Measuring backpressure
 

Where is the best place to measure exhaust backpressure? I hear from the O2 sensor. But which one, assuming that is the best solution?

The best place to measure exhaust bak pressure in my opinion would be after the exhaust manifold to prevent high fluctuations from the exhaust pulses and before the catalyst as it contribute to a significant part of flow restriction.

I would find a way to take each piece off of the car and measure each section for backpressure on a form of flowbench (homemade or otherwise). This will tell you more than just simply how much total loss you have. It will tell you where it is at. No point in replacing the least restrictive part.

!!!!!??????

I think it would be an interesting experiment if I could find a steady-state form of the stock exhaust backpressure. I would like to know how much backpressure the stock exhaust has; I would like to design my own exhaust when I get some money, after I buy some suspension parts of course :D. Of course, this is going to take some serious thinking...

Is it worth the time finding total backpressure? Personally, I would like as many reference variables as possible. I don't like trial-and-error part picking/installing. It's time and money consuming, two things I wish I had more of :(.

BTW, what does backpressure depend on? Is it temperature and volume related? How can you use measured backpressure to create more power? Now I know that backpressure is bad, and inescapable. I'm assuming it leads to power loss, as well as other things. That is to say, is there any way to use backpressure against itself to gain power? I am looking for a mathematical *cough cough* ideal solution for more power. Of course, this is math, and it is worthless in real life.

backpressure is the resistance against the flow, man. ask someone smarter than me for a better explination.
backpressure is completely bad, and no there is no way to apply it to make more power.

ideal solution for more power?? easy: find out what is the biggest hurdle to getting 50 more horsepower out of this motor, and get over that first... i'll give you a hint, it sure as heck isn't the meagre amount of energy consumed in fighting backpressure even at 9k, full throttle, under load. assuming you could reduce that to a real-life zero (ie, no energy lost in moving exhaust out of the engine), you're no way in hell even close to whereever it is you wanna be power-wise as it'd be the same amount of power made but used more efficiently, so think again about what really needs to get fooled with.

A part of the exhaust system (the manifold) actually has an active and positive contribution on the exhaust gases at some operating points by cleverly synchronising pressure waves.

Back pressure increases with load, and engine speed (as more gas flow in the exhaust).

I know where the problem lies. To my laptop!!