# 2003 SE-R Spec V exhaust mystery



## skye3000 (Nov 13, 2008)

I'm trying to figure out the exhaust system on my sentra. The owner before me put a custom exhaust on. It was a muffler and larger pipe from the middle back to the muffler. I thought they cut the catalytic converter out but according to the muffler shop the catalytic converter is on the exhaust manifold. I thought there was also a rear catalytic converter before the muffler. He's telling me that there might just be a resonator. Can anyone shed some light on this for me?

My ultimate goal is make my exhaust quieter. I have the stock muffler on it but it doesn't sound right at all. I also want to make my service engine light go out. The code says something like Catalyst system efficiency below threshold. I assumed that was because it had no cat.


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## saint0421 (Sep 24, 2006)

Too lazy to post the pics, so I posted the link. 

The Exhaust System Explained - MSV


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## skye3000 (Nov 13, 2008)

Thanks! that helps.

looking at the diagram and comparing it to mine, it looks like they removed the catalytic converter and replaced the pipe from the midpipe, clear back to the muffler. They had an aftermarket muffler on it but I took it off because it rattle the hell out everything. Too loud. 

So I guess my next question is, what kind of muffler can I get that will be nice and quiet? And can I fix the sensor for the catalyst efficiency threshold so it doesn't trip my service engine light?


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## El Duende (Jun 4, 2009)

skye3000 said:


> Thanks! that helps.
> 
> looking at the diagram and comparing it to mine, it looks like they removed the catalytic converter and replaced the pipe from the midpipe, clear back to the muffler. They had an aftermarket muffler on it but I took it off because it rattle the hell out everything. Too loud.
> 
> So I guess my next question is, what kind of muffler can I get that will be nice and quiet? And can I fix the sensor for the catalyst efficiency threshold so it doesn't trip my service engine light?


I'd go with the stock exhaust. It should be subtle at lower speeds, but throaty at WOT. As for the sensor, are you referring to the ones in the header? I don't know about the QR25DE models too well, but seeing as how I know people who do, I can find that out for you.


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## skye3000 (Nov 13, 2008)

I have the stock muffler on now. I don't really like it. I put it back on after I bought the car because the aftermarket one was really loud. It is fine at lower speeds but when you get on it, it sounds sorta girgley and higher pitched. I don't know how to explain it. I would like something that is a little deeper but still quiet at idle and lower rpm (3000 to 4000 is usually cruising rpm I think)

As for the sensor. I have no idea which one is throwing the code. I'll have to hook it up again and see what the exact code is. I assumed there was a sensor in the rear cat. The one in the precat at the header should still be intact.


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## El Duende (Jun 4, 2009)

skye3000 said:


> I have the stock muffler on now. I don't really like it. I put it back on after I bought the car because the aftermarket one was really loud. It is fine at lower speeds but when you get on it, it sounds sorta girgley and higher pitched. I don't know how to explain it. I would like something that is a little deeper but still quiet at idle and lower rpm (3000 to 4000 is usually cruising rpm I think)


I see. Perhaps that exhaust piping was too big for your application. I'm not sure if you're aware of this, but the Spec-V has more horsepower than the SE-R because of a _revised exhaust system_. Knowing that, I'd keep the stock exhaust on. But hey, if it's impressive sound that you're after, I really can't answer your question. I know that the HKS exhausts made for the Sentra SE (SR20DE) fit my platform (1.8L Sentra) perfectly and produced a very bassy tone. That made the engine sound louder and more powerful than it really is. It was hushed at idle, but more commanding at high RPM. Maybe they'd be worth looking into. 

HKS USA Driving Performance - Homepage

If you want some clips, just let me know and I'll provide some links.

And here's a link validating what I was referring to earlier about the stock exhaust:

2002 Econosport Sedans Comparison Test


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## saint0421 (Sep 24, 2006)

HKS doesnt make an exhaust for the QR powered B15s
There's. . . 
Stroming
Apexi WS2
Apexi N1
OBX
Nismo
XS Power
Megan
Magnaflow
Greddy
Borla
Vibrant
Thermal R&D
and of course ebay knockoffs

I personally have the WS2. subtle @ idle and comes alive at WOT


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## El Duende (Jun 4, 2009)

saint0421 said:


> HKS doesnt make an exhaust for the QR powered B15s
> There's. . .
> Stroming
> Apexi WS2
> ...


Oops! My bad OP! 

That is a very good list! You've got many choices.


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## skye3000 (Nov 13, 2008)

do you think converting the section of larger exhaust pipe back to the stock size would make a difference in the sound and/or performance even without the cat?


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