Has anyone done this yet? I have the opportunity since my neighbor runs his own exhaust shop, but I don't know what the end result will be. A couple of weeks ago we cut out the 3rd CAT and the "3ft long" resonator on mine and I think it sounds good. Let me say this, I’m not trying to turn my Max into a race car, but I would like for it to have a nice low rumble. Somewhere between Luxury and 4DSC. I've read where some of you guys think a true dual would sounds like a G35 or 37? What do yall think?

 

cutting ur 3rd cat made a sound difference? do u gain hp?

 

I've been talking about this idea with Ghozt for a little while now. The issue is going to be clearance in the tunnel. Starting from scratch, this is the approach I would take:

1) Custom mandrel bent 2.5" SS pipe from each catalyst to the start of the tunnel
2) Even out the pipes and see if there's any clearance to run a 16" bullet race muffler on each pipe (staggered on each pipe to fit in the tunnel)
3) from there on, custom hangers to keep everything tight, then run to whatever muffler setup you want

All of this seems like it works in my head, but in practice, might prove more difficult

 

Unfortunately, there is no dyno machine anywhere close to where I am, so I don't know. My butt dyno tells me I didn't lose or gain any HP's. But yea, cutting out the 3rd CAT and resonator makes a difference in sound. Doing what I did, is just like buying a Y-Pipe, just cheaper.

 

My guy has 30+ yrs in the biz, so I know he could make it happen. I'm just still on the fence about being the guinea pig. I'm glad you mentioned the Bullet mufflers, because I was curious about what to put in there. GM what are you thinking the sound result will be?

 

But a y-pipe does add some performance gains, not just sound.

 

To start first with headers (like IFux has) I think would would be optimal. Not sure he has all the kinks worked out though?

 

The sound result should be deep and throaty with a nice warble. Since you won't have any choke points by ditching the factory Y-pipe and also the rear y-pipe split, the flow should be super smooth. I have the 16" Dynomax race bullet as my resonator, going into the Stillen mufflers and I love the tone.

Y-pipe is deleted since he's trying to run a true-dual setup.

Headers do produce some solid gains, however you'd be running zero catalysts with this kind of setup. If the emissions in your state are anything like here in Northern Virginia, they'll fail you the second you pull up to the station

 

No test required here (WA) all new vehicles 2009- have to meet CARB.
They don't even bother to test these cars.

 

Lucky....

My dad actually oversees the Emissions program in our area... sooooo if I modified any emission control stuff on my car, I'd never hear the end of it

 

No tests here in Arkansas either.

 

I'd love to hear a Max with a true dual...like GM said we've been talking about this for a while...definitely would produce a nice sound. And yea no Y-pipe with a true dual the pipes don't join each other anymore

 

What about this? I'm still running the stock mufflers, so would you guys definitely change those to Stillen or another manufacturer with the dual set-up?

 

well for it to be true dual each bank has to be of same length. That might be near imposible given that we have a transverse mounted engine. It should sound sound just like the 350z and g35s with the trueduals.

 

I was thinking about this myself. Unless running an H or X pipe, not sure if equal length plumbing from each manifold would be absolutely necessary. The thing i was wondering is if the piping isn't the same length for each cylinder bank, if the exhaust pulses would get out of sync.

 

I asked my guy about the exhaust pulses and how it might get out of sync with the different lengths and he said there wouldn't be any issues with that setup.

 

I didn't *think* it would be an issue since it would be a true dual setup, but hey, that's what professionals are for, right?

If you go ahead with this setup, I think the sound would be epic, and very close to how G's and Z's sound. I just wouldn't go any larger than 2.5" diameter pipe. You could just run bullet mufflers as the resonators, and the actual rear tins would be up to you. I think that Dynomax or Magnaflow mufflers would be a great pairing with that setup.

 

By true duals are you meaning 100% tuned exhaust which is the same as each pipe is exactly the same length?
Oh and to throw another stick in the spokes of true dual, what do y'all think about 180* headers? Talk about major gains from the headers!!!!

 

I would love to hear it after you've had the work done.

 

I'm assuming nothing has happened with this as the last post was about a year ago. I've been doing a lot of research lately on exhausts, and I've come to the following ideas:

If there is space under the car for a true dual...
-custom 2.5" true dual exhaust with resonated x-pipe connecting to tail pipes with aftermarket mufflers on each pipe

If there is no room for a true dual exhaust...
- custom 2.5" y-pipe with resonator and split to custom 2.5" to tail pipes, each run with its own aftermarket muffler

I think either option will allow for good hp gains on a N/A car with not too much exhaust noise.

I haven't had the chance to look under the car myself... Does anyone have an undercarriage photos or has had a detailed look under the 7th gen Maxima?

 

Not sure if this is what you're looking for but here are few that I took during my cat-back install. I'll look around and see if I've got anymore.

I know there are some other threads with undercarriage pics. Look in the AAM exhaust threads, one of the first guys to pick up that cat-back took a bunch of good pics.

There is not a lot of room under there, not sure if a true dual would work without some major modifications to the heat shields. Dunno though.

 

yeah ive been working with CXJ on the HFC's prototype and there isnt much room for under the car piping outside of what is already run.

 

The second option makes much more sense. The "true dual" option would accomplish the following....A. Add more weight to an already portly car. B. Going with dual 2.5 inch pipes would kill low end torque. I have run cars making significantly more power with 2.5 inch pipes. For the power level most of us are running its not necessary. The torque curve would move up significantly. The transverse motor poses a lot of problems that you wouldn't see with a rear drive platform such as a G-37. The other issue to keep in mind is cost. The time required to fab up a system and work out all the kinks would get costly. Materials would add up as well. The odds are most people would want stainless steel due to the fact that aluminized pipe would last about 2 -3 years here in the north east at least. There are so many great options out there from borla, stillen, aam etc. if you are looking to have a "performance" system. If you want to just improve the sound there are other options like changing mufflers or resonator deletes. A " true / tuned" exhaust could not happen for any type of practical cost. People constantly complain about how expensive the aftermarket systems are as it is. I couldn't imagine how catastrophic of a flop trying to sell that system would be. Just my opinion. It would be a cool project though.

 

^ I love this guy.

 

Me 2!

 

I appreciate the quick responses, guys! Thanks for great photos and the helpful information. Sucks that we have no space for true dual... Woulda been a fun project. Oh well...

Option 2 it is! Working on a couple projects this season (modular intake mod, replacing a faulty door lock actuator, window tint), so maybe next year I can visit some of the local exhaust shops here in Northern VA and get some quotes on custom work.

In the meantime, looking forward to news on the CXJ hi flow cats and possibly a new y-pipe!