View Full Version : Stock exhaust with gutted cats
cspcrx
10-23-2018, 01:51 PM
Anyone have a video of how this sounds?
I don't have a video. Don't have an S4, only a Q5 with the same engine. But, with every car I've ever owned that I have modified to run catless in a number of different platforms (quite a few over the years), there has been one common denominator:
DRONE. I mean serious, headache producing drone after the cats are deleted.
Of course, it will be louder as the cats do tend to reduce volume. But, I could live with that were it not for the drone. I've always had to make downstream changes -- usually some straight-through resos, to make it bearable in the cabin at cruising speed and when decelerating through the rpm band where the drone develops.
Maybe I'm wrong. I hope so. I'd love to hear a video of stock exhaust and cats deleted, but I'd need to know not only how it sounds at idle or at WOT, but also what it sounds like when cruising and decelerating in normal driving -- where the driver spends most of his time.
bhvrdr
10-23-2018, 02:17 PM
https://www.audizine.com/forum/showthread.php/811965-Does-anyone-run-test-pipes-with-a-completely-stock-exhaust
Mike
Morritse
10-23-2018, 02:21 PM
I have gutted cats. Mostly stock system. Sounds fine. The only mods I did are center res delete and magnaflow X pipe in place of baby res. No rasp. No drone.
drone at 90MPH (https://youtu.be/BGQWzhAfK1g)
some revs (https://youtu.be/ExubD7CckSE)
https://www.audizine.com/forum/showthread.php/811965-Does-anyone-run-test-pipes-with-a-completely-stock-exhaust
Mike
Sounds like the adding the Magnaflow resonated X-pipe takes care of the drone. I wonder how bad it would be without it. The resonated X-pipe would work much like the Vibrant Ultraquiet straight-through resos that work so well for big power turbo four bangers running catless.
When (not if) my cats fail that resonated X-pipe may be the route I go.
Morritse
10-23-2018, 02:24 PM
Sounds like the adding the Magnaflow resonated X-pipe takes care of the drone. I wonder how bad it would be without it. The resonated X-pipe would work much like the Vibrant Ultraquiet straight-through resos that work so well for big power turbo four bangers running catless.
It's fucking terrible lol. I drove it for a week or so without it. Rasp is even worse.
bhvrdr
10-23-2018, 02:34 PM
Sounds like the adding the Magnaflow resonated X-pipe takes care of the drone. I wonder how bad it would be without it. The resonated X-pipe would work much like the Vibrant Ultraquiet straight-through resos that work so well for big power turbo four bangers running catless.
When (not if) my cats fail that resonated X-pipe may be the route I go.
Yup thats what im doing and adding a couple bullet cats in the "Y"
I ordered these just in case...
https://rover.ebay.com/rover/0/0/0?mpre=https%3A%2F%2Fwww.ebay.com%2Fulk%2Fitm%2F26 3439982802
Who knows. Maybe ill never need to do it.
cspcrx
10-23-2018, 03:11 PM
I have gutted cats. Mostly stock system. Sounds fine. The only mods I did are center res delete and magnaflow X pipe in place of baby res. No rasp. No drone.
drone at 90MPH (https://youtu.be/BGQWzhAfK1g)
some revs (https://youtu.be/ExubD7CckSE)
That's not bad at all! that is exactly what I was looking for. I do not want a loud exhaust but know its only a matter of time before my cats let go. UC goes in next week which will further accelerate this. So the X-pipe is the key.
Looks like Magna flow is a universal item at $95 vs ECS at $225. Which model Magnaflow did you get? I presume you just had an exhaust shop do it.
Morritse
10-23-2018, 03:25 PM
That's not bad at all! that is exactly what I was looking for. I do not want a loud exhaust but know its only a matter of time before my cats let go. UC goes in next week which will further accelerate this. So the X-pipe is the key.
Looks like Magna flow is a universal item at $95 vs ECS at $225. Which model Magnaflow did you get? I presume you just had an exhaust shop do it.
