[officedog]

I am in the process of swapping cars and would like to remove the M Performance Exhaust that was fitted as part of the MPPK. I have heard that if I simply remove the exhaust and do not get the ECU reflashed with stock software it will potentially make the car having running issues. As I am possibly going to be selling to a friend, I would like to make sure that I am not going to cause any issues before doing so as he does not want the exhaust.

Thanks

[Nebelhinten]

Originally Posted by officedog

I am in the process of swapping cars and would like to remove the M Performance Exhaust that was fitted as part of the MPPK. I have heard that if I simply remove the exhaust and do not get the ECU reflashed with stock software it will potentially make the car having running issues. As I am possibly going to be selling to a friend, I would like to make sure that I am not going to cause any issues before doing so as he does not want the exhaust.

Thanks

Are you talking about the MPPSK? If so then it could be a problem since the tune is designed to work with the exhuast. It's a catback system designed to reduce back pressure and let air flow more freely. What exhaust is he planning to put on? Probably best to remove tune and let him do his own tune/exhaust combo.

[officedog]

Originally Posted by Nebelhinten

Are you talking about the MPPSK? If so then it could be a problem since the tune is designed to work with the exhuast. It's a catback system designed to reduce back pressure and let air flow more freely. What exhaust is he planning to put on? Probably best to remove tune and let him do his own tune/exhaust combo.

Thought as much. Unfortunately, I am not sure it is feasible to get both the tune and exhaust removed.

He wants to run the stock exhaust as it is quieter.

Oh well, he can have it with the tune and exhaust or sort it himself!

Cheers

[DrifterX]

Not sure if the tune can be "downgraded" to the stock tune - that's something you'd need to ask the dealer if they can do (although, I think he'd be insane to do it )

You definitely can't transfer the tune to another vehicle as it's tied to the original vehicle's VIN when the MPPSK is ordered from BMW AG.

One suggestion is he could get a DINAN mid-pipe installed with the stock exhaust which removes the two resonators. This should work better with the MPPSK tune but it should be quieter than the MPPSK exhaust.

[babyboss]

Im runnin mppk xh only in my new 440i ..
No issues ..
Need 2 dyno & see diff ..
Wil do som test runs with buds 340i mppk & see results.

[NISFAN]

You are definitely overthinking the importance of the SK exhaust. A 240i comes with nearly as much power as an MPPSK 340i, yet it still has a very similar exhaust to stock 340i. Running the MPPK tune on stock exhaust will be fine. They are the same diameter pipe, and the CAT is more restrictive, which is unchanged.

[F32Fleet]

Originally Posted by officedog

I am in the process of swapping cars and would like to remove the M Performance Exhaust that was fitted as part of the MPPK. I have heard that if I simply remove the exhaust and do not get the ECU reflashed with stock software it will potentially make the car having running issues. As I am possibly going to be selling to a friend, I would like to make sure that I am not going to cause any issues before doing so as he does not want the exhaust.

Thanks

No worries.

[kern417]

Originally Posted by Nebelhinten

Are you talking about the MPPSK? If so then it could be a problem since the tune is designed to work with the exhuast. It's a catback system designed to reduce back pressure and let air flow more freely. What exhaust is he planning to put on? Probably best to remove tune and let him do his own tune/exhaust combo.

Not true. A catback does not affect the tune's operation, especially with the stock downpipe still in place.

[paul e]

Originally Posted by kern417

Not true. A catback does not affect the tune's operation, especially with the stock downpipe still in place.

Everything I have read about the 340/440 MPPSK states the exhaust is the key component of the MPPSK....unlike the previous 335 MPPK.

I mean, it’s right from the stick on top of this section....

“There's two ways to increase power - intake more air, or reduce back pressure allowing for faster air exit. With the previous MPPK (for the N55 engine) we went the route of more air intake, but for the 340i (B58 engine) we modified the the exhaust system to reduce back pressure and allow the air to exit the car faster, which together with the modified ECU, results in more power.”

So I’m confused about why folks are saying the exhaust has no effect.

[kern417]

Originally Posted by paul e

Everything I have read about the 340/440 MPPSK states the exhaust is the key component of the MPPSK....unlike the previous 335 MPPK.

I mean, it’s right from the stick on top of this section....

“There's two ways to increase power - intake more air, or reduce back pressure allowing for faster air exit. With the previous MPPK (for the N55 engine) we went the route of more air intake, but for the 340i (B58 engine) we modified the the exhaust system to reduce back pressure and allow the air to exit the car faster, which together with the modified ECU, results in more power.”

So I’m confused about why folks are saying the exhaust has no effect.

Because that's not how cars work and many people on the forums understand that.

