengths of pipes available in the restricted area, » he says. « In older cars – where the cat was under the hallway – it is possible to design relatively long tubular collectors that always adapt to the positioning and function of the cat. » A Shorty header is not too heavy an upgrade. If you want to spend a comfortable day in the garage or driveway, you can do the work yourself. We decided to test our results on the test bench with a VP Racing Octanium fuel additive in the tank, new PerTronix spark plug wires and a new homolo exhaust for the JBA Performance Exhaust CARB. Good news: the PS were on the rise! JBA Performance Exhaust has an interesting feature hidden in its short headers, a spike in speed. This tip, located in the manifold, helps to increase the purification of the exhaust gases. Hot roding may require a little more effort to stay legal today than it did before the late `60s, when emissions compliance wasn`t an issue. But with more than 450 horsepower and fuel economy as high as in the top 20 in a modern muscle car, many will say that « the good old days » are right now. So there is a small price to pay. According to Evan Perkins, digital content manager at Holley, « A long-tube header, when properly adapted to the application, shows strong improvements in the middle of the RPM tape to the top.
There are many more variables to consider, such as the length, diameter, and routing of the primary pipe, so a long pipe head works better universally than « that speed » would not be accurate. There is so much testing and engineering that goes into a set of application-specific headers. It`s a mistake in the industry that changes to emissions law are only a problem in California, Lindfors says. (left) In the welding device is PN 1850S-2. This is a 1 5/8-inch Cat4Ward header suitable for select GM trucks and SUVs from 2002 to 2010. The finished headers (right) come with high-quality hardware and detailed instructions for professional, leak-free installation. « In addition, coated headers are worth the extra money because they keep the heat inside the header, which increases speed. It also helps to light the cat faster to reduce emissions. « If you`re considering a header upgrade for your late model muscle, Don has this to say, `If you`re looking for legal late model headers from 50 states, the customer is a bit restricted. As a manufacturer, there is a limited amount that we can do with the design due to the space limitations and the position of the catalyst. The enthusiast wants to look for a reputable company that has been creating legal headers for some time to know that they have solved the problems of quality and sustainability.
Anti-reversion isn`t a big deal with short headers, Lindfors says, because the catalyst helps break the reversion wave. Lindfors says the company was recently involved in a project on a Coyote-Powered Mustang with a spare emission compressor. It has been tested with Cat4Ward JBA headers with factory converters and JBA long tube headers without converters. Above is the difference between the shorty header and a long tube header. The long-tube collector eliminates the catalytic converter (in some applications) and makes it illegal for on-road use in many cat-equipped vehicles. The Shorty keeps the OEM cat(s), so it can be legalized in all 50 states. Regarding the length of the primary tube, Don itére: « With Cat4ward headers, the length of the primary tube is dictated and limited by the available space and the positioning of the cat. The « equal length » theory is somewhat polluted, as there are many factors to consider. Ideally, the headers would be as straight as possible with minimal or even no curves. The airflow is laminar – it likes to roll straight, it doesn`t really turn.
For this reason, curves cause restrictions that can slow down the speed. Much of this is caused by the boundary layer that occurs between the airflow and the pipe. In a straight pipe, it is consistent. But when you introduce a curve, the boundary layer tenses when the air has trouble getting around the curve, resulting in limitations. How does that answer the question? Newer model vehicles have catalytic converters that are much closer to the exhaust manifold or manifold, and this original equipment position must be maintained for the proper functioning of the converter. This means that long-tube headers usually cannot be used. JBA Performance Exhaust (PN 1850S-4) short headers screwed without much drama, which says a lot about installing the header. Shorty headers are legal because they do not affect the position or use of factory catalysts. The headers are JBA with a high temperature coating. We started our adventure in the store with the JBA Shorty headers.
The passenger side was simple. We unscrewed the standard exhaust manifold from the exhaust pipe Y (three screws on the flange) and then unscrewed the head manifold. The JBA part came in like butter, and we used their graphite seals to prevent annoying exhaust leaks. After closing a few screws, we ended up on the right side of the truck. Since this is a Californian truck, it is prohibited for 91-octane parts and CARB legal parts. While a trip across the country to the east quickly takes us to the 93-octane Promised Land at gas stations, this plan is not practical. The only way to achieve a higher octane in California is to use an octane additive in the tank. Fortunately, VP Racing Fuels manufactures Octanium Unleaded Octane Booster.
« In most cases, in order to get the same pipe lengths, we need to create more folds. This makes the tube have more restrictions and claim to be longer than it is. Fortunately, a few centimeters of length difference don`t really change the end result. The power curve moves slightly up and down with the length changes. I discovered and proved on the test bench many years ago that this can actually extend the overall power curve and that some cylinders produce more power than others at lower speeds. With a long-tube header, this can easily affect peak performance, but in short, you won`t see any significant difference. Ideally, we don`t want a drastic difference, but some vehicles leave no other choice. The distributor (top) creates a bottleneck in the airflow because the first three pipes actually converge in the first pipe.