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View Full Version : Exhaust piping diameter ?


oorx7
09-17-2008, 09:34 AM
I have 535i 5 with a pretty large hole in the muffler. Although I kinda like the sound I really want to replace it. I have looked into replacing it with an aftermarket one, but feel I can make my own for quite a bit less money. I plan on not really making much more than an extra 100 hp, through out the cars life with me. That is a high number at that. Not really going for a loud exhaust either. I am now 30 and must be getting old because I think it is too loud now. When I was younger the first thing I did was remove the mufflers and or cat. :( I will be replacing the cat with a resonator or two as well. I don't have emissions testing were I am registered. :p

So my question is, what diameter piping would you suggest?

Should I stay duel till I get back to the muffler?


Thanks
Brandon
Jon K
09-17-2008, 10:21 AM
Making another 100 hp? Whoa baby...
oorx7
09-17-2008, 11:02 AM
I am just saying that I might make an extra 100hp in the future, and don,t really like to make things twice. Definitely am not gaining 100hp from an exhaust upgrade. LOL!!!!

Currently I am not going to add any thing more than this exhaust, air filter, and maybe a chip.

Here are some of my past and present projects. http://www.cj-motorsports.com/projects.htm
Jon K
09-17-2008, 12:05 PM
Anything remotely close to 100 hp on an M30 is going to require a turbocharger in which case your exhaust will be of little concern :)
oorx7
09-17-2008, 12:30 PM
True. I was thinking about twin gt28r's. But again exhaust would have to be redesigned around that system.

So lets forget about the HP goal or limit.

What size is stock piping?
icesoft
09-17-2008, 12:40 PM
Roughly 2"... I ran a flowmaster 2-2" into 1-2.5" collector and ran 2.5" all the way back from where the stock x-pipe was.


True. I was thinking about twin gt28r's. But again exhaust would have to be redesigned around that system.

So lets forget about the HP goal or limit.

What size is stock piping?
oorx7
09-17-2008, 12:58 PM
That's the kinda stuff I am looking for.

I was thinking of running stock diameter to a Y off some sort, then to 3" back to a muffler.

Any reason to use an X pipe then Y it a couple of feet past, maybe closer to the muffler?

Some thing like this as an X pipe. I really want to use a resonator of some sort and this would fit perfect, I think. http://store.summitracing.com/partdetail.asp?autofilter=1&part=WLK%2D17552&N=700+318531+115&autoview=sku