Right off the turbo you have a catalytic converter that is literally a series of screens and mesh blocking the air way. The MPPSK does nothing to change or remove that obstruction. And nothing in the catback system has that sort of obstruction in the sense that it would reduce back pressure by straight piping the exhaust.

Keep in mind that BMW also claims that their aero package is specifically design to optimize the cars balance so you must install the front lip with the rear trunk lip and diffuser. Someone actually asked in another thread if it would throw off t he balance of the car by installing a front lip. But I think all of us understand that it's just marketing and the mperformance parts they offer are just for show.

Basically all they are doing is forcing you to buy the exhaust with the tune because too many people were just buying the tune and then an aftermarket exhaust system for much less.

[paul e]

Originally Posted by kern417

Because that's not how cars work and many people on the forums understand that.

Right off the turbo you have a catalytic converter that is literally a series of screens and mesh blocking the air way. The MPPSK does nothing to change or remove that obstruction. And nothing in the catback system has that sort of obstruction in the sense that it would reduce back pressure by straight piping the exhaust.

Keep in mind that BMW also claims that their aero package is specifically design to optimize the cars balance so you must install the front lip with the rear trunk lip and diffuser. Someone actually asked in another thread if it would throw off t he balance of the car by installing a front lip. But I think all of us understand that it's just marketing and the mperformance parts they offer are just for show.

Basically all they are doing is forcing you to buy the exhaust with the tune because too many people were just buying the tune and then an aftermarket exhaust system for much less.

So you know better than BMW what the MPPSK is and how the MPPSK works.....and you can support this engineering “viewpoint” by quoting what facts, exactly?

[Antec800]

Yes a lot of us do, it’s not science or engineering it’s marketing your fine with just the tune

[kern417]

Originally Posted by paul e

So you know better than BMW what the MPPSK is and how the MPPSK works.....and you can support this engineering “viewpoint” by quoting what facts, exactly?

c'mon dude. put the ///m tea down. It's not about "knowing better than BMW." It's about understanding simple physics, and the fact that nothing in the stock catback creates back pressure that is holding back power.

Look at every tune on the market. There are tunes for stock cars, tunes for downpipes, and some even make tunes for intakes. Why isn't anyone making a tune for a catback?

BMW saying that they specifically designed the MPPSK to run with their exhaust is no different than saying the stock tune was specifically designed to run with the stock exhaust. So what happens when you swap out the stock system without a tune? Does driveability suddenly go out the window? Is everyone that has an aftermarket midpipe on a stock car just driving a ticking time bomb? Are we leaving a bunch of hp on the table? Just think about it.

Regardless, since you want facts, here's the inside of a stock F30 muffler. It's a straight pipe with holes in it to muffle the sound. Where's the obstruction? Where is the excessive backpressure?
https://f30.bimmerpost.com/forums/sh...d.php?t=819125





And if you're one of the guys that thinks exhaust gases are just bouncing a round in there and limiting flow, there are plenty of articles and videos online that explain how exhaust flow actually works. Here's a good one.

Start at 19:10

Hope that helps lift the veil.

[paul e]

Okay, I guess all the info on the sticky is just BMW fake news, they have no idea what the MPPSK they designed does or how it works.

I guess I’ll believe you when you show me the dyno results of the MPPSK with the MPPSK exhaust and another without....on your car. Because I’m sure you have the courage of your convictions.

Thanks also for the videos. Lucky that BMW didn’t make those or they’d be fake too.

[kern417]

Originally Posted by paul e

Okay, I guess all the info on the sticky is just BMW fake news, they have no idea what the MPPSK they designed does or how it works.

I guess I’ll believe you when you show me the dyno results of the MPPSK with the MPPSK exhaust and another without....on your car. Because I’m sure you have the courage of your convictions.

Thanks also for the videos. Lucky that BMW didn’t make those or they’d be fake too.

You're hopeless dude. Reminds me of the guy that was convinced his suspension got stiffer in sports mode even though he didn't have adaptive suspension. You can put all the facts and evidence in front of a person, but if they want to be ignorant anyway theeeen....

[F32Fleet]

Originally Posted by paul e

Okay, I guess all the info on the sticky is just BMW fake news, they have no idea what the MPPSK they designed does or how it works.

I guess I'll believe you when you show me the dyno results of the MPPSK with the MPPSK exhaust and another without....on your car. Because I'm sure you have the courage of your convictions.

Thanks also for the videos. Lucky that BMW didn't make those or they'd be fake too.

It's marketing. Turbos and the catalytic converter are the bottlenecks.

Catback exhaust is mostly about sound and maybe something like 5hp.

