[XM Label]

I found a way to keep valves open. Cold start, with tailgate open, pull fuse 203 from rear right fuse box and valves stay partially open. I think it sounds louder but didn’t measure scientifically. No CELs. Wonder what everyone else thinks when you try it, easy mod.

[XM Label]

Ok. I have been driving with this mod for two days now. If you have an XM and want a little louder exhaust you need to do this ASAP. Have someone cold start for you in the morning and immediately pull the brownish red fuse 203 (has 7.5 written on it) from fuse box in right side of rear trunk behind removable felt door.

Here is my honest opinion on what it does.

More burbles and crackles. I notice this when I rev the engine after a cold start. Unfortunately it doesn’t stay that loud all the time (I wish) but much improved from stock. Also before pulling fuse after driving for five minutes the cracks and burbles usually stop as system becomes warmer. Now I can cause cracks and burbles all the time as long as under 55mph. The cracks and burbles don’t disappear after 5 minutes. You won’t regret it!

[XM Label]

One more thing I would like to add. Before doing this mod after 60 mph I couldn’t make any burble noises. Today I was up past 75mph and hearing burbles….not just the piped ones from speaker but real ones with windows down…..

[r33_RGSport]

Originally Posted by XM Label

One more thing I would like to add. Before doing this mod after 60 mph I couldn’t make any burble noises. Today I was up past 75mph and hearing burbles….not just the piped ones from speaker but real ones with windows down…..

I have been having quite some burble.
Not sure if it is because the secondary or not, since I have had the secondary installed not long after I got the car.

[XM Label]

Originally Posted by r33_RGSport

I have been having quite some burble.
Not sure if it is because the secondary or not, since I have had the secondary installed not long after I got the car.

Do secondaries have cats?

[XM Label]

If pulling fuse at cold start the valves stay open at 30%. Today I pulled fuse during full throttle at 45 mph and valves are 100% open now.

[r33_RGSport]

Originally Posted by XM Label

Do secondaries have cats?

The ER doesn’t have it.

[XM Label]

Originally Posted by r33_RGSport

The ER doesn’t have it.

How does one pass emissions without cats?

[r33_RGSport]

Originally Posted by XM Label

How does one pass emissions without cats?

Secondary is not monitored.
At least for US market.

[XM Label]

Originally Posted by XM Label

If pulling fuse at cold start the valves stay open at 30%. Today I pulled fuse during full throttle at 45 mph and valves are 100% open now.

Pulling fuse did cause fault seen on OBD reader FYI. So do it at your own risk!

[xxrobo818xx]

Originally Posted by XM Label

If pulling fuse at cold start the valves stay open at 30%. Today I pulled fuse during full throttle at 45 mph and valves are 100% open now.

So have to have someone in the trunk and full throttle when it gets to 45 pull out?

[XM Label]

Originally Posted by xxrobo818xx

So have to have someone in the trunk and full throttle when it gets to 45 pull out?

Yes.

[mani_is_kool]

New XM owner here as I just picked up a 2023 two weeks ago. The exhaust is super quiet. Does this change after the 300 mile ICE unlock ?
I barely notice any difference in sound between comfort and sports plus. Also on my precious cars and current M550, u can hear the valves close n open when switching drive modes but not on this one.

[r33_RGSport]

Originally Posted by mani_is_kool

New XM owner here as I just picked up a 2023 two weeks ago. The exhaust is super quiet. Does this change after the 300 mile ICE unlock ?
I barely notice any difference in sound between comfort and sports plus. Also on my precious cars and current M550, u can hear the valves close n open when switching drive modes but not on this one.

It gets louder with the more you drive it in ICE mode.
Yes, it is quiet from the inside since this car is luxury sport SAV. A lot of insulation.
But, from the outside, it is pretty loud.
I am not sure if mine is loud because of the secondary cat delete, or just because I have been driving a lot in ICE mode.
All of my customers that visited me said it sounds pretty loud when I revved it for them.

[mani_is_kool]

Originally Posted by r33_RGSport

It gets louder with the more you drive it in ICE mode.
Yes, it is quiet from the inside since this car is luxury sport SAV. A lot of insulation.
But, from the outside, it is pretty loud.
I am not sure if mine is loud because of the secondary cat delete, or just because I have been driving a lot in ICE mode.
All of my customers that visited me said it sounds pretty loud when I revved it for them.

Thanks for the response. Unfortunately just leased ours and won't ve able to cat delete. So did you mean that driving more on ICE gradually makes the exhaust louder over time?
And also, 300 mile unlock wont make any difference ? Previously on the 1200 mile unlock on my m3cs and m8 both changed the sound much deeper and louder.

[r33_RGSport]

Originally Posted by mani_is_kool

Thanks for the response. Unfortunately just leased ours and won't ve able to cat delete. So did you mean that driving more on ICE gradually makes the exhaust louder over time?
And also, 300 mile unlock wont make any difference ? Previously on the 1200 mile unlock on my m3cs and m8 both changed the sound much deeper and louder.

Mine and many are also on lease.
It is not full catless, just the secondary.
Just drive on ICE mode as much as possible.
I drive mine 99% ICE mode.
With exhaust gas heat to the muffler packing material will makes it less dense, hence more sound.