*Was posted in the 5th Gen Forum but thought i'd post it here*

Hey everyone. I dont own a Maxima but I became in need of a variable capacity but HIGH FLOW muffler. I didnt know Maxima's had such things i didnt even know if variable capacity mufflers existed.. but when I did a search I saw they came stock on these cars.. my question is does anyone know the flow specs on these mufflers? and inlet and outlet sizes?

my car is just asking for a better muffler than I have.. it only flows 400 CFM (Dynomax Superturbo) but the thing is.. that 400 CFM is a perfect flow volume when the car is between 3500 - 4000 rpms.. but after that 400 CFM becomes a restriction.. I need it to open up about a 100 or 150 CFM for each 1000 rpm increase.. so 400 at 4000, 550 at 5000 and so forth..

oh and the reason i dont just grab a 1000 CFM muffler from magnaflow is because i would just lose all the low end torque the car has..

any comments are welcome.

p.s.. basically what im looking for is the flow specs on the variable capacity mufflers on the 2001+ maxima's and others..

 

You are not going to lose low end with a better flowing muffler number 1. Number 2, focus your research on a mod that will actually give you meaningful horsepower. When I select a muffler I go based on looks, price, and sound. The difference in HP is going to be so small that it's not going to matter.

 

looks, price and sound are the absolute least thing i look at when im doing performance mods. my mods are listed:

Upper Engine Mount Insert
Lower Engine Mount /w Upgraded Bushings
NoyzBoyz Cat-Back 2.5" Dynomax Exhaust w/ Magnaflow Resonator
Induction Dynamics Cold Air Intake
Stage V Port & Polish w/ 5 Angle Valve job
RSM 59mm Throttle Body
Nology Powercores
Ported Exhaust Manifold
2.5" downpipe
2.5" High Flow Catalytic
Exhaust Cam: 200 DEGREES @.050 WITH .375 LIFT (coming soon)
Intake Cam: 200 DEGREES@.050 WITH .360 LIFT (coming soon)

..the cams are sitting here waiting to be installed..

My exhaust system is 2.5" from the manifold but my muffler flows 400 CFM .. if you wanna see my dyno sheet I can post it as well and you can see where it becomes a restriction.. right after 4000 RPM's..



the reason im thinking about the Variable Capacity muffler is because it can flow when needs to and also maintain back pressure when needs to..

 

Why dont you upgrade to a Greddy. A pan by itself is not going to give you almost no power. How about a Y pipe and the complete exhaust system to feel some good HP gains.

 

He doesn't have a Maxima...and a Y-pipe on a 4-banger is just silly.

People with 4th gens have put the 5th gen muffler on their cars with mixed results. Unless you can get one next-to-free, I don't think that they are worth it.

Do you know that the muffler is the restriction? Have you dynoed with it off?

 

ejj: I can get the muffler for 130 CDN .. which is about $80 US (new from dealer is $450 CDN WHOA!) ... no your right i havent dyno'd without the muffler.. but i dont see any other explanation for that drop in power .. im going to dyno again when i swap the cams in..the extra lift on the exhaust cam should help flow more.. but looking at the dyno sheet.. the restriction will just come faster with the extra flow from the head..

 

Your HP curve looks similar to a 4th gen, and that shape of the curve has almost nothing to do with exhaust. Mods will raise the whole thing, but the engine still chokes at high rpm's, and in our case it it totally due to the intake mainfold. Do a search for MEVI to learn more.

Like I said, I think you'll be really dissapointed for $80.

 

thanks ejj.. i talked to the guy that did my exhaust and said go with a straight through magnaflow.. which i am leaning towards.. but when I read about the variable rate muffler.. i got intrigued and wanted to learn more about it..

 

The nice thing about the 2000+ maxima mufflers is that they give maybe slightly better performance without the crappy noise usually associated with aftermarket mufflers. I don't know if that is what you are looking for. The good thing is that the maxima unit was designed for a 3.0 V6. I don't see how it couldn't flow enough for your 4 cylinder. Good luck anyway. I respect the research.

 

I didnt read the whole thing, my bad.

 

Thanks Jeff. You wouldnt happen to know the inlet and outlet sizes on the muffler? the stock 2000+ maxima's.. i did a search and i read its like 1.9" or something?? just wanting to confirm.. thanks!

 

I have one on my 3-gen and like it. If I remember correctly, it's bigger than 2", more like 2.25"-ish.

 

2.25 wont be bad at all.. the system i have right now.. the car sounds really nice.. its low and deep and doesnt get loud unless u punch it.. i like the sound of it.. thanks again..

 

What I like too about the 2k2 muffler is when I installed it it does not get loud or sound obnoxious. It is nice in the sence that if you want it to still stay sort of stock sounding it is the way to go.

SuDZ

 

The exhaust isn't the restriction. It is most likely your intake manifold and cams. The 00-02 max muffler will just give you a quiet ride. It was dynoed test and it produces 1-3whp/2-4wtq less than a straight through design. There would be better gains in a different header design and intake manifold. Your torque curve is simular to a stock nissan VQ30DE, but with alittle more power up top. If anything get a new higher flowing intake manifold, more agressive cams and do some PCM tuning. How much whp are you looking for NA?

 

I am inclined to agree with everyone else on this thread, its not your muffler that's making the power fall off towards redline. Again it's uncanny how much that looks like a 4th gen maxima dyno scaled down about 20%, and basic bolt ons only serve to inflate the graph upwards but they DON'T change the shape of the curves. I'd say its the goings-on with your intake manifold/cams. I don't pretend to know alot about J-bodies, but I'd eat my foot and give you my car if a simple muffler change would cure your high-rpm woes.

 

WOW! That is one awesome dyno for a J-body! And yes, the curves *DO* look amazingly similar to a 4th Gen VQ30DE dyno. Just check out some of the dynos in my sig.



Chevy must have done a tear-down analysis of a VQ engine or two. The only big differences as far as curve shape goes is that your resonance humps are shifted up several hundred RPM, and your torque stays flatter towards redline, which is a good thing. Hell, even your "rated" peak torque / peak power RPM's are the same as 4th Gen's (4000 and 5600)

Anyhow, I too agree with the opinions already stated in this thread. The only things that are really going to alter the curves significantly are manifold work (intake or exhaust) or cams. I like the suggestion of dynoing without the muffler to see what difference it would make. Just be sure to have earplugs in.

 

I did a quick cartest sim of a Z24 with that dyno and it shows a 15.2 @ 89-90mph with a 2.20 60'. Also compared with a stock 4th gen 5spd it would hold its own too. It wouldn't beat it but it does stick with it. That is until you get over 100mph .

 

thanks a lot guys.... Im actually aiming towards 200 WHP (hehe i know its a ways off..) My stock cams are a restriction.. the new ones should definetely help.. they have proven to gain 10 WHP .. my throttle body was upgraded to 59mm.. and I could go upto 62mm.. problem is the intake manifold is only 58.5 mm at its opening (i could port it to 60mm) and only venom makes a different manifold.. ($400 US )

hopefully by the end of this week i can get the cams installed.. do another dyno and compare..

 

I paid about $650 for my intake manifold when all was said and done

 

gotta pay to play...

 

Thats for sure. Just ask my wallet.

SuDZ