DC Sports Header install and evaluation - Toyota Yaris Forums

SirDigby · 04-24-2017, 12:21 AM

i'd say, "you get what you pay for" in most cases. cheap manifolds usually don't line up just perfect or have the best geometry or welds. i had an obx on my civic for over 200,000 miles without any issue. ($50) but, i'm also a cheap-ass and look for a better deal, and the complete exhaust was custom, so it did not matter if it lined up when purchased. i would not pay $500-$1000 for a TRD seeing how the gain is so minimal.
i do disagree with the 4-2-1 vs 4-1 for performance stated above. 4-1 manifold gives a better top end torque because of where the collector location is in reference to pressure point of cylinder pressure drop during high rpm. (high rpm=high pressure scavenging further in the tube) 4-2-1 allows high pressure scavenging to occur at lower rpm, between sister cylinders; wile high rpm scavenging still occurs, but at lower pressure, so it has a less dramatic effect on high end performance. since i do a lot of city driving, the most noticeable gains should live in the 500-3500 range. (4-2-1)
i do not believe there is a "better" design, i think it all depends on where in the RPM range you want the gains to be most noticeable. in the civic, i was driving from denver to phoenix every weekend. (1500 miles r/t) the obx was a 4-1 because it was always on the highway running as fast as possible. it all depends on your utility.

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04-24-2017, 12:21 AM	#39
SirDigby View User's Garage Drives: 2007 yaris 3 door Join Date: Sep 2015 Location: Denver, Colorado Posts: 1,000	i'd say, "you get what you pay for" in most cases. cheap manifolds usually don't line up just perfect or have the best geometry or welds. i had an obx on my civic for over 200,000 miles without any issue. ($50) but, i'm also a cheap-ass and look for a better deal, and the complete exhaust was custom, so it did not matter if it lined up when purchased. i would not pay $500-$1000 for a TRD seeing how the gain is so minimal. i do disagree with the 4-2-1 vs 4-1 for performance stated above. 4-1 manifold gives a better top end torque because of where the collector location is in reference to pressure point of cylinder pressure drop during high rpm. (high rpm=high pressure scavenging further in the tube) 4-2-1 allows high pressure scavenging to occur at lower rpm, between sister cylinders; wile high rpm scavenging still occurs, but at lower pressure, so it has a less dramatic effect on high end performance. since i do a lot of city driving, the most noticeable gains should live in the 500-3500 range. (4-2-1) i do not believe there is a "better" design, i think it all depends on where in the RPM range you want the gains to be most noticeable. in the civic, i was driving from denver to phoenix every weekend. (1500 miles r/t) the obx was a 4-1 because it was always on the highway running as fast as possible. it all depends on your utility.