[alexchen86]

I'm sure this question has been asked a million times, and everyone will say talk to so and so service manager because he will let it slide...some say the manufacturer will investigate whether or not the aftermarket item you put on caused the damage to your vehicle and the manufacturer is not to blame...

So far I'm taking it real easy one step at a time...

Well seems like the more subtle power I add to my F30 the more I want!! I'm done with aesthetics until I burn out my new set of Michelin Pilot Super Sport XL's...

I really want to addd the ER Competition catless 4" DP to complement the JB4 Stage 2 and the M Performance Exhaust....but won't that fail my emission tests? I know several guys that can let me slide with illegal stuff but kind of out of my way.

[infinitigor]

a catless down pipe will void your warranty, don't even bother asking anyone at the dealership to let it slide. you will also fail emissions with a catless.

even if they do let it slide, they will put a note of it in their system and if god for bid your transmission fails or engine blows don't expect to be covered.

[tturedraider]

Originally Posted by infinitigor

a catless down pipe will void your warranty, don't even bother asking anyone at the dealership to let it slide. you will also fail emissions with a catless.

even if they do let it slide, they will put a note of it in their system and if god for bid your transmission fails or engine blows don't expect to be covered.

^ this. Even just the JB4 is taking a risk. If you ever have a problem that can be remotely traced back to it you will be sol. If you want to protect your warranty coverage you need to use Dinan products.

[stevehecht]

Originally Posted by tturedraider

^ this. Even just the JB4 is taking a risk. If you ever have a problem that can be remotely traced back to it you will be sol. If you want to protect your warranty coverage you need to use Dinan products.

Just to be clear, using Dinan products does not protect your BMW warranty. Dinan supplies its own warranty coverage. But the Dinan warranty will not protect you if you have other non-Dinan mods that they determine caused the damage to your engine/suspension/whatever. Be careful out there.

[jddssc121]

I played it safe and did the PPK

[Polo08816]

Originally Posted by infinitigor

a catless down pipe will void your warranty, don't even bother asking anyone at the dealership to let it slide. you will also fail emissions with a catless.

even if they do let it slide, they will put a note of it in their system and if god for bid your transmission fails or engine blows don't expect to be covered.

Depends on the state and how they do emissions. NJ only plugs their diagnostic computer into your OBD2 port. They no longer stick a probe into the exhaust.

[RoundelM3]

A probe in the exhaust doesn't matter - if there are no cats, the engine's OBDII system will indicate "not ready" status and it'll fail. There are gizmos out there you can get to "fool" the ECU into thinking all is OK, but the 02 sensors aren't going to like the absence of the catalysts. That condition will not allow the ECU to properly balance the fuel mixture, and the exhaust will stink really bad. Reminds me of the days of leaded gas and no catalysts - the exhaust would make your eyes water and your head hurt. There's no way the vehicle inspection people aren't going to notice the absence of the converter. At one time, tampering with federally-mandated emissions control components carried a $10,000 fine. Beyond all that, without the catalyst to burn the unburned hydrocarbons in the exhaust stream, it's polluting the air in a bad way.

Best recommendation if you just HAVE to get the few extra horsepower from a larger downpipe is to get a catted one, especially if you can get a "race" catalyst that is less dense and therefore less restrictive. Yep, even race cars have catalysts these days due to all the emphasis on pollution control at racetracks.

[S4NoMore]

Originally Posted by roundel335

There are gizmos out there you can get to "fool" the ECU into thinking all is OK, but the 02 sensors aren't going to like the absence of the catalysts. That condition will not allow the ECU to properly balance the fuel mixture, and the exhaust will stink really bad.

The post-cat O2 sensor is for determining whether the catalytic converter is working. The pre-cat sensor is for AFR adjustment. Deleting the cat will make the exhaust smell funny but the car will still be able to adjust as it normally does via the primary O2 sensor.

[utenigma]

Originally Posted by roundel335

A probe in the exhaust doesn't matter - if there are no cats, the engine's OBDII system will indicate "not ready" status and it'll fail.

Correct

Devices like the JB4 do not intercept or modify the OBDII sensors, what they do is auto-delete the check-engine code for catalytic converter/secondary O2 sensor failure. They clear the code for failure, but do not set the "emissions ready" code. Your car won't have a light, but won't pass OBD2 emissions

There are gizmos out there you can get to "fool" the ECU into thinking all is OK, but the 02 sensors aren't going to like the absence of the catalysts. That condition will not allow the ECU to properly balance the fuel mixture, and the exhaust will stink really bad. Reminds me of the days of leaded gas and no catalysts - the exhaust would make your eyes water and your head hurt. There's no way the vehicle inspection people aren't going to notice the absence of the converter. At one time, tampering with federally-mandated emissions control components carried a $10,000 fine. Beyond all that, without the catalyst to burn the unburned hydrocarbons in the exhaust stream, it's polluting the air in a bad way.

Best recommendation if you just HAVE to get the few extra horsepower from a larger downpipe is to get a catted one, especially if you can get a "race" catalyst that is less dense and therefore less restrictive. Yep, even race cars have catalysts these days due to all the emphasis on pollution control at racetracks.

The ECU can nail the AFR just fine, it doesn't care what the secondary O2 says, that's just for emissions reporting

The rest of your statements are valid, the exhaust will smell like a lawnmower and it's illegal as balls in most places. Race cat's are defiantly better than stock for performance, and likely won't trip your emissions flag, but under the letter of the law, using them carries the same penalty as using a catless downpipe. They are not approved for on-road use, nor are they "functionally equivalent" to the OEM parts which exclude them from legal use. If asked every reputable vendor will tell you the exact same thing.

From an environmental standpoint, they pollute more than the OEM design, less than not having one

Originally Posted by S4NoMore

The post-cat O2 sensor is for determining whether the catalytic converter is working. The pre-cat sensor is for AFR adjustment. Deleting the cat will make the exhaust smell funny but the car will still be able to adjust as it normally does via the primary O2 sensor.

Correct

OP, IMHO do what you want, just be informed of the consequences. Also as a fellow Texas resident, revert to stock before going to the dealer or going to inspection. You do not want to get on the list of people in texas known to bypass their emissions equipment - the DPS will pull you over for fun once you're on that list

That being said, map2 with a catless is a whole different magical world

[BEAR-AvHistory]

Originally Posted by tturedraider

^ this. Even just the JB4 is taking a risk. If you ever have a problem that can be remotely traced back to it you will be sol. If you want to protect your warranty coverage you need to use Dinan products.

You just take the JB4 off for warranty service, about 1/2 hour job..

For regular stuff, oil change, filters & brakes etc leave it in. Just zero out the codes shift to MAP 1 & lock out the steering wheel buttons.