Real Talk: Catless downpipe (my experience)

[forum_ghost]

Just wanted to briefly share my experience an opinion for anyone wanting to get a catless DP. Another member said something and it made me realize that i feel the same and just wanted to say something.

A lot of times, people do certain mods and won't own up if it was a bad decision. I see a lot of people talking about their experience with DPs and I'm beginning to think that some are not honest about it.

I have a F85 X5M, AFE intake, a few cosmetic mods and running BM3 tune. yesterday I installed a set of VSRF ceramic coated DPs after listing to all clips i could find online. Installation went great and before even driving it aggressively (shop is down the street and was stuck in traffic), I went home and immediately flashed to the BM3 stage 2, 93 octane tune. I took the car for a test drive right after.

My findings?

The Good -the car was definitely more powerful, the acceleration felt almost uncontrollable as the nose of the vehicle lifted up when I did a launch from a dig....butt dyno says significant power (mostly due to the tune, DP, intake combination.....Great

The Bad - THE CAR IS WAAAAYYY TOO LOUD! I didn't buy an X5M for it to sound like a freaking 90s civic with a fart can on steroids!...granted my exhaust is stock but for some reason, my car is louder than any clip i've heard....it's so loud that i find myself driving in efficiency mode very conservatively. because as soon as i open it up, every person on the street will get whiplash and the dead will rise.....I can't do it.

Long story short, I'm removing them next week and will either go catted or back to stock. Hope this helps anyone thinking about buying.

Oh. lastly there is definitely a smell, but i think i can live with it if it wasn't so loud....just thought i would share my negative experience.

[StatenEye]

Yea never go cheap with catless pipes, will sound like a tin can. Gut stock pipes and you wont get waste gate rattle.

[StatenEye]

Originally Posted by forum_ghost

The Bad - THE CAR IS WAAAAYYY TOO LOUD! I didn't buy an X5M for it to sound like a freaking 90s civic with a fart can on steroids!...granted my exhaust is stock but for some reason, my car is louder than any clip i've heard....it's so loud that i find myself driving in efficiency mode very conservatively. because as soon as i open it up, every person on the street will get whiplash and the dead will rise.....I can't do it..

Furthermore, I would inspect the installation when they put the car up. Sounds like they didn't put the vband clamps back on or the pipes have terrible fitment if its that loud. Even if you leave off the gaskets it shouldn't be that loud. Mine sounds stock unless I get on it, especially with the valves closed. If I drive in normal mode, what ever the car's default is, it sounds very pedestrian. I have 2 cars with this engine with no cats and my brother has an F10 M5 and all 3 sound slightly louder than stock under normal driving conditions. I did the install for all 3 so i know everything was done correctly. 2 have nice AR pipes and my brothers we hollowed out stocks.

Should sound something like this. https://streamable.com/2utnlv

[NikNala]

Originally Posted by StatenEye

Furthermore, I would inspect the installation when they put the car up. Sounds like they didn't put the vband clamps back on or the pipes have terrible fitment if its that loud. Even if you leave off the gaskets it shouldn't be that loud. Mine sounds stock unless I get on it, especially with the valves closed. If I drive in normal mode, what ever the car's default is, it sounds very pedestrian. I have 2 cars with this engine with no cats and my brother has an F10 M5 and all 3 sound slightly louder than stock under normal driving conditions. I did the install for all 3 so i know everything was done correctly. 2 have nice AR pipes and my brothers we hollowed out stocks.

Should sound something like this. https://streamable.com/2utnlv

M5's have X pipes in the factory exhaust so the tone is different from the F85/F86 which have no H or X pipe. The X5M without cats and the factory exhaust has rasp under high load around 3k RPMs. Most likely this is what he's talking about.

[StatenEye]

Originally Posted by NikNala

M5's have X pipes in the factory exhaust so the tone is different from the F85/F86 which have no H or X pipe. The X5M without cats and the factory exhaust has rasp under high load around 3k RPMs. Most likely this is what he's talking about.

Which downpipes do you have?

[StatenEye]

We should use this as an opportunity for everyone to post which pipes they have and their experience for reference... for others to know which setups to avoid. I never went with an aftermarket exhaust with catless because the truck just sounds perfect like this.

[1norseman]

Originally Posted by forum_ghost

Just wanted to briefly share my experience an opinion for anyone wanting to get a catless DP. Another member said something and it made me realize that i feel the same and just wanted to say something.

A lot of times, people do certain mods and won't own up if it was a bad decision. I see a lot of people talking about their experience with DPs and I'm beginning to think that some are not honest about it.

I have a F85 X5M, AFE intake, a few cosmetic mods and running BM3 tune. yesterday I installed a set of VSRF ceramic coated intakes after listing to any clips i could find online. Installation went great and before even driving it aggressively (shop is down the street and was stuck in traffic), I went home and immediately flashed to the BM3 stage 2, 93 octane tune. I took the car for a test drive right after.

