Down-pipe with stock exhaust

[OneM]

Anyone knows if is it a louder than stock after adding a cat-less down-pipe? Would it be as loud as removing the mid-cat instead..

[stormzusmc]

It's hardly noticable honestly.

[richb811]

Originally Posted by OneM

Anyone knows if is it a louder than stock after adding a cat-less down-pipe? Would it be as loud as removing the mid-cat instead..

I'd say you wouldn't notice a huge difference in sound. Maybe a few extra pops and burbles on throttle liftoff and downshift.

If you are going for more sound, doing the the rear muffler is probably your best bang for the buck.

[OneM]

Nope, definitely ain't going for sound.. not a fan of loud exhaust. Going for performance, ..is it worth it, the down pipe ?

[Rob Daman]

removing any cats will always help on performance on basically any car but then you're not emissions legal.

[stormzusmc]

DPs coupled with a tune yes very well worth it. DPs alone, not so much. You won't notice much at all, but it does increase a little bit...but not enough for it to sound like a tractor.

[richb811]

Originally Posted by stormzusmc

DPs coupled with a tune yes very well worth it. DPs alone, not so much. You won't notice much at all, but it does increase a little bit...but not enough for it to sound like a tractor.

Exactly this.

I usually recommend to my clients that they go for a Tune first, then the downpipes. Downpipes without a tune are, in my professional opinion, a waste of money.

[octainejunkee]

I run catless downpipes and catless mid's.
it's alot louder on cold start..
Not as loud as an after market rear section from inside the car- sounds nice and the oem rear allows decent back pressure for more lbft..

A kid taking photos at Spa asked if i'd do some do nuts for him in exchange for a copy of his track photo's- have listen see what you think?

Cheers Jamie

[OneM]

Thanks to everyone for their input..

[Vrumpkin]

I just did a tune and DP's and it did make a difference in noise.. noticeable for sure but I do have madad mid pipe as well that adds to the equation. Reduction in turbo lag is great, throttle response far improved.

I am waiting on a rear section to complete a full setup, that coupled with the above should be a screamer. For now I love this in between sound of just aggressive enough without being a screamer. Still very BMW.

The rear section as Bane would say.. that comes latahhh!

[serial`]

For sure is noticeable, and mine already had 1 cat blown just previous to installation so it was already louder.
I never got all the hate/strongly divided opinions towards DP's on 1M's on this forum, it made no sense at all from what I was taught and had experience with on other cars.

I'll do you one better than just another opinion and post pre and post catless DP video's later this week.

On a verified fully stock map.

Sounds noticeably louder to both myself and the mechanics that installed it and got to drive it a couple days later.

M mode off is quite a bit more responsive now, M-mode on not so much, except maybe just a tad after fully releasing the gas and then going WOT again.

And 1M downpipes being "high flow"?
Compared to 135i's maybe, but more bends+cats = lots of extra and unwanted resistance at the point where it matters the most... (compared to catless dp's)

Here is how "high flow" they are after 25k miles of heavy use:

View post on imgur.com

Guess you could call that high flow on a budget.

[Artemis]

Originally Posted by serial`

Here is how "high flow" they are after 25k miles of heavy use:

Guess you could call that high flow on a budget.

Uh-oh...

[Em/1]

Originally Posted by Artemis

Uh-oh...

Wow that is UGLY! I need to get serious about DP's!

[serial`]

Originally Posted by Em/1

Wow that is UGLY! I need to get serious about DP's!

definitely if you are using this car on track or for driftevents more than just once a year (and even then...) and/or want to remap the engine...
/endreplytoquote


Knowing that our cars tend to have difficulty dissipating all the engine heat as is, it is no wonder that the parts closest to where loads of that exits from, suffer the most from all these variables (EGT's anyone??) added up. Not the midpipes or exhaust.

Why anyone with any mechanical knowledge at all would even for a second think to advise against catless dp's on a remap where the extra power is used on track, is beyond my comprehension.

Sorry if I put it a bit bluntly (and simply, I'll admit) but this isnt just an issue of performance gains vs comfort, this is about facing the inherent issues of our cars if we want them to be more than just garage queens, and dealing with them accordingly.

[BMW Gator]

Just a comment - I ran Akra catless DP's for about a year with berk midpipes with the stock rear section and no tune. Loved it. Deeper sound, quicker spooling, more smell - yes, and regardless what others say - I had more power. The tires definitely broke loose much easier so you can make your own conclusions.