I have 2.5' cat back system on my car, and notice i have lost a bit, actually quite a bit of low down torque when i did this?? would i be right in saying i dont have enough back pressure, as mine is just a lil 3.0l, when i rev high and back off I get a bit of a pop sound or back crackle. So I am changing a part in the pipe back to 2,1/4' so still keep the note? would i be correct in assuming that there is not enough back pressure???


Thanks
Pat

There was a very informative discussion a couple of days ago in either "Magna Mods" or "Tech Talk" on the topic of "Back Pressure" and the physics of exhaust gasses in general. It was under the topic of "Dual Exhausts" or something very similar.

I suggest finding it and having a read - you'll learn something, I definetly did. Based on what I read..... it's very likely that the larger diameter exhast has robbed you of lower RPM power - but just saying "not enough back pressure" isn't entirely accurate.

Edit: Here's the link http://www.aussiemagna.com/forums/showthread.php?t=17084

When I had my Redback system installed by Midas the guy talked to me a bit about back pressure saying it was quite necessary and recommended that I installed a 'Z' flow design muffler.... it seemed to make sense.

http://www.aussiemagna.com/forums/showthread.php?t=17084&page=2

this is the post Black Beard is referring to.

oh my goodness, this theory and talk of back pressure is really just as bad as pod vs. panel....it will be a never ending battle, and no side really has more people or power than the other..

some belive that back pressure is just utter BS...you don't really need it for anything, just change the timing.

some think back pressure is definately needed, because it does wonders like create a vacum effect and keeps the gas particles happy or something.

meh, i dunno.

some belive that back pressure is just utter BS...you don't really need it for anything, just change the timing.
Not really, it's a misnoma. Back Pressure is just the name that dumb heads initially used to explain their thought and it stuck.

Should ask people that say "Backpressure is required" why backpressure is so good or is needed. Wonder what they come up with. I bet 85% of those wouldn't even know. Just heard it from someone else...blah blah

Should ask people that say "Backpressure is required" why backpressure is so good or is needed. Wonder what they come up with. I bet 85% of those wouldn't even know. Just heard it from someone else...blah blah
I took took it for granted that Midas... the exhausts specialists, would have known in my case... but I had it done ages ago now and I cant rememebr why... (old age)