One of my teammates stumbled upon some diagrams, and I thought I'd post them here, as I think it's really interesting information. These diagrams are the exhaust differences between the regular and the Nismo 370z:

Regular:


Nismo:


I found it quite interesting that on the Nismo 370 they decided to go with a true dual system. I'm curious now how much less restrictive this exhaust is as compared to the regular 370z.

-Colin

 

If they gained 18 crank HP i guess its a good bit less restrictive. I was just thinking this to myself today, nice find.

 

Cool diagrams. Thanks for posting. I'm curious as to why they used a H-pipe rather than an x-pipe.

It's a bit presumptuous, but from early tests of the nismo 370Z, I think there may be some speculation of whether the exhaust and tune adds much power. Other exhausts, such as stillen may offer more hp gains.

 

where did you find these diagrams?

 

i wonder if custom H pipe on the regular, will work or gain the same HP as the nismo.

 

Nice info, thanks for posting..

 

The 18 is from the exhaust and a tune. Nissan claims only 5 from the exhaust on paper but I read someone got about 10 on a dyno but can't remember who it was.

 

I don't know much about exhausts but the loop that occurs in the muffler portion of the regular 370z, also looks very restrictive. Is that done just for sound; like to bring down the disciples?

 

OP: Did someone actually cut open the exhaust to see what is inside? The OE system path seems a little simplified. The paths you show do not take advantage of the full muffler volume.

I used to work for Tenneco Inc who supplies OE exhaust to the big 3 and the Jap 3. Just before I left, we were working on a project with Futaba in Japan for Nissan Z. I recognize this design from prototype samples we had in the pole barn. (At that time, I was an engineer designing systems for Toyota)

I haven't looked closely at the 370Z system, but if the tailpipes are not directly across from each other (one pipe exits the center of the muffler end cap and the other exits offset from center), then it is safe to say the exhaust paths cross the muffler. Right side exits the left tailpipe and vice versa.

See if you can get photos of the OE system and I will be able to tell. If I had drawings or photos of the inside of the muffler, I could tell the design philosophy and restriction points.

 

I was given the information by the founder of *******.com, who has many contacts in the Nissan industry.

Very cool stuff! I wish I had some questions to ask you so I can pick your brain.

I'm not exactly sure as to how the people went about creating the exhaust flow characteristics for these diagrams. It would be pretty awesome to get your analysis on any kind of exhaust. I feel like I won't be able to source pictures of a cut up exhaust though. I will definitely post up pictures if I do come across any.

Thanks for the input everyone!

-Colin

 

H pipe instead of a Y pipe? I could do that myself.

Also, no cats please.

 

I don't have a 370Z muffler, but I have one from a G37. If they are the same muffler bodies, the flow path on the the OEM diagram isn't correct. The inlets cross at almost 90 degrees once the inlets get into the body of the muffler. The outlet pipes actually aren't offset though, the right half of the muffler is a mirror image of the left, minus the hangers.

TK

 

Yes and no. Assuming the OEM dual section pipes are the same diameter as the pipes on the Nismo, then replacing the single collector, which I assume to be at or near 2.5in diameter should net a similar gain due to piping change. The muffler should cause the remaining differences.

TK

 

What are the advantages if any to changing from a normal system to a cat back system?

 

go away

 

Which chassis are you referring to? This one covers the Z34. If you are talking about the Nismo exhaust that this thread discusses, I'd say "not worth it." The Z34 Nismo exhaust is pretty decent. (I swapped the exhaust on my Z34N to an S-Tune and it resulted in not much more than a little rumble so I swapped it back and sold the S-Tune before I gave the car away.) If doing something to any other trim level, still not a lot of gain.

The same answer applies to Z33. Doing a low restriction catback on any Z doesn't net a lot of power. We're talking very little noticeable gains unless you match the exhaust with some intake modifications AND do/get a re-map of the ECM (tune) on the dyno. Sound, on the other hand, is what most swap their exhausts for.