[proTUNING Freaks]

Over the past while community members such as Jake (jyamona) have been busy with new DME table discovery for the N54. As some of you are aware tables such as various idle tables, injector configuration and knock sensor calibration tables are now available for tuning via an open source tool called Tuner Pro and loadable via some popular N54 flashing tools such as Android's MHD and the free PC/Windows based app more commonly referred to as a BB flash. While table discovery is certainly awesome and as tuners we can never have too many tables, its even more important understanding the logic and outcome of the changes being applied. In some cases like idle tables for instance, the changes are straightforward to test and adoption is easy. In other cases however, such as knock tables, making changes is easy obviously but understanding what exactly is being changed and what impact it has on the motor is something that needs to be tested a lot closer with instrumentation hardware (such as external knock sensing equipment, e.g. KS-4 or similar, http://www.phormula.com/KnockMonitor-KS-4.aspx).

While its a GREAT feeling to see logs not have timing being pulled after making changes to values in the newly discovered knock tables please take some caution when doing so. What we mean by being cautious here is to understand that not a single 'tuner' using these new tables has implemented and gathered data on actual knock on the N54 with such equipment to prove that changes to the new knock tables aren't in fact desensitizing what is a well known factory knock sensor calibration tested and established over years of testing that the N54 engines went through with BMW's engineering staff prior to their release. We know very well that its the awesome knock detection and handling in the N54 DME that has saved and is still saving many motors from destruction in cases of low octane, bad/aggressive tuning, etc.

In a nutshell, new table discovery AWESOME! We just hope it goes hand in hand, for tables such as the knock calibration ones, with appropriate in-field testing/instrumentation to prove the changes being made are safe or otherwise.

[135Pats]

Agreed on all fronts, that's well put. Jake deserves huge credit for the work he's been doing/continues to do.

But for the broader community, this should't be seen as a means of eeking out every last ounce of power for stock turbos. IMO you really shouldn't be fiddling with these knock tables unless you are shooting for major, major WHP in a high boost situation. The 'false' knock issues some folks are experiencing generally only crop up as you approach 30+PSI with a single; so important to keep that in mind.

Really good work moving the platform forward though. The idle tables appear to be very well-defined and stable in terms of removing the cold start behavior.

[CarAbuser]

I noticed that the JB4 back-ends for MHD have knock table adjustments in.

Very tempting to use them but the fear of messing with safety related functions has kept me away. Especially since I've seen no real justification for the values used other than Terry claiming the changes are minor.

I do think it's a little strange that even the pump back-end files have these implemented.

[Jeff@TopGearSolutions]

Well said, I wouldn't touch the knock tables either.

[135Pats]

Originally Posted by CarAbuser

I noticed that the JB4 back-ends for MHD have knock table adjustments in.

Very tempting to use them but the fear of messing with safety related functions has kept me away. Especially since I've seen no real justification for the values used other than Terry claiming the changes are minor.

I do think it's a little strange that even the pump back-end files have these implemented.

I wouldn't touch them unless there is a very specific issue you are experiencing.

Vast majority of people experiencing timing pulls are seeing those 'correctly'. Whether its actual knock, preignition etc; the DME is doing its job. This shouldn't be seen as a solution to that, which I fear some in the community will do.

[proTUNING Freaks]

We have always believed and still strongly feel that post shift timing pull is fuel/timing control related when it comes to 6AT cars in some way and not something to recalibrate knock sensors for as we've noticed in some situations adding meth on its own on the car help with post shift timing. Once more tables get added we're hoping that the reasons behind that on 6AT cars will become clearer.

In Terry's case he's got a built N54 in one of the single turbo cars that may see an advantage in changing the values as knock frequency to listen on will shift due to changes in bore size, materials used for internals, etc have changed.

[musc]

Originally Posted by CarAbuser

I noticed that the JB4 back-ends for MHD have knock table adjustments in.

Very tempting to use them but the fear of messing with safety related functions has kept me away. Especially since I've seen no real justification for the values used other than Terry claiming the changes are minor.

I do think it's a little strange that even the pump back-end files have these implemented.

I thought it was just the E85 flashes? I don't have any issue with them if one is running E60+ and has worked through the process of investigating a rogue cylinder timing pull but I probably wouldn't use them for pump gas.

[musc]

Originally Posted by proTUNING Freaks

We have always believed and still strongly feel that post shift timing pull is fuel/timing control related when it comes to 6AT cars in some way and not something to recalibrate knock sensors for as we've noticed in some situations adding meth on its own on the car help with post shift timing. Once more tables get added we're hoping that the reasons behind that on 6AT cars will become clearer.

In Terry's case he's got a built N54 in one of the single turbo cars that may see an advantage in changing the values as knock frequency to listen on will shift due to changes in bore size, materials used for internals, etc have changed.

Some tuners have fixed these post shift timing pulls long before the knock tables came around, lol.

[proTUNING Freaks]

Age old argument...Some tuners, including us, have fixed them on some cars and some of those logs have floated around here. Some others, not so much though, depending on octane and other variables. Our experience has been that there is no single fix but there are cars that have been addressed via various strategies from boost control, vanos, fueling etc YMMV

[Milan]

LOL

Never in a million years will I believe that external knock sensing equipment is going to work better than what the factory offers in modern (especially boosted) vehicles.

Sounds to me like you guys are trying to justify being behind the curve and still using Cobb

[CarAbuser]

Originally Posted by Milan

LOL

Never in a million years will I believe that external knock sensing equipment is going to work better than what the factory offers in modern (especially boosted) vehicles.

