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05-29-2018, 11:09 AM | #155 | |
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05-29-2018, 12:51 PM | #156 | |
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I do know that you can code it out with NCSExpert...
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2012 BMW 328i 6-Speed Wagon | Deep Sea Blue with Grey Dakota Leather | Manual Swap, 330i Intake + Tune, 3.15 Helical LSD, Öhlins R&T
(SOLD) 2009 BMW 128i 6-Speed Coupé | Monaco Blue with Black Sensatec | chris_flies' 128i thread |
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10-14-2018, 12:48 PM | #158 | |
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I've totally disconnected the dsc module, and removed both rear speed sensors, and disconnected the accelerometer under the driver seat and still got power reduction when slip or spin should occur. This is with the gas pedal to the floor. The dealer foreman assured me I was not experiencing any braking via the brakes with those things disconnected but rather the dme using torque limiters and ignition timing to brake the vehicle. The car was more loose though. Thankfully, MHD and xhp have discovered several torque limiter. I have auto trans and would get a lot of post shift timing corrections. Also, timing correction before the shift. The more power I made, the more torque limiters started popping up. I started seeing limiter 4, 8 and 2048. I used the shift bog option to get rid of 4 and 2048. Shifts recover faster now but torque still being limited by dme. Not sure what torque limiter 4 is. I'm running xhp stage 3 which supposedly eliminates tranny limiters. The car drives better but still controls the amount load and torque to compensate a little for the changes I've made. After all this, I was still getting ridiculous post shift timing corrections all over the place for no good reason. I've seen some corrections on 15psi 18psi stock turbos. I'm running 22psi low midrange by the way custom tune e70. After much research, I decided to use the desensitized knock sensor feature on mhd. I finally got to the place where I wasn't afraid to try this because I know my car so well and prayer. Also, I read that knock detection is still there but at a reduced level. Well, every single timing correction disappeared! Car drives more normal, shifts better, accelerates faster and cleaner. I've been pushing the car real hard lately. I very rarely see maybe a minor correction when the ecu is trying to stop wheel spin. The dme still controls torque and power to the ground. I notice this more the colder it gets outside. It's as if the car levels up and allows just enough power for the amount of surface adhesion I have. With all the changes, I'm going faster and the car feels better but, i still haven't conquered the problem yet. One last thing. Stickier rubber does allow the dme to release more power to the wheels. I noticed this when going from PSS tires to pilot sport 4s 265 35 18 out back. 235 40 18 up front. There nice but not enough to satisfy the power I'm running. The ecu will just adjust to them and compensate for slip. I believe this is why some guys can run big power in cold weather without sliding off the road. I need stickier 285 30s which should be enough. I don't plan on keeping the knock sensors desensitized. From what I hear, mhd is trying to solve the post shift timing issue. |
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10-14-2018, 03:25 PM | #159 |
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I'm not sure if you are aware but the DME on some models (I can't say all because I don't recall. N55 at least) also uses input from the DSC to more accurately detect knock by way of wheel speed sensor input. It's the rough road detection feature. The way I understand it works is by detecting a mildly oscillating rear wheel, ie the wheel is bouncing up and down under acceleration. The wheel will gain speed in the air.
It might be worth cleaning the wheel speed sensors and their reluctor ring if yours are of the exposed type. |
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10-14-2018, 03:44 PM | #160 | |
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10-14-2018, 06:04 PM | #161 | |
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Yeah, you know who doesn't use mechanical LSDs? McLaren! Of course, the way these eLSDs are programmed makes a big difference, so I'm not saying the BMW's eLSD equals McLaren's, but the concept is the same. Plus, BMW programmed their eLSD for only 300hp, so I'm sure it isn't optimized for those running big horsepower numbers around here. Here are two fun quotes from Chris Harris about the McLaren P1's eLSD. "A typical passive mechnical or active electrohyraulic cross axle differential is not actually as good as the brake steer system used by Mclaren on the P1 because it acts to equalise the speed differential across the axle, and not to control it (to a value which ensures BOTH driving tyres are maintained at their optimum longitudinal slip value). Some people believe a conventional mech (or electro-mech) diff to be "optimum" because it allows you to do big, smokey, and easily controlled skids. Which to a large degree it does. However, whilst you are doing those aformentioned big skids, the driving tyres are effectively locked together, and the more torque you want to shuffle across to the outside (more heavily loaded) tyre, the more locked-together those tyres are (and hence the lower the speed differential across them). That means that during that time, neither tyre can be held close to it's optimum dynamic slip ratio, and as such, the perfect absolute longitudinal acceleration of the vehicle for that surface friction cannot actually be achieved. However, by using a conventional open differential, and