10-13-2019, 02:22 PM | #67 |
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This is alarming to hear. I have an X2 M35i on order, currently on a boat mid Atlantic. My X1 has this type delay but only in comfort mode. In sport mode acceleration is fine. My understanding is this is due to how the transmission is programmed.
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10-13-2019, 02:28 PM | #68 | |
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10-13-2019, 05:46 PM | #70 |
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I don’t find it any worse than the x1, which is why I asked if those guys had one prior. I got used to it and learned how to overcome it.
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10-13-2019, 07:05 PM | #71 | ||
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10-13-2019, 08:27 PM | #72 |
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In my opinion, I think the whole electronic braking + transmission system is poorly designed and not optimized at all.
Compared to my previous car which had a "mechanical 5AT", I like that my M35i 'disengages' the gear from the engine when sitting at a red light. There are no annoying vibrations transmitted to the cabin. However, I dislike how there is a noticeable 'thunk' when I release the brake to take off. And, the transmission becomes unpredictable when I'm creeping along in slow traffic. It becomes a jerky start & stop and sometimes the brakes will 'shudder'. With all this shit going on, it's not too surprising that acceleration can also become unpredictable. For me, these 'NEAR DEATH EXPERIENCES' occur when I release the brake in the left turn lane and slowly creep forward. I can feel my heart explode as I press my right foot deeper and deeper... |
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10-14-2019, 04:47 AM | #73 | |
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10-16-2019, 03:44 PM | #74 |
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Yup.. I complained that it's taking me time to "learn" how to stop with the car in comfort mode because it always disengages that transmission just as I'm about to stop so it makes it jerky. Honestly I've been driving on sport mode all the time and only flip it to comfort when I'm cruising on the highway and want the exhaust flap closed for the extra quietness. I'm just about to order the pedal tuner just to sharpen things up a little more, seems that everyone else has been more happy than not installing it that it should be a win win.
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10-16-2019, 04:24 PM | #75 | |
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10-16-2019, 07:23 PM | #76 | |
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I drive almost exclusively in comfort mode and stopping 'smoothly' is next to impossible. 9 times out of 10, there is a final jerk when coming to a complete stop. And I am concentrating real hard to feather the brake pedal. Same thing in Ecopro mode. Jerky stops. |
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10-16-2019, 08:26 PM | #77 |
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seems to be different issues between the M35i and the rest-of-the-world version of the FWD S2.0i.
At least on my FWD (7 speed dct), the stopping is smooth...no tranmission grabbing. Even in crawling traffic it's pretty good. My main issue is the strong hesitation/lag when I try to accelerate fast from standstill, or when I need to quickly accelerate when already cruising say at 100kmh. The BMS pedal tuner helps a little, but doesn't eliminate what is either transmission lag, or turbo lag. Though I can't see how turbo lag could be that bad in a modern small-turbo, relatively low power engine. (remembering the non US 2.0i has only 141kW). Which is less than my 1994 Nissan 200SX 2 litre turbo, which had no noticeable turbo lag
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10-16-2019, 08:47 PM | #78 | |
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Does the car seem to lurch forward or sort of hiccup backward when this jerk happens? If it's a forward jerk, my new theory is that it's the battery charge regeneration holding on too long. The torque converter is locked in this mode, and of course it has to unlock before the car fully stops. If that happens late, the idling engine will briefly be pushing the car forward. If it's backward hiccup, it could still be the same cause but maybe harder to explain. One way to test this might be to fully charge the battery, then immediately take the test drive. In theory, regeneration would either not happen, or make a tiny effect. This theory does not, however, account for the lag in taking off, as has also been reported. But who knows, maybe it is! |
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10-16-2019, 09:30 PM | #79 |
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I would have to say it ultimately is a disengaging feel, so it would be a lurch forward as if you popped the car into neutral. It would make sense of the regenerative braking but in my mind I *KNOW* it's literally the transmission disengaging, because it's the same "jerk" when you take the foot off the brake and it clunks back in gear/engages. This is NOT present at all in the sports mode. It actually is not at all present in my wife's 2016 X1. The dead spot is a completely different issue that is also exaggerated by the transmission clunking back into gear AND the dead throttle input.
I would think that it does not matter if the battery is fully charged or not, because the regenerative braking is a function of braking to gain energy. Even if the car is fully charged and then started I would think the charging system will still act the same in that aspect. |
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10-17-2019, 07:39 AM | #80 |
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It never happens in sport for me. In comfort it rarely happens. With throttle controller installed it still happens. When in comfort and it does happen, I use the paddle and then I am good. And it wasn't always from a stop.
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10-17-2019, 10:00 AM | #81 | |||
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10-17-2019, 12:27 PM | #82 |
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Definitely agree with all of the above statements... I feel that after my software update and new turbo recall the disengage while stopping is slightly delayed in terms of the car is more fully stopped before the clunk. With all these talks I just ordered the pedal tuner just to see how things improve. I still am biased to sport mode but in a way hope to drive more in comfort with the pedal tuner. Still the the torque converter locking and unlocking I really don't like much.
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10-17-2019, 12:34 PM | #83 | |
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I just think BMW didn't thoroughly test this when designing the car. I don't know if they'll fix it though. Nissan had a similarly dangerous issue called ice brake that caused many accidents and it was NEVER fixed. It was on the 370z. |
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10-17-2019, 12:38 PM | #84 |
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So I did more digging and found an article from 2012 talking about BMW linking up with it's navigation system to sense when to decouple the trans...looks like it's finally made its way into cars now that Navi is standard:
When set to Eco Pro mode, BMW claims that fuel efficiency can be boosted by as much as 25 percent, and if the driver selects the Foresight Assistant feature, their Bimmer will choose the most efficient driving route and provide tips on maximizing fuel economy through the center-mounted display. Additionally, the system can recognize when coasting would max out the MPGs, decoupling the transmission from the engine at the most opportune times. |
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10-17-2019, 12:57 PM | #85 |
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Further sleuthing...so this info isn't available on the U.S. (maybe we're #DumbAmericans, I suppose), but it was available on the international sites. Anyway, it's for the X1, but I'm sure it applies here.
For those with this issue, it looks like Sport may be the solution OR perhaps we can code off the transmission decoupling feature in EcoPro mode? I know you all said comfort, but the literature only says EcoPro and during coasting. ECO PRO MODE. The ECO PRO Mode helps drivers reduce their fuel consumption by up to 20 percent, depending on their driving style – according to an internal BMW fuel consumption study. The additional coasting function and ECO PRO Route offer an increased savings potential. |
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10-17-2019, 01:05 PM | #86 |
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The jerking forward thing even happens while in sport for me. I have to put a big gap between the car in front and mine. It's not really fun when I'm coming to a lower speed. I also find it dumb about the whole decoupling issue. Why offer it on a performance model that's pushing 300+ HP. Offer that feature on the 28i.
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10-17-2019, 02:59 PM | #87 |
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To add fuel to this slowly burning fire...has anyone noticed how harsh the auto start-stop is? My friend has an F48 X1 and his is much smoother.
My guess is that all of these issues are connected somehow. |
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10-17-2019, 03:00 PM | #88 | |
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