LKwok

Hello everyone, I just bought a 2004 545i SMG transmission and was hoping to get some tips on driving it smoothly since this is my first nonautomatic car. The car is in good condition with almost 110k miles on it. I've had it for about a month now and have tried different ways of driving it. I heard from others that I am suppose to let go of the gas completely when I shift and then after the gears change, apply some gas. I've notice that when I do this, the car jerks (usually from 1st to 2nd gear) since I am going at a relatively low speed (15 mph usually) so when I do let go of the gas, I can feel the deceleration of the car instantly. I have found that leaving my foot on the gas pedal while I shift reduces the jerk and makes the shift a lot smoother (almost unnoticeable). As for the rest of the shifts, I do the same usually, leaving my foot on the gas pedal, staying at constant speed, then shift and apply more pressure on the gas pedal afterwards.

Another issue I am noticing is my car is very jerky when I am driving at a slow speed (usually in traffic). I notice this happens whenever I am in traffic and usually driving under 10 mph. It feels like the car jerks although my foot is slightly on the gas pedal or even when I am letting the car slow itself to a stop, it'll jerk around 7 mph (feels like a gear change although I am on 1st gear). This also happens when I reverse slowly.

I'd appreciate any tips on how everyone else drives their SMG transmission. Thanks!

dmclaren

When upshifing, don't take your foot completely off the accelerator. Just ease off, maybe 20%, shift, then roll on more gas. Works great for us with M5s. We find that if we don't back off the throttle, there's that little hit as the computer slams the throttle back on as the clutch is let out. Of course,when we're gunning it we don't bother with that, but for mild driving we want to be gentle on the machinery.

You'll soon find the groove with smg. I can drive my car about as smoothly as I can a conventional manual.

Wolrab

I'd say about the same thing. Ease off to the point that you're no longer accelerating, then pop the up-shift. With a bit of practice, it can be really smooth. Downshifting can be a bit more tricky. If you either don't brake or brake steadily, there's a moment while the transmission is out of gear that feels like a surge, because there's no engine braking. With a bit of care, you can modulate the brake to "fill in" while the trans is out of gear.

At slow speeds, the key is to take control, and initiate all the down-shifts yourself. If you let it downshift for you, sometimes it's between gears when you want to go and you press the gas. Then it goes into gear and applies the gas, and you get a jerk.

The auto mode isn't much use. I just use it for parking valets and anyone else who doesn't understand SMG. Other than trying it out on day one, I've never used it in 170k miles.

LKwok

Cool, thanks for the tip! At least now I know I am not driving it COMPLETELY wrong lol.


Can you please elaborate on downshifting? I am still trying different things because I am not sure which is the "proper" way of downshifting. I drive in the city and usually just cruise and when I do not apply brakes, I generally downshift maybe 5mph below the shiftpoint to get to that gear. I.E. I usually upshift to 4th at 45mph. If I am cruising and the car slows down to 40 mph, this is usually when I downshift to 3rd. I usually do this for all my gears. But when I am driving a little faster and have to slow down in a hurry, I usually just downshift 1 gear down then apply the brakes, i.e. downshifting to 2nd from 3rd at 30-35mph. I heard from a friend I should only downshift when I am slowing down, but sometimes I downshift to lower gear to get the power right before accelerating. Is this normal?

Wolrab

I guess most of us came from manual transmissions, and a lot of this is learned through years of driving a manual. It may not be intuitive if you're coming from automatics.

So I follow the same downshifting paradigm as when driving a manual - which doesn't help here! Anyway, unless I'm downshifting to give me more acceleration 'coz I'm about to floor it, I downshift when the RPM gets down to between 1500 and 2000. I press the brake gently and pop the shift, then partially release the brake when the clutch engages and the engine braking kicks in. With some practice, you can make this seamless. That's basically what I do when I'm approaching a red light, then I'm always in the right gear in case it turns green. I usually let it go into 1st by itself if I know I'm about to stop. It uses some gas to do all this downshifting, but my brakes last a long time - 161k on the first set of brakes.

Then there's a completely different situation when you're downshifting to zoom away at highway speed. You can click the shifter 3 times quickly to go straight from 6th to 3rd at 70 mph, for example, and have your foot already on the floor when the computer decides to re-apply the gas. You WILL leap forward. These cars are SO much fun! Great way to scare the piss out of Granny.

subterFUSE

I have been an SMG owner since November 2004.
When I first got the car, I was disappointed by how rough the shifts seemed to be.
However, after driving the car for a few weeks, I learned that I must drive the car differently than an automatic.

What others have said so far is true... you need to moderate your throttle during shifts to make them smoother.

Here is what I do:

1. From a stop, with car in 1st gear, accelerate until you are ready to shift.

2. Click the shifter, and slightly decrease pressure on the accelerator pedal. (I don't lift my foot off the gas, but just ease off the pressure a bit. Think of curling your toes upward inside your shoe)

3. Wait for the gear to shift and clutch to disengage, then you can apply more pressure to the accel pedal.

4. Repeat Step 2 - 3 for the remaining gears.


The time required for shifts will depend on your shift mode. (Normal = longer shifts Sport = quicker shifts)


After a few weeks driving the SMG it will become second nature. I find it humorous when I drive a rental car and catch myself accelerating, pausing, accelerating... even though the rental is an automatic.

LKwok

I guess I've been driving it like a girl the whole time, paranoid that I might make the engine blow by letting the RPM go so high. I've usually never gone over 3000 RPM before I shift and the thought of downshifting to third gear or even to 4th gear at 70mph from 6th never crossed my mind. Of course this is probably not the best thing to do, but is it really "safe" to do so once in awhile? Meaning dropping the gear to 3rd or 4th and smash on the acceleration while at 60-70mph? Again I apologize for the newb question since this is my first "manual" car.


Thanks! This really helps, and I know what you mean. I've driven the SMG for about a month now and when I recently drove my friends automatic, I was freaking out when I first put it on drive and the car was moving until I realized it was suppose to do that haha.

Thanks for all the tips and advice everyone. Anymore would be deeply appreciated

Wolrab

It doesn't hurt to red-line it once in a while. I don't spend a lot of time at high RPM, but it happens once in a while. This is how I've driven it the last 170k miles, and it burns zero oil. Currently it doesn't leak any either, which is amazing.