Mods so far are Fujita CAI, IM spacers, cattman y-pipe.


I may just have the shop fab up new piping the same size as OEM from the y-pipe to the mufflers, just get rid of the restrictive bottleneck at the resonator and the crimped section.

 

I guess no one listens to me

 

About what?

Not doing a catback?

 

So you don't think about expanded hot exhaust gas? You get nice intake system and Cattman headers and leave the crimp there to restrict the flow?

 

As far as I know cattman uses a Mustang dyno which has a rep for low tq/hp #'s...something to the tune of 5-7% below a dynojet yno

 

RHMax,

If it was your car....how would YOU have it? Dup the cattman specs?

 

I care about expanded gas as much as I care about politics. I have dyno run files to prove that crimps are the least of our problems.

 

Larger MAF housing

 

dyno run files just showing impressive #'s w/ the crimped section, or dyno run files showing a crimp run (before) and uncrimped run (after)?

 

The MAF housing is the intake pipe right?

 

It's nominal, (2-4whp) dyno error factor. Don't worry about the crimp, worry about your ore-cats.

 

So you are saying from my y-pipe back to the mufflers...keep that all stock as it doesn't matter.

You don't think there's power to be gained in those crimps?

I have the new mufflers your saying just swap the mufflers and touch mothing else?

I understand there is much room for improvement in the headers w/ their pre-cats, however it's my understanding that these header installs are a MAJOR PITA, which may sway me from doing such. And as Brian Catts stated it's VERY important to retorque the header bolts a few days after the install which is going to make it a DOUBLE MAJOR PITA.

 

Not so much the pre-cats, it's the stock exhaust manifolds themselves; hot expanded gas. Same reason why Stillen headers are POS.

 

Jesus, you fellas are difficult.

 

If my theory is correct, pulling the motor may make it easier to install headers. I may go this route. If I do, Im throwing in a new stage 1 or 2 clutch and lightened flywheel and maybe cams too.

 

.. .. . .

 

I can do that too

.. .. . .

 

Dude, you just post up " Larger MAF housing" .....how does that help. Not everyone here is as knowledgable about engines as you are. Lots of people here are just learning, talking, getting ideas. Your one liners don't really add any value. Expand on what you are talking about, post pics, links, explanations etc. Sure you've done it on different threads, but this is a new thread.

How do you install a larger MAF in with a Fujita intake? You will need to give some instructions first.

 

Don't worry, you're set with Fujita.

 

It be hard w/ a Fujita, since it's got it all packaged into one piece (MAF housing, etc). A34 MAF's are different with respect to A33B's.

But, that is an advantage since A34 MAF = Z33 MAF. So the aftermarket is better. There's a good thread on my350z re: the subject. I have a thread on here, but that wouldn't do much good since that housing (M62) wont work with your sensor.

Bottom line:

Some AFR control and monitoring is essential. If you're not willing to go that far, stick with what you have (Fujita/Nismo/Injen etc), keep it simple.

 

NmexMAX I went to Fujita because of your MAF advice, it seems to be a larger tube than my Nismo had, particularly where the MAF is housed. I do have the SAFCII but the only way I could see getting a larger MAF housing would be to cut the Fujita, and I think the once piece is a better design. (Another reason I made the switch.) Maybe one day I'll really dig into and try that out but......keeping it simple for now.

 

BTW, NmwxMAX, do you have data on the differences in stock MAF versus larger MAF?

 

Like? . . . . . .

 

Yeah sorry JG1 , 2.5" throughout (no crimps)

 

Before and after dyno?

 

Not as it being the only change.

 

Im trying to get feedback on just replacing the center resonator and center pipe with a straight pipe from the cat back to the stock rear y pipe, if anybody has tried just that how does it sound and does it help performance, thanks.

 

Sounds like this.


I added a Magnafow resonator which made it a little deeper, less raspy. It's not very loud, you can still hear the engine and intake. And te poping sound is because of CE y-pipe w/ no cat.

It makes some power; not quite as much as full catback, but less noise.

 

Increasing tubing size is not required unless you're real intention is racing/force inducted car.
For example, our dual system for the SL600, a V12 beast, is 2.25" inlet.
It's a true dual however, not a y-pipe based system, but still, it goes to show you that before thinking about increasing your inlet size, think about deleting restriction inside your exhaust system.

 

So instead of me spending the money on a custom y pipe back I could have gotten rid of the mid section and better flowing cats and done just as well?

 

That's a fair translation...

 

On these cars, headers > any other exhaust mod(s) put together.

 

And I am patiently waiting for that to come out.

If I was looking to upgrade the exhaust (and I have the Fujita) all I would really need is the Cattman Ypipe and their headers when they come out? Mufflers do nothing (I am told) besides sound. All this coupled with an Emanage would be the best system? As in, I would no longer need an SAFC or anything else in the exhaust dept. (I would have the NWP spacers as well)?

Joshua

 

Sounds like a great set-up. You guys also have it made in that you can buy the y-pipe and headers are available separately, but are still compatible with each other.

 

Mufflers do add some power. A good exhaust system can give you 10-12HP gain, not as significant as headers as a stand alone mod.

 

I endorse this comment, not because I have headers but more so because the dyno proven gains generated by every car who installs headers is something that cannot be disputed. Y-Pipes are great (I had a CE Y-Pipe for over 2 years) but the air must still flow through your precats and this is the single most restrictive item on our exhaust system that prevents our Maxima's from having real lungs...


This is a picture of the precats along side my old CE Y-Pipe to get an example of what air must flow through before it hits your Y-Pipe and out your exhaust, big fat heavy honeycomb restricters!!!



Replaced with these lungs:

 

Wrong

We've proven it over the years that our axle-backs have shown as great as results in terms of performance, if not better, than some cat backs.

 

But universal gains can't be applied to this specific car (from what I've heard) mufflers for the Maxima don't really add anything (3-5 horses being nominal).

Have you dyno tested specifically on the Maxima? If so I withdraw my comments of ignorance.

Joshua

 

No you are indeed right, our comments were regarding our specific systems, not universals.

 

I am saving up for your mufflers, just so you know

Joshua