Hey Doug! I didn't even know you were on here.

I agree, as when I read the title of this post I thought to myself, "man, you've got to be kidding me!"

Some guy's with fbody's (which have a single in/dual out setup stock) also run a "true dual" setup but they run an X pipe.

Vettes already have an optimized "true dual" setup, without the X pipe we would all be running a sub par exhaust setup and would be listing one of our mods to include an X pipe

 

My online banking balances itself.

 

When the exhaust valve opens a pressure pulse is created which will travel down the exhaust system at a given velocity; this velocity is mainly a product of initial pressure and the cross section of the pipe (and thus the reason why going with overly large header or exhaust pipes causes a loss in low end torque. Read on). As the pressure pulse travels down the pipe the cylinder empties itself of all exhaust gas. When the cylinder is completely empty the exhaust gas is still moving at considerable speed, so, by virtue of its momentum, it will continue to travel down the exhaust system despite there not being any more pressure inside the cylinder to push it out. When this happens, the column of fast moving gas in your exhaust system acts as a piston and partially evacuates the cylinder. This phenomenom is called exhaust gas scavenging and greatly increases the engine's volumetric efficiency, as that partial vacuum will help with cylinder filling once the intake port opens.
The crosspipe will effectively reduce the length of the exhaust system before the pressure pulse finds more room for expansion. Once the pressure wave reaches the crosspipe a few different things occur; it will slow down considerably as it expands into the second set of pipes, some of it will be reflected back, and it will also interact with the pressure wave from the adjacent cylinder bank. This interaction can greatly aid the scavenging effect if the cylinders are firing slightly out of line or if the pipes are of slightly different lengths as the vacuum from one bank aids scavenging the other and vice versa. These effects will reach peak efficiencies at certain RPMs which is why you can tune peak torque gains from headers by changing their length and the distance to the crosspipe.
Eliminating the X pipe eliminates this benefit and is therefore not recommended.

Hope I made sense... I've been in bed with the flu for the past couple of days

 

All those years of studying Calculus has paid off . Great read, hope you feel better soon.

 

Ahahahha... Actually as much as I don't like to admit it more than half of my car knowledge came from studying outside of my degree. I arrived to this country with just two suitcases and my acceptance letter into the University I would eventually get my degree from. There were no cabs left at the airport so I asked this older gentlemen if he could give me a lift. On the way I found out he was one of the Mechanical Engineering professors for the school. My only question for him at the time was: "So, do you fix your own car?". I was really surprized that he said no. Five years and two degrees later and now I know why; your average M.E. Major can probably tell you a hundred different ways in which you could make your engine more efficient, or more powerful, but would be no better suited at troubleshooting specific mechanical problems or identifying specific issues with an engine than, say, a lawyer. For real world experience you need... The real world :P

That's why I work on all my cars, and my friends's cars. I also like to read a lot of subject specific books on forced induction, nitrous, etc...

 

yeah what he said. and yes there is no substitute for practical knowledge.
Powerlabs congratulations on your pursuit of knowledge and your degrees, not to mention your clear and concise explanations.
Cliff Notes version see below.
X-pipes assist the headers by scavenging the cylinder exhaust further, evening out the exhaust pulses and can result in real hp gains (small but quantifiable). The scavenging creates a sort of vacuum which draws in new A/F to be combusted, a denser A/F in the cylinder equals more HP.

 

Yeah what he said....................................

 

I enjoy every one of your posts with precise tech info and hands on knowledge. Before Spinmonster made the move to Colorado, I, spinmonster and a few friends were having a good bye party dinner for spin, Spinmonster commented " that powerlabs guy is no joke, serious tech guru " maybe not in these exact words but pretty close.

Keep up the your tech posts as I am sure everyone here enjoys the reads..

 

Wow, thanks That means a lot to me
You know, Spin is my biggest inspiration on this forum; I have learned a lot from him (and I'm sure others have as well) and I try to keep the same attitude sharing knowledge and documenting my mods so others can learn from what I've learned.
Actually, make that Spin and Glass_Slipper. I don't know what Glass_Slipper does for a living but I'm guessing he is not only an Engineer, but also a very accomplished one. His explanations put mine to shame!
I told Spin I was going to make a car page putting all his mods together so we at the Corvette community can have a place to go for detailed "how to" explanations on mods. Still planning on doing it (have to buy a new copy of Macromedia Dreamweaver since I lost mine moving to NJ), but I guess the good news is my A&A Supercharger install documented how-to will be there as well

Hope I get to meet some of the NY/NJ Crew one of these days, you guys all sound like a lot of fun

 

You, spin and glass-slipper must be triplets.......You guys sure make this forum an educational experience for the C6 crew...Keep it coming...

 

My opinion is that true duals sound like blah. The tone is just more bland compared to the tone with an X-pipe. The X-pipe gives the note a little more of an exotic sound, which this LSx motors sound awesome with. Not to mention that an X-pipe makes a little more power than true duals and even an H-pipe.

If you want to keep the signature sound of the Corvette I would stay the X-pipe route. Just my opinion.