Broken Cat...decisions decisions

[westwest888]

people don’t generally care about the efficacy. They just don’t want a CEL or a restriction.

$900 is 3 times the price of a set of aftermarket catalytic converters, and 5 times more expensive than going catless.

And OEM makes your car slower. That’s why it’s not an option.

Before you argue for the environment, don’t forget that your car is chipped (illegally in California) and that your excess tire wear over 5 years from track days vs. a conventional S4 owner creates a greater environmental impact than 5 years of running catless.

Yeah, fake catalysts without the precious metals are cheaper than real catalysts with real rare earths. There are many threads of cheap exhaust components ruining downstream exhaust components when chunks of baffling soaked in gasoline come loose and combust somewhere near one of your mufflers.

If OEM makes your car slower, then I’d like you to explain Skywagon.

I have 42,000 miles on my 2010 and people like @infinkc just crossed 100,000 miles. My urban California mass transit and walk lifestyle has a low impact.

The biggest issue with running catless is your car will smell and sound like a 1969 Mustang with straight pipes. Catalytic converters offer refinement luxury car buyers want and on a 3.0T no one has proven dyno gains from removing them. They’re simply not that restrictive and provide needed back pressure to help the engine make power at lower RPM.

[westwest888]

This is certainly a choice. I would rather weld the cat back together than spend 900 on a new cat.

But the main issues I see are: (1) we’ve seen the stg 2 tune kill cats before, so really this is something that will eventually happen; (2) how do I know the breaking apart problem won’t happen again, even if the weld is reinforced.

The JHM test pipes will be stronger, so I doubt either issue happens going catless. Plus, I’ll get to see how the car performs without the factory restriction. I’m sure I can find an aftermarket cat that performs. The issue with the aftermarket cat will be proximity to the exhaust manifold, and the factory ECM won’t dump fuel during cold start. But I’m fine with that compared to all the other disasters on the road.

You’d basically be going full racecar, as the car would have compromised resale value or technical debt that you have to rectify before you sell it. You’d be one step away from Recaro’s and a cage.

[drob23]

You’d basically be going full racecar, as the car would have compromised resale value or technical debt that you have to rectify before you sell it. You’d be one step away from Recaro’s and a cage.

So everyone here and on AZ who is catless is “full racecar”? And no shit on the other points. I don’t think your/my cars are gonna be worth anymore than the local chevy dealer will give.

[sakimano]

people don’t generally care about the efficacy. They just don’t want a CEL or a restriction.

$900 is 3 times the price of a set of aftermarket catalytic converters, and 5 times more expensive than going catless.

And OEM makes your car slower. That’s why it’s not an option.

Before you argue for the environment, don’t forget that your car is chipped (illegally in California) and that your excess tire wear over 5 years from track days vs. a conventional S4 owner creates a greater environmental impact than 5 years of running catless.

Yeah, fake catalysts without the precious metals are cheaper than real catalysts with real rare earths. There are many threads of cheap exhaust components ruining downstream exhaust components when chunks of baffling soaked in gasoline come loose and combust somewhere near one of your mufflers.

If OEM makes your car slower, then I’d like you to explain Skywagon.

I have 42,000 miles on my 2010 and people like @infinkc just crossed 100,000 miles. My urban California mass transit and walk lifestyle has a low impact.

The biggest issue with running catless is your car will smell and sound like a 1969 Mustang with straight pipes. Catalytic converters offer refinement luxury car buyers want and on a 3.0T no one has proven dyno gains from removing them. They’re simply not that restrictive and provide needed back pressure to help the engine make power at lower RPM.

So you’re saying that placing a restriction in the exhaust stream is NOT going to make your car slower? This just shows you’re out to lunch.

I recognize that the exhaust modifications (eliminating cats) don’t do much on these cars. But they don’t do zero.

[justincredible]

The choise is really simple. The cat is built with being restrictive in its definition. as it needs to trap and heat air. Cats have gotten better over the years but they still are a restriction. Knowing that stage 2 cars can kill cats further shows how there is a restriction issue.

If this was a 2000 B5 S4 I might say getting rid of the cats might make the car smell bad on cold start up. But the tech advancements on these cars changes things much more then in 2000 let alone 1969. The impact of removeing the cats can be all but eliminated in the tune. I decided to remove my cats and the JHM tune for no cats makes it so in cold weather I dont have unessessary fuel to warm the cats I dont have. Knowing how big APR is I would assume this would be part of there tune as well. Even if it was not the car has a wide band 02 and your not going to get wasted fuel.