[paul e]

Originally Posted by kern417

You're hopeless dude. Reminds me of the guy that was convinced his suspension got stiffer in sports mode even though he didn't have adaptive suspension. You can put all the facts and evidence in front of a person, but if they want to be ignorant anyway theeeen....

Show me the dyno numbers. Prove your theory.

[kern417]

Originally Posted by paul e

Show me the dyno numbers. Prove your theory.

It's going to sound crazy, but with the maybe whole 2 dynos done that i've seen with the MPPSK, the chances of finding one with a stock exhaust or other aftermarket catback are little to none. Maybe you can find some dyno numbers that prove the catback is critical to making power with the MPPSK tune? Otherwise you're going to have to use your imagination on this one.

And no, I don't have wind tunnel test results to prove that an mperformance front lip with out the trunk lip won't throw off the balance of your car. You probably believe this one too. Clearly it's because of all the aerodynamic engineering that went into designing the part, not just BMW trying sell more parts in a package.
https://www.shopbmwusa.com/PRODUCT/4...FRONT-SPLITTER

To ensure proper driving behavior/aerodynamic balance, it is strongly recommended that the rear trunk lid spoiler be installed in conjunction with the front splitter.

But there are dynos showing stock power figures. I can only imagine your reaction when people tell you that our cars make more power stock than BMW claims. I guess that at least proves that BMW is willing to publish "fake news" as you put it. The rest of us will just continue thinking for ourselves.

[Beek]

The difference between marketing as in the context under discussion here vs real accepted good practice like following the manufacturer's new car break in recommendations can be subtle but if one accepts F32Fleet's assertion that "Catback exhaust is mostly about sound and maybe something like 5 hp." I would point out that 5 hp is a significant amount of the 35 hp gain claimed with MPPSK, that is not just marketing. Just as a point of reference I will also point out OP stated the reason to remove the exhaust was to revert back to stock so that is 5 hp gone and not being made up for with a different aftermarket exhaust. Just throwing my two cents worth into the discussion, I got no dog in this fight.

[kern417]

Originally Posted by Beek

The difference between marketing as in the context under discussion here vs real accepted good practice like following the manufacturer's new car break in recommendations can be subtle but if one accepts F32Fleet's assertion that "Catback exhaust is mostly about sound and maybe something like 5 hp." I would point out that 5 hp is a significant amount of the 35 hp gain claimed with MPPSK, that is not just marketing. Just as a point of reference I will also point out OP stated the reason to remove the exhaust was to revert back to stock so that is 5 hp gone and not being made up for with a different aftermarket exhaust. Just throwing my two cents worth into the discussion, I got no dog in this fight.

You could say that, or you could say that the 5hp is nothing when relative to 350+hp. You could also say that if you dyno'd 2 cars with the full MPPSK, they could have a 5hp difference between them. Or if you put the same car on the dyno twice, it could have a 5hp difference between pulls. Not uncommon, and a reason why we say there aren't any noticeable gains to be had with a catback exhaust.

Also both AA and JB4 maps for stock engine setups make more power than the MPPSK. And that's with just a piggyback. So either the almighty BMW lack some competency in their own engine design, or they choked the power output which begs the question, why would an exhaust modification be needed anyway?

Basically it comes down to the statistics, because your car and engine are constantly dynamic and performing in a dynamic environment. If sometimes it doesn't show a gain (even 1hp), then it's not creating a gain. There's too much noise in the system to truly identify what caused the improvement (or loss). This goes double when the science behind it proves that it doesn't make a difference.

[paul e]

5 HP is a number you just made up, a pretend number .

Still no proof. And we aren’t talking about aero mods.

Show me the numbers.

[kern417]

Originally Posted by paul e

5 HP is a number you just made up, a pretend number .

Still no proof. And we aren’t talking about aero mods.

Show me the numbers.

Man you're dense. 5hp was thrown out there as a reference because other people in the thread know it's typical. Pretty much all companies that sell catbacks advertise 0-5hp as potential power gains.

There are multiple posts on here that explain why the exhaust isn't critical. NISFAN clearly explained how they were able to pull the same MPPSK level of power out of other B58 cars without the MPPSK exhaust. even babyboss said that there were no issues after removing the MPPSK exhaust and will try to get a dyno to pacify you.

And I added the comment on aero mods because it is just another example of a bmw claim that isn't true, despite the reference that I linked. Go to the general section and you'll see another new thread started where someone explained how BMW says we don't have to rotate tires on our cars because the 50/50 balance means it's not necessary. I've read that before and, again, most people on here have the mental capacity to realize that it's not true.

So like I said before, if despite everything on the table you still believe that the mppsk exhaust is critical to making mppsk power and everything else that BMW tells you, you're hopeless. Good luck on your future endeavors.

I'll bow out now.