a high band width speed controller using the rear brakes to torque balance, the brake steer system can both maximise drive torque across the axle AND optimise the dynamic slip ratio at EACH individual rear tyre. This is why Mclaren use the system and not a conventional locking diff. When you factor in the lack of additional mass, and the complete tune-ability of the active brake slip control, it is a no brainer to use this solution on an ultra high performance car." -and- "I'm the biggest critic of these electronic non-differentials. I think the 12C suffered for not having a mechanical LSD, and even though I do buy all of the engineering arguments that see then as a malign influence in the search for optimum road behaviour, I think modern power outputs require them (and I like doing skids) The P1's system is the first I've driven that actually works. When you see the video next week, you'll see. The response from the rear axle under power feels like there is a mechanical locking diff. It's uncanny. But I just judge these things on confidence - in a 12C, even in its latest brake-steer calibration ( and late cars are much different to early ones) you never quite know if one or both wheels will spin-up. In the P1, it's always both. Sounds terrible, but you need to feel it from the cabin to see how it works. For me it was the big question mark over the car's specification, having driven it, it's a compete non-argument. The perfect suspension system for a RWD car would have no locking rear diff. It corrupts pretty much everything: it effectively adds spring rate under load, it causes understeer,it harms height speed stability in a straight line, and in the case of a plate-type diff it can cause havoc as/when/how it loads and unloads. But with today's massive power outputs, cars are traction limited and tend to run such stiff springs that the LSD effect is less pronounced because the chassis is already so compromised for road use. And on a practical level, not fitting one to your new super sports car precludes big, controllable slides for the media push. Ask McLaren about that one. The holy grail I suppose is a constantly variable locking diff that gives 100percent when you need it (post apex) and zero when you don't (braking and turn-in) (the SLS Black has the best one of these I've tried, but BMW M do a good job too) I don't like stuff with heaps of power/torque and an open diff. It spoils the fun - ergo, I'd sacrifice some Lotus-like compliance to feel that LSD connection between my right foot and the rear axle. This is where those early 12C's struggled. And hence my genuine sense of alarm when I asked C.Goodwin if the car ran an open diff and he smiled and said 'Yes, but drive it before you start shouting at me'. I'm probably stirring a hornet's nest here, and people with greater knowledge/experience will flame me down, but that's a brief summary of how I view the subject. Mechanical locking diffs are like a good cigarette: destructive, probably non-justifiable. But in the right circumstances they're perfect and easily justified. To extent the metaphor: The P1 is the first e-cigarette that could persuade a hardened Marlboro red puffer to go electronic. " |
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10-14-2018, 07:34 PM | #162 | |
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Your right. It's sort of bitter sweet for me. Almost a love hate thing. I've come to enjoy the benefits of the electronic aids in most cases. On the street, I can carve some corners or curves pedal to the floor and electronics allows maximum acceleration the suspension will allow. It's amazing how power is adjusted seemingly instantly and precisely to the driving situation. Even in damp or cold conditions. It feels like your defying physics sometimes. I also have a quaife diff. Braking can occur on either axle. Power adjustment from the engine is managed very well. My car is way faster since BMW updated my software. Before the update, even with the diff there was no way I could do what I'm doing now. I was spinning endlessly and freely before. There was no controlled slides when dsc was off. If you didn't know how to drive a rear wheel vehicle, you were in trouble real quick. Electronics enable you to amazing things like 0-60mph 3.6 sec in 40° f temps on street tires in a straight line. It's Amazing how the car adapts to the surface and keeps you moving full steam ahead. The bitter part for me is not being able to extract all the power the car can make due to adhesion problems. Stickier tires like extreme summer or drag probably will solve this making the car blazing fast. On rare occasions I'll get power adjustment or reduction when trying to get out in traffic while turning. It depends on my steering angle and how fast I'm going though. Other than that, the system is genius but not flawless. I'm at the point that I'm not even sure I know how to drive without the the aids. Especially when driving on the ragged edge. I'd rather have these aids than not too. Many more benefits like you said especially when you up the power. It's only some instances I wish I could have just a little more freedom. Bottom line is a mechanical diff on its own cant compare to how much more performance you can get out of these cars with these power aids. Great article! |
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03-16-2019, 01:53 PM | #163 | |
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Turbo lag, a mushy rear suspension and no LSD make issues with the rear of this car a bit nebulous. |
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05-30-2019, 05:25 PM | #165 |
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I wonder if there are different versions of DSC firmware for 135i 2011. I believe I have the latest one, but it is just ok at best.
