None of the exhaust systems are 'true dual'.

[Healed Will]

This all came out in the 'Gauging Fast Intentions' thread, but none the less....

None of the exhaust systems offered for the AC are true dual systems.Notice when Fast Intentions made systems for the g35 and 370z, they we're true duals, x'ed over.

I would pay $1000 or maybe even $1100 for a dyno proven, stainless, mandrel ben true dual system, with high flow cats and x pipe.

I tell you why:First of all: Thats where you see your huge gains in HP. The x pipe usually frees up 10 extra horses. Not only that but maximizes the efficiency of your engine, thereby creating a longer engine life span.You get equal back pressure flowing to and from your v-block.

And most of all: Im guessing you guys are gonna get 'that sound' your looking for when you do this. I cant speak for certain, but if you lived on the west coast and went to Tony, requesting a custom system with high flow cats, mid pipe that's x'ed over, resonator(s), and two mufflers.....that system would pur like a kitten.

In the mustang world...systems arent even taken seriously by enthusiasts unless they are x'ed over.

Why are we all running around debating on exhaust systems while nobody has even considered this route?

[CoupeVQ35CVT]

Umm this is a wild guess, but since the A/C's engine is transverse mounted, they just figured a Y-pipe to a single exhaust would be the most simple and economical, solution while still offering tons of power.

Plus, back pressure doesn't do anything. I hope you realize that it's a myth in today's fuel injected cars...It's more or less a symptom, not the reason, for a good/bad setup exhaust system. Of course I'm just a n00b so what do I know, right?

A true dual exhaust would be killer, but not to excited about the $1000 price. But seeing how other existing A/C exhausts are already around that price range, I suppose some would consider that a "bargain" for a dual exhaust. Or others like me, might get one custom bent and fabbed for cheap.

[Throckmorton]

A two word answer: No room

Have you looked at the Altima when it was on a lift, and high enough in the air so you can see the bottom of whole car, front to rear?

If you have seen it, you will notice that there is no room to install the exhaust system you are referring too, unless serious modifications are made.

[AZhitman]

Simple answer:

A true dual is unnecessary and for looks only.

The 3.5 has insufficient displacement (unless boosted) to necessitate anything that large.

Cooling of the exhaust gases slows their flow, and it's counterproductive.

A 1.8" system cross-section is 2.5 square inches.

A 2.5" system is 4.9 square inches (nearly double).

A 3" system is 7.1 square inches (nearly triple).

Dual 2.5" is 9.8 square inches. Pure silliness for a motor with such small displacement.

Boosted VQ's are making the most power through a single 3" system.

[Healed Will]

So in the case of Fast Intentions G35 and 370 exhausts, the x pipe is just for looks? With tons of engineering and dyno's??

How come on fancy truck systems, take for example the 4.0 ford motor, the x pipe showed greatest gains. Thats a .5 cubic feet difference of displacement.

[AZhitman]

I never said that.

If you DO run a true dual, the x-pipe (a tangentially siamesed crossover) will help. It's more useful in old-style v-style pushrod motors where exhaust pulses overlap and compete for "space", usually an issue with V8's. Think NASCAR.

It's fine for low-rpm engines, to balance out pulse collisions due to the one time in the firing order when the system becomes overloaded on one side due to competing exhaust pulses.

Small sixes? Not so much.

And a 4.0 is only 500cc's larger than your motor. Not .5 cubic feet.

.5 cubic feet = 14,158 cubic centimeters.

Having spent some time on a dyno, I can tell you it's real easy to generate attractive numbers in order to sell a product.

[FGFCacoupe]

This all came out in the 'Gauging Fast Intentions' thread, but none the less....

NOTHING CAME OUT

Please leave Fast Intentions exhaust business in the Fast Intentions exhaust interest thread. The link to the correct thread is below.

http://forums.altimas.org/zero...age=3

Thank you

[FGFCacoupe]

Also, just to help you out because I understand that you are new here.

Stop why you are ahead, you are arguing with the wrong person. If you check below his forum name, you will see why.

[AZhitman]

Thanks (I think).

Disregard my role here, I'm simply educating a member. Exhaust design and construction is an oft-misunderstood topic.

Certainly nothing against the FI exhaust - I think it's gorgeous, functional, and well-constructed... I'd run one on my G35.

[Healed Will]

FGFCacoupe... Chill bro. I dont intend on arguing with ANYone while Im around here, regardless if its the cat who owns the club or a 17 year old kid. I had stated in other threads that I most familiar with v-8 systems. I talked to Tony yesterday, and I haven't even checked your response to that, but your acting as if your feelings are hurt because he basically agreed with me in the matter of an x pipe.

