Deceleration during acceleration

[Piloto3524]

Test drove the Smart the other day and noticed that the car's engine decelerates when I acelerated upward throught he gears. Just as it was shifting into the next higher gear the engine bogged down, then shifted, then accelerated again until the next higher gear was engaged. Then the engine again bogged down while shifting the next higher gear. Is this normal or was it a bad demo car???

[Okie Boy]

Originally Posted by Piloto3524

Test drove the Smart the other day and noticed that the car's engine decelerates when I acelerated upward throught he gears. Just as it was shifting into the next higher gear the engine bogged down, then shifted, then accelerated again until the next higher gear was engaged. Then the engine again bogged down while shifting the next higher gear. Is this normal or was it a bad demo car???

You do understand that the smart has a automated-manual transmission and a dry clutch. The transmission controller shifts the transmission the way you would shift a manual transmission.

[Flashman]

Originally Posted by Piloto3524

Test drove the Smart the other day and noticed that the car's engine decelerates when I acelerated upward throught he gears. Just as it was shifting into the next higher gear the engine bogged down, then shifted, then accelerated again until the next higher gear was engaged. Then the engine again bogged down while shifting the next higher gear. Is this normal or was it a bad demo car???

It is not a CVT...

1. car accellerates, RMPs rise towards redline
2. engine needs a new gear
3. clutch engaged, engine RPMs drop
4. new gear engaged, engine RPMs rise to next gear evel
5. car accellerates, RMPs rise towards redline
6. repeat process until no more gears or speed limiter is reached

[bottlerocket]

Originally Posted by Flashman

6. repeat process until no more gears or speed limiter is reached

You've been spying on my driving?

[Piloto3524]

for your very cryptic replies. However, On page 13 or so under "Do you like that tranny", I found that this is apparently normal. And one has to work the gas pedal as one would do if shifting through a manual transmission.

[16d @ 4]

Originally Posted by Piloto3524

Test drove the Smart the other day and noticed that the car's engine decelerates when I acelerated upward throught he gears. Just as it was shifting into the next higher gear the engine bogged down, then shifted, then accelerated again until the next higher gear was engaged. Then the engine again bogged down while shifting the next higher gear. Is this normal or was it a bad demo car???

The tranny for our Smart is basically a manual tranny with an electronic clutch. Therefore, like all stick shift cars, when shifting from lower gears to a higher gear, you'll get a "boog".

Imagine this: when you step on the clutch to shift to a higher gear your RPM drops until you completed your gear change and start acceleration again, right?

[16d @ 4]

Furthermore, our tranny is consider a SMG (Sequential Manual Gearbox). This is different from the CVT; I think the difference is w/ or w/o a torque converter.

My old 02' BMW M3 had a SMG tranny, however, the bimmers SMG has a button that you can use to adjust the speed of the shift. I always had mine at"S6", which is the quickest shift (0.08 sec.). This is faster that I can manually shift . I wish Smart would incorperate this button.

[Piloto3524]

What is a "boog"?? I understand that when shifting a manual transmission I ease off on the gas to decelerate the rpms. So I thin this is what is necessary for this car when it wants to shift. Correct?

[Okie Boy]

Originally Posted by Piloto3524

What is a "boog"?? I understand that when shifting a manual transmission I ease off on the gas to decelerate the rpms. So I thin this is what is necessary for this car when it wants to shift. Correct?

Correct. The car throttles down, disengages the clutch, shifts, engages the clutch and then throttles back up.

[Piloto3524]

So the trick is to learn when it wants to shift and be ready to lift up my gas foot as it shifts, then depress it again when I feel it has completed its shift; which is only a second or two?