Sounds to me like you guys are trying to justify being behind the curve and still using Cobb

I don't think that's what he was trying to say.

I read it more as "Knock tables are dangerous because there has been very little testing done on the effects of adjusting the stock values"

The use of external equipment was just a suggestion for testing. You could use external knock sensors to act as a feedback for adjustments. So when you make a change you can see the result.

Just fudging a few knock table values by 10% might lower corrections but do you really know how those changes will effect more extreme knock as a result of fuelling issues.

[jwzimm]

Originally Posted by Milan

LOL

Never in a million years will I believe that external knock sensing equipment is going to work better than what the factory offers in modern (especially boosted) vehicles.

Sounds to me like you guys are trying to justify being behind the curve and still using Cobb

You do realize that the OEM knock sensors are "external" as well, right? They are simply bolted to the side of the block forward and aft. All a knock sensor is is a microphone that is tuned to a specific frequency. Predetonation has a very specific sound and these sensors are tuned to hear it and relay that information to the DME.

What he is saying is that adjustments to this table can be very dangerous without thorough and complete testing that includes an independent knock sensing system (external to the DME). This table is one that was generated by BMW during the development of the engine and likely required a great deal of research and development. Coming in and ham-fistedly changing it without going through similar or at least delta testing is dangerous and can compromise the self-protections that the DME has built in.

[Mike@N54Tuning.com]

Originally Posted by jwzimm

You do realize that the OEM knock sensors are "external" as well, right? They are simply bolted to the side of the block forward and aft. All a knock sensor is is a microphone that is tuned to a specific frequency. Predetonation has a very specific sound and these sensors are tuned to hear it and relay that information to the DME.

What he is saying is that adjustments to this table can be very dangerous without thorough and complete testing that includes an independent knock sensing system (external to the DME). This table is one that was generated by BMW during the development of the engine and likely required a great deal of research and development. Coming in and ham-fistedly changing it without going through similar or at least delta testing is dangerous and can compromise the self-protections that the DME has built in.

Well said...

Mike

[proTUNING Freaks]

Originally Posted by CarAbuser

I don't think that's what he was trying to say.

I read it more as "Knock tables are dangerous because there has been very little testing done on the effects of adjusting the stock values"

The use of external equipment was just a suggestion for testing. You could use external knock sensors to act as a feedback for adjustments. So when you make a change you can see the result.

Just fudging a few knock table values by 10% might lower corrections but do you really know how those changes will effect more extreme knock as a result of fuelling issues.

Spot on CarAbuser

@Milan, FYI, we have nothing against MHD. In fact, we are huge supporters of what @Jyamona (Jake) is working on these days in opening up tables further. Its just another tool for us as tuners to use in getting things done. This thread is more to gauge discussion and interest in people to r&d with these motors further before diving into serious changes such as recalibrating knock control that can be cause for some of the most expensive repairs on a platform.

[musc]

Originally Posted by proTUNING Freaks

Spot on CarAbuser

@Milan, FYI, we have nothing against MHD. In fact, we are huge supporters of what @Jyamona (Jake) is working on these days in opening up tables further. Its just another tool for us as tuners to use in getting things done. This thread is more to gauge discussion and interest in people to r&d with these motors further before diving into serious changes such as recalibrating knock control that can be cause for some of the most expensive repairs on a platform.

I would agree, change them at your own risk. If someone went wild with them it could spell disaster, kind of like guys turning off misfire detection. I do think that Terry@BMS tends to err on the side of being conservative so I don't think changes in the backend flash are that aggressive. Then again, who knows. This is new territory for our platform.

[proTUNING Freaks]

Every table is a "change at your own risk" situation

[Mike@N54Tuning.com]

Originally Posted by proTUNING Freaks

Every table is a "change at your own risk" situation

True, but like you rightfully mentioned some tables are more dangerous (risk) then others. Was a good post. Glad you made it.

Mike

[335NJ]

Awesome to CONSTANTLY hear about how people at companies like PTF are working hard to keep the platform chugging along!

And to everyone else who pitches in on developments like these. I can't wait to see what this platform is doing in a few years, and at this pace, it might be a lot sooner.

[Miller335]

I am kind of curious to see how all this pans out.

I dont have a solution on how one would go amount making sure these knock sensor adjustments are solid without actually just trying it but I know the LS guys remove them altogether in the ecu and rely on the dyno tuner somehow to make sure all is good.

[matthewo]

I did some LS tuning and their knock sensor were pretty sensitive and could pick up a lot of false knock. Sometimes I would see 4-6 deg on a stock timing table. But sometimes it was real knock, so it was hard to say.

I remember tweaking sensativity of the sensor a little and bringing down the amount of kr, but made the kr be applied and removed much faster than stock like with decay tables

[secretsquirrel]

We are now at power levels where I would want security systems to be MORE sensitive, not less. I guess I shouldn't care, since it isn't my car. You've got to have people on the cutting edge to move things forward, just don't do it on my car

[spxxx]

This is a reason why I'm concerned about locked maps that you can't actually view in tuner pro to see what you're running... this knock sensitivity table business is a slippery slope for tuners as consumers require their logs to be timing correction free and now with a simple tweak of tables you can make a log look A LOT better until the consumer forgets to fill up with enough E85 or their gas station switches to winter blend E85 and octane level drops...