View Full Version : Question on Manifold design.

steve shadows
07-13-2005, 04:34 PM

I was thinking, I currently have a manifold similar to the above on my car.

I was thinking the firing order of the sr20det is 1-3-4-2.

How big of an issue is firing order in manifold desgin?

I have yet to read a book my friend john has told me about "The Scientific Design of Intake and Exaust Systems."

Just thought i would start an open forum discussion on the topic.


07-13-2005, 05:39 PM
The firing order only really come into play if you have a divided manifold and housing. If all the exhaust pulses come to the same spot before entering the turbine housing, it shouldn't matter which ones come in first. I am sure it will affect things slightly, but not as much as an NA tuned header would. This is of course on boost with a positive pressure in the exhaust manifold. If you are trying to maximize power both on and off boost, that is another story. In that case, I would think equal length and the best entry angle into the collect would help the most, but firing order again wouldn't factor into it that much.

steve shadows
07-20-2005, 05:23 PM
Thats what I was leaning in my theory and other stuff john has tossed at me as well.

Thanks chief.