My findings?

The Good -the car was definitely more powerful, the acceleration felt almost uncontrollable as the nose of the vehicle lifted up when I did a launch from a dig....butt dyno says significant power (mostly due to the tune, DP, intake combination.....Great

The Bad - THE CAR IS WAAAAYYY TOO LOUD! I didn't buy an X5M for it to sound like a freaking 90s civic with a fart can on steroids!...granted my exhaust is stock but for some reason, my car is louder than any clip i've heard....it's so loud that i find myself driving in efficiency mode very conservatively. because as soon as i open it up, every person on the street will get whiplash and the dead will rise.....I can't do it.

Long story short, I'm removing them next week and will either go catted or back to stock. Hope this helps anyone thinking about buying.

Oh. lastly there is definitely a smell, but i think i can live with it if it wasn't so loud....just thought i would share my negative experience.

So, I "only" have the 50i, not X5M, and no downpipes, ...yet. I have been considering them, and thus noticed this post...
I'm thinking I should pipe in with my experience... (pun intended)

Due to many circumstances, I ended up driving without midpipes for a few weeks. Had temporarily installed 90° bends pointed towards the ground, right after the resonators. I'm sure my neighbors hated me for it. Was loud AF.

The other day I finally got my midpipes back from welding shop, now with my custom made X-pipe installed. Currently(again temporary) the 90° bends are pointed towards the ground, but right after the rear axle instead. (Hope to get time for tailpipes next week)

To make a long story short... The x-pipe toned the exhaust way way down. What a difference in sound. Now more than tolerable as it sits, a totally acceptable sound level, even when stomping on the gas. I could leave it like this, except I want to vent the exhaust out from the bumper, not under the car.

Anyway, my suggestions before you remove the DP:
Install an X-pipe or at least get an H-pipe in the system.
Also, in the muffler delete thread, people have posted about installing different resonators, when going catless, and it that helped with the sound. You can try this before you give up on the catless DPs.

[cr8tive]

I have the same setup, forum_ghost. My thoughts exactly like yours. However, I will be keeping them on and put up with the sounds until I can get an aftermarket exhaust.

[F85MTuNED]

I'm running Active Autowerks downpipes and thank GOD I know nothing of this civic sound lol.. now I do agree that the tone can be deeper and there's a few ways to fix that but as for now my car sounds pretty damn good.

[StatenEye]

Originally Posted by F85MTuNED

I'm running Active Autowerks downpipes and thank GOD I know nothing of this civic sound lol.. now I do agree that the tone can be deeper and there's a few ways to fix that but as for now my car sounds pretty damn good.

Yea same here, AA pipes.

[KLR X5M]

All downpipes sound the same on this platform. Its people's idea of what sounds "good" that varies. Catless with stock exhaust sounds rattling and raspy on part throttle when the valves open. Fact. It sounds wild and aggressive at WOT, so some people accept the trade off. The power when combined with tune makes it 100% worth it. But if you're like the op or myself, i wanted a bit more refined sound. I added 3" vibrant ultra quiet resonators in place of the stock bottle style ones and added an x pipe. Problem solved. Was almost too quiet at first, but as the resonators broken in it's perfect now. Refined, quiet when you want it to be, aggressive and mean when you are in sport modes and shifting manually. Downpipes always come with trade offs. Some smell alot, some cause smoking issues, some exacerbate the bad frequency pulses. You have to decide if the power trade off is worth the extra work.

[forum_ghost]

Originally Posted by KLR X5M

All downpipes sound the same on this platform. Its people's idea of what sounds "good" that varies. Catless with stock exhaust sounds rattling and raspy on part throttle when the valves open. Fact. It sounds wild and aggressive at WOT, so some people accept the trade off. The power when combined with tune makes it 100% worth it. But if you're like the op or myself, i wanted a bit more refined sound. I added 3" vibrant ultra quiet resonators in place of the stock bottle style ones and added an x pipe. Problem solved. Was almost too quiet at first, but as the resonators broken in it's perfect now. Refined, quiet when you want it to be, aggressive and mean when you are in sport modes and shifting manually. Downpipes always come with trade offs. Some smell alot, some cause smoking issues, some exacerbate the bad frequency pulses. You have to decide if the power trade off is worth the extra work.

Hmmm now i'm interested. I love the power but the noise is just too much. Do you have links to the resonator and x pipe that you used? and/or a sound clip? If i can get it to quiet down i might just keep the DPs on.

[Sophisticated Redneck]

Originally Posted by forum_ghost

Hmmm now i'm interested. I love the power but the noise is just too much. Do you have links to the resonator and x pipe that you used? and/or a sound clip? If i can get it to quiet down i might just keep the DPs on.

