Hackjob (Sort of) Downpipe + 2-Cat Delete

ZyroXZ2

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Sooo, I'm a little slow getting the K&N Intake pics posted mostly because I wanted that 400HP mark...

I had my exhaust guy slap together some piping I picked out from Summit Racing and do a 2-cat delete (as we all know, there are 4 cats: two bolted to the turbos, and two bolted at the ends of the downpipe). What you're about to see looks jenky because the polished 304 stainless bends were on sale and cheaper than the non-polished 409 stainless bends. But because I was clearly trying to be cheap, the non-polished 409 straights were cheaper then the polished 409 straights. Trust me, I'm not proud of it, but for $450 total (parts + labor), the top-end gains were worth it:



Now that your eyes have been hurt, there are some interesting things to note about doing a 2-cat delete downpipe setup.

1) My setup is definitely custom: you can see that the S-bend is almost entirely removed. This reduces pipe length and restriction, and my exhaust guy felt that the mounts were sufficiently stiff enough that the 3/4" clearance I had with the chassis would never be a problem. So far, he's proven correct. You'll also notice that one side is actually further out than the other, and my exhaust guy got caught off guard after making two identical downpipes. I didn't even notice it at first, either, but looking at the factory ones also shows that the bends are slightly different on each side. Strange, because I didn't notice they weren't identical until I actually had the factory downpipes in my hands.

2) The loss of low-end and mid-range torque is off-putting. However, over a few dozen miles, the ECU adjusts, and you find yourself getting used to the more linear pedal feel instead of that "quick" accelerating lurch that 99% of cars from the factory come like. It does make the pedal feel "heavy", though. Not physically, but engine-response wise.

3) The gain in top-end power starts around 4K RPM, and combined with my catback and intakes, makes the 1-2 shift significantly harder to catch on the paddles/shifter. However, since every shift thereafter stays above 4K RPM, the increase in pull at this range is incredible and could easily equate to 400HP. I plan on getting a "baseline" dyno before I move forward with more aggressive mods like the chip and ECU tune I have planned.

4) Your engine and exhaust will become significantly louder. I noticed more growl in my exhaust, and resonance points are significantly more of a rumble than a vibration. The engine at full throttle is signficantly louder, too, as you're generating a lot less backpressure and a lot more pipe noise just underneath the firewall.

All-in-all? A downpipe + 2-cat delete brings out some power for sure. It makes your car growl more and pulls noticeably harder above 4K RPMs.

And no, I don't have any jokes for this 2-meow neutering mod. :whistle:
 
Wow! impressive. Excuse my ignorance, but this is ran with the remaining exhaust stock? or are you running an aftermarket catback system?
 
Looks good to me .
 
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Wow! impressive. Excuse my ignorance, but this is ran with the remaining exhaust stock? or are you running an aftermarket catback system?

I know the post was a bit long, but I did state I have a catback exhaust in there, lol

Looks good to me .

Looks like trash to me, but since 2-3 years down the road all the pipes will be covered in discolored surface oxidation, I let my budget-self get the best of me :rofl:
 
From interior to exterior to high performance - everything you need for your Stinger awaits you...
The sad thing is, we here in switzerland can't do things like this. The law is to strict. So if a cop see me without the secoundary cats, they give me a big fine and in the worst case, they can impound my car (hope its the right word). For that reason i just cleared the inside of the cat out on my audi s4 b6. Sounded so much better and accelerated better.
 
The sad thing is, we here in switzerland can't do things like this. The law is to strict. So if a cop see me without the secoundary cats, they give me a big fine and in the worst case, they can impound my car (hope its the right word). For that reason i just cleared the inside of the cat out on my audi s4 b6. Sounded so much better and accelerated better.

How would a cop notice your cats are missing though? Do they actually get under the car for a visual inspection?
 
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It doesn't look bad. Like you said, a few months baking from the heat and getting dirty will make them all look the same.
 
The sad thing is, we here in switzerland can't do things like this. The law is to strict. So if a cop see me without the secoundary cats, they give me a big fine and in the worst case, they can impound my car (hope its the right word). For that reason i just cleared the inside of the cat out on my audi s4 b6. Sounded so much better and accelerated better.

That's a good point - that's what we do with motorcycles. The cat is built into the standard exhaust pipe, and you can remove it with a long heavy screwdriver and a hammer. We call it "gutting" .. which is the term for pulling the internals out of a fish or animal for preparing to eat it.

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From interior to exterior to high performance - everything you need for your Stinger awaits you...
That's a good point - that's what we do with motorcycles. The cat is built into the standard exhaust pipe, and you can remove it with a long heavy screwdriver and a hammer. We call it "gutting" .. which is the term for pulling the internals out of a fish or animal for preparing to eat it.

3472945874_75e1498677_o.jpg


imageproxy.php
Yea I was thinking about gutting my cats also so that nobody would know especially kia since I take my car to the dealer for maintenance. But is it a easy to do or is it a PITA job that takes patience.
 
The sad thing is, we here in switzerland can't do things like this. The law is to strict. So if a cop see me without the secoundary cats, they give me a big fine and in the worst case, they can impound my car (hope its the right word). For that reason i just cleared the inside of the cat out on my audi s4 b6. Sounded so much better and accelerated better.

Actuallllllyyyyyy, we can't really do these things over here, either... ... lol... If a cop is feeling particularly vile, we'll suffer all the same things you just said :rolleyes:

How would a cop notice your cats are missing though? Do they actually get under the car for a visual inspection?

They can if they're suspicious enough and really want to ruin your day. A cop can on reasonable suspicion check for illegal mods on a vehicle. That's why I'm worried about all the noise I make with the new intakes: you just don't want to give the wrong cop any reasons to start poking around. It's the same reason I don't tint my windows on any car I've modded. The more "open" you seem about yourself and your car, the less likely they are to see what you've got going on ;)
 
How would a cop notice your cats are missing though? Do they actually get under the car for a visual inspection?


If they want to "f*ck" you... Yes they doo. The cops over here are very avere of tuned car driver's. Hope thats the correct word. If they dont like your nose they search till they find something....
 
From interior to exterior to high performance - everything you need for your Stinger awaits you...
A set of test pipes would be the easiest way.

Like one of these: High Flow Cat
 
Gutting cats can be a pain (and is messy). I generally wouldn't even dare do that unless it's a last resort because you know your local cops are the "pick on a noisy ricer" kind of mob. That, and you're basically gutting the most expensive part of a cat making it kind of sad when you could still use that cat as a swap for smog or something.
 
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