DuSh, you could be right, I’m no expert. But no offense, I do try to find people who know a lot more than I do, and ask questions..
I know I'm fairly new to this forum, and there's lots to learn from you "old timers".
Nonetheless, in regards to the Venturi effect, I remember playing with it in physics class while reading about Bernoulli, long before there was a google! LOL
Anyway, according to the exhaust people I spoke to, I was told I was wrong about how the H-pipe would not work, when they suggested it, and I said I needed an X-pipe.
But as we spoke about it and other factors started come to light, they said I would be better off with the correctly made x-pipe.
So in this case, stamped crappy X-pipe<H-pipe<proper X-pipe
I was also told that if I had a naturally aspirated engine, the smaller diameter would be good (venturi effect). However for a turbo charged vehicle, I would be better off with an X-pipe that matched the existing size piping.
Smaller diameter will help some at lower RPMs, but be restrictive at higher rpms. There is a reason BMW went with 71mm pipes. (now, if BMW only could have better flowing cats too...)
Then on top of that, the stamped X-pipe I received with the obstructions would negatively effect the system too. A smooth flowing 2.5” would be ok, but one that does not have a smooth flow, would be a bottle neck, especially on a 400+hp engine. This coming from someone who builds race car exhausts, so hopefully they have a good grip on what they do.
Just to make it clear, the inside of the stamped X-pipe I received had like a cone going into the X-chamber, past the weld, for each pipe, this creates a lot of turbulence, not a smooth flow. So the venturi effect would be somewhat negated by the turbulence slowing the speed of the exhaust. Also, we are dealing with a double venturi effect, due to the inlets on both side of the larger chamber of the X. I have never studied two venturi chambers in close series, but I have a feeling it just creates more turbulence in the X chamber. Would be interesting to see a flow simulation..
When it comes to the sound, I was told an H-pipe would still make the exhaust sound great, but as you mention, not have the better flow.
Real life trumps what people might believe it should sound like without actually doing it.
So thank you for your feedback, I don’t want to steer anyone in the wrong direction..
Myself, I have no plans to go with an H-pipe, I’m working on getting a 2.75” X-pipe made, or fix the 2.5" one. More on that later.
I have read and seen the pictures, an X-pipe can be welded in without removing the exhaust true, but a correctly made H-pipe might be a bit harder to cut holes for, and weld properly, thus my comment about removing it.
Anyway, thank you again for the reply!
Maybe I'm overthinking this, but I like to do things right the first time. Measure twice, cut once! LOL