4-1 vs 4-2-1 EL headers - which is best?
Yesterday we finally got around to heading to PVS Tuning and testing the Sydney Motorsport Engineering 4-2-1 race header which has been developed for the 2.4L cars, on our 2L Prod Touring race car. In the process I also figured out why the racecar was so down on power (checkout the Vlog for more on that below), in this blog we’ll be going into more details about these headers and what sets them apart from other offerings on the market.
As we already know, these headers yield awesome gains on the 2.4L equipped cars as we’ve shown in previous videos and blogs, but how do they stack up when you bolt them onto the older 2L cars? These headers are identical to what we’ve previously tested except they feature a 2.5” outlet flange which is perfect for 2L cars or 2.4L cars looking to retain the factory front pipe to keep exhaust sound at a respectable level. When compared to a 4-1 header we found the 4-2-1 header filled the torque dip nicely without compromising any top end power and i’m very happy to say it was an even bigger difference on the FA20!
Above you can see the dyno results from 4-1 header directly compared to the 4-2-1 header. This was a true back to back test completed within an hour of each other (requiring changing the headers while they were still red hot), letting the engine oil temps reach 75 degrees before completing 3 back to back dyno pulls with a 10 second duration. You can see how well the 4-2-1 design fills the torque dip with a massive increase of 25Nm, albeit with the same peak torque figure. The same effects are noticed on the power curve too whilst creating a really nice top end power result. Keeping in mind no ECU tuning took place here, this is purely a bolt on back to back test.
Below you will see the 4-2-1 run against the most popular UEL header, the Tomei UEL. Bear in mind this is on a different car on a different day so the peak outputs are rudimentary numbers but it’s still a good indication of the power and torque curves. As you can see the 4-2-1 EL header still doesn’t provide the dead flat torque curve of the UEL header but it is right up there and it blends the line between a traditional EL and UEL header. What you can also see is it retains the classic EL top end power. The OG SME 4-1 race header was widely regarded as one of the best headers on the market for top end power albeit with a bit of a torque hole in the mid range. What we have now is a header with even better peak power whilst having MUCH better mid range power and efficiency!
We’re now shipping these headers to customers and still have a couple in-stock. Jump on the website to secure yours and of course if you have any questions, please don't hesitate to reach out!
