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I disagree. Old school thinking about how cars were without knock sensors. "Lugging" these days is more a subjective term and relates more to performance than damage to the engine.
You may not understand either what it means to "lug" an engine or the reason for knock sensors.
Knock sensors detect the vibration from detonation which occurs under conditions of pressure and temperature with low octane fuels. It also happens after normal spark ignition. Detonation is the result of several flame fronts colliding and producing a rapid uncontrolled burn that the engine cannot handle. High octane fuels are more resistant to producing the end products in advancing flame fronts which tend to auto ignite under the conditions mentioned producing the additional flame fronts.

As far as lugging is concerned - it occurs when the engine is operating at too low an rpm level for its ability to deal with the torque required for acceleration at wide throttle openings. That kind of situation can easily occur in high gears and low rpms when climbing hills. Under these conditions the oil pump may not be circulating oil fast enough or with enough pressure to protect the plain bearings in the crank journals. Too much pressure is being placed on these bearings and connecting rods for safe operation of the motor. You can hear the mechanical sound when this happens. Don't confuse mechanical knock with spark knock.
This situation is particularly critical with a three cylinder engine.

If the car won't accelerate or accelerates very slowly at wide open throttle, then you are in too high a gear - and that can easily happen in 5th gear under 50 mph with the smart.

The shift arrows are fine for normal driving on level roads with average acceleration. They will improve MPGs.
Actually they are not "fine". The computer programming is designed for maximum fuel mileage but is not suitable for drivability. The rationale behind the ultra low rpm gear shifting is that maximum fuel mileage is obtained at wide throttle openings and low engine speeds. This is a marketing decision, not a practical or drivability decision and is not designed for engine longevity either.

The transmission is for good reason the number one complaint of nearly every reviewer. It sucks. When someone comes out with a similarly sized car with a better transmission the smart will lose sales quickly. (Toyota iQ). In this day and age it shouldn't take elaborate instructions on how to shift to make a car smooth and enjoyable to the average driver.
I'm absolutely in agreement with that statement.

Before you tell me I don't know how to shift or drive a manual, I'll just say, you're wrong.
I don't recall telling you that.
The manual shift in the smart is not a normal manual shift. It does take some experience and perhaps advice to obtain the smoothest shifts since some of the operations are computer controlled and they have to be reacted to in specific ways that are not issues with normal manual transmissions. Drivers accustomed to normal manual shifting will still take some practice with this transmission to obtain the smoothest shifts from it.

If this was a dual clutch automated manual this discussion would not have to take place.
 

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I still can't get 1-2 shift smooth, I got the others down near perfect...
You're probably just revving too high in first gear. Think about that gear as the one that merely gets the car started moving. Shift between 2500-3000 in first gear, shift first and immediately lift the throttle slightly then reapply it smoothly. Treat the throttle not as an on-off switch but like a knife cutting through butter.

By the way, if you want maximum acceleration at high revs and wide open throttle, much as I dislike the auto mode, that may be the easiest way to get that result - it won't be smooth, and you will need the space for accumulating speed, but it will probably accelerate faster than you would be able to do that by using the manual mode with this transmission. In this case hold the throttle at the floor and do not modulate.
Of course that is generally an impractical way to drive the car under most circumstances. It also does not rationalize using the auto mode for general use instead of the manual mode.
 

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my TWO smarts NEVER lug. they down shift VERY smoothly to a lower gear if my speed starts to drop on a hill - BTW this is like every automatic.

my smarts shift very nicely ON THEIR OWN. they have an "automated manual" which is GREAT. I don't defend the car or make things up to be endearing - I can complain as good as anyone else 1poke

In our smart club, I can't find anyone using paddles 100%. Now believe it or not these people are ALL very bright (and smart :D), very experienced (even old in some cases) and don't need anyone telling them they are anything else. Let's see; if that is a decent sampling size and representative, then probably more than 90% of the USA smart owners are using and liking there auto mode! These are all people who have high IQs, know alot about cars, have lots of experience driving and spent their money wisely.

if you want a clutch to do full manual shifting SELL YOUR SMART. if you want an automatic that does not have any feeling of gear changes SELL YOUR SMART.

now back to why they only gave the smart two cup holders - what were they thinking?????

But I do have lot's of endearment of that climate control :kissyou:
 

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Discussion Starter #25
The computer rev matches very well on downshifts so throttle modulation is not as important. Just be careful to not downshift until the rpm level is low enough.
thanks. do you still lift off on the downshift?

i installed my pods today so it will all be easier now that i have a visual as well.
 

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I still can't get 1-2 shift smooth, I got the others down near perfect...
light on the pedal in auto mode. try to be light enough to be accelerating but letting it shift below 3 grand. let 2nd shift into 3rd the same way - light on the pedal and shift lower than 3500. now you decide if you want to pull or not in 3rd. If you hit this well you'll walk the car next to you (up to 6000 if you want). Basically you'll be using very little 1 and 2 but the car will have begun moving and you'll be higher in the power band to bring on 3rd. it will feel pretty smooth, keep up in traffic and give you 45mpg. going down hill slip in neutral, about 3 seconds before needing pedal slip back to D wait 2-3 seconds and then apply gas pedal - done right you won't feel any lag or jerk into gear and you'll get 80mpg. have fun.
 

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thanks. do you still lift off on the downshift?
I don't think I do - will go out this evening and see.

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fasturb - the automated manual is really in reference to automating the clutch and rev matching. The fact that you can leave the computer to also choose the gears to use is just icing on the cake and normally with other automated manuals the programming is more rational. In the case of the smart, the programmers wanted to be able to market the car as being very fuel efficient since that is important for marketing a micro car in North America. Virtually everyone who has asked about the car wants to know what the fuel mileage is. Unfortunately, the fact that this version of an automated manual only has a single clutch and that the programming is oriented towards fuel economy instead of drivability is at the center of the discussion.

