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Discussion Starter · #1 ·
I just had the system installed about an hour ago. For a refresher, check out my original post when I first purchased the system.

http://infinitifx.org/phpBB2/viewtopic. ... 5649187bfa

After debating over the winter whether to go completely custom or to try and have the OBX catback modified to fit, I decided on the modified route. (Besides, it took up too much space in the garage.)

I ended up talking to Ron at Performance Autowerks out in Naperville, IL.

http://www.performanceautowerks.com/Pag ... Frames.htm

Their site mentioned custom fabrication, and they recieved a good word from some EvoM members.

I wanted to fab up a custom y-pipe since none of the Fuji/Nismo style y-pipes will fit our AWD system. Since the materials would have to be ordered, we just decided to mod the catback for now.

The tips were lengthened to about 1/2" past the bumper (per other members recommendations, especially since I had no idea if this was a loud system). An 8" extension was welded onto the B-pipe. (SS piping section). The factory tips were used, since the OBX tips looked a bit too comical for my tastes.

So basically, the entire catback system is stainless steel. The OBX system is polished 304 SS, the factory tips and piping is 409 SS (I believe)

The modification costs came out to $210, the catback I bought off of Ebay for $295. So in total, it comes out to about $500 for a complete 3" mandrel-bent stainless steel system. I think that's pretty reasonable.

As for sound, it's actually quieter than stock at idle and part throttle driving. This makes me wonder how restrictive the rear muffler is. Did I mention how quiet it is??

When you go WOT, it sounds smoother than stock and is probably just as loud. It actually sounds pretty awesome. It's hard to describe the tone. It doesn't sound like Flowmasters (blatty/pulse-like). It just sounds smooth.

From the seat-of the-pants view, the power delivery is smoother. The engine doesn't seem to strain as much getting up to speed. At WOT, it seems to have a bit more pick up, but the Butt-dyno is infamous for that.

I'll head out to the track tomorrow night to see if there's any improvement. Last time I trapped at 90mph fighting a pretty good headwind, so I'll set the bar at 91 mph.

Since the system is so quiet, my assumption is that the muffler is restrictive. So power-wise, I'm not too optimistic about tomorrow.

I'm sure I'll get more power from the y-pipe change when I get it fabbed up. (from under the car, the factory y-pipe looks ridiculous, as does the factory cat-back piping. Heck, the stock system from my Evo used bigger piping and mandrel bends)

I'll keep everyone posted on the results.
 

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All this chit-chat and work and no pics. :shock: man, you whet my appetite and didn't feed me :? I'm hungry! - I know, you just did it an hour ago. :D
 

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Discussion Starter · #3 ·
PINITI-FX said:
All this chit-chat and work and no pics. :shock: man, you whet my appetite and didn't feed me :? I'm hungry! - I know, you just did it an hour ago. :D
Haha, just bought a digital camera while waiting for them to do the work. So I don't have any pics of the cat back under the car. (And it's freaking cold outside, so I'm not gonna back the car up on ramps and lay down to get a shot, either. )

With the stock tips in place, you can't even tell there's an aftermarket system.

As for how the OBX catback looks like, just look at ANY picture of the Nismo system. It looks just like that, but with a larger resonator. OBX is known as the KING of copying their competitors.
 

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Looks great. Inexpensive too. Keep us posted.
 

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Very nice Exhaust, btw nice sneek peek :shock: of your lowering springs, Eibachs?
 

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Im new to the exhaust scene but I was wondering that isn't it not go to put that exhaust on the 45 because it came from the g/350 and thats a 3.5L engine...just wondering.


Jay
 

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Discussion Starter · #10 ·
carsunltd32 said:
Im new to the exhaust scene but I was wondering that isn't it not go to put that exhaust on the 45 because it came from the g/350 and thats a 3.5L engine...just wondering.


Jay
It's a 3" exhaust, which, IMHO, is way too large for a N/A 3.5L V6. But it happens to perfect for a 4.5L V8.

And regarding the springs............yes they are Eibachs. You don't see the coil bind because the car is on ramps, with most of the weight over the front wheels. When the car is on level ground, the upper coils bind.
 

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Very pretty/clean system...the old adage:"Know what you want and pursue it...no substitutes"
 

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The question now is........ how much more improved is the torque, horsepower, and MPG. What was the end result of these three requests. Good, or Bad. Is it worth that Best Bang for the Buck response. Lets us all know. :)
 

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Discussion Starter · #15 ·
Back from the track. It was pretty **** cold, with temps in the low 40's. 5mph winds from the east.

Run# 60' 1/4 time Trap Speed
1 2.243 15.130 92.07
2 2.446 15.241 92.91
3 2.189 14.927 92.72
4 2.207 14.994 92.64
5 2.238 14.995 93.28


These runs were made with over a 1/2 tankful. The last time I was at the track, I had just under a 1/4 tankful, so to try and even out the comparison, starting with Run#2, I removed the floor mats, rear cargo mat, jack, and spare tire.

I consider 91 mph as my baseline prior to the exhaust install, so it looks like I picked up about 10 hp, also taking into account the colder temperature. 10 hp is right in line with what is to be expected with any exhaust upgrade for an N/A vehicle.


I think if I had less gas, I might have been able to squeeze a 14.8, maybe a high 14.7x.

Next mod up is a custom Y-pipe. If it's true that the Y-pipe gives more gains to 3.5L than the cat-back, it should definitely bring some decent gains for the 4.5 L
 

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Discussion Starter · #16 ·
johnblaz2000 said:
The question now is........ how much more improved is the torque, horsepower, and MPG. What was the end result of these three requests. Good, or Bad. Is it worth that Best Bang for the Buck response. Lets us all know. :).......................................What type of top end mods have you done?
The only mod for top end is a K&N panel filter.

Torque.......I noticed today that right off the line, I could hear and feel a 'thud'. My guess is that the tranny is sensing a bit of spin at the rear wheels and shunting power to the fronts. The car NEVER did that before the exhaust. So I would guess that there's a bit more torque off the line, enough so that the trans computer feels the need to send some of power to the fronts.

Also, the car seems to pick and go easier, like there's less strain on the engine. I can accelerate at highway speeds in 5th gear at a decent clip. Before, to get the same rate of acceleration (not WOT, but at part throttle), the trans would have had to kick down into 4th.

HP..........I think it gained 10 hp up top. My traps seem to back this up.

MPG.........Too soon to tell. I just had the exhaust done yesterday (monday). I guess I'd pick up about a 1/2 mile more per gallon. (I DON'T use the trip computer, I write down the gallons at fill up and reset the odometer after every fill up. Right now, I'm averaging 18 mpg. 40/60 city/hwy. In winter, it goes down to high 16's , low 17's.)
 
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