My main issue with the software is that under first wheel slip detected I usually get massive clunk due to engine torque cut. It almost feels like engine blow up or something. But next time wheels are about to slip during the drive it doesn't happen anymore. It's just gradual engine intervention. That is with No-DTC or DTC button one press. I have no idea what it is. It is almost as if DSC needs to adapt wheels friction coefficient or something. But each time I drive... and each time it scares the hell out of me |
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06-30-2019, 10:19 AM | #166 | |
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07-09-2019, 07:51 PM | #167 | |
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The golf r could pretty much approach an Alex from any angle then rotate the chassis seperatly based on steering angle The 1ers really demand that you take a smooth driving line in order to maximize the traction circle and not get power cut. Much more rewarding when you get it right but also more punitive (in the opposite if a Corvette kind of way) The real key would be getting a program to make adjustments to the elsd metrics. |
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07-10-2019, 07:17 AM | #168 | |
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I agree with you. Hopefully, someone discover how to this. Take a look at this thread. https://www.e90post.com/forums/showthread.php?t=1610143 New throttle discovery tables in the dme. I had my tuner update my custom map with the tables changed to zero. Very nice change in driveablility. Cornering shifting and acceleration improved. Traction control has been softened so I can accelerate and lean into corners before electronics steps in. I have the BMS pedal tuner too. Fun to drive for sure. I've done all I can do in the dsc module. I believe the key is found in undiscovered dme tables. It's been brought to my attention that the newer generations vehicles use the dme to control alot more vehicle dynamics than people know including some commands on steering inputs or adjustments. At least thats what i read from some dme programmer guys. |
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12-11-2019, 01:43 AM | #169 |
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I ran across this neat test and even though it's not our cars, it's a great example of how well designed/implemented software can work very well.
And what I'm saying by this is, there is ZERO reason to turn the ediff off. Skip to about 2:20 in the video |
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12-11-2019, 08:05 AM | #170 |
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Good video. This is basically what my car does. Full power under extreme conditions is just asking for trouble. I believe most cars now have some type of assistance built in that cant be fully turned off. With it, I'd just be burning up too much rubber and going nowhere.i have my dsc and dime tuned in a way that gives me the most fun right and power at the edge of traction and still accelerating forward.
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12-11-2019, 08:08 AM | #171 |
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To be honest, our e-diff works pretty well on the snow.
But it's struggling to provide fast enough response on much stiffer system that is the tarmac - especially if it is irregular or with changing surface. It is just a bit unpredictable. And it sucks on the bumps. (I am talking in general of stability control). E-diff still better than nothing, IMO. Anyways, BMW is branding its new cost-cutting solution as ARB - they can reduce the number of controllers by integrating the stability control in the ECU. https://www.greencarcongress.com/201...90527-bmw.html This may help with lags a bit since they can more precisely control engine torque and with less delay. Cuts down at least 10ms probably from CANbus communication. |
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12-11-2019, 09:30 AM | #172 | |
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I have to agree with you on this. BMWs inherent subsystem wont allow some traction safety features to be completely disabled for good reasons and enhanced performance is part of it. On the tarmac, the delay in some situations is just awkward. But, all cars are not equal. One vehicle may have less delay or recovery time after traction/ediff because of how suspension is tuned. Too soft or too hard a setup etc. The same with putting down enormous amount of power and torque. The safety systems have to work harder and faster to overcome or control forces that induce too much slip in extreme conditions. A quicker recovery time is welcomed. Fine tuning everything to work together is a must especially if the dme is requesting more power than the other ecus can effectively manage. It just causes a traffic jam on the CANbus hwy resulting in slower actions and recovery times after slip with throttle delays, shift delays, short shifts, power cuts braking etc. I've tuned out as many nannies possible in the dsc and tailored it to my driving style. I recently disabled ECBA(electronic control braking actuation). There is still very little assistance(slight power reduction and brake adjustments) when needed. I'm on the edge with cornering and don't want to lose all assistance. Not necessary anyway for most unless your building a track car. Then of course remove the ecus. I have throttle sensitivity turned off in dme and custom dme tuning with jb4 pedal tuner and xhp stage 3. All together, these changes made the car a lot of fun, more allowed power, quicker actions and response times. |
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12-11-2019, 10:36 AM | #173 | ||
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The suspension.., but I also am wondering how different brake pad materials affect the control. Next time I am putting OEM on the rear (I don't know what I have currently, but experiencing this one issue I reported earlier
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I am asking because it pisses me off that in my DME the DTC disables Sport throttle mapping. Maybe the BMS Pedal would be a solution for me. I wasn't aware of that! Though I am a bit concerned about safety since this is surely not certified hardware which is messing with critical ASIL D level safety system. I guess it was tested on other people though |
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12-11-2019, 11:54 AM | #174 | |
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The dsc tuning does effect all modes, dsc, on or off and dtc. I'm not sure if it will fix the sport issue. We have different dsc modules. I have dsc full off most of the time. Xhp for trans or someone who tunes dme may have an answer for that. The pedal tuner makes a good bit of difference on a tuned car. Power comes on fast initial throttle. Part throttle is great. Altering the dme throttle sensitivity tables is icing on the cake. A little more throttle allowed during cornering. Dsc/dtc less intrusive and lets car corner more naturally. Suspension allowed to do more of the work less some brake work. DME still ultimately in control as well as other modules. I had the same concerns with the pedal tuner at first. Once you get it, you'll probably never drive without it! |
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12-11-2019, 11:57 AM | #175 | |
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12-11-2019, 12:04 PM | #176 | |
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A dme software update may help slightly but nothing like the above. A custom tune will overwrite dme anyway. |
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