I've read through all the header y-pipe combo sticky and I've seen tha nearly all y pipes are 2 1/16.
I just got back from several muffler shops and the majority of them were recommending I jump up to a 2 1/4 sized y pipe. I know i'd be losing torque, but gaining top end right?
Being that the VQ is a torque beast and it sits in my 4th gen, do you guys think I would benefit from it rather than lose out?
Has anyone tried doing a 2 1/4 y pipe yet?

 

You will benifit... drastically
I have went from stock to 2 1/4" to 2 1/2" 3' yipipes on N/A 3.0' & 3.5 swaps. and have noticed a difference. I would suggest a real 2.5" inside diameter catback to go with the y pipe.

 

I'm planning on doing a 3 inch catback. I'm just contimplating on keeping it 2 1/16", 2 1/4", or ven 2 1/2". I can afford to lose torque, I really want to gain some good top end.

 

Are you referring to the primaries of the y-pipe? Because I've never seen a 2 1/16" y-pipe, that sounds like a nasty choker. All the ones that I've dealt with have at least 2" primaries merging into a 2.5" section>flex>flange for catalytic.

Dont you have a 3.5 in your car? I'd say forget the whole 2.5" catback and just go with a 3". That's what my car has and it works great (with a 24" resonator and a 20" long case dynomax muffler) its super quiet relative to other 3" catbacks.

The ypipe if staying NA I would PERSONALLY keep it at 2.5" and with a stepped pipe at the cat (if you dont run a cat) step it from the 2.5 to a smooth transgression into a 3.0 flange. But I'd base that on my gut feeling, because as far as I know, no NA 3.5 has installed a 3.0" ypipe and proved dyno-gains from it.

 

So whats the best dimensions for a VQ30?

2.25 to 2.5" flex section to 2.5" y collector? I don't want to loose any torque. I'm keeping the rest of the exhaust stock for the moment

I had a custom Y made for my old car and I think it was 2" primaries

 

kinda off topic, but its still so strange to see a I30 spd, i'm thinking all I30 are auto 'cause they are the luxo maxima

 

and RHD

 

3.0s gain from doing the 3" catback, not as much as the 3.5 but it is noticable.

I would personally, do the 2.5" y-pipe into a 3" collector and 3" the rest of the way back.

 

there are 4th gen styled I30t's that came in manual....but the RHD means its not from this country.

 

Prolly not a maxima or i30 then lol

 

it would be a nissan maxima over in europe...my guess sweeden or finland

 

Its a Maxima And is the shape the 4th Gens came out in for the New Zealand & Austrailian market. 5 speeds are uber rare here with 99% being automatic and any 5 speeds being the base model Maxima (ours go S, SE, SEL)


Are you recommending 3" for a VQ30 with stock exhaust? On my cefiro I have a Y with 2.5" exhaust and straight thru muffler and I had to add a 2.25" resonator to regain low end torque.

Warpspeed has 2" downpipes and 2-1/2" collector (stock is 2")

What dimensions are the cattman and budget Y's?

 

bump bump really want to know... is 2.25" going to loose low end, should I stick with 2"?

 

at your power level (and much more beyond) you have no need for a set of 2.25" primaries. So dont worry about it. If you already had to add a 2.25" resonator on the b-pipe to get back some low end, what makes you think having 2.25" primaries wont have the same effect (loosing low end)? It will make it MUCH worse (at your power level) lol.

Stick a supercharger on it and then it's another story

 

I have 2 cars - the Cefiro (selling soon) and Maxima

The Cefiro is the one I added the 2.25" resonator too

The Maxima is all stock exhaust & Y

Update: I just got a custom Y (to long/costly to ship cattman/warpspeed)

2" primaries > 2.5" Collector > 2.5" flex > 2.5" tail connecting to stock exhaust

 

now thats more like it!