Launch lag..new affliction?

[kingnonis]

Hey guys...before u flame me, I did a search and came up with nothing specific to what I was looking for, so:

Last night I was out and about and came up to a red light on an empty road, so I decided to kick the step into m1, turn off DSC/DTC, and "launch" (forgive my using of a manual tranny "term"). For like the first second it was as if I'd floored a geo metro.. my 1er slow motiones until it hit a little over 2K rpm and then it took off like the beast we know it is. Now..this has never happened or at least I've never noticed it before...and it SUCKED. What's the deal? Did I just miss it earlier and this is a common thing? I swear it sucked so bad until 2K that I wanted to cry.

[bigmicj]

NEVER launch in M1. Always start in M2. Trust me that M1 gear is useless.

[kingnonis]

Originally Posted by bigmicj

NEVER launch in M1. Always start in M2. Trust me that M1 gear is useless.

If I floor it in M2 though the step will kickdown to M1 for me...so should I just floor to WOT and stop before reaching the kickdown to prevent downshit to M1? does this eliminate the launch lag?

[jotapeh]

Originally Posted by bigmicj

NEVER launch in M1. Always start in M2. Trust me that M1 gear is useless.

What? Can we get some justification on this? I'm not saying you're wrong necessarily but "trust me" is not valid logic

[dbtheo]

Originally Posted by jotapeh

What? Can we get some justification on this? I'm not saying you're wrong necessarily but "trust me" is not valid logic

agreed, every 135/335 that we had here, 1st gear has always been better. That said, I'm not sure why the op had the issues he had. I'm thinking maybe a software issue with the tranny itself.

[x97Melbourne]

I had a post about my experience with a 335iA loaner (sweet car). I didn't really have much luck with the "manual" feature of the auto trans either. I had much better accel with it in D.

For those who don't like M1 in the step....you should try 1st gear in the MT....my gosh....its so powerful I rarely even use it in everyday traffic. When I do get the urge though, it'll dust any car on the road......and snap your neck back!

[bigmicj]

I never start in M1. You can definitely start in M2 in the 128 and run clear through to 6800 RPM if you want. At least that's as far as I've been brave enough to try.

It sounds like you might be hitting the kick down button under the pedal as well. Are you pressing the accelerator all the way down? If so, when you start in M2, it will automatically kick down to M1. This is not a good move.

[m7ammed]

What you can do with an Auto is apply the brakes Rev(maybe around 1500 RPM or so) the car a little all while it is in M1 then full throttle and releasing the brakes at the same time, should give you a much better launch

[italiantank26]

This is funny cause i have a 128i but im definetly not having this problem, in 1st gear in manual mode (car is auto) this car absouletly destroys anything.

[tbird]

I had this very same problem in my last BMW, a 325xi. I even went through the Lemon Law process on it to force my former dealer to even do anything about it really. They kept reloading the car's software, and it would help for a while, but then the problem would get worse again. I would have between .5 seconds to a 2 second lag before the car would kick in.

According to BMW NA, this lag is "normal operation of the XDrive system and off all AWD vehicles built". On my research, I started leaning towards the software operation of the vehicle, and after doing a LOT of research, I was able to find one article about a GMC pickup that was having the same lag issue, and it came down to its stochiometric ECP programming. The truck was geared to drive its massive 8cyl 2mpg vehicle in an "enhanced mileage" programming unless you stomped on the pedal and then the truck would reprogram itself to have full thrust, but that lag between pedal and thrust was up to 4 seconds. Clearly BMW has a form of ECP in all cars, so I asked BMW dealer to turn off the programming, they said it was impossible.

Now, to your specific situation, when you have a turbo car, there is the standard lag. In the 135/335's twin turbo engine, it has the one small turbo and then the big turbo. The small turbo spins up for "off the line" power until the big turbo kicks in at normal place and really gives you power.

My "guesses" are as such, 1) Your small turbo has an issue, or 2) the software in your car needs to be reloaded and then your "performance chip" needs to be reset.

