So my engine mods are mrev2, 5/15 iso spacer, and nismo headers. I don't want hfc or test pipes and have no current plans on going F/I. I had ordered the weldina exhaust for my G--but was discontinued (btw--all jdm nismo exhausts for the cpv35/z33 platforms are discontinued!). I'm not interested in any other after market exhaust.

I do have a new nismo y-pipe however. It is 2.5 piping--but is a 3 inch opening to the midpipe. The stock midpipe is 2.5 inches. Would this create backpressure and negate any benefits gained from the nismo y-pipe?

Do you guys think I should come my exhaust stock w/ my setup or put in the nismo y-pipe, keeping everything else stock from the y back?

 

but i suggest a jic y pipes its much better then nismo. i have nismo exh, jic y pipe and test pipes. honestly there r better exh systems then the nismo exh, and u should get some test pipes they help a lot on top.

 

go jic very nice

 

JIC--more gains and I like the welds--but isn't the exit diameter to the mid-pipe even larger than the nismo's 3 inch exit to the midpipe--Should this not concern me when using the stock exhaust components from the y back--which are 2.5 inches?

 

Can you explain why it is better? Perhaps you have before and after dynos?

To the OP: If you plan to keep a stock y-back, there is little reason to not keep the stock y pipe as well.

 

Although I am unsure how big the exit of the JIC y pipe is, I would recommned against mismatched piping, especially going from larger to smaller.
The JIC y-back exhaust comes in 3 different sizes, 70mm, 76.xmm and 80mm.
Also, do you have proof of the JIC y pipe gains?

 

No proof of gains--just hearsay regarding the jic y pipe. It's just the exit point on the y-pipe that is is different--the main pipes themselves are the same as stock since the nismo y is 2.5 inches while the nismo exhaust components from the y back are 3 inches--So there is only a small area in which there is a mismatch in pipe size--Is this still enough to cause turbulent air flow/bottlenecking/negative effects iyo?

 

Yes.

 

Nismo is better than stock I would imagine, but there are better options than the Nismo y-pipe.

 

Neither. Both are crap. JIC FTW.

 

Have Nismo y-pipe, with topspeed exhuast and could tell a dif.(louder) but thats not to say something else is better and the fact that I got the pipe used for 150 bucks so no complants here..