Yes, I'd also like to hear more about this. In another thread I was told that the X- or even H- pipe generally gives more HP but the goat was kept separate for the sound quality. But like you, I don't know what is considered true dual and what is not. It's pretty clear what ISN'T-- both manifolds dumping into one pipe and muffler etc is obviously not duals. Also two pipes going into one muffler, even if split back into two exit pipes is not true duals. Beyond that I do not know..............Razinhell said:I'm kinda confused what the meaning of True Dual exhaust is. I know the GTO has seperate pipes from heads to the exhaust pipe end. Is that the true dual exhaust? I see some people advertising true dual exhaust with an x-pipe attached. Can this still be true dual exhaust?
The original term for the crossover or X pipe was 'balance tube', and it helps two ways as said elsewhere here, a scavenging effect for the out of phase cylinders in the other bank, and a noise amelioration effect for the cylinders in the other bank that can get highly technical in discussing. All that said, there is a formula around here somewhere for determing the proper size and length of a 'balance pipe' to tailor these effects to your desired ends...suffice it to say I will look and post whenever I might (and if) find it. It also makes an engine and exhaust system more efficient and has been known to add one or two MPG. The effects are most pronounced in a restrictive system. Right on the money Dan!DANSLS1 said:'True dual' is used with many different meanings. The GTO has a true dual with separate flow from the engine to the outlets. Many performance vehicles as stated have duals with an 'x' or 'H' or 'Y' crossover. I often see this still referred to as true dual exhaust - but I would technically say it isn't really. The crossover - given appropriate tuning of lengths of exhaust - can give a bit more hp than a completely separate system. This is due to a 'pull' or 'scavenging' affect of one bank helping to pull exhaust gases from the other bank system.
NICE '65 convertible Chris!chris_wiz said:"True dual exhausts" typically refers to systems that have two pipes out of the engine, through two catalytic converters, and out through two seperate outlets. The X or H pipe is there for pressure leveling purposes, not to allow exhaust to flow freely oiut both sides.
The opposite is a Y pipe setup, where the pipes out of the engine come together prior to the catalytic converter, run through a single cat, then together for some distance, before exiting either a single outlet or through dual outlets (but not dual exhaust).