AZhitman, your obviously a lot more knowledgeable about motors than I am. Excuse my ignorance. Thats the point of this whole thing, is to live and learn, right?I thought the .5 was for .5 cubic feet. I guess I've been hanging around stereo boxes for too long

Im just going off of what I've gauged from v-8 systems and mustangs and such. But taken into consideration thats without access to any dyno whatsoever. I hung around some motor heads and was told a lot. I picked up, X pipes cause some type of 'venturi' effect, same principle as a supercharger?

Then again, Im not n engineer and I wasn't arguing with AZhitman. I refuse to argue, especially over the net over something as minute as my car. Discussing is a whole 'nother issue.

[AZhitman]

All good, my man- I never take this stuff as "argumentative". I'm a little crass sometimes, but then again, I'm an old musclecar doofus too.

I can get pretty in-depth as far as exhaust "theory" goes, but the bottom line is this:

For your purposes, going to a mandrel-bent system of a slightly larger diameter will MORE than accomplish your goal, and from there you run into the "law of diminishing returns".

There's no way I'd spend an extra 400 bucks for that last 2 hp. Weight reduction would be a smarter route. Take out your spare tire or go take a good healthy dump if you need that added power.

True duals add weight for negligible gains - But I don't disagree that they look amazing.

As an aside, I didn't mean to be snotty about the displacement math. 3.5 liter engine = 3500 cc's (really like 349x).

Or, in "old-guy speak", 213 cubic inches. Doesn't sound quite as cool...

[rjdmmfl1]

Greg is probably filled with more random information than anyone else on this forum.... not random in the sense of unimportant, but random in the sense that he knows a crap load of info about a lot of different topics... its actually quite impressive...but I have more TV's in my car than he does... .. lol

[LongBeachCoupe]

I hands down know more useless random information than Hitman does... without question!

[Nissan_luver08]

What's a dual exhaust?

[rjdmmfl1]

I hands down know more useless random information than Hitman does... without question!

Either you're joking, or you've never had a conversation with him.. and since the latter can't be true, I'm guessing you're joking...

[Hussain]

first off, in order to go true dual you would need to get rid of a cat or add a cat. taking one off is illegal and adding one is just stupid. take a look at the racingline Y-pipe that deleted the cat. in order for them to even have a Y pipe, the pipes had to be bent all crazy looking, theres no room for a clean and simply Y-pipe. true dual might be possible but VERY expensive and a pain in the a**! the Greddy cat-back is what $1,200? thats just a cat-back. you would have to replace all the piping starting from pretty much the headers. you would have to mess with the pre-cats and the sensors (which arnt as easy as mustangs like my brothers) then you would have to get the X-pipe, double the piping.... i think something like that would be like $2,000. in the end, how much of a gain are you REALLY going to get over a regular cat-back exhaust system? not worth the hassle in my opinion. i love the way my custom cat-back exhaust sounds and when i want the power, i got my electronic exhaust cut-out that i can open any time

[XXplosive990]

Weight reduction would be a smarter route. Take out your spare tire or go take a good healthy dump if you need that added power.

lmfao hate to kill the intensity in this conversation but that quote just made my week

[Dexion]

Good topic here, yes a true-dual would be useless and a waste of money for a transverse mounted motor. The Y-pipe serves its purpose.

[FGFCacoupe]

Thanks (I think).

No problem at all

[AZhitman]

Greg is probably filled with more random information than anyone else on this forum.... not random in the sense of unimportant, but random in the sense that he knows a crap load of info about a lot of different topics... its actually quite impressive...but I have more TV's in my car than he does... .. lol

Thanks Doc.

Hell, only 2 of my 9 cars even have a stereo!

[rjdmmfl1]

Thanks Doc.

Hell, only 2 of my 9 cars even have a stereo!

hmmm, that means you have more cars than I have TV's... so I still lose...

[Hussain]

[AZhitman]

hmmm, that means you have more cars than I have TV's... so I still lose...

Not necessarily -

Keep in mind, some of my classic Datsuns cost less than your ICE.

We just choose to spend our hard-earned $$$ differently.

Besides, I'm too ADD to have a TV in the car.

[Healed Will]

Hey AZhitman,

Can you shoot me a personal email? I had a few questions regarding your real world experience with this stuff.

I tried to find a way to shoot you one, but couldn't find it.

Thanks

[AZhitman]

Just click on my screen name above my avatar. Simple, y0.

[AZhitman]

Update:

I posted this in another thread, but it bears repeating here:

That's NOT an X-pipe.

As far as I can tell, it's a dual-in dual-out Magnaflow pre-muffler, which makes no sense in this application.

http://www.magnaflow.com/02pro...=8203

A tangentially-siamesed crossover (X-pipe) looks like this:



Correct me if I'm wrong.