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Discussion Starter · #1 ·
If you were to get a Hotshot Header a Stromung Mid-Pipe and a Stromung Cat-Back would this be a complete new exhaust? I am just wondering what the weak point of the exhaust would be. I figure the Headers bypass the first Cat altogether and the Mid-Pipe either connects to or replaces second Cat??? and the Cat-Back connects to either the Cat or Mid-Pipe?? Which is it?
 

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Ive got a 91 and on my car the cat sits between the downpipe (header part) and the mid-pipe. FWIW, on a NA car youre gonna need some backpressure.

When you say weak link in the exhaust, if you go with a new midpipe, youre freeing up *maybe* 1-2hp. But on NA, a little backpressure can sustain what torque you have.

In fact, I replace my Stillen exhaust with a no-name-whatever-was-in-the-back-room exhaust of my local fix-it shop when my Stillen rusted. The sound level was WAY lower, plus I didn't feel any seat-of-the-pants difference.

The biggest difference I could feel was in the header (I have a HS).

SCC removed the cat of a NA 240sx and was dyno'd with *less* torque and hp than with it.

Save your money. Bypass the complete exhaust and go with header&muffler.

Although now that I think about it, its not like you could save up for cams or ECU. Oh well.
 

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Discussion Starter · #3 ·
cmon guys, someone has to know this. Don't some of you guys run this setup and if so Does it leave anything Factory on exhaust??
 

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Bottom line: the cat stays.

The midpipe bolts up to the cat. The header bolts up to the cat. But don't replace the cat. Stock does not equal suck (unless you are turbo). Its been proven that removing the cat does *not* free up any hp.On the contrary, removing the cat and replacing it witha straight pipe may rid you of a couple of ft/lbs of tq.
 

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The header collects the exhaust gases from the cylinder. (This bypasses the first close coupled cat that is on the factory manifold). Then the exhaust gases go through the factory cat. Then after this, it goes on to the Midpipe...then out the exhaust. Cat-back exhaust means exactly what is in the name. It replaces all the piping after the catalytic converter. If you want, you can always buy an aftermarket free flowing cat from Random Technology or Edelbrock. Or if you really want to free up horses, do a straight pipe. But be warned that your car is gonna be really loud and sound like a Harley and you will not pass inspection.

If you also want to free up the airflow more, do the Cold Air Intake, bore out the Throttle body, get a fuel pressure riser and get your cylinders ported and polished. This will give you maximum gains in the flow department.
 

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Discussion Starter · #6 ·
So you say that the Cat-Back Replaces all piping after the cat. You also say that after the Header connects to the second Cat. Question is if this is True, Why do we need a Mid-Pipe!!! Brain Fart or am I missing something.
 

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Just to reiterate, but its been *dyno* tested time and time again, an aftermarket cat does nothing for hp. Neither does removing it.

Slapping a K&N sticker on your windshield will get you more power than those options. ;)

The cat is only robbing power if you are *boosted*

An aftermarket cat is a solution if you need a *cheaper* alternative to OEM and yours is hollowed out, but I cant imagine a 2k Sentra like that. My 91 SE-R cat is fine.

Cat replacements are a waste of brain energy according to exhaustive (ugh) testing done by others before us in the SR20DE domain. (check se-r-lists.org archives)
 

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If you have a B15 SE then I would consider the factory midpipe as the weak link. The Variable capacity muffler on the SE is not supposed to be that bad. I have the Stromung midpipe w/ the factory muffler and I noticed a small gain on the butt dyno. My opinion is to get the header then save for a full catback(midpipe and muffler included) that way you will have no weak link. just my .02. later
 

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Ok Fellows correct me if I'm wrong but it sounds like from all this...that if you want to help engine breathing you should probably do the following in order:
1. CAI
2. Headers
3.CAT-back

SOunds like the cat-back does'nt do anything but make noise if you're not changing out the whole piping, is that correct?
The reason I'm asking all that was I was planning on doing my mods (just thinking) and I was trying to decided which to do first..headers/cat-back? I'm getting my PLace racing CAI Any advice? :)
 
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