headers and intake box
Discussion
Hi guys: To Tony and the entry above his. Yes it does matter somewhat how the tubes enter the collector they should be in firing order as the go around the collector. This is a fine point but if your going to do it, this is the way its done. As to equal length headers I completely disagree with Tony there is horsepower to be had, not a great deal but why leave it on the shop floor for the lack of a little effort. Even perhaps more importantly is sound, the extreme example of this is the Subaru STI that I used to own, great car but the stock unequal length headers are what causes the off beat almost sounds like its running on 3 cylinders NOISE that comes out of the back of a Subie I changed mine to an equal length headers and it transformed the car. The sound was more like a Porsche much more even and it made about 2% more h.p. and torque. iF you get the lenghts just wrong on the L.S. motor you can wind up with a very unpleasant sound at cruise that you will not like at all Lee
I do not know where your matter of record comes from but just to make sure I looked up results that other folks have documented on the internet on back to back pulls with the same engine, equal and unequal length headers and I will tell you that the 2% I quoted is conservative. I will also say that collector length and diameter has an impact on power. As far as the rest of your response all L.S motors have a firing order of 18726543 and this causes a space or void in the exhaust flow when the 2-6 and 3-1 cylinders fire. This causes the uneven sound of these v8s by running all of the cylinders into one collector and timing the collector so that each cylinder pulse is preceded by a pulse right next to it you get a steady stream of exhaust gas and a accompanying higher pitch more even sound, thus generating a better scavenging effect at all RPMS As I have stated before, on my engine this flattened the torque and horse power curves on both the bottom and top end of the rev range thus making the car easier to drive due to a reduction in the torque spike it had previously at 4200 RPM. lEE
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