Pipe inside a pipe; pipe dream?

Sitting in the SLC airport on my way to COTA, and BORED. 

Random thought: what would happen if you shoved the proceeding end of the pipe of the exhaust a few inches inside the next proceeding pipe? 

In essence, 3-6” of each segment of pipe goes into the next pipe downstream. With a slight taper on that section that is inserted, but the next pipe downstream maintains the diameter of the entire exhaust until it’s 3-6” section also inserts into the next pipe downstream. 

What you end up with is a constant diameter of exhaust pipe through out, yet the exhaust is a lot longer than it actually is  

Im guessing it could prohibit flow, but what about sound? Any acoustics geniuseseses?

In reply to Trackmouse :

Seems like you would have more weight that a similar length of single walled exhaust pipe and also now you would have protrusions into the exhaust gas flow which may restrict flow. The double walls could act like an insulator keeping heat in though. 

In reply to Dr Ribs Revere :

Keep in mind the previous tube wouldn’t go the entire length of the tube after it. So I wouldn’t say much heat insulation. They do a similar thing on bosozoku exhaust and it has the effect of “ricening” the exhaust note. 

The exhaust system on my old Talon that I had made was sort of like that. The flange on the downpipe was welded on about an inch up from the end of the pipe. The cat had the first inch or so flared out to fit over it. The gasket between the flanges rode on the protruding length of pipe, so it was not exposed directly to the exhaust gasses. It sealed very well and was easy on the gaskets. The other end of the cat where it bolted to the cat back was the same way. 

I have read your description several times, and I can't picture what you are trying to accomplish.  Expanding and shoving a bunch of pieces of pipe together creates a heavy piece of pipe, but doesn't change anything else that I can see.

In reply to Streetwiseguy :

It sounds like any non-flanged connection, but maybe a little longer overlap. 

I’m not sure if you’re after an effect or just thinking “out loud”.

i usually use anthropomorphism when trying to figure these things out: what does the exhaust “see” and does it “care”. I can’t see it affecting the flow in any way except for very minimally negatively due to any minute disruption.

(I’ve seen Roadkill Garage bash the E36 M3 out of headers creating all kinds of disruption to the flow and did dyno runs before and after and there was negligible change to the hp)

when Triumph built the TR series with the straight six they used bits of a broom handle in the pipe to get the sound they wanted. Or so I read somewhere.

bored..............I'll say

759NRNG said:

bored..............I'll say

I was bored, man! I was just thinking aloud too. I have no idea what effect this would accomplish. It kinda came from the nascar stepper headers. The tapered end of each exhaust piece would be inside the piece of pipe. Creating a sort “bugle” within a pipe. Again, I’m sure it wouldn’t help flow, but might do crazy ish with noise. Like this: http://www.bosozokustyle.com/2009/10/13/how-to-create-your-own-zokusha-muffler/