A question about exhaust ... - The Unofficial BMW M5 Messageboard (m5board.com)

noxcape · 8th August 2007, 05:57

My question is:
-what about if I keep both exhaust pipes separate from the cats all the way to the end?
The exhaust comes as two separate pipes left and right from the engine (headers, cats, etc) to the silencer.
The silencer unites them and they go all the way to the back again as two separate pipes.
What about if I remove the silencer and replace it with two separate pipes (SS X-Pipe Style) but not an X pipe ... let say two paralel pipes?
First picture is a stock exhaust
Second one is what I'd like to do!
What difference in exhaust sound I will get? Any ideea?

jrhaile · 8th August 2007, 06:08

Seems like a lot of work for probably very little improvement in sound...

Get some Magnaflow's if you want to keep it cheap.. I did and I couldn't be happier

http://www.youtube.com/watch?v=dKtxuHSGvls

noxcape · 8th August 2007, 06:09

In fact I'm thinking about Tubi ... but ... X-Pipe or Paralel Pipe?
That's the question ...

Olyar15 · 8th August 2007, 07:23

Big question is why? Is it purely for acoustic tuning? Are you looking for better performance? Just for the hell of it?

According to a book I have (Four-Stroke Performance Tuning, by A. Bell), V8 exhausts should have the left and right pipes joined together for approximately 10-12" or failing that, at least a balance pipe. I guess this is the same idea as an X-pipe. This supposedly increases hp, especially joining the 2 pipes together for 10-12".

I am not an engineer, and I haven't read any other books that corroborates that statement, so take it for what it is. You can always do a pre-and post-mod dyno to see if there is any noticeable difference.

ECB · 8th August 2007, 16:48

Quote:

Originally Posted by noxcape

In fact I'm thinking about Tubi ... but ... X-Pipe or Paralel Pipe?
That's the question ...

The tubi is a cat back system so it already replaces the stock resonator with an x-pipe.

SoCalJD · 8th August 2007, 16:52

Quote:

Originally Posted by noxcape

My question is:
-what about if I keep both exhaust pipes separate from the cats all the way to the end?
The exhaust comes as two separate pipes left and right from the engine (headers, cats, etc) to the silencer.
The silencer unites them and they go all the way to the back again as two separate pipes.
What about if I remove the silencer and replace it with two separate pipes (SS X-Pipe Style) but not an X pipe ... let say two paralel pipes?
First picture is a stock exhaust
Second one is what I'd like to do!
What difference in exhaust sound I will get? Any ideea?

<<<

I'm no wrench, but it looks to me like you're just talking about removing the resonator ("silencer"?)

. I just did this yesterday. It's my understanding that this *really* improves the sound of the stock exhaust. I have Sebrings, and I'm loving my "new" sound.

DouglasABaker · 8th August 2007, 16:57

You want to combine the 2 exhausts for a short distance to equalize the back-pressure between the 2 different banks of cylinders.

d-

Ted · 9th August 2007, 06:26

I know exactly what you mean. I've been talking to some exhaust places and they all say parallel pipes will increase sound and performance due to the straight path of the exhaust and minimal bends. I am about install a custom Borla exhaust using the same concept, it's gonna be LOUD!!!

Cantresjr · 9th August 2007, 06:41

buy a magnaflow x pipe and delete the resonators. do a search. it the least expensive route

alijonny · 9th August 2007, 07:01

you may need a good balance between the two banks for scavenging of exhaust gasses. look it up, the less bends the better of course, but an x-pipe is the cleanest way to make a bend and keep the flow going properly. IMO,one should not remove a balance pipe/X-pipe unless you are a hillbilly. for me it kinda falls in the lines of "if its smaller diameter pipe, it will be louder". I have never seen any benefits to seperating banks of exhaust unless you are talking massive hp #'s. then you can run open individual primary pipes!