SeanAndKate

so i was just woundering what would happen if someone ran strait from there headers to each muffler without ever conecting the 2 sides and without having cats so just strait headers to mufflers?i think its called divorced duals...how would it sound and how would it run? just kinda was woundering any info would be really cool thanks!

r.barn

There is some reason for the h and x pipe connection.
Something do with the exhaust pulses and keeping flow back pressures balanced on both sides.
I wouldn't do it.

SeanAndKate

yeah there there to help with back pressure and in case somehow one side has a blockage to keep the air flowing im just wondering what the heck is going to block my air so much that changing direction completely 2 times like through a H pipe ismore easy then going strait. but i have the time and the metal to throw them together while making sure i can just put my stock h back on and i cant find anyone else who has done it (not really a good sign) but would be cool to be the first lol

FoxGT

the h & x is there to help pull exhaust gasses out of the other side. When a pulse goes through the left side of the h or x it creates a lower pressure on the right side & same with the other side. It creates a scavenging effect.
The only thing backpressure is good for is quieting the exhaust sound & making your car slower.

SeanAndKate

from what i understand from here http://www.dsmtuners.com/forums/freq...kpressure.htmlit sounds like it has alot more to do with gas velocity and the only thing i can see the X and H being good for is maybe keeping that even? or is there something im misunderstanding?

pioneer06

if you want your car to sound like it has 2 4-bangers, go for divorced duals...I have heard some cars that have this and they sound terrible. From reading above, they also do not let the engine run as well either.

SeanAndKate

thats what im looking for! ill be like yeah i got 2 engines in here. civic engines to be exact haha when you put it that way then maybe it wouldnt sound so good....

FoxGT

It wont sound like two 4 bangers, the rotating assembly is different. American v8's aren't a 1,4 up 2,3 down design, foreign v8's are. American v8's are offset & use counterweights, so it won't sound like 2 4 bangers.

I guess I had a sh*tty description for it. Next time you look at a 4cylinder with the head off notice the middle two pistons are in the same location, as are cylinders 1 & 4. Same with foreign v8's, not american v8's.
No think about it more like this... imagine each exhaust pulse as a ball of gas, now imagine that every pulse has a magnet on it. When the exhaust passes through the x it pulls exhaust gas from the other side of the x. It does this because of the vacuum effect.

To get a good idea of how the vacuum effect works you can take a hose, hang it out your window so one end is facing toward the rear of your car, then go 60mph. the end that's in the car will be sucking air through it due to the vacuum created at the other end, which is caused by a low pressure spot at the back of the hose. Basically you want a small enough size pipe to create high exhaust velocity for max scavenging effect, but a big enough size to keep backpressure to a minimum. Obviously if you size it for the amount of exhaust gasses at max rpm it's going to require a bigger size & same with lower rpm requiring a smaller exhaust size for max power, this is why you can't aim to max both high & low end without a variable size exhaust.

Does this give you a better idea? The red arrow is where the gasses are pulled out because of the vacuum caused by the other travelling air (blue arrows) around creating a low pressure spot.

SeanAndKate

i get it... but dont get why the vacuum effect is more effective when there connected. wouldnt i just have the same vacuum effect on each side if they never connected? or why would the effect not work?

PSUSkier

Aren't our engines timed so that only one cylinder is firing at any given point in time? If this is the case, you'd have only one "ball of gas" in the entire exhaust system at any one point in time. So then when it hits the X/H, it'll evenly distribute through the two exit lines.