[bigdonnyd40]

I recently installed the CG DS-1 High Flow Catted Downpipe on my 540i. The performance results were positive; slightly increased volume, slight burbles on off throttle, and possibly a placebo effect of the throttle being more responsive, but it's there. I'm currently running BM3 Stage 2 as I'm waiting for the TU fuel pump that I ordered to arrive (when it does I plan to go Stage 2+), but I must say.... this thing smells awful.

I was really hoping that it would smell similar to stock but it truly smells like I'm not using a catalytic converter. I was enjoying a spirited driving around town last night and I was getting nauseas in the car due to the exhaust smell.

Unfortunately, I didn't realize that a new downpipe gasket didn't come with the kit until my old downpipe was off the car so I had to reuse the old gasket, but my car is fairly low miles, so I doubt that is the issue as there is no audible exhaust leak.

Has anyone else deal with this issue? Does it get better as the car "breaks in" the new cat (doubtful but hopeful). I'm a little upset with the outcome here and I'm thinking about returning the TU pump, putting the old cat back on and just keeping it stage 1 (which sucks as I came from a twin turbo V8 and was hoping to get the legendary bolt on power from the B58).

Thanks.

[buddyboy]

Originally Posted by bigdonnyd40

I recently installed the CG DS-1 High Flow Catted Downpipe on my 540i. The performance results were positive; slightly increased volume, slight burbles on off throttle, and possibly a placebo effect of the throttle being more responsive, but it's there. I'm currently running BM3 Stage 2 as I'm waiting for the TU fuel pump that I ordered to arrive (when it does I plan to go Stage 2+), but I must say.... this thing smells awful.

I was really hoping that it would smell similar to stock but it truly smells like I'm not using a catalytic converter. I was enjoying a spirited driving around town last night and I was getting nauseas in the car due to the exhaust smell.

Unfortunately, I didn't realize that a new downpipe gasket didn't come with the kit until my old downpipe was off the car so I had to reuse the old gasket, but my car is fairly low miles, so I doubt that is the issue as there is no audible exhaust leak.

Has anyone else deal with this issue? Does it get better as the car "breaks in" the new cat (doubtful but hopeful). I'm a little upset with the outcome here and I'm thinking about returning the TU pump, putting the old cat back on and just keeping it stage 1 (which sucks as I came from a twin turbo V8 and was hoping to get the legendary bolt on power from the B58).

Thanks.

Those downpipe gaskets are single use, so thats most likely your culprit, you probably have an exhaust leak at that join and its getting sucked in through the aircon, also check the clamp on the bottom of the downpipe and both sensors are snug.

I've no issues with smell into the cabin with my old VRSF sports cat , so you should rule out a leak first

[bigdonnyd40]

Originally Posted by buddyboy

Those downpipe gaskets are single use, so thats most likely your culprit, you probably have an exhaust leak at that join and its getting sucked in through the aircon, also check the clamp on the bottom of the downpipe and both sensors are snug.

I've no issues with smell into the cabin with my old VRSF sports cat , so you should rule out a leak first

Okay. Hoping that's the case.... It will be such a pain reinstalling this thing again lol.

I'll get a gasket and reinstall this stupid thing.

[mike@x-ph.com]

Originally Posted by bigdonnyd40

Okay. Hoping that's the case.... It will be such a pain reinstalling this thing again lol.

I'll get a gasket and reinstall this stupid thing.

Let us know how it goes

[bigdonnyd40]

Turns out there is an audible and visible (leaks condensation + fuel on startup) exhaust at the clamp (not vband) where the downpipe meets up with the exhaust pipe.

To be clear, this is the exhaust clamp that is closer to the rear of the vehicle, not the clamp that connects to the turbo (which is where I reused the gasket).

Going to fix it tomorrow and report back.

Does anyone know what size exhaust clamp I need for that connection? Might replace the factory one or weld it (which I would prefer to avoid).

[BWilson263]

Originally Posted by bigdonnyd40

Turns out there is an audible and visible (leaks condensation + fuel on startup) exhaust at the clamp (not vband) where the downpipe meets up with the exhaust pipe.

To be clear, this is the exhaust clamp that is closer to the rear of the vehicle, not the clamp that connects to the turbo (which is where I reused the gasket).

Going to fix it tomorrow and report back.

Does anyone know what size exhaust clamp I need for that connection? Might replace the factory one or weld it (which I would prefer to avoid).

Did it fix the problem of gas fumes. I have a catted downpipe and there's some smell. I just got use to the smell and enjoy the performance.

[mike@x-ph.com]

Originally Posted by BWilson263

Did it fix the problem of gas fumes. I have a catted downpipe and there's some smell. I just got use to the smell and enjoy the performance.

with high-quality catted downpipes the smell should be barely noticeable (unless you are really sensitive to smells).

if the smell is strong, the cat might have failed

[BWilson263]

Originally Posted by mike@x-ph.com

with high-quality catted downpipes the smell should be barely noticeable (unless you are really sensitive to smells).

if the smell is strong, the cat might have failed

I have a Evolution Racewerks Catted Downpipe.

[Info@mad-us.com]

Sure its not just running super rich ? Have you logged the car with at all?

[darkrom]

Originally Posted by bigdonnyd40

Turns out there is an audible and visible (leaks condensation + fuel on startup) exhaust at the clamp (not vband) where the downpipe meets up with the exhaust pipe.

To be clear, this is the exhaust clamp that is closer to the rear of the vehicle, not the clamp that connects to the turbo (which is where I reused the gasket).

Going to fix it tomorrow and report back.

Does anyone know what size exhaust clamp I need for that connection? Might replace the factory one or weld it (which I would prefer to avoid).

Did this fix it? My catless one stinks like hell compared to other catless cars. I'm convinced theres a leak. They used a new gasket on the turbo side, so leaning towards this clamp. Was it easy to spot the leak somehow?

[BWilson263]

Originally Posted by bigdonnyd40

Turns out there is an audible and visible (leaks condensation + fuel on startup) exhaust at the clamp (not vband) where the downpipe meets up with the exhaust pipe.

To be clear, this is the exhaust clamp that is closer to the rear of the vehicle, not the clamp that connects to the turbo (which is where I reused the gasket).

Going to fix it tomorrow and report back.

Does anyone know what size exhaust clamp I need for that connection? Might replace the factory one or weld it (which I would prefer to avoid).

Did you find what was causing the smell?

[kmac1980]

FWIW I’m getting a bit of an exhaust smell at slow speeds and idle at times with my newly installed vrsf catted.

The installer said the midpipe connection was a bit loose. The factory downpipe came out very easy, almost like the mid pipe was a bit big. The factory band clamp can only close so far and it still wasn’t tight enough.

They are saying the solution is to cut off the factory band clamp (it’s spot welded on) and put an aftermarket band clamp on.

It’s strange to me as many Vrsf owners have had to use a pipe expander to get theirs to fit….