My obx Y is rubbing underneath my car and instead of cutting metal and rewelding stuff, I'm thinking about doing a custom Y. With my mods, would a 3" y benefit me? Is that even the best size, 3" coming off of both headers and collecting into another 3"? I tried PMing sparks the other day but it said his box was full. I remember something about this, I just can't find the topic. Hopefully, I can get some input from you guys

 

I take it you have the unequal y piped OBX's?

 

Yes, although they seem semi close to equal legnth after the bends coming off the rear header.

 

Is there a 180* turn in the pipe off rear header?

 

Yes, I think they're v2's.

 

If theyre the ones for the 3.5's then those are equal length. If you were to custom a y, would you make it equal length like it is now? Mandrel bent?

 

It all starts about here for that custom 3" ypyipe...
http://forums.maxima.org/5th-generat...r-here-10.html

 

I made a thread about it some months ago before I got my headers. http://forums.maxima.org/all-motor/6...pe-sizing.html There hasn't been much proven info on a 3" y pipe that I've seen. DrunkieTheBear says 2.5" into 3" is necessary to extract the most power out of the VQ. Sparks isn't convinced that his 2.25" into 3" y pipe makes more power than the 'stock' y pipe for his cattman headers. His recent dynos and track times are not with the 3" y pipe. My 3" y pipe ( 2.25" into 3") was installed at the same time as my headers, so I don't have any comparison of the 3" vs. a 2.5" y pipe.

 

Ah, thanks for the links guys, really appreciate it. just trying to figure this out by tomorrow since it might be getting done then. I just worry about loosing power if the piping is too big.

And I wouldn't have an equal legnth made. I know the sound will change but no one around here has a mandrel Bender and I don't want to pay a ton for this y pipe.

 

I know for the KL motor we have seen the best power from a 2.5" equal length y-pipe into a 3" merge..and these are 1L larger motors..I would not be surprised to see nice gains on a 2.5" y into a 3" merge..

 

Great, thanks for the info! So 3" into 3" wouldn't be beneficial?

 

I dunno about 3" before the Y-pipe merge..I was suggesting maybe 2.5". Personally I would rather be a little on the small side rather than too large. If you got 2.5" into a 3" merge you are increasing the size for sure, but in a 'safer' manner I suppose..rather than going too big right off the bat.

 

GBOGH

(go big or go home)

 

I would say go with a 2.5 if Iwas in the repair frame of things since 2.25 collectors to 2.5 y-pipe to 3" exhaust...might be a good combination...

 

2.5" manifold collectors and merge into a 3" collector might be the ticket but I'm sure the Cattman setup is the best all around....performance and mannerism!!!

 

So what is the size of the catt-mans y-pipes on his headers.

 

2.25" into 2.5"