Google UEL vs EL header if you haven’t already. You’re going to be bombarded with everyone fighting over why one design is better than the other. If you’re reading this because you’re in the market for an aftermarket header and you haven’t decided which style you want, then you’re in the right place.
I encourage you to educate yourself on this subject before you make a purchase. Just make sure you’re learning from a credible source. My goal is to have you leave this page feeling educated enough to separate the crap from the real facts, the next time you google this subject. With that being said, let’s start with the header design that your car came with.
From the factory, your BRZ/FRS had an exhaust manifold with unequal length runners, but just barely unequal. The stock exhaust manifold behaves more like an equal length header because the variance between the runner lengths only differ by 30%. Even if we didn’t take out the tape measure to confirm this, we can still prove it by the way the FA20 makes power way up high in the rpm range (just like an equal length header would) and by the lack of the Subaru “boxer rumble”.
Just to clear things up, the boxer rumble isn’t actually caused by the horizontally opposed engine layout, but by the unequal length headers used. The unequal design creates unequally spaced apart exhaust pulses, and these pulses end up colliding with each other, creating that rumble sound. Consequently, equal length headers have a smoother tone because their exhaust pulses are evenly spaced, and never collide. Now that that has been cleared up, let’s get into the big differences between the two headers.
- Greater peak power but less mid-range torque
- Better exhaust scavenging
- Equal exhaust pressure and temperature across all cylinders
- More mid-range torque but less top end power
- Lighter weight
- Exhaust RUMBLE
Here’s an clip to compare the unique sound characteristics of these two headers.
Equal length headers will always make more power, but unequal length headers will always be more useful in everyday driving. So when you’re deciding which header to buy, it will come down to where the power is made and how the exhaust note sounds. If you want the Subaru rumble and the extra mid-range power then the UEL header is your pick. But if you’re passionate about extracting every possible drop of horsepower from your engine and you don’t mind losing that rumbly exhaust tone, then the more efficient EL header is made for you.
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