Throw these at your dealer, see if they will check these out for you. And, of course, be prepared to take them on a test drive and recreate the situation. Study what makes your car do the lag, and then know EXACTLY how to recreate it. Like on my old 325xi, the car had to be warmed up, and you would have to do about 3-4 quick off-the-line starts, and then whammo-the lag would be up to 2 seconds.

Good luck, and definitely post your results. I still research what was wrong with my last car, there still is no definitive answer.

Oh, and to note for people who have been part of some of my previous postings on S. FL dealers, the problem was with my OLD dealer of Lauderdale BMW, not my new one of Braman. Braman has been great.

[Citizen Z]

Originally Posted by Pirate

I suspect it was the e-diff kicking in and applying the brakes until your tires hooked.

I'm inclined to agree. I've had some really funny launches because of eDiff and the other nanny's, and especially when going round corners with slippage.

[tbird]

Wouldn't "EDiff" be part of DTC/DSC and shut off? ABS could act like that no matter what, but if going in a straight line and just spinning tread off the line, ABS would not activate. That would be my guess.

[m7ammed]

Originally Posted by tbird

Now, to your specific situation, when you have a turbo car, there is the standard lag. In the 135/335's twin turbo engine, it has the one small turbo and then the big turbo. The small turbo spins up for "off the line" power until the big turbo kicks in at normal place and really gives you power.

There is no small and big turbo in the 135i , it has to same size turbos each is feeding 3 cylinders

[tbird]

I read a couple articles that described the turbo setup as such, hence the information I gave. I am searching for those articles again.

However, in my search so far, I found this.......
http://www.motorauthority.com/bmw-ac...re-update.html

[tbird]

Oh, and Adood84, in looking at the features of your car in your signature, are all those things actually separate options? I know that in different countries, there are different engines and options, but I would think that things like the rain sensor and automatic A/C and exterior mirrors would always be standard in any country?

Anyone else have these things as options in their respective countries? Geesh, I hope not, that would really send the price of the car up sky high.

This might be an interesting point for an individual thread.

[m7ammed]

Originally Posted by tbird

Oh, and Adood84, in looking at the features of your car in your signature, are all those things actually separate options? I know that in different countries, there are different engines and options, but I would think that things like the rain sensor and automatic A/C and exterior mirrors would always be standard in any country?


Anyone else have these things as options in their respective countries? Geesh, I hope not, that would really send the price of the car up sky high.

This might be an interesting point for an individual thread.

Well yes , I can order anything I want . You got to remember that there is nothing for free in this life , wither they call it standard or not you pay for it in the end.

[tbird]

Adood84, I agree, nothing is free. But the scary thought to me is that when I watch Top Gear/BBC, and I hear of their prices on cars and their cost in Pounds is equal/higher than our cost in dollars, and then you run the currency conversion, it would be scary to think that you get less options for a higher price.

Basically, if an American 128i comes with rain sensor and auto a/c and all those standard little bits, and costs $29,900 to start, and a non-American 128i does NOT come with those standard but then costs 29,900 Pounds (sorry, no PoundSterling symbol on my typeset on my work computer), then by the time you add those options to just match the American model, you could end up paying $40,000 for the exact same car. To me, that's a bit nuts, and I would hope that it is not such a pronounced difference for you guys "on the other side of the pond".

So that is basically my point. I would hope that pricing would be fair & equal for all.

[KVMan50]

I have a 128i and have discovered (read in the manual) that if you push the DTC button for 3 seconds it turns off most nanny functions. I then put it in M1, hold the brake, rev it to 1500 or so let off the brake and at the same time floor it, I get a really good strip of rubber and a pretty potent launch. If you don't hold the button for long enough, some of the nanny features are still active and it reduces wheelspin and cripples the launch. I also found that hitting a right angle corner hard, and trying to fly out of it, the traction control really dampens the fun. Safer, mind you, but not as much fun.
Dave