I look at it like this. If removing the cat helps keep the motor safe then thats a savings of a 15k motor

[CCWS4]

You’d basically be going full racecar, as the car would have compromised resale value or technical debt that you have to rectify before you sell it. You’d be one step away from Recaro’s and a cage.

So everyone here and on AZ who is catless is “full racecar”? And no shit on the other points. I don’t think your/my cars are gonna be worth anymore than the local chevy dealer will give.

Running EC headers catless for some time now and my car doesn’t smell or sound like a 69 Mustang. Quite the contrary it sounds awesome with a very slight gasoline whiff that I enjoy.

[westwest888]

Running EC headers catless for some time now and my car doesn’t smell or sound like a 69 Mustang. Quite the contrary it sounds awesome with a very slight gasoline whiff that I enjoy.

Interesting. My car has to go in for its first smog inspection in March 2016. California makes you do the exhaust sniffer test on a dyno. They don’t have 4 wheel dynos so they’ll do mine with the gear shift in neutral. Kind of fucking ridiculous. They can technically fail me for changing a pipe in the intake manifold but I doubt they’ll notice. The stock airbox is there. I know it’s restrictive but it also muffles a lot of supercharger whine, a sound I don’t want to amplify.

[westwest888]

The choise is really simple. The cat is built with being restrictive in its definition. as it needs to trap and heat air. Cats have gotten better over the years but they still are a restriction. Knowing that stage 2 cars can kill cats further shows how there is a restriction issue.

If this was a 2000 B5 S4 I might say getting rid of the cats might make the car smell bad on cold start up. But the tech advancements on these cars changes things much more then in 2000 let alone 1969. The impact of removeing the cats can be all but eliminated in the tune. I decided to remove my cats and the JHM tune for no cats makes it so in cold weather I dont have unessessary fuel to warm the cats I dont have. Knowing how big APR is I would assume this would be part of there tune as well. Even if it was not the car has a wide band 02 and your not going to get wasted fuel.

I look at it like this. If removing the cat helps keep the motor safe then thats a savings of a 15k motor

Surely the -3 MPG from the tune is worse than doing 1100 RPM at idle for two minutes instead of 400 RPM.

[drob23]

The choise is really simple. The cat is built with being restrictive in its definition. as it needs to trap and heat air. Cats have gotten better over the years but they still are a restriction. Knowing that stage 2 cars can kill cats further shows how there is a restriction issue.

If this was a 2000 B5 S4 I might say getting rid of the cats might make the car smell bad on cold start up. But the tech advancements on these cars changes things much more then in 2000 let alone 1969. The impact of removeing the cats can be all but eliminated in the tune. I decided to remove my cats and the JHM tune for no cats makes it so in cold weather I dont have unessessary fuel to warm the cats I dont have. Knowing how big APR is I would assume this would be part of there tune as well. Even if it was not the car has a wide band 02 and your not going to get wasted fuel.

I look at it like this. If removing the cat helps keep the motor safe then thats a savings of a 15k motor

Surely the -3 MPG from the tune is worse than doing 1100 RPM at idle for two minutes instead of 400 RPM.

Fuel economy is fine with the tune

http://images.tapatalk-cdn.com/15/08/01/5749b726905f97f101bc94d378ea4b65.jpg

[infinkc]

Running EC headers catless for some time now and my car doesn’t smell or sound like a 69 Mustang. Quite the contrary it sounds awesome with a very slight gasoline whiff that I enjoy.

Interesting. My car has to go in for its first smog inspection in March 2016. California makes you do the exhaust sniffer test on a dyno. They don’t have 4 wheel dynos so they’ll do mine with the gear shift in neutral. Kind of fucking ridiculous. They can technically fail me for changing a pipe in the intake manifold but I doubt they’ll notice. The stock airbox is there. I know it’s restrictive but it also muffles a lot of supercharger whine, a sound I don’t want to amplify.

They don’t do the sniffer anymore if you go to a star station.my last smog all they do now is plug into the obd port and check readiness. They do a visual check still, so they might notice no cats.

