Quote:
Originally Posted by Nigel_S
Quote:
Originally Posted by Madact
Based on this, I think I'll keep my original plan of an anti-reversion step at 14-15" to capture the first rarification pulse reflection (especially useful at high RPM), and a merge at 32"... between harmonics and the fact the the flow-rate-based formula and 1/2 total length rule agree on ~32", it can't be too terrible  |
I still think this is wrong. I've just had a look at the calculations I did when I changed my header and the result is 31.49 inches which agrees with your figures, however I'm using 16" primaries so why does practice not coincide with the calculations? The headers that are on sale tend to be either 16" primaries & 16" secondaries or 24" & 8" both designs giving 32" total, I've not come across 32" primaries for sale. |
Haha! Vindication! Apparently Larry Meaux, maker of the pipeMax software, advised this guy that you can double the lengths of the primaries and the secondaries in a tri-Y, and it will both (a) work well as a tri-y and (b) achieve more torque at the expense of some top-end power.
nissan 240sx (S14) with Modded GTO pan (tons of pics) - Page 9 - LS1TECH
This is exactly the info I needed - I was worried I'd have to build and dyno-tune at least two designs (standard tri-y and double length tri-y) to confirm that the double-length design really worked ... and at that rate, I may as well pick me up a copy of pipeMax, I figure the guy already saved me at least that much money, so it's a well-deserved sale
, and apparently it calculates stepped primaries, too, which I'd be very interested in seeing the recommendations for (I'm currently just guessing, pretty much).