Any "true dual" system, replaces the stock Y-pipe.

Ivry 6mt sed
Crawford Pleneum
Injen CAI
22" resonator
Cusco sway bars
350Z springs&struts
Enkei RPM2

 

Dave, yes absolutely the HP increase and sound were directly affected by the removal of the pre-cats. I saw pics in this thread of the G's stock Y-pipe and it looks like it has 3 cats?!?! I would hope a good aftermarket replacement would drop some of them, hence similar gains and sound. Maybe I'm wrong, dunno.

Obviously, a true dual exhaust will necessarily *not* have a Y... I've seen something about an H-pipe though, to equalize exhaust pressure on both sides... Does $teallin sell a dual exhaust system for the G? I looked and all I found were cat-backs.

-Max

'03.5 Ivory Pearl 6MT

 

maximafia,

Coupe or Sedan!

For Coupe exhaust systems, you might want to check out the fall issue of Sports Z Magazine. You can download the exhaust system sound files from Sports Z Magazine's website.

Yuichi's 350Z Exhaust Shootout article in this issue is simply outstanding.

After "studying" the dyno charts, to me there was one clear winner.

While others may have a different opinion, I base my statement on these points.

1 - This true dual catback system provided the highest average Hp and torque across the majority of the the rpm range.

2 - It smoked the other systems by 30% to 97% in in peak torque.

3 - It essentially matched the system with the highest peak Hp. (Ok, I give. It did loose to another peaking system by .1 Hp - that's one tenth of a Hp.)

4 - While it did loose a little HP & torque below 1800 rpm, some of the others were far worse. (One of the other systems lost no Hp or torque.)

5 - The sound is very throaty. Ilike it as well as any of the others.

DaveO

 

Sooooo, is this the Borla you speak of???

BTW, I thought Stillen was a dual catback exhaust?

"Use the Forced Induction Luke!"
-Jedi
2003 G35C, 6MT, Navi, Black Obsidian/Graphite

 

Good try, but you guessed wrong. In fact some posters on my350Z have stated their concerns that at least one system with a single muffler canister may not a true blue dual system.

By the way, there was also pictures of each system tested on Sports Z Magazine's website.

Here's a picture of the (for sure) true dual exhaust system I spoke about.

DaveO



102289-Sound 350Z Stillen Picture.JPG

 

wait wait wait. you guys drive sedans right. how are you goign to fit this y-pipe on your sedan? am i mistaken here? personally, im waiting for some true-dual systems to come out for us. maybe ill put a high flow cat...but its illegal and i dont like the trouble.

btw, what does that resonator you guys have do? does it improve power any? or just sound.

G35S 6MT
K&N Typhoon intake
Technosquare ECU
350Z Springs & Struts (soon)
6-wire ground kit

 

The current Sedan dual exhaust system status as I now understand it;

Borla - Backed off on building one for the Sedan.

Injen - Rumor, a system is under development

GReddy - Has single pipe system. Dual system may be coming at some future date.

Stillen - True dual catback prototype done. Being fine tuned. Should be available soon. Uses their Coupe/Z y-pipe with x-section and 3/4 of the Coupe/Z dual midpipe/resonator assembly.

If you try a search, I think you'll find some interesting information.

DaveO

 

nuttyprof (Registered)
09/12/03 11:28 AM

wait wait wait. you guys drive sedans right. how are you goign to fit this y-pipe on your sedan? am i mistaken here? personally, im waiting for some true-dual systems to come out for us. maybe ill put a high flow cat...but its illegal and i dont like the trouble.

btw, what does that resonator you guys have do? does it improve power any? or just sound.
__________________________________________________ _

Z and G Y-pipe's are the same. Get down stream of that and their you have your differences. Premuffler size and what not and of course the coupe/Z muffler placement ect.

My magnaflow resonator improved the sound quality of the car, with Zero BAD sound quality aspects, only got better. It felt slightly more powerfull. But for only $70 installed, I love the deep idle sound that's present to around 2k. At higher RPM's I have no idea what change sound wise if may have done, my Injen intake over rules the exhaust, sound wise.

Ivry 6mt sed
Crawford Pleneum
Injen CAI
22" resonator
Cusco sway bars
350Z springs&struts
Enkei RPM2

 

Here's another shot of the stillen true dual, in this case on the Z. Notice how they use a x pipe where the stock exhaust would normally join into one as in a "Y".


The borla use's a H pipe, while the stillen use's a X pipe.

Here's some info that I found on the net concering H pipe's and X pipe's. Important to me as I imagineer a true dual system on my own for my sedan.

H Pipe:

An H pipe helps equalize the exhaust pressures between the two banks of tubing as the hot gases and sound waves travel down the tubing. This, in effect, relieves the exhaust pressures as they travel through the H tubing, generally creating an increase in torque. This will also give an added sound reduction when the sound waves combine inside the H tubing.