[drob23]

Kind of disappointing, but me and a buddy attempted to get the stock cats out. The upper driver side bolt was a bitch, as the only socket we could get on it was a 1/4" deep wall 12 mm, and that thing was going to take a lot more torque to get off than we could give it. The 3 extension multiple wobble method could not give the needed torque. No way I was gonna get a torch in there. Didn’t even waste time pb blasting it at that point.

We were able to take off AK and sort of remove the false firewall, but didn’t attempt to slightly drop the trans. Sucks but I’ll probably just let a pro do this :-\ At least I gave it a shot.

[OldSport]

At least you made an attempt Drob, hope they can get you fixed up w/o too much expense on your part!

[drob23]

This isn’t a good sign…sigh…

http://www.audizine.com/forum/showthread.php/662728-JHM-Catless-Downpipes-installed-exhaust-sounds-horrible-please-help!

[primetime]

This isn’t a good sign…sigh…

http://www.audizine.com/forum/showthread.php/662728-JHM-Catless-Downpipes-installed-exhaust-sounds-horrible-please-help!

I wouldn’t put much credence in this example honestly… What one person hates others may like and vice versa… I’ve heard multiple B8 S4’s with headers/catless and they all sounded good… Was it loud? yes, but it was fairly mild when just cruising… You should hit Jeff up to see if he can take you for a ride in his car as he has headers so it would give you a flavor of what to expect. Just my .02

[boro92]

Catless almost always sounds bad.
Prepare your anus XD

Catless with straight pipe sounds better than catless with a baffled muffler. It will sound very tinny and raspy.
But as for the B8, I have never heard it setup this way, so primetime may be right.

I have gone catless on other cars (m3, civic, corolla gts) and all of them did not sound any good.

[drob23]

This isn’t a good sign…sigh…

http://www.audizine.com/forum/showthread.php/662728-JHM-Catless-Downpipes-installed-exhaust-sounds-horrible-please-help!

I wouldn’t put much credence in this example honestly… What one person hates others may like and vice versa… I’ve heard multiple B8 S4’s with headers/catless and they all sounded good… Was it loud? yes, but it was fairly mild when just cruising… You should hit Jeff up to see if he can take you for a ride in his car as he has headers so it would give you a flavor of what to expect. Just my .02

Yea, guess I’m just getting cold feet lol…have been in Jeff’s car but that was a while ago. I’m gonna check out mrmomo’s car tomorrow, he is awe track, so pretty much catless with straight pipes :o. Said he got a noise ticket on while cruising woodward with some likely right foot action 8)

[FastEddie]

i know we are talking two different cars but on my car ive had catless dp’s with FI exhaust and Catless JHM headers with FI exhaust into Borla XR-1 mufflers and i absolutely LOVE the sound. I get nothing but compliments from everyone.

[Jake]

The stock exhaust system never sounds good in my opinion, however with a complete exhaust it will sound pretty bad ass with the test pipes. Of course, that is my opinion again.

[drob23]

I guess the one upside of all of this is getting to unbox shiny parts ;D

https://farm1.staticflickr.com/320/20157860058_3083cd1649_b.jpg

And of course the main event

https://farm1.staticflickr.com/426/20345903485_95676a177e_b.jpg

Jake - one question I have, and excuse the paranoia (which I think is somewhat justified given what happened lol) - the welds on the flanges appear to be tack welds? So the real load bearing weld is on the inside? Would it make sense to have my installer reinforce these flanges welds just because I’m paranoid? Or there is absolutely no reason to…

Inside of flange

https://farm1.staticflickr.com/434/20319634336_a212cc0bfc_b.jpg

I know I’m being paranoid about this…

[drob23]

Another question i have is why there are a pair of O2 sensor bungs? I thought the primary O2 was on the exhaust manifold and the secondary was on the Cat. I only see one going into the factory cat.

https://farm1.staticflickr.com/292/20353420251_465a6fa476_b.jpg

The picture here only shows one

https://jhmotorsports.com/shop/catalog/images/JHM-B8-30T-Test-Pipes.jpg

and 034 only has one

http://store.034motorsport.com/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/0/3/x034_B8_S4_Downpipes_1.jpg.pagespeed.ic.HqQEgG6_Xl.jpg

What am I missing here?

Edit - on some quick searching, I pretty sure I’d just plug one of them. No biggie, just $5 part from autozone.