Vibration absorbing section at front of exhaust
 

The Nismo exhaust and, as I recall, the original factory exhaust both have a small section of flexible pipe near the front that appears to be designed to absorb vibration. Most of the aftermarket pipes like Stillen don't have it. Was this just unnecessary over engineering by Nissan or is there some negative to not having it? I'm thinking about getting something a bit louder than the Nismo and have been reading everything here on pipes but I haven't seen anything about this, possibly since I don't know what this little section of flexible pipe is called so I can't find it with search.

I bought the Nismo because I didn't want the car too loud since I have the top down all the time and like to hear the radio. I had a Magnaflow on my last car and liked that. It's hard to tell the actual loudness from sound clips since the camera used to make the clip and the speakers on the PC determine the sound level. So far Stillen seems to be the next step up in loudness from the Nismo. I don't want to make another $1400 exhaust mistake.

Get the fast intentions CBE

its delicious

That is certainly a possibility, but I'm still curious why Nissan put the section that looks like woven stainless steel in the pipe and the aftermarket companies like Fast Intentions don't. Is it to isolate engine vibrations from the rest of the exhaust, to allow the system to bend a bit there to make it fit perfectly, or what?

The flex joints really just allow for greater manufacturing tolerances. It ensures that every exhaust system will bolt right up and there'll be no need for adjustment which can be very costly on the assembly line.

Thanks. I figured that was one of the possibilities, but since I never saw anything like it in a factory exhaust system before I though it might be something special about these engines. I guess the relatively low volume aftermarket companies just count on making theirs more perfectly. Most people seem happy with the fit of their aftermarket systems, other than the earlier ones when they first came out.

The GT-r has the same flexible stuff between the cats and exhaust.

it looks all gold and stuff :rofl2:

No! They are designed to absorb movement in the pipes as the engine moves during accel/decel. Without movement, you can wind up with catalysts that pop their welds. Ask me how I know.

Then why don't all cars have this?

That's what I though they were for when I first saw them, but then how do the Stillen, Fast Intentions, and many other exhausts get by without them? There's a lot of guys with those exhausts on here and I haven't seen complaints about problems. I guess that's why I started wondering about it.

Somewhere in that thread of a billion posts, Tony from FI talks about why you need/don't need flex joints.

Thanks for mentioning that. I was able to find it. It was interesting to read Tony's responses, especially that they consider how stiff the motor mounts and exhaust hangers are when designing a system. It's obvious they put a lot of thought into it. I guess I won't worry about that aspect. The videos of the FI 18" systems vary greatly in how loud it sounds. The one made by the fellow in Dubai sounds like it is REALLY loud. Others don't. The Stillen with factory cats doesn't sound that loud. I'm thinking I might stick with the Nismo until I can hear one or both of these in person. I can't afford to trial and error this at over $1000 a try!

Our engines do move a bit as well when you mash the throttle down, but the rubber mounts that aftermarket exhausts use are more than enough to deal with those movements.

I believe the Ark exhaust has flex joints.