[DavidXJ]

Hey folks,

In what follows, I feel like I'm reprising issues discussed quite authoritatively some time ago by folks like Simon H and Sullyrityres, along with threads launched a few years back by Mightyhoof (in assessing the Akrapovic exhaust), so apologies if this feels like well-trodden ground.

But! Now that time has indeed passed, and with it warranties too for those of you who've hung on to their MY2020 cars, I just wondered what your preferred options have been in terms of restoring the crackles that we all know were mapped out of the MY2020 models from July 2019 onwards. My Feb 2020 build Comp sounds terrific in its own right, and certainly deeper and more sonorous than the more recent LCI iteration. But of course it lacks those pre-MY2020 crackles and pops on the overrun, even though it'll bark and burble quite aggressively on a warm restart.

So, for those of you who have gone down the exhaust upgrade route, what have you opted for? Akra, Remus, Miltek, or Schnitzer? In the UK we still have the option of an OPF delete (as we all know cars still pass the MOT without them) so that would obviously enhance the sound even further. In any case, I'd be interested to hear whether you've retained or opted for the bypass sections--and to what effect.

Second, what has been your preferred provider? I was thinking in the first instance of going to Litchfield (since they do the Akra and also could provide a map that restores those crackles that were originally there on the Comps before the nannyish EU sound regs kicked in); but Evolve and DMS also seem to be pretty experienced in this area.

Having now transferred to BMW extended warranty, I realise a map would potentially imperil parts of the drive train coverage, though my local BM dealer has said that there's pragmatic flexibility when it comes to diagnosing faults, especially when they have nothing to do with an aftermarket map. But again, I'd welcome any thoughts from folks who've implemented these kinds of ECU refinements (I'm not interested in any extra power, just in restoring something of the exhaust note and character!).

Thanks in advance,

D

[dcohen13]

Hi David, I recently wanted more bark out of my 2019, even thought it has the crackle and pops in Sport Mode. I opted for the Meisterschaft setup. This was their catback and midpipe resonator delete kit. No CEL and no warranty issues. I have the same extended warranty for another 3 years and did not want to tarnish that. The car is very aggressive sounding in sport mode and with the flaps open. When I put the car in comfort mode, it sounds completely stock, like a 530i. I made a quick video of it below. Also, the Meisterschaft works with the OEM exhaust button, so there is no extra controller you have to have with you. I worked directly with them, and spoke with Mike to get everything sent out. Let me know if you would like me to put you in touch with them!

https://gthaus.com/product/bmw-f90-m...bo-sedan-2018/

https://www.youtube.com/shorts/rn2oNxjGX1I

[DavidXJ]

Thanks for the gen here! Sounds awesome. I think the added issue I have is that unlike your car (presumably a pre-MY2020 build) is that I don't even have the pops and crackles to start with on my stock map. A new exhaust in and of itself won't bring them back, even if it raised the overall volume (esp with a removed OPF and resonator delete). So, either way, I'm looking at a remap, in order to restore the ignition timing that BMW must have adjusted on the ECU for MY20s. But thanks for the product info--definitely one for the wishlist when the time comes to taking the plunge!

D

[Simon H]

Originally Posted by DavidXJ

Hey folks,

In what follows, I feel like I'm reprising issues discussed quite authoritatively some time ago by folks like Simon H and Sullyrityres, along with threads launched a few years back by Mightyhoof (in assessing the Akrapovic exhaust), so apologies if this feels like well-trodden ground.

But! Now that time has indeed passed, and with it warranties too for those of you who've hung on to their MY2020 cars, I just wondered what your preferred options have been in terms of restoring the crackles that we all know were mapped out of the MY2020 models from July 2019 onwards. My Feb 2020 build Comp sounds terrific in its own right, and certainly deeper and more sonorous than the more recent LCI iteration. But of course it lacks those pre-MY2020 crackles and pops on the overrun, even though it'll bark and burble quite aggressively on a warm restart.

