equal length exhaust ? (Page 1/2) crashmydaytona SEP 26, 11:04 AM I was showing my exhaust to my dad and he told me that the tail pipes coming out of the muffler should be equal length. The way I am doing it they are not close. It will take some effort to change everything at this point what problems will occur with unequal pipes? HP loss? Bad tone? The exhaust is for a 3800sc. dobey SEP 26, 11:26 AM It mostly will affect tone after the muffler, as most of the exhaust gas will be expelled out of only one side of the piping, rather than equally distributed at the exit. So it will be louder than if they were equally distributed, and the tone will be slightly different (but most people probably wouldn't notice the difference). As for effect on power, it will be minimal if any, after the muffler on a Fiero. Not enough to worry about. Ken_86gt SEP 26, 11:26 AM Due to the nature of our cars a race tuned exhaust would take a lot of effort. Are you running equal length tube headers? If not, dont even think about different length exhaust tailpipes. dobey SEP 26, 12:32 PM quote Originally posted by Ken_86gt: Due to the nature of our cars a race tuned exhaust would take a lot of effort. Are you running equal length tube headers? If not, dont even think about different length exhaust tailpipes. Eh? Stock 2.8 exhaust is equal length from muffler exit points to tips. It's not that hard to get a tuned exhaust. Using Y-piped headers designed for a FWD car on a swap in a Fiero makes fitting things a bit more difficult though, as the exhaust dumps right where the stock muffler sits. As for "race tuned" it's not that hard, but it's not street legal either. Equal length headers with no exhaust after the collectors, is "race tuned" exhaust. Ken_86gt SEP 26, 12:53 PM Doby- This isnt for a stock 2.8 car. At this point we dont have any other information as to header type used, exhaust routing, equal length pipes from manifolds/headers to muffler. Since it was mentioned that he is talking about a 3800 we can make assumtions that he is using the stock manifolds other wise it should have been stated. Pictures would have helped as well. You may have been following a build thread that describes what he has done, but it isn't referenced here. dobey SEP 26, 01:30 PM I haven't been following a build thread. The stock 2.8 does not have equal length primaries or Y-pipe. And the question was only about the exhaust piping after the muffler, so I concentrated on explaining that. Even with equal length primaries and Y-pipe, the effects of equal length after the muffler will be the same; negligible, and primarily will affect the tone and volume of the exhaust sound. It will sound unbalanced, to a trained ear, or when standing between the exhausts, most likely, to not have equal length after the muffler. Beyond the sound, it will have basically no effect on power, in the Fiero. Less than the margin of error from consecutive runs on a dyno. crashmydaytona SEP 26, 02:25 PM Sorry for the lack of info the build thread is http://www.fiero.nl/forum/Forum2/HTML/130946.html the first few pictures show the headers I am using and toward the end of page 3 shows my exhaust. using all 3" mandrel bent mild steel with a magnaflow 3" in dual 3" out. If the HP loss if any is negligible and the tone difference unoticable while sitting in the drivers seat I don't think I will go to the effort of changing things. If I do change it up do the # of bends have to be equal (that would not be possible) or just the length from the muffler to end of each pipe regardless of bends? Thanks for helping guys dobey SEP 26, 02:34 PM quote Originally posted by crashmydaytona: If I do change it up do the # of bends have to be equal (that would not be possible) or just the length from the muffler to end of each pipe regardless of bends? Thanks for helping guys Different bends will affect flow and sound pulses, so they should be equalized as well, if you want equalized exhaust. But yeah, it really won't make any big difference to you, and if you find yourself annoyed by the sound, should be pretty easy to change later on if you have the welding skills for it. I wouldn't bother unless the sound bothers you and you want to try to smooth things out a bit. Yellow-88 MAY 27, 01:17 PM Hi I know that this is an old thread but it caught my interest. Interesting that no one has mentioned the reason for "equal length headers" in this thread. It's about getting the exhaust gas out of all cylinders equally, nothing to do with sound. So far no one sells them probably because they are extremely difficult to design. I've been playing with a 3D CAD model on and off for a few years and it is really difficult. My design uses 18" x 1.25" primary pipes feeding 24" x 1.75" secondary pipes. After that it's a 2.5" regular Fiero exhaust. Exhaust is a huge part of engine performance. Tube volume is based on engine size and RPM. Road cars almost never see RPM over about 5K so small diameter long primaries are more realistic for normal cars. The firing order of the V6 lets one split the headers into a "Tri-Y" system making it a good bit (easer) to fit the pipes into a Fiero. Is any one else looking at equal length header design in real life? Yellow-88 ericjon262 JUN 04, 03:53 AM quote Originally posted by Yellow-88: Hi I know that this is an old thread but it caught my interest. Interesting that no one has mentioned the reason for "equal length headers" in this thread. It's about getting the exhaust gas out of all cylinders equally, nothing to do with sound. So far no one sells them probably because they are extremely difficult to design. I've been playing with a 3D CAD model on and off for a few years and it is really difficult. My design uses 18" x 1.25" primary pipes feeding 24" x 1.75" secondary pipes. After that it's a 2.5" regular Fiero exhaust. Exhaust is a huge part of engine performance. Tube volume is based on engine size and RPM. Road cars almost never see RPM over about 5K so small diameter long primaries are more realistic for normal cars. The firing order of the V6 lets one split the headers into a "Tri-Y" system making it a good bit (easer) to fit the pipes into a Fiero. Is any one else looking at equal length header design in real life? Yellow-88 your ideas are way oversimplified, and I'm not sure I understand what you mean by a "Tri-Y", that's typically a style reserved for V8's and 4 cylinders. the only thing I've seen done on a V6 that could be called mistakenly called a "Tri-Y" would be a system where companion cylinders merge, then the 3 pipes from those merges, merge into one. A few guys have attempted to replicate this on a Fiero after a guy in Taiwan did it to his car. in theory, this would produce a strong scavenging signal in the pipes, and offer some level of increased performance, how much over a typical header isn't clear, as it requires longer primary tubes than a typical header that would bring each bank's 3 cylinders together. Primary diameter and length have different effects on performance, and while they comprise the volume of the tube, the tube volume isn't really a recognized factor for most exhaust builders, you could install a pipe 1" long with the same volume as a pipe 100" long, and they would have massively different performance. as far as equal length is concerned, it can have an affect on performance, both positive and negative, but it really comes down to what you can package in the vehicle. I have a Suburban that I'm putting a 454 in, the same header ideas I can apply to that, I would have a much more difficult time applying to a Fiero with a V8, just based on space, and those headers will be built with unequal length headers in a Tri-Y configuration, to hopefully produce a very large gain in low to mid range torque. as someone who has built more than one header, it's not easy, it's not cheap, and it's not a fast process.