The magnaflow and ECS part are different. One replaces the center res and one replaces the baby res. You it's like 11385 or something for the magnaflow.
cspcrx
10-23-2018, 03:30 PM
I was just looking and it is that part number 11385. Great thank you
the interior sound isn't horrible, I don't actually recall any drone to be honest. However, without an X-pipe, it'll sound like 2 3cyl engines....
cspcrx
10-23-2018, 06:02 PM
Thanks all. Anyone have any pics from underneath that shows the exact location and placement of Magnaflow?
Zackpistols
10-23-2018, 06:36 PM
I to am curious on this.
How it would sound?
Is there any power added?
I came from the b6 s4 platform and piggies are normal so this would be equivalent to that correct?
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EAFLO88
10-23-2018, 06:45 PM
No power added, that I can confirm. You’ll have the companies selling test pipes mention that you’ll gain X amount of whp. That’s all BS and it’s simply pure sound added. I’ve been running Becker Test Pipes for months and I’ve combated the drone/raspiness, with the MF 11385. It literally quiets things down by 90%. The only drawback with test pipes or gutted cats is the horrible gas smells..
Zackpistols
10-23-2018, 07:34 PM
Very interesting.. no power added.
I wonder why its has no effect on power when removing them. Now i will have to google the hell out of this since it will not leave my brain. If any one has sites or better yet dyno sheets this would help.
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Morritse
10-23-2018, 07:36 PM
Thanks all. Anyone have any pics from underneath that shows the exact location and placement of Magnaflow?
I do!
https://i.imgur.com/HkCutuz.jpg
cspcrx
10-23-2018, 07:40 PM
That fits really nice in there! Thanks!
cspcrx
10-25-2018, 10:54 AM
I have been reading through a bunch of threads and links, thanks again all. Morritse it looks like this illustration may be yours or someone who did exactly like you did.
http://www.mys4.org/uploads/4/0/8/5/4085984/1882e398-ba3b-4de3-901e-bc36e048b319_orig.png
I imagine if all I did was swap the resonators in the down pips with the Magnaflow 11385 and left the center resonator it would be even quitter. It does not appear, based on all the threads I have read anyone has done that. Some of left the down pipe resonators and swapped the center resonator with the 11385.
Morritse
10-25-2018, 12:45 PM
I have been reading through a bunch of threads and links, thanks again all. Morritse it looks like this illustration may be yours or someone who did exactly like you did.
http://www.mys4.org/uploads/4/0/8/5/4085984/1882e398-ba3b-4de3-901e-bc36e048b319_orig.png
I imagine if all I did was swap the resonators in the down pips with the Magnaflow 11385 and left the center resonator it would be even quitter. It does not appear, based on all the threads I have read anyone has done that. Some of left the down pipe resonators and swapped the center resonator with the 11385.
Well. In that diagram you still have cats. If you are planning on going catless. I would probably keep the center res in and see if it's loud enough for you. I have some buddies that did what you were referring to. Tone was good, but too quiet for their taste.
cspcrx
10-25-2018, 02:12 PM
My plan would be gutted cats, so physically they are still there, then put Magnaflow in place of downpipe resonators like you did and leave the center resonator in place. I do not want loud I just want to control rasp and drone of having gutted cats.
This is all future planning as I know its only a matter of time before the cats go and I have another pair sitting in the garage gutted.
mys4.org
10-25-2018, 03:33 PM
I have gutted cats. Mostly stock system. Sounds fine. The only mods I did are center res delete and magnaflow X pipe in place of baby res. No rasp. No drone.
drone at 90MPH (https://youtu.be/BGQWzhAfK1g)
some revs (https://youtu.be/ExubD7CckSE)
Assuming you are using the Magnaflow 11385 (https://amzn.to/2CChUDX) it is crazy when I compare it to my setup, which is nearly the same, plus cats still in place, how the sound is the same. (Listen here: https://youtu.be/XWc-EatwLmY)
I almost dare say the the shape of the cat piping is more of a factor of sound vs the material in it.