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-   -   Can I do this w/ SMG? (http://www.bimmerfest.com/forums/showthread.php?t=47464)

marksmith 12-07-2003 07:57 AM

Can I do this w/ SMG?
 
I have a new M3 w/ SMG (which I love) but I have a question :
#1: It is often my habit w/ manual cars to roll to a stop in neutral. I do this w/ my SMG by clicking the shift lever L to "O" (or neutral.) This seems to work fine & appears to be perfectly OK for the SMG programming. Any reason (mechanically) not to do this w/ an SMC car? (FYI: I do not always like the rolling stop SMG downshifting programming w/ the car in Auto-mod: the shifts can be a bit abrupt or pre-mature in settings 3-4.)
#2: While driving in the manual mode (any setting 1-5) is it advisable/OK mechanically to roll to a stop and allow the SMG to downshift "automatically" (as opposed to downshifting manually & thus use the engine to brake the car?) I don't always want to use the engine to act as a brake (SMG's tendency to downshift in slow, passive city driving. ) In the manual mode the car will roll to a slow stop and shift down automatically at the last moment from 3rd to 2nd & then first w/o my intervention. Does this create a problematic engine load? The car never seems to stall, struggle or lug in this context.

My experience w/ the SMG has been very positive but I do not always "agree" w/ the programming choices relative to city driving situations IE: In my usual manual setting of #4, upshifts are perfectly paced but downshifts from 3rd to 2nd are best in setting #3 (smoother transitions.) I wish there was a way to "save" this preference in say a "Daily commute mode".
Thanks for your SMG feedback!

Pinecone 12-07-2003 11:49 AM

1) With SMG there is no reson to do this. I don't think you will hurt anything, but there is absolutely no reason to do so.

2) In S mode, the SMG downshifts so that if you were to forget and just step on the gas, you will not hurt the engine by lugging it. That is ALL.

You can downshift at any time, or not as you feel like doing.

Where you are putting it in neutral, I just gently stop, letting the SMG downshift as needed. If I think I will be going before stopping (light getting ready to change) I will downshift myself to be in an appropriate gear for the acceleration. remember SMG only selects a lower gear based on excessively low revs, NOT for performance in any mode.

Realise how SMG downshifts and upshifts is not only determined by the mode slection. SMG will downshift more quickly under HEAVY braking, or with a bit of throttle. So either get on the brakes HARD, or do a bit of heel and toe, giving the throttle a little blip at the right time. The amount of blip doesn't matter, as the SMG will supply the proper rev match. You just need non-idle throttle to cue the system for a more prompt downshift.

For upshifts, similar. A little lift as you shift will smooth out the shifts totally.

I run exclusively in S5 (except on the track, then S6). For normal putting about, a lift on upshift makes them as smooth as can be, but I have instant shifts available instantly also. For downshifts, I like the system do its calm downshift off throttle, unless I am starting to drive spirited, then the little heel and toe gives a nice rev matched downshift.

Realise that the blip (downshift) and lift (upshift) will tke practice to develop the proper timing.

Cowboy Bebop 12-07-2003 11:51 AM

I flick the thing into "0" all the time. Remember, this is a Manual tranny!
If you would do it with 3 pedals you can do it with SMG.
as to the engine braking, it is always better to stop a car with a $100 set of brake pads, than a $5k engine.
In the long term this causes extra wear on the engine that may bite you in the A$$ later.

Think of the rolling to a stop ? this way... if you were driving a 3 pedal car you could press the clutch pedal in and shift through the gears without engaging the clutch without any risk, and "coasting" to a stop with SMG, foot off the gas, or even covering the brake, is the same thing.

no worries.

HUMMM 3 12-07-2003 12:00 PM

Quote:

Originally Posted by marksmith
I have a new M3 w/ SMG (which I love) but I have a question :
#1: It is often my habit w/ manual cars to roll to a stop in neutral. I do this w/ my SMG by clicking the shift lever L to "O" (or neutral.) This seems to work fine & appears to be perfectly OK for the SMG programming. Any reason (mechanically) not to do this w/ an SMC car? (FYI: I do not always like the rolling stop SMG downshifting programming w/ the car in Auto-mod: the shifts can be a bit abrupt or pre-mature in settings 3-4.)
#2: While driving in the manual mode (any setting 1-5) is it advisable/OK mechanically to roll to a stop and allow the SMG to downshift "automatically" (as opposed to downshifting manually & thus use the engine to brake the car?) I don't always want to use the engine to act as a brake (SMG's tendency to downshift in slow, passive city driving. ) In the manual mode the car will roll to a slow stop and shift down automatically at the last moment from 3rd to 2nd & then first w/o my intervention. Does this create a problematic engine load? The car never seems to stall, struggle or lug in this context.

