new custom exhaust system

turbocad6

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brooklyn, ny
ok, I've been driving my fx35 bone stock performance wise since October, now, I want to add some performance. one of the first things I want to do is an exhaust. there are several options available & I guess any one of them would be ok, but none of the options available really jump out at me as the system I really want.

first thing is I really don't want a transverse muffler out back for several reasons

out of all the exhaust systems I see available, I think the one that comes closest to what I would want is the fast intentions intimidator exhaust, true 2 1/2" dual exhaust with there version of a resonated x-pipe(they use a magnaflow dual inlet/outlet resonator for this) & there using mufflers & tips made by some company called sterling... the problem is, this system is not a direct fit for the fx, & I don't know how crazy I am about the mufflers really, this is close to what I want, but not exactly perfect as-is

so, I started thinking about building my own system, or rather, having a system built for me. I have a friend who builds headers & exhausts on a large scale, ships all over the world. he builds headers & turbo headers for many tuners who then sell the end product as there own & he also specializes in headers & exhausts for mostly American cars that he sells under his own label.he's big in the corvette scene, he builds awesome viper headers & he does the mustangs & the hemi Chrysler's etc..., he also builds headers for nhra pro stock guys... he's got some really nice equipment including a huge cnc mandrel bender, he does some real high quality work & I know he can build a system every bit as good as the fast intentions piece, but, to my specs & fit to my fx perfect & using mufflers that I choose...

I visited his facility yesterday to discuss & consider the exhaust I want to build, got to check out the machinery & the processes first hand, we spent a few hours at his shop & then went out to grab a bite to eat. I tell you I learned a lot, both about the industry in general & the exhaust designing & building process, also learned a lot about the BS that goes on with a lot of these manufactures & vendors, you'd be surprised how many companies don't even build there own stuff & have it built by a guy like this, & then put there own label on it. you'd also be surprised at some of the stuff that comes out of china & the differences in stainless steel in general, not all 304 stainless is the same just because it's called 304 stainless, there is a lot of crap out there. he prides himself & his whole business on the fact that he only uses high quality 100% USA stainless in all his products. he doesn't even offer an alternative like most do, with cheaper aluminized mild steel, if someone wants inferior components there are plenty of other people that can sell you that, he only deals with higher end components.

I spoke to him about the system I want to build & also the possibility of duplicating it for all fx's, that is a possibility at some point, but first priority is building my exhaust & seeing the results before I want to discuss more deep in that area really. because of this possibility I can't reveal the name of his company or who he is, that's one of his requirements to consider him supplying these exhausts, I can honestly say that I agree with some of his reasons for this & don't agree with some too, but I will respect his wishes & keep him anonymous for now.

anyway, my thoughts are a true dual, manifolds back, including high flow cats & everything, & with a real x-pipe instead of a common baffled resonator like the magnaflow. there is a big difference in the scavenging affect with a true x pipe, the magnaflow is not giving the same benefit at all & is just combining the exhaust pulses for sound. when we first started talking about it we were thinking of using borla mufflers but after we drove to the diner & he heard the fx & really paid attention his comments were he doesn't think the borlas are the way to go, he thinks they'll be too high pitched & not sound great. he also tells me that a true x pipe on a dual system does change the pitch higher by itself, & he wants to use something that will give a deeper tone... were thinking maybe a pair of flowmasters stainless new mufflers... I'm not a huge fan of flowmasters & was more enthusiastic about borla's, but he tells me borla is not what it used to be & isn't necessarily all that anymore anyway & that the stainless steel flowmasters are every bit as good as the borlas

at this point I can choose any muffler I want & he's willing to play with a few different ones to fine tune the sound for me...

now, my tuner is a big import guy, has made a name for himself in the import market, he specializes in Mitsubishi's & offers a few different turbo & superchargers with his own label, he is supplied his headers & exhaust from my other friend. he has a 4 wheel dyno & from the conversations I've had with him he really seems to know his stuff. he suggested to me that I build a staggered system, start out at 2 1/4 & then up that to 2 1/2 as it reached the middle & starts to go through the bends & use 2 1/2 mufflers... now my exhaust guy tells me he doesn't agree, he talks about velocity & how the exhaust cools as it reaches further down the pipe, he actually said that to keep velocity up as the exhaust cools further down the past he would if anything do the opposite & have the exhaust larger at the front, as it narrows down this would help retaining the heat which aids in the scavenging affect, in the end he recommends I do 2 1/2 front to back. so, here I got 2 different seasoned veterans in my corner willing to help me, but both with differing opinions as to what the best solution actually is:tongue: so yeah, some help there...

anyway, I am looking for any input on this, also if anyone knows of any other good mufflers I should be looking at, & also, does anyone think there is a lot of interest in an exhaust like this... building a one off & building a system that is slated for production are 2 different things & require 2 different approaches... I honestly am not very interested in going into the wholesale exhaust market myself, but he will not add something like this to his regular product line & the only way he'll do any sort of production is if I was in the middle.

man, I can't do anything without writing a friggin novel:tongue:

here are a few shots of his setup, this is the viper 2 piece headers he does:

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this is what a header jig looks like to build those headers:

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here is another mustang header jig:

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here are a few shots of the computer controlled mandrel bender... this thing is a monster, $300k machine, or so he says anyway...:

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OK, that was a long read :tongue:
From what little I know, small DIA to large has been the rule of thumb, but it would be interesting to see what evolves with the opposite of that. The theory of increased velocity at smaller DIA make sense on paper, but I've never seen this done.
The 2.5" plumbing with a true dual should be fine w/ FI, but it's gonna kill the bottom end on NA. Maybe a 2.25 might work better overall? Dunno
 
yeah, see that's another one of my problems, I'm going to be installing a supercharger after I dyno the exhaust, & I need to spec the best exhaust for me, which is probably not the best for a NA car really anyway...
 
Yep, it's either one or the other.
Look at at it this way, the Stillen (2.5" Dual) bites Donkey on N/A with big loss on the bottom, while the Nismo (3" Single) rocks it over the entire range (although not by alot).
 
OK, that was a long read :tongue:
From what little I know, small DIA to large has been the rule of thumb, but it would be interesting to see what evolves with the opposite of that. The theory of increased velocity at smaller DIA make sense on paper, but I've never seen this done.
The 2.5" plumbing with a true dual should be fine w/ FI, but it's gonna kill the bottom end on NA. Maybe a 2.25 might work better overall? Dunno

I agree on most points. IMO, for an FI system you can go big at the headers and smaller at the end if you're worried about a too loud system. I don't know how doable is this but I was thinking about getting 3.0 piping from cats and extend it as much as possible beyond the shields in the middle and then use an X-pipe to split to 2 mufflers at the end. I was thinking of using 2.5 or even 2.25 after the X. This was when I was thinking about Stillen SC..

For the NA exhaust, I actually bought some mandrel bent 2.25 piping and was thinking about a similar thing but the other way around. That is, 2.0 or 2.25 from cats to the X and 2.25 or 2.5 from x to the mufflers.

As far as I know, if you don't increase the overall pipe diameter, it won't hurt your power/torque at the low range whether it's dual or single. AFAIK, the loss comes from traveling pulses slowing at a larger D pipe and slowing down the next pulse coming up thus creating back pressure.. For NA, speeding them up at the beginning (smaller D), and slowing them down at the end (larger D) should be fine. For FI, you want a high volume at/after the headers so larger D at the beginning should be fine. If you want to silence it up a bit, use smaller D at the end and it shouldn't affect your power much..

Also for NA, the longer they travel in the large D exhaust, the higher the loss should be. So keeping the cats & the mufflers big but keeping a long, narrower main piping should be fine in both sound and power/torque..
 
Wow...lots of great information for a noob like me. Thanks for the read, turbo! Can't wait to see what comes of this!
 
ok, I looked some more at the stillen, honestly I never really looked to hard at it because that whole dual transverse muffler design is kind of a big turn off for me. I now see that it looks like it might be 2 1/2 ? straight back duals AND it has a real x pipe, cool....

I have no sound on my work pc but I'll check out some clips later, any idea what they use for mufflers? they also use 2 resonators... I wasn't too sure if I want to add resonators or not, maybe...

yeah, so aside from the 2 transverse mufflers that looks about as close to what I want as I've seen so far... my whole thing was I had a few ideas of what I could use the extra space for if I eliminate the transverse muffler design... other than that the stillen looks nice for sure.... hmmm... like you said bert, interesting for sure :)
 
Take a look at my Mod Signature

Here is a detail work on the added stuff I had to do to make it work on my FX and it should give you a better idea on the diameter of the piping.. it is at 2 1/2.. and it sounds sexy. especially in the Gerage.

Stillen Exhaust
 
I checked out your thread already, but 45.. I want to hear in on a 35.. plus, I guess a 35 won't have the fitment issues you had maybe....

the stillen is worth me considering maybe... I mean cost is not so much the issue because by the time this guy does my whole thing with cats it will be over $1,700 anyway, the transverse muflers ahhh, maybe I could live with that... I dunno, got something to think about now at least.... the stillen I might be able to get it quicker really, my guy is saying maybe 3 weeks before he can take my fx & then he's gonna want to keep it for a few days too...

any idea what they use for the mufflers?
 
been happy with my Stillen from local Infiniti dealer. Can't remember what I payed , but they beat stillens price by couple hundred dollars.
 
IMO, for an FI system you can go big at the headers and smaller at the end if you're worried about a too loud system. I don't know how doable is this but I was thinking about getting 3.0 piping from cats and extend it as much as possible beyond the shields in the middle and then use an X-pipe to split to 2 mufflers at the end. I was thinking of using 2.5 or even 2.25 after the X. This was when I was thinking about Stillen SC..

this is something like my exhaust guy is telling me, he also told me that there would be major improvements NA if he did long tube headers, not so big of a deal for FI though... he thinks I should get headers too either way...

damn bert, now you got me keep staring at the pictures of the bottom of your car:smile: I dunno, tougher choice now... still probably go custom but the stillen is more tempting now I think...
 
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