The idea behind Tri-Y's is to increase scavenging effect, having a nearby cylinder help pull the gases from another as it passes the intersect joint where they connect. Same basic philosophy as happens with your miracle gro plant feeder. The feeder attaches to your hose, and there is a small ofifice connecting the feeder to the water supply. The moving water draws miracle gro out of the container.
Does this happen in our real world headers? It can. Especially on a chassis car if an experienced exhaust builder is building them......and there are probably a handful of those around the country. But truthfully the individual pipe lengths need to be specific to get this maximum effect, and OUR Tri-Y headers are designed more to FIT in a particular car with design parameters almost exclusively tailored to the fit.
Some may argue with me, but I feel that my new tri-Y's would not necessarily be worth HP over any other type of header with similar sized tubes. So if thats what you are looking for they may not be any better than what you have. None of us has yet had these on a dyno, and the right way to do that would be to do it side by side with other headers. Even then......you are most likely talking about a few HP difference.
BUT, the Tri-Y design DOES offer incredible clearance under a car like the 2nd gen firebirds. Other headers out there tend to get smashed on the road as time goes on because they hang too low.......a problem difficult to correct when you have 4 tubes trying to merge near the collector.
My car with its old Tri-Y's on it cleared the road very well. Considering it made 1064 hp with these old smaller tube diameter pipes at 1 and 5/8", I'd say I was pretty happy. Of course I have a turbo contributing.
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