My experience w/ the SMG has been very positive but I do not always "agree" w/ the programming choices relative to city driving situations IE: In my usual manual setting of #4, upshifts are perfectly paced but downshifts from 3rd to 2nd are best in setting #3 (smoother transitions.) I wish there was a way to "save" this preference in say a "Daily commute mode".
Thanks for your SMG feedback!

First, rolling to stop in neutral, I don't believe will harm the car other than cause additional brake wear. (By the way knowing how to slap the transmission into neutral is a handy thing to know - its the equivalent of "in a spin clutch in") I do very little bumper to bumper gridlock type driving so I haven't developed a strategy for it. I leave the Drivelogic switch in 5 and always drive in the manual mode. The automatic mode never felt like it could accomplish crisp shifts unless you really stand on it (not many opportunities for that).

As for coming to a stop I try to anticipate it beforehand. Example: I'm city driving in third gear, I come to stop sign/light, I brake, manually shift to second, (approximately 15 yards from the stop) and as soon as the "2" light stops flashing (gear engaged) I manually shift to first. Once you get this technique down you'll be able to come to stop smoothly without throttle blips, jerks and clunks and be ready to go again. I have also found that downshifting manually from speed, say, on a freeway off ramp you don't aways get a throttle blip if you coordinate your braking and your shifts right. This technique is handy when you don't want attract attention from the cop hiding at the top of the off ramp.

I have found that occasionally when, say, rounding a corner in third slowly and I want to shift to second the transmission may not want to shift right away, but by manually using a light throttle blip it shifts smoothly right away. This also works in heavy traffic when you've just shifted into second and you need to get back to first.

HUMMM 3 12-07-2003 12:10 PM

Quote:

Originally Posted by Pinecone
1) With SMG there is no reson to do this. I don't think you will hurt anything, but there is absolutely no reason to do so.

2) In S mode, the SMG downshifts so that if you were to forget and just step on the gas, you will not hurt the engine by lugging it. That is ALL.

You can downshift at any time, or not as you feel like doing.

Where you are putting it in neutral, I just gently stop, letting the SMG downshift as needed. If I think I will be going before stopping (light getting ready to change) I will downshift myself to be in an appropriate gear for the acceleration. remember SMG only selects a lower gear based on excessively low revs, NOT for performance in any mode.

Realise how SMG downshifts and upshifts is not only determined by the mode slection. SMG will downshift more quickly under HEAVY braking, or with a bit of throttle. So either get on the brakes HARD, or do a bit of heel and toe, giving the throttle a little blip at the right time. The amount of blip doesn't matter, as the SMG will supply the proper rev match. You just need non-idle throttle to cue the system for a more prompt downshift.

For upshifts, similar. A little lift as you shift will smooth out the shifts totally.

I run exclusively in S5 (except on the track, then S6). For normal putting about, a lift on upshift makes them as smooth as can be, but I have instant shifts available instantly also. For downshifts, I like the system do its calm downshift off throttle, unless I am starting to drive spirited, then the little heel and toe gives a nice rev matched downshift.

Realise that the blip (downshift) and lift (upshift) will tke practice to develop the proper timing.

Right on! Good advice. The key word here is practice, practice, practice!
It's hard to learn this transmission driving back and forth to work. You need to get out of the traffic to find out how the thing works.

marksmith 12-07-2003 05:48 PM

Thanks.....
 
Thanks for the responses. Actually I do most (75%) of my driving on sweeping rural backroads in N. Texas where I can drive aggressivly w/ realtive impunity (the biggest danger is cattle but the visability is excellent.)
-I have only logged 1800 mlies on my SMG M3 and of course it's a slow learning curve w/ this tranny (but it's great fun to experiment.) I am mostly preplexed by the heavy traffic situations where, as it's been pointed out , subtle throttle modulations can remedy most problems.
-As for the overall SMG experience I must say that this transmission is simply too engaging to be dismissed as a mere techno-gadget. In particular I find that driving the SMG M3 demands a greater degree of driver focus & concentration than a manual. This may diminish w/ time (one get's more comfortable w/ it?) but I have the sense that this transmissiom can do many, many things well and may in fact be more fun than a stick manual!
-Here is an example of SMG fun and something I just discovered: I'm driving along in 6th. at 60mph in auto mode #5 w/ the "sport" mode engaged. I need to pass 2 cars poking along on a downhill section w/ a gentle sweeping radius. I hit the gas, the tranny drops into 3rd, revs to 7000 & explodes all the way to 135 mph, just hitting in 5th gear ALL in a BLINK (w/ rpms reaching 7800.) My God, it was wicked fun: I would never do this w/a manual tranny. Never so quickly nor with the confident feeling of a fighter pilot. It's hard to explain but in agressive driving situations the SMG M3 is perhaps the most sensual, sexy, powerful and addictive driving experience I have known (and I have had lot's of BMW & Porsches since 1966.)
Please share your tips & Thanks.