So, for those of you who have gone down the exhaust upgrade route, what have you opted for? Akra, Remus, Miltek, or Schnitzer? In the UK we still have the option of an OPF delete (as we all know cars still pass the MOT without them) so that would obviously enhance the sound even further. In any case, I'd be interested to hear whether you've retained or opted for the bypass sections--and to what effect.

Second, what has been your preferred provider? I was thinking in the first instance of going to Litchfield (since they do the Akra and also could provide a map that restores those crackles that were originally there on the Comps before the nannyish EU sound regs kicked in); but Evolve and DMS also seem to be pretty experienced in this area.

Having now transferred to BMW extended warranty, I realise a map would potentially imperil parts of the drive train coverage, though my local BM dealer has said that there's pragmatic flexibility when it comes to diagnosing faults, especially when they have nothing to do with an aftermarket map. But again, I'd welcome any thoughts from folks who've implemented these kinds of ECU refinements (I'm not interested in any extra power, just in restoring something of the exhaust note and character!).

Thanks in advance,

D

Hi David,
Did you get any further with this ?.

[DavidXJ]

Hi Simon,

Well, I think it's going to come down to finances (as ever!) with two routes, as I see it:

I. The budget solution would simply be a map to restore some crackles and overrun character, while retaining the Comp's existing M Sport exhaust system. I see that Litchfield (who I'd more than likely go with in the end, given that they have their own F90 which they've been using to calibrate their software products) say that the version of the OPF on the Comp isn't too restrictive. So the stock system might still allow for some acoustic improvement, but ultimately it's going to require a remap. (Of course, there's a certain degree of risk with that, when running Extended Warranty, but also my local dealer suggested that they're pragmatic when it comes to covering issues/repairs that aren't linked to any map/mod).

II. The indulgent route: get the Akra slip on back box system, plus their OPF bypass section. Obviously, that would also need an ECU adjustment, to compensate for the removal of the OPF; but I believe the resulting sound would be terrific.

There is also a middle route, which would involve just the Akra rear slip on unit, which wouldn't require any ECU adjustment. But adding that, just in and of itself, wouldn't bring back any crackles/burbles, but rather simply improve the tone.

I'm going to give it some further thought. I'm tempted to see what Litchfield can do simply with a software adjustment that can tweak the fuel map and improve the character that way, with the stock exhaust still in place. But clearly the most desirable solution is to get that OPF off, using By-Pass pipes (which Miltek do too, incidentally) and let the beast breathe. And more desirable still would be the titanium-enhanced resonance of an Akra product. But you're looking at 5-6K for that..! Still, my F90 is a keeper, so it's already in the territory of a long-term-investment (man maths).

D

[Simon H]

Originally Posted by DavidXJ

Hi Simon,

Well, I think it's going to come down to finances (as ever!) with two routes, as I see it:

I. The budget solution would simply be a map to restore some crackles and overrun character, while retaining the Comp's existing M Sport exhaust system. I see that Litchfield (who I'd more than likely go with in the end, given that they have their own F90 which they've been using to calibrate their software products) say that the version of the OPF on the Comp isn't too restrictive. So the stock system might still allow for some acoustic improvement, but ultimately it's going to require a remap. (Of course, there's a certain degree of risk with that, when running Extended Warranty, but also my local dealer suggested that they're pragmatic when it comes to covering issues/repairs that aren't linked to any map/mod).

II. The indulgent route: get the Akra slip on back box system, plus their OPF bypass section. Obviously, that would also need an ECU adjustment, to compensate for the removal of the OPF; but I believe the resulting sound would be terrific.

There is also a middle route, which would involve just the Akra rear slip on unit, which wouldn't require any ECU adjustment. But adding that, just in and of itself, wouldn't bring back any crackles/burbles, but rather simply improve the tone.

