RomRaider

Im still running cat and middle muffler, only the end exhaust has been changed.
Sounds quite nice. Big thanks to everyone who has posted their settings here.
Here is a short clip:
https://drive.google.com/file/d/1EVmoJf3kMP9KuQ_utwWXBNZhGv3EKJBy/view?usp=sharing

Hi Guys,

Thank you for your settings.
Has anyone already switched on and off using the climate button?

Search for this possibility.

greetings

I have done exactly this about a year ago. By only editing the ac off map, I get pops with the ac off, and when I drive normally to civilized places, I can turn on the ac like normal and have a tamer exhaust. Im surprised no one had mentioned this before from what I saw.

Its "saw" and tested years ago, but you have to read the hole threader to find... for s*** pop and bang things.

Been a while since Ive read it. Useful info nonetheless.

hello please how to create tune ms41 m52b20 for popcorn? please share map for setting thanks

only read mate, read read read and then little testing.

and on ms43 popcorn info is for m54b30 or b25?

Mate, read the forum. Everythin is explaind. Rest ist testing.
If you arent able to or dont want and want get solution made... get local tuner.

need some help, spent around 12h on this , was up till 4am last night going thru all 28 pages of this topic . The car is a e39 523i '97 with no cat , empty mufllers and custom pipes.

I want to have the pop and crackle on high revs >4k , but I am having the same issue as a lot of people in this thread, I can get it to pop and bang on the hole rev range always, and i got it to pop on low revs for a few seconds after throttle release, but I tried everything mentioned in here except changing the base fuel maps, and cant get it to do what I want so any help would be appreciated, I have just probably overlooked the answer in some post but cant figure it out

Double check that you have fuel on when you want pops. If you want them through the whole range, set fuel restore to for example 8000rpm.

Then, make sure your IACV is open in the area where you want pops.

Lastly, retard ignition enough to get them. I increase the amount of retard by about 10 or 15 in all decreasing throttle maps, and that seems to work for what you are trying to achieve.

If it still doesn't work, do a log while driving and post it, then it is easier to help.

So, I have an interesting problem.

I'm trying to dial in the perfect amount of revhang for my friend's daily driver with an m52b25. It's pretty much bang on, just the right amount. It sometimes also very briefly pops a little bit on shifting at high rpm, which is perfect for what we were after.

The minimal amount of rev hang is perfect, if you quickly close the throttle. For example, you are driving on a straight road, holding about 10% throttle opening. You quickly let off the gas, it takes about a second for the car to enter fuel cut mode and completely retard ignition. That's great. Makes shifting easy, while removing the spongyness of the stock rev hang, which seems to be made for grandmas that shift very slow.

The issue is this: If you were to very slowly decrease the throttle in this same situation, the moment it closes, the fuel cuts immediately and ignition instantly retards fully. This makes a very jarring "twitch", since it sends a shock through the driveline. This is even more pronounced if you are driving downhill with very little throttle, and slowly close it, it will very annoyingly and abruptly twitch.

In the logs, I see that in the first example ignition will first start gradually retarding, then after a bit less than a second, fully retard and shut fuel injectors at the same time. Even though in the logs, the injectors are still shown as firing, the econo gauge in the cluser shows they aren't, and the exhaust note clearly changes indicating that there is no fuel being burnt. But in the second example, ignition instantly jumps to fully retarded, without that gradual slope and fuel is immediately cut. This is probably what shocks the driveline and makes the car twitch. Again, it only does this if you very slowly close the throttle, and moreso if going downhill.

Is Fast Decreasing Throttle responsible for this? If anything, I was under the impression that it should be the exact opposite: Retard ignition immediately if FDT is detected, but retard it slowly if FDT is not detected. I am attaching the map of the car in question. FDT should be disabled anyway below 4500RPM on this map, and this problem does happen in the entire rev range.

Map is for 41.2, in case anyone wants to try, but I hope your driveshaft is in good shape, since this will shock it quite a bit...

I was just reading through this for the first time and it occurred to me that this could be used as an autoblip sort of thing for downshifting on the racetrack. Could I intentionally make my ms41.2 revhang? It did not do that stock, so what direction would i need to go to get it to intentionally rev hang so I could downshift without worrying about heel toeing? Would that be impossible to have it rev hang for downshift and somehow not do it when accelerating. I guess that would be the hard part.

Creating revhang is quite easy like you said. leave the ICV open, remove fuel cut, and keep high ignition angle on decceleration maps. but no way do make a difference on up or downshift

Correct, FDT is not the issue. If you log Switch LV_PUC, I believe you'll see a 1:1 correlation between it and the effect you're seeing.

The Dashpot function affects fuel cut as well as the IACV. One of the checks for transitioning to fuel cut is whether any of this dashpot is still in effect or if it has completely diminished to 0.

In your tune, the values may be too low in the 2.3% column (2nd TPS column). You could also add some non-zero values to the 1st column to add some more 'damper' effect when transitioning to closed throttle from an already very low throttle.

Unfortunately, the ECU doesn't know when the engine is disconnected from the trans via Neutral or Clutch switch so this dashpot can only apply to one or the other. Recommend you tune it for proper operation in gear. Again, not knowing exactly which gear isn't ideal. The strength of this dashpot 'spring' needs to suit the amount of engine braking for a given gear.

Same applies to your Decreasing TPS - Step Size for really low loads. No reason to allow for timing to get reduced so rapidly at low loads.