X Pipe:

An X pipe will actually help to scavenge exhaust pulses from one bank as the opposite exhaust pulse passes through the X, thus creating a vacuum effect at the valve, resulting in a cleaner burn in the cylinder. This generally equals added torque and, like the H pipe, a reduction in sound as the sound waves combine in the X pipe.

(another discription of the X pipe)
X-pipes are used in dual systems to increase the velocity of the gas flow to encourage scavenging of the exhaust gases. The actual crossing and merging of the gas flow also increases torque across the rev range. This type of system was pioneered for use in race cars.

Based on the descriptions, the X pipe is a more effective means to improve torque and increase exhaust gas volocity. And it's important to note that stillen true dual produced more torque and power than the Borla true dual. Even though the Stillen use's 2.5" pipes vs Borla's choice of 2.25", which should actually be more sensicle, volocity wise. That's why I'm putting in a X pipe into my true own true dual system.



Ivry 6mt sed
Crawford Pleneum
Injen CAI
22" resonator
Cusco sway bars
350Z springs&struts
Enkei RPM2

 

Gsedan35,

Excellent points as usual!

I did note something interesting from Yuichi's excellent Sport Z Magazine Exhaust Shootout article. According to the provided specs, both Borla and Stillen used 60mm pipe in their systems. The other manufacturers used 50mm, 58mm and 76mm pipe. Surprisingly, there was less correlation between pipe diameter (exhaust gas velocity) and torque gains than one might think. I'd still like to see what the highest torque system could do with 2" or 2.25" y and midpipes.

DaveO

 

I've alway held to the that Borla's are 2.25 and the Stillen use's 2.5. To reaffirm my position I ran a search on my350Z and I found that ever instance where the pipe size's between the 2 brands is asked, or quoted, the Stillen is 2.5" and the Borla is 2.25" Looking at my dail caliper 58mm is 2 1/4" and 64mm is 2 1/2"

I got curious and I measured the stock pipe, it's 65mm, yet at the crimp bend points, it shrinks down to as little as 59mm. If someone was bend on doing a single pipe only system, I'd replace all the stock piping with mandrel bends instead.

BTW, the stock Y-pipe measure 58mm or 2.25", when they merge than it's 65mm or 2.5"





Ivry 6mt sed
Crawford Pleneum
Injen CAI
22" resonator
Cusco sway bars
350Z springs&struts
Enkei RPM2

 

so if im planning on getting a true-dual, i shouldnt get a resonator right?
but if i do get a resonator, it should cost me about 70 dollars installed?
and the longer it is the quieter it is? anyone have any sound files to post the difference...i doubt it, but whats the recommended size resonator to get?
will it increase any hp or torgue. i take it that my tq will go down a tad bit and hp will increase a tad bit. correct?
thanks. this resonator business is all very new to me.
oh, but back to the original post, if i get a true dual, then i have no need for a y-pipe right? thanks again

G35S 6MT
K&N Typhoon intake
Technosquare ECU
350Z Springs & Struts (soon)
6-wire ground kit

 

Thanks Jim (Gsedan35) for the correction. The Sport Z article has a misprint or they tested a "special" Borla system. I tend to think it's a misprint.

DaveO

 

nuttyprof (Registered)
09/12/03 09:50 PM

so if im planning on getting a true-dual, i shouldnt get a resonator right?
but if i do get a resonator, it should cost me about 70 dollars installed?
and the longer it is the quieter it is? anyone have any sound files to post the difference...i doubt it, but whats the recommended size resonator to get?
will it increase any hp or torgue. i take it that my tq will go down a tad bit and hp will increase a tad bit. correct?
thanks. this resonator business is all very new to me.
oh, but back to the original post, if i get a true dual, then i have no need for a y-pipe right? thanks again
__________________________________________________ _

Well if you build one yourself, I'd think a fellow would be crazy not to have one on each pipe, IMO. And all the coupe and Z systems I've seen have some sort of resonator on them. Yes, the longer it is, the quieter it is. I think my 22" resonator is perfect in the amount of resonating it prevent's. A resonator isn't about power or torque, it's about controling unwanted, sometimes nasty sound's. The design I used is a straight through design, it did give me a slight boost in power compaired to the stock premuffler. My total cost ws $70 for my magnaflow. Which is actually a round 4" muffler that is used as a resonator, rather effectively I can say.

Yes, if you buy the upcomming stillen true dual for the sedan or if you wait for one of the other rumored, they will do away with the stock Y-pipe.

Ivry 6mt sed
Crawford Pleneum
Injen CAI
22" resonator
Cusco sway bars
350Z springs&struts
Enkei RPM2