If your opinion is that the auto mode is suitable then enjoy what you have -but this is side-tracking the discussion. For those who prefer the auto then it is not my intention to make them change the way they enjoy their car. People do things differently and enjoy things in different ways.

This discussion also has nothing to do with being "bright", having high IQs, spending money wisely, "knowing alot [sic] about cars, or having lots of experience driving. If you interpreted it in that manner maybe I failed to communicate well enough.
Being an experienced driver, even with manual transmissions also has nothing to do with the discussion.

Yes downshifts are smooth because the computer does effectively rev match. My discussion is about upshifting using the manual mode.

I have other vehicles with manual transmissions and do enjoy driving them - also vehicles with automatic transmissions and enjoy them as well. I did not buy the smart because it has an automated manual or because it can be driven manually or as an auto. I also have no intention to sell the car. It is used as a tow vehicle as my moniker should have indicated.
I am participating in this discussion because of a recognition that there are complaints of a rough shifting transmission and my contributions are related to being able to shift smoothly and enjoy the automated functions of the transmission instead of accepting its flaws.

It's not uncommon for people to have been influenced to buy the smart because they thought it had an automatic transmission. That discussion was common a year ago, but now most do realize the transmission is manual. The discussion now centers around whether to use the auto mode or the manual mode for the most satisfying experiences with this car. There are proponents on both sides of that fence. Unfortunately, because it was not unusual for people to have purchased the car thinking it was an automatic, many of those are reluctant to use the manual mode since they have not been trained to drive manual transmissions. They do not realize how simple and easy this automated manual can be when driving it as a manual.

There are many owners who do use the manual shifting primarily if not solely such as myself and my wife. My opinion of the auto programming is not unique, it is common.
 

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I've learned to make sure I am in manual when I am about to dart through a hole in traffic across 3 lanes of traffic or the ecu will put the clutch in mid dart as if to quote Glenda the good witch who said "You have no power here..." In manual mode I get to power my way across with no fear. There are some very nice reasons to retain manual mode control. The smooth ride is just a compliment to my success at learning how to manipulate this machine to my liking. The scangaugeII also assists with positive feedback regarding mpg. Instead of neutral, I simply coast and watch the scan gauge reveal the closed throttle position and the advancing avg. mpg as I coast with the throttle closed and injectors shut off. In neutral, the injectors are still on idling the engine. So better gas mileage in gear than in neutral while idling downhill.
Rich and the BB Benz
 

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So better gas mileage in gear than in neutral while idling downhill.
Rich and the BB Benz
for you maybe:). You think the injectors are off huh? well next time you drive down a 1/4-1/2 mile hill, turn your radio and ac off and anything else making noise and listen to your car. the engine is running! it won't run without gas (or diesel for some). yeah they are air pumps but that spark plug is trying to ignite fuel and with no fuel - no engine will run. remember the 4-6-8? well that motor shut down the cylinders. when you coast in gear, the ecu can vary duty cycle dependent of various sensors and throttle. It may lower the fuel consumption due to pulse modulation but there is still enough fuel flow to keep the engine running. When you coast in N, ecu runs the motor at idle conditions PLUS THERE IS LESS TRANSMISSION DRAG.

but enjoy however you like to drive it:)
 

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I took the car out tonight and with nothing better to do, recorded speeds and rpm's and drove at varying levels of performance - so here's the result; (close approximations) (manual shift mode was used)

Max speed shifting at close to redline (6000 rpm);
first gear - 28 mph (45 kph)
second gear - 50 mph (80 kph)
third gear - 68 mph (110 kph)
fourth gear - 94 mph (150+ kph) max speed governed

slowest logical speed shift points (shifts at about 3000 rpm):
first gear - 12 mph (20 kph)
second gear - 25 mph (40 kph)
third gear - 37 mph (60 kph)
fourth gear - 50 mph (80 kph)

slow (casual) speed shift points (shifts at about 3500 rpm);
first gear - 16 mph (25 kph)
second gear - 28 mph (45 kph)
third gear - 40 mph (65 kph)
fourth gear - 55 mph (90 kph)

Good performance (keeping ahead of traffic) shift points (4000 rpm);
first gear - 20 mph (30 kph)
second gear - 35 mph (55 kph)
third gear - 50 mph (80 kph)
fourth gear - 60 mph (100 kph)

  • It is virtually impossible with this engine to gauge rpm levels by sound.
  • There's not much advantage to take the shifts to redline since the shifts are very slow which precludes any real pretense of performance.
  • It's not a good idea to shift to 5th gear below 50 mph since there's a good possibility of lugging the engine particularly if climbing hills. Also, there is very little torque available below that speed in that gear making any thought of acceleration merely a figment of one's imagination.
  • The auto mode programming wants to shift gears at ridiculously low rpm levels unless too much throttle is applied for most practical circumstances.
Don't use the suggested arrow prompts for shifting manually. If you don't have a tach - get one.
  • The shift points were determined by using varying throttle openings according to the parameters set at the different driving levels - narrow openings for slow speed shifting and wide for high and max speed shifts.
  • For most of my daily driving the shifts take place between 3000 to 4500 rpm's. No shifting is ever done below 2500 rpm and at that rpm driving is very slow and with narrow throttle openings!!!!
What model/year is this
 

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Welcome to SCoA!! Glad to have you aboard Florida451passion08. To answer your question, I would say fortwo has an 2008 since he started posting that year. He has not been on the forum since October 2014. Even if his car is newer, he had to be referencing a 451 as in 2014, that was the only model availale except for the Electric Drive.
 
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