It has been on track a couple of times since, and has shown a great amount of potential. Since it's last outing, Dick has changed a few things geometrically with the front suspension, and the car is ready to go back out. We will be bringing you a few different tests in the next few issues. Now that you know Dick and his Mustang, let's get back to the story. We wanted to see if what Dick has been doing for years is actually beneficial -- after all, engine builders recommend header sizes for a reason, right?
We made a call to Bill Hufstetler at Schoenfeld headers, and he sent an extra set of headers to test. Along with the headers, Schoenfeld sent us collectors for both size headers and an X-style crossover pipe to complete the test. The test started like any other chassis dyno session. We rolled the car onto the lift, backed it onto the roller, and strapped it down. Being that we had engine dyno numbers on the engine hp at 7, rpm we were excited to see how efficient or inefficient the drivetrain was, and where we could improve.
After warming the car up and making three quick runs as a baseline, the Mustang laid down rear wheel horsepower rwhp.
That's roughly a 7. We didn't believe it at first either, but the math doesn't lie! Kooks headers and Exhaust has been in the business since We are three generations of family deep and are still run by the man who founded it all. We can say that we have been through it all; from motorcycle exhaust, to street cars, drag cars and are now the only spec approved header of NASCAR. We have literally taught our competition everything they know about headers and are continually pioneering different header and exhaust combinations to fit and perform the absolute best.
We invite anyone to come take a shop tour of our 50, square foot facility and see the Kooks Advantage first hand! With our years of experience we have built Tri-Y headers in the past, but based off our experience we do not feel these are the best fit for your average enthusiasts looking to get the most out their application.
Kooks Headers are designed to be the best performing, best quality, and best fitting headers on the market. Tri-Y Headers or 3-collector headers are designed for maximum performance for a specific engine combination, desired engine RPM, race track, etc. For a Tri-Y header to have the proper effect the cylinder firing order must be properly paired so that the next firing cylinder is separated. You also need to have the proper primary size for the engine displacement and application.
The collectors also need specific convergent angles degrees for optimum efficiency and cannot be a random bend angle. We have seen horsepower and torque numbers dramatically affected by these angles in Tri-Y headers. The data we have collected over the years proves the Tri-Y design does have advantages in race applications with the right vehicle and the right engine combination on the right track.
Most professional teams will have several sets of headers and engine combinations for different tracks and conditions. The reason we went with the Tri-Y on these cars is for packaging in the car and ground clearance. When it comes to performance there is but one steadfast rule: All the good air that goes into making horsepower must eventually find its way out. This means that the addition of everything from camshafts to intake manifolds, even superchargers to help improve airflow into the engine, will be useless OK, maybe not useless but certainly much less effective if the engine is not able to rid itself of its exhaust.
Cork up a serious performance engine and watch it struggle and gag on its own fumes. Adding the right header can add some much needed exhaust flow as well as additional power by means of the scavenging process because a header is much more than a simple set of tubes welded together in hopes of directing exhaust flow. A true header provides not just a path for the exhaust but can also help draw spent gases out of the combustion chamber.
The effectiveness of this so-called scavenging process is determined by a number of design criteria, some of which we'll examine and test. When it comes to long-tube Honda headers-or headers in general for that matter-there are basically two primary designs: the tri-Y and the 4-into As the name implies, the tri-Y refers to a group of three Y sections created by joining the primary tube of runner one with runner four and runner two with runner three. Once the four runners converge into two tubes these two eventually merge to form the final Y section to complete the tri-Y design.
In the case of many tri-Y headers, like our test piece from Airmass, the final Y section merges to form a short collector. By contrast, 4-into-1 headers feature no such Y sections, instead merging its four runners into one short common collector. We've also seen short versions of the 4-into-1 design but the Airmass version features long primary runners to help enhance low-speed and midrange power production.
The commonly accepted theory is that the 4-into-1 header offers more top end power, while the tri-Y header is designed to bolster midrange torque. Though there is a great deal more to the performance of a header than simply its overall design 4-into-1 versus tri-Y , our testing indicates that the basic layout makes for a strong indicator as to what to expect performance-wise-no matter what brand you might be considering.
Before we get to our test engine and comparison results we should take a closer look at additional header design criteria that might affect power output. A number of variables can be changed within both designs, most of which affects performance.
With either the tri-Y or the 4-into-1, it's possible to change both primary and collector tubing diameters and with the tri-Y, add to that the secondary tubing's diameter, which can also be altered. In addition to tubing diameters, it's also possible to change the primary pipes' length, prior to their merging, to form the secondaries or collector in the 4-into The same is true of the secondary pipes' length and even the collector for that matter.
Speaking of collectors, it isn't just lengths and diameters that can be tailored but also shapes. Collectors can be tapered, converging or even diverging at the exit. The exit diameter can be altered as well. By now the many great possibilities when it comes to header design should be obvious. Throw in the near infinite number of engine combinations, even within just one engine family-like the B-series, for instance-and it isn't hard to imagine how difficult if not impossible it is to build a header that works best for all applications.
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