Interesting finding - related to manual tranny only

[Lester]

Originally Posted by grish

Is that a fact? How did you arrive at that conclusion? Did you actually look at the software and what it controls?

There are no servos or electronic controls at all on the manual transmission, clutch or shifter mechanisms. The software will shut fuel to the engine if it experiences an over rev condition, but it can't disengage the clutch, or shift gears. If it could, it would be called an automatic transmission.

The MT and clutch really hasn't changed in design for about 70 years. Over the years, the materials have improved, and the designs have become more compact and efficient. The clutch is hydraulic, the linkage is mechanical, and the control mechanism is the drivers' brain.

The computer can watch what's going on, and gives the driver feedback by the tachometer, speedometer and fuel consumption. But what gear you are in, what rev you are at, and what your speed and fuel consumption is at, is up to the driver. Note the warning in the manual - about possibly damaging the engine if the driver shifts into the wrong gear. Would that be necessary if the computer had any control at all?

[Monterra]

How about this theory:
When DSC, DTC are both switched off, driver's habits: acceleration, focus, shift points and speed of shifts are all heightened eliminating jerkiness caused by lack some/all of the aforementioned. Unless I'm on the highway I normally drive windows down, radio low or off in order to give the car the full attention it deserves. It always rewards. Listen to the engine, watch the tach as you shift. This motor requires quicker shifts (than I was used to) and/or higher shift points due to its very quick revving (light flywheel) nature and the 6Ms tightly spaced gear ratios.

[Lester]

You may feel a hesitation upon launch, and shifting from first to second if the rear wheels start to spin while DSC/DTC is on. Not real hard to do with a 300 HP rear wheel drive car. This is a symptom of the fuel being cut to the engine as part of the computer control under DCS/DTC, and has nothing to do with whether or not the car is an automatic or a manual transmission.

Methinks the driver's age should be programmed into the key, and prevent turning off DSC if you are under 25 years old.

[jeremyc74]

Originally Posted by Lester

Methinks the driver's age should be programmed into the key, and prevent turning off DSC if you are under 25 years old.

Now you've done it!

[Monterra]

Really? I think there should be a mandated emergency vehicle maneuvering course that all licensed drivers must pass to retain it.

[grish]

Guys,

• I do not spin the wheels
• I've been driving stick for 15+ years
• I know what I am doing, my driving habits are fine, I don't need to listen to the car to know what it's doing, I can feel it
• I drive a more manageble 128, not monstrous 135
• I know what I feel and don't really care WHY it works even though the charts suggest otherwise

[BlackjackMulligan]

I notice a difference from when the climate control is on and when it's off with regard to jerkiness.......really. And this isn't the first car that I've noticed it. It's much smoother with the climate control off....I believe it's because the A/C compressor puts an additional draw on the engine, pulling the RPMs down faster when you depress the clutch and let off the accelerator. This is pretty noticable, try it out.

[scorcherjf]

Well the one thing the computer does control is the throttle since it's drive by wire (which has some lag that's annoying to me but that's another topic!). But I'm not sure when or where the computer cuts throttle, but I know it does it when it detects wheel spin and you have all the traction controls turned on.

And yea, AC off helps too since there's a belt that doesn't have to rob the engine of power anymore =)

[jeremyc74]

Originally Posted by BlackjackMulligan

I notice a difference from when the climate control is on and when it's off with regard to jerkiness.......really. And this isn't the first car that I've noticed it. It's much smoother with the climate control off....I believe it's because the A/C compressor puts an additional draw on the engine, pulling the RPMs down faster when you depress the clutch and let off the accelerator. This is pretty noticable, try it out.

I've noticed that as well, and it's common on most of the vehicles I've owned. You're right about the compressor. It puts a lot more drag on the engine and brings the RPM down faster.

[lib]

Originally Posted by grish

• I know what I feel and don't really care WHY it works even though the charts suggest otherwise

Fair enough. For some reason you can't explain, your shifts seem smoother when you disable the traction & stability control. Completely plausible.

But, you admit that you don't know what's going on in there. Perhaps you should stop telling people that actually do understand the system that they must be wrong when they try to direct you towards an actual cause for this behavior.

[grish]

Originally Posted by lib

...Perhaps you should stop telling people that actually do understand the system that they must be wrong when they try to direct you towards an actual cause for this behavior...

The funny thing is NOBODY understands the actual cause of behavior

Every single "techy" who thinks they understand the system actually don't because of so many "soft" components...

[scorcherjf]

Originally Posted by grish

The funny thing is NOBODY understands the actual cause of behavior

Because I think most people don't experience this behavior on their car. I know my shifts from 1 to 2 aren't affected by my traction control unless I'm really gunning it, in which case it'll kick in AFTER I complete the shift to 2 and kill my wheelspin. For casual driving, I notice no difference. What I DID notice was my 1 to 2 shifts were smoother when I got my clutch delay valve removed.

[dmvsw]

Grish... ignorance is bliss, eh?

[grish]

Originally Posted by scorcherjf

What I DID notice was my 1 to 2 shifts were smoother when I got my clutch delay valve removed.

So, lets agree to disagree...

• Some, or maybe I am the only one, feel the difference in clutch response with DTC/DSC off.
• Some do not feel the difference switching the electronics off.
• Some only feel the difference with the CDV removed.
• Some do not feel the difference with the CDV removed.
• Most couldn't care less either way.

[grish]

Originally Posted by sw4ng

Grish... ignorance is bliss, eh?

That's why only 1% of all BMW owners, at most, visit sites such as this one and couldn't care less of all the issues raised here.

[Monterra]

Grish: Shift the car properly (faster action or hold revs longer to give you more ticks on the way down the tach while shifting) and you won't get jerked around with or without turning the nannies off. Then turn them off and take a sharp corner in 1st with the revs @ or above 5k, then bang 2nd and kick the tail out with a healthy chirp for a good time.

[grish]

Originally Posted by Monterra

Grish: Shift the car properly...

Thank you, but no thank you.

I know how to shift a manual tranny properly and how to have good times with the manual.

I had enough experience with top notch manuals from Honda, Mazda, VW and Audi without running into this notchy 2nd gear issue.

BMW does not have the best/smoothest shifting manual tranny by far as many here believe.

[jeremyc74]

Originally Posted by grish

The funny thing is NOBODY understands the actual cause of behavior

Every single "techy" who thinks they understand the system actually don't because of so many "soft" components...

There are no soft components involved in the clutch or the shifter.

[Monterra]

Originally Posted by grish

Thank you, but no thank you.

OK

I know how to shift a manual tranny properly and how to have good times with the manual.

Me too and have been driving them exclusively for 17 years and this one had the nicest clutch engagement of any. It did take me a little time to get the feel for how best to row through the gears smoothly when not hammering.

BMW does not have the best/smoothest shifting manual tranny by far as many here believe.

Probably not THE best but I'd say its in the top tier. I don't think any current VW/Audi product in the same price league can match or even come close IMO.

Mazda Miata was real nice, possibly better as I recall.

[ATR1]

If turning off DSC/DTC does give you quicker throttle response than that could be it right there. Less throtle lag when you give its gas while letting the clutch out = better sync = less jerk.

[grish]

Originally Posted by Monterra

Probably not THE best but I'd say its in the top tier.

If I had to rate them it'd be, in this particular order: Honda, Mazda, BMW, Audi and VW.

[Monterra]

Which Honda product do you think is better, my 06 TL was smoother but I like my 128s much better esp. when hammering through