Ams catted downpipes ?

[bigfra]

Fair enough

[JR429]

This is a common problem with high flow cats. They just run dirtier and with the sensitivity of the delta of the 02's these days you'll most likely get a CEL. The other known problem with the catted downpipes is the cat rupturing out. The M5 at ~300HP per cat RIGHT BEHIND the turbo, I would bet these cats only last 20k miles or so.

Anyone have the specs to the turbine and compressor wheels? I'd be curious to see what those numbers are.

[boots]

Matt did it happen from the tight fit or by putting the cover back on?

[mstmng]

Originally Posted by Pertplus

Apparently my CEL is due to a damaged O2 sensor. I will know definitively later this week when the new sensor arrives and is installed.

Pic courtesy of HG Motorsports fixing my issues.

do you have catless or catted dp's?

[boots]

He has catted G.

[mstmng]

Originally Posted by boots

He has catted G.

[Jay-K]

so basically even those catted downpipes still get CELs...

[gmd2003]

Originally Posted by Jay-K

so basically even those catted downpipes still get CELs...

We can thank California emissions standards ( toughest on the planet ) which every US car must meet .

[greentrbo95gst]

Originally Posted by JR429

This is a common problem with high flow cats. They just run dirtier and with the sensitivity of the delta of the 02's these days you'll most likely get a CEL. The other known problem with the catted downpipes is the cat rupturing out. The M5 at ~300HP per cat RIGHT BEHIND the turbo, I would bet these cats only last 20k miles or so.

Anyone have the specs to the turbine and compressor wheels? I'd be curious to see what those numbers are.

I am surprised that all these big name companies did not take this into consideration. It seems like any way you go somehting will get damaged.

[greentrbo95gst]

So people that paid $1500 more for catted versions now they have to pay for new o2 sensors.

[JR429]

Originally Posted by greentrbo95gst

I am surprised that all these big name companies did not take this into consideration. It seems like any way you go somehting will get damaged.

there's just not a whole lot of engineering work that goes behind these products, especially when the cat companies are willing to cut corners and not inform the exhaust maker. To do it right on the M5 with the cats so close to the turbos you should be running extruded cells that are cut then tacked to the pipe which is then sent to the coaters for rare-earth catalyst spraying. I bet a lot of these cats are rolled metal cells which might be fine for your 300HP V6 normally aspirated (150HP per pipe) but not fine for a boosted 300HP+ per pipe application. Hence something lets go and destroys your 02.

Well look on the bright side - at least it's not your primary 02 that takes a beating

[JR429]

Originally Posted by Pertplus

Well, there is a question as to whether some of the material ACG applied to the O2 sensors when installing my downpipes last fall caused one to fail. Now, I didnt have a CEL for about the first 5000-5500 miles - so I dont know whether the O2 sensor went bad due to the initial installation, something unrelated to the downpipes altogether or the downpipes.

Check the cats for fractures. Typically only debris or extremely high EGT will destroy the 02. That said your 02 doesn't look like it's been in a fuel rich environment...

[bigfra]

Maybe supersprint might be the best option, it's certainly the most expensive!

[boots]

Rpi FtW!

[gmd2003]

Originally Posted by greentrbo95gst

So people that paid $1500 more for catted versions now they have to pay for new o2 sensors.

Not those of is with OEM HJS catalyzers

[Jay-K]

Originally Posted by gmd2003

We can thank California emissions standards ( toughest on the planet ) which every US car must meet .

CEL is Engine CHeck right?

[gmd2003]

Originally Posted by Jay-K

CEL is Engine CHeck right?

Yes you will get an emissions code on you're car almost immediately with catless DP's , and after 1000-5000 ish miles with the catted , depended on conditions etc . This will cause a check engine light . Also people with catless DP's and some AMS catted DP's have gotten drivetrain errors on prolonged high speed runs , likely from the ECU seeing very high exhaust gas temps on the secondary 02 sensors. The ECU thinks you are going to have a catylzer failure and shuts power down .

[Jay-K]

Originally Posted by gmd2003

Yes you will get an emissions code on you're car almost immediately with catless DP's , and after 1000-5000 ish miles with the catted , depended on conditions etc . This will cause a check engine light . Also people with catless DP's and some AMS catted DP's have gotten drivetrain errors on prolonged high speed runs , likely from the ECU seeing very high exhaust gas temps on the secondary 02 sensors. The ECU thinks you are going to have a catylzer failure and shuts power down .

so sad, i think i'm going to have to stay away from this.
had catless dp back then on my 1M, and boom problems right away with the o2 sensors...

[JoeyLeeBMW]

What is the point of getting downpipes with cats?

The point of getting the downpipes are to get rid of the cats no?

[JR429]

Originally Posted by bigfra

Maybe supersprint might be the best option, it's certainly the most expensive!

In the european tuning world price doesn't always equal quality

[JR429]

Originally Posted by JoeyLeeBMW

What is the point of getting downpipes with cats?

The point of getting the downpipes are to get rid of the cats no?

The OEM cats are typically very dense and focused on keeping the minimum emissions possible while not completely choking out the car. Aftermarket cats typically allow a lot more flow and actually probably wouldn't pass emissions testing when tested on a REAL CAFE emission test platform. But when you go to jiffy lube and load up on their dyno you can probably pass haha and it eliminates some of the smell & noise associated with fully catless exhaust systems.

[PetrolFumes]

Is the moral of the story here to keep the stock cats on?