Pinecone 12-13-2003 10:21 AM

Even more fun is to do it in S5 mode, and a couple taps or so will have th ecar at lose your license speeds pretty quickly. :)

BTW using Sport mode may reduce your ability to play the throttle as well for some things. To me it is just a gimmick. Like A mode. :)

HUMMM 3 12-14-2003 10:09 AM

Quote:

Originally Posted by Pinecone
Even more fun is to do it in S5 mode, and a couple taps or so will have th ecar at lose your license speeds pretty quickly. :)

BTW using Sport mode may reduce your ability to play the throttle as well for some things. To me it is just a gimmick. Like A mode. :)

I agree. When/if BMW upgrades to SMG III they should remove the auto mode, and the sport button, delete S1, S2, S3, and S4. Leave S5 for normal driving, S6 for driving without DSC and add an S7, which would be for WOT and the european launch control. :)

marksmith 12-15-2003 06:42 AM

Dinan SMG software
 
I wonder what the Dinan SMG software will do? Also, what is the goal of the Dinan SMG software relative to the Dinan 3.91 Diff mod?

mrtm2008 12-15-2003 08:27 PM

Quote:

Originally Posted by Pinecone
BTW using Sport mode may reduce your ability to play the throttle as well for some things. To me it is just a gimmick. Like A mode. :)

Not sure what you mean. I feel the difference in the throttle response by just putting the "Sport" mode on & off. Also I get a much different mpg when using the "sport" mode & when I'm not. :dunno:

HUMMM 3 12-15-2003 09:28 PM

Quote:

Originally Posted by marksmith
I wonder what the Dinan SMG software will do? Also, what is the goal of the Dinan SMG software relative to the Dinan 3.91 Diff mod?

I've been told Dinan developed their S/W on a std 6 speed. When installed on an SMG II car the S/W thought it had reached redline @ about 4K RPM. Apparently there is a sensor somewhere in the SMG II set up that doesn't exist in the std 6 speed. In any event they theoretically have it figured out and are shipping diffs with an additional S/W mod.
This is the story I've been told by the dealer as to why it's taking so long to get my diff. If true, it reinforces my belief that when buying a set of mods as I am, it's a good idea to get it all from the same source so there will be a better chance it will all play together.

The main benefit (?),I'm told, of the S/W package is to remove the top speed limiter, raise the redline to 8150 (this allows you to reach 60 mph in 2nd gear - not sure this applies to the 3.91 diff mod) and provide a more linear throttle mapping.

Pinecone 12-16-2003 02:33 PM

Quote:

Originally Posted by mrtm2004
Not sure what you mean. I feel the difference in the throttle response by just putting the "Sport" mode on & off. Also I get a much different mpg when using the "sport" mode & when I'm not. :dunno:

The only thing Sport mode does is remap the throttle. This means that for a given amount of pedal movement, the throttles open more. It FEELS like better response, because the throttles open quicker at lower pedal moements. As for the gas mileage, it is because you are using more throttle more of the time playing around. :)

Pinecone 12-16-2003 02:35 PM

Quote:

Originally Posted by m3jlk
I've been told Dinan developed their S/W on a std 6 speed. When installed on an SMG II car the S/W thought it had reached redline @ about 4K RPM. Apparently there is a sensor somewhere in the SMG II set up that doesn't exist in the std 6 speed. In any event they theoretically have it figured out and are shipping diffs with an additional S/W mod.
This is the story I've been told by the dealer as to why it's taking so long to get my diff. If true, it reinforces my belief that when buying a set of mods as I am, it's a good idea to get it all from the same source so there will be a better chance it will all play together.

The main benefit (?),I'm told, of the S/W package is to remove the top speed limiter, raise the redline to 8150 (this allows you to reach 60 mph in 2nd gear - not sure this applies to the 3.91 diff mod) and provide a more linear throttle mapping.

a) How come people putting the diff in without any software change donīt have this problem?

b) you can more reach 60 in 2nd stock or with the 8K redline with the 3.91 rear.

HUMMM 3 12-16-2003 05:18 PM

Quote:

Originally Posted by Pinecone
a) How come people putting the diff in without any software change donīt have this problem?

b) you can more reach 60 in 2nd stock or with the 8K redline with the 3.91 rear.

I was just responding to a question. It's only what I was told. I'm not smart enough to know if it's true or makes sense. Next time I'll ignore the technical questions, since I don't know what I'm talking about. :)

Pinecone 12-18-2003 08:02 AM

It just struck me as strange that Dinan had prob lems, but Turner doesn't with 3.91 diffs.

WRT speed in gear, there is a site with a calculator, but I have posted the forumla on this board, and also did my own Excel spread sheet to calculate max speed in gear based on RPM and diff ratios, considering the tranny ratios fixed.

I was surprised to see that the M3 would hit well over 60 in second, and even just go over 60 with a 3.91.


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