I'm going to give it some further thought. I'm tempted to see what Litchfield can do simply with a software adjustment that can tweak the fuel map and improve the character that way, with the stock exhaust still in place. But clearly the most desirable solution is to get that OPF off, using By-Pass pipes (which Miltek do too, incidentally) and let the beast breathe. And more desirable still would be the titanium-enhanced resonance of an Akra product. But you're looking at 5-6K for that..! Still, my F90 is a keeper, so it's already in the territory of a long-term-investment (man maths).

D

All that sounds good David,
Just be aware that if you do go down any mapping route, that as soon as any BMW dealer plugs their machines into the car, they have no say in the info that gets sent to Germany, which could invalidate any warranty etc. But the very best of luck with your decisions, and keep us informed

[DavidXJ]

Belated thanks, Simon. Will keep you posted.

Now that I'm beyond manufacturer warranty, the alleged Germany surveillance manchine is no longer a factor. With Extended Warrenty, I'm now basically dealing with an independent insurance product, which obviously carries certain exclusions. (EW doesn't include coverage for the exhaust system anyway, OEM or otherwise.) But I am aware of course that any software adjustments have implications for engine management-related faults. But my own local dealer has said that they're pretty pragmatic when it comes to working around mods, and would usually have to link a fault to the map itself--contra the usual doomsaying that insists that any aftermarket components will automatically and universally void any repair claims.

For standard services, dealers don't embark on in-depth diagnostics anyway, and I suspect I may end up using Litchfield themselves as a service/MOT provider in the long term.

First, though, the piggy bank needs a bit of replenishment before any kind of Akra hardware becomes feasible!

D

[meds1976]

What about a back-box delete? Assuming it'll be too loud and obviously not as refined or civilised as a proper after-market exhaust setup.

[DavidXJ]

Originally Posted by meds1976

What about a back-box delete? Assuming it'll be too loud and obviously not as refined or civilised as a proper after-market exhaust setup.

I imagine that would certainly make things more sonorous! But I'd wonder about what tone removing the box would create--and I'd also worry about the potential for drone at motorway cruise, though maybe if the valves could be retained drone would be less of an issue.

Right now, my (inexpert) sense is that--irrespective of ECU ignition timing--both character and volume are being constrained around the post-cat mid-pipe/link section, where it seems like a lot of the overrun sound is buffered thanks to the flow being interrupted by the OPF.

It would be good to find a back-box delete vid: I'm sure the guys at Evolve must have done one by now..!

[meds1976]

DavidXJ so I have a X6 M50i with the V8.

Not familiar with the M5 setup, but on mine, there are two resonators leading to the back box.

I had them both removed and added an x-pipe and then also removed the back-box but retained the valve. So the car sounds different on Comfort v Sport.

You could retain the resonators, add the x-pipe and remove the back-box.

EMP Performance in St. Alban's is where I had my work done.

You could also try Evolve Automotive in Luton.

[DavidXJ]

Thanks, meds1976, for the gen!

How would you describe the improvements in sound, character, and crackles etc in your revised set up vs OEM? Presumably, your V8 had a similar engine map, depending on its year. But I also assume you had to remap/adjust the ECU software to compensate for those various mods?

[meds1976]

DavidXJ

No other changes. Car is bog standard. I was tempted to remap with Evolve but have paid for extended warranty so not touching the engine.

Car is a 2017 X6.

Sound? It's loud. Especially on a cold start. Settles down after a few seconds. In Comfort it's relatively quiet but you can hear it. In Sport, it's mental.

There is definitely drone. But I don't do that much motorway mileage so it hasn't bothered me much. That's with a wife and two kids (12 & 8).

So I would recommend retaining the resonators to start with. The x-pipe will also help of you decide to go with the back-box delete mod.

[meds1976]

DavidXJ

Only video I have.

X6 back box delete

[meds1976]

DavidXJ there is also PCW Exhaustmods. He basically modifies the back box but leaves it in-tact. To the naked eye, it doesn't look it has been modified at all.