Go to the F15 forum and check out the sticky at the top about the 50i muffler thread, I have links to everything in there on the last few pages. E70, F15, F85, n63/S63 and TU variants all suffer the same horrible fate with downpipes....that horrific rattle noise, especially during upshifts that sounds like absolute garbage. Reason is BMW tuned the exhaust for the cats, that's why you have two different sized resonators from the factory. To fix, x-pipe plus two race resonators will eliminate that nasty raspy crap sound and still leave it medium loud with the flaps open (just slightly louder then stock with them closed). If you don't want it much louder the stock under full throttle with the flaps open, replace the resonators with the magnaflow ultra quiet.

If you dig a bit, you will find some threads of both F85 and E70 X5M's that did this and love the sound. They posted sound files clips too.

[forum_ghost]

Damn thanks. Gonna do some digging before i remove.

[Sophisticated Redneck]

Originally Posted by forum_ghost

Damn thanks. Gonna do some digging before i remove.

Found some of the videos with the race resonators:

F86:

E70 X5M:

My 50i (your M will sound similar to this with flaps closed)

Revving from Idle: https://soundcloud.com/project-n63/b.../s-Xqryt3Ij9oU

Drive By: https://soundcloud.com/project-n63/b.../s-ULu9mQdpe4e

Cold Start: https://soundcloud.com/project-n63/b.../s-ANJ39IanIVS

[cr8tive]

Originally Posted by KLR X5M

All downpipes sound the same on this platform. Its people's idea of what sounds "good" that varies. Catless with stock exhaust sounds rattling and raspy on part throttle when the valves open. Fact. It sounds wild and aggressive at WOT, so some people accept the trade off. The power when combined with tune makes it 100% worth it. But if you're like the op or myself, i wanted a bit more refined sound. I added 3" vibrant ultra quiet resonators in place of the stock bottle style ones and added an x pipe. Problem solved. Was almost too quiet at first, but as the resonators broken in it's perfect now. Refined, quiet when you want it to be, aggressive and mean when you are in sport modes and shifting manually. Downpipes always come with trade offs. Some smell alot, some cause smoking issues, some exacerbate the bad frequency pulses. You have to decide if the power trade off is worth the extra work.

what size x-pipe did you get? 3" or 2.5"?

[Sophisticated Redneck]

Originally Posted by cr8tive

what size x-pipe did you get? 3" or 2.5"?

Get the 3", the F85/86 exhaust pipe diameter is 2.75inch(70mm) but they do not make a 2.75" X-pipe that is easy to get so the 3" as it works great, any exhaust shop will be able to expand the factory to 3" to make it fit. If you install yourself, you need to purchase a pipe expander too. I used one from Lisle off Amazon and it worked excellent.

[1norseman]

Originally Posted by cr8tive

what size x-pipe did you get? 3" or 2.5"?

Be aware, many stamped X-pipes are cheaply made. Inlets and outlets are crimped to make it easier to weld them, and thus becomes restrictive, and doesn't have a smooth flow...
You have to look into the X-pipe to see it. I would rather have an H-pipe, than a cheap X-pipe.

This X-pipe was sitting at buddy's shop for quite a while, so it's dusty inside. I had asked him to see if he could remove the excess tubing inside, and he gave up on it.
I ended up not using it, finally made my own...

[StatenEye]

Now this is a productive thread. Can we change the title to garner more interest / input?

[TheVazha]

Originally Posted by KLR X5M

All downpipes sound the same on this platform. Its people's idea of what sounds "good" that varies. Catless with stock exhaust sounds rattling and raspy on part throttle when the valves open. Fact. It sounds wild and aggressive at WOT, so some people accept the trade off. The power when combined with tune makes it 100% worth it. But if you're like the op or myself, i wanted a bit more refined sound. I added 3" vibrant ultra quiet resonators in place of the stock bottle style ones and added an x pipe. Problem solved. Was almost too quiet at first, but as the resonators broken in it's perfect now. Refined, quiet when you want it to be, aggressive and mean when you are in sport modes and shifting manually. Downpipes always come with trade offs. Some smell alot, some cause smoking issues, some exacerbate the bad frequency pulses. You have to decide if the power trade off is worth the extra work.

+1 on all. Catless is loud af. Some are chasing that sound, others want the performance boost, and maybe pick up a bit of sound in the process, but certainly not the amount that catless gives.

Here's a vid of my old e63 with shorty headers and catless dp's. I hated it. I ruined a perfectly good $100K lux hot rod and made it sound like I don't even know what and all for a handful of unnoticeable ponies.

Also, here's a video of my E70 with Eisenmann race which I thought was way too loud. I installed the Vibrant resonators and they helped a ton, but I don't think they're powerful enough to tame catless dp's:

[KCTiger]

OP, I think you would be happy with high flow catted DPs. Just had some installed on Tuesday. It is louder but not a great deal louder, at least imo.

[KLR X5M]

I used 3" Magnaflow x pipe, and vibrant 1142 3" ultra quiet resonators. I also coded the valves to be permanently open in sport modes for more growl. You'll still get nice down shift pops, but no longer obnoxious like with just downpipes.