Open pipes

[DeNguyen]

I was wondering if anyone has ever ran pipes from the cat back with just tipsat the end of it (eliminating the muffler). I figure since the aftermarket exhaust is "freeflow" anyway, eliminating the muffler would just lessen the constriction. The car would probably be loud like no other, but it would be a nice sound. Can you guys think of any other pros/cons ?

 

[NeoNSX]

* very loud
* environmentally unfriendly.
* additional 10HP

 

[DeNguyen]

is it really environmental unfriendly? even with the catylytic converter still on there?

 

[supercharged]

Moving the car around the garage like this - it sounds every bit as loud as a NASCAR entry

 

[The REAL nsxtasy]

is it really environmental unfriendly? even with the catylytic converter still on there?

I don't know the answer to that specific question. However, the term "open pipes" usually refers to pipes that bypass the catalytic converter ("cat bypass pipes") entirely, rather than the "cat-back" pipes that you are proposing.

 

[DeNguyen]

I don't know the answer to that specific question. However, the term "open pipes" usually refers to pipes that bypass the catalytic converter ("cat bypass pipes") entirely, rather than the "cat-back" pipes that you are proposing.

sorry, i meant to say cat back pipes...

 

[ncdogdoc]

Not too loud

Rob Morrison was running just this at VIR with his new (almost) Speed Vision GT NSX. It is not the most harmonious sound, but it is not as loud as my Dream 28. He did have bent tips pointing down toward the track on each cat which may have helped reduced the noise level a little.

 

[NA1 #2853]

Pipes Only

I pulled off the stock muffler, and was test fabricating a manifold for a turbo. Started it up and drove it to pick up a couple stainless steel u-bends, for sh*ts and grins. It definitely loud, sounds awesome at idle, but sounds like crap thru the midrange. I would atleast use a couple of straight through N1 type mufflers to tone down the unpleasentries. But if you do that, then you would have a Dream28 exhaust like mentioned above.

But REALLY, in reply to the original question, it sounds like Dookie, at anything other than idle.

And over a nice exhaust like a Taitec or such, the gains of stright pipes (after the cat) only will be basically unnoticeable.

-Ray

 

[DPG]

I have straight pipes with no cats and I love the sound. It is gross 3000 to 4500, but after that it is wonderful.

 

[The REAL nsxtasy]

I have straight pipes with no cats

THAT is environmentally unfriendly.

 

[Juice]

I've done this. It sure does sound like crap. Forget about impressing anyone, even LOUD note lovers like me.

 

[Vytas]

THAT is environmentally unfriendly.

I agree but have heard that NSXs run so clean that some have passed California's tough emissions tests <b>without</b> the cats.

 

[ncdogdoc]

I have heard the same thing. A friend in GA could not get his car to pass because the levels were lower than "normal" levels the sniffer was looking for. LOL.