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Discussion Starter #1 (Edited)
hi all,

i am enjoying my new smart and have just turned over 300 miles. I do not have a tachometer installed and have been mostly driving gently as prescribed in the manual.

since i plan to drive it like i stole it after the break in period i want to start pushing the motor harder without hitting the rev limiter/forced shift point.

can anyone approximate what the rev limit is in each gear in MPH? right now with spirited driving i have been shooting for:

1st gear limit 20mph
2nd gear limit 35mph
3rd gear limit 50mph
4th gear gear limit 65mph
5th gear limit 90mph

appreciate any help.
 

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I have never hit it or tried to hit it, I'm afraid mine would be the first car to have a busted rev limiter and the engine would blow up.:blowingup:
 

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Do a search here, I know that someone posted max rpm at what speed on a thread in the summer of '08, just can't remember who. I know in 4th, you hit the speed limiter(90 mph) before you hit redline.
 

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From Road & Track Magazine March 2008

Top speed in each gear

Gear 1 Max speed: 28 Mph 6500 Rpm
Gear 2 Max speed: 49 Mph 6500 Rpm
Gear 3 Max speed: 74 Mph 6500 Rpm
Gear 4 Max speed: 90 Mph 6000 Rpm (Electronically Limited)
Gear 5 Max speed: 90 Mph 4500 Rpm (Electronically Limited)
 

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I have never hit it or tried to hit it, I'm afraid mine would be the first car to have a busted rev limiter and the engine would blow up.:blowingup:


I hammer on mine at nearly every shift.
It will hit the rev limit and shift for you faster than you can guess which rpm is the best.

Then when it goes again it is in the powerband again. kinda foolproof,
 

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Yowch, every shift? Let us know how long that transmission lasts. That's got to be murder on the clutch, no? Even with RPM matching, the clutch still slips a bit when it engages at full power, doesn't 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!!!!
 

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hi all,

i am enjoying my new smart and have just turned over 300 miles. I do not have a tachometer installed and have been mostly driving gently as prescribed in the manual.

since i plan to drive it like i stole it after the break in period i want to start pushing the motor harder without hitting the rev limiter/forced shift point.

can anyone approximate what the rev limit is in each gear in MPH? right now with spirited driving i have been shooting for:

1st gear limit 20mph
2nd gear limit 35mph
3rd gear limit 50mph
4th gear gear limit 65mph
5th gear limit 90mph

appreciate any help.
This is simply a matter of gearing and tire size. If you google speed versus RPM you should get a couple of hits for calculators that will do the calculation for you. I posted this once after researching what the transmission gearing and final drive.

geosynch
 

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- It is virtually impossible with this engine to gauge rpm levels by sound.
You bring up a very good point. Under load (not being lugged) this engine is quite smooth and never really seems like it is turning hard. Unless you are really giving it hell it doesn't seem to be exerting itself. It seems to take nothing to make its revs zing up the tach.

Most of my shifts come at about the same RPM as you - 3,500 or so under normal driving. If I am just loafing around, I'll get it to shift at 2,500 or so - and actually in inner-city traffic it keeps right up doing that.

I was trying to get around some jackass last night, and caught it mid-shift into 5th with a full throttle application - it was probably the smoothest shift I have ever had under those conditions - it dropped right down into 2nd and I was off.
 

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Discussion Starter #11
thanks for all the helpful info.

i bit the bullet and ordered a set of smart gauge pods yesterday. i was wanting to put in an aftermarket tach for aesthetic reasons but after weighing the time involved to install and that one needs to cut into the coil pack wiring for the tach adapter, i decided to go with the factory option.
 

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Discussion Starter #12
I
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)
i see i was pretty close to optimum going by my seat of the pants:

1st gear limit 20mph
2nd gear limit 35mph
3rd gear limit 50mph
4th gear gear limit 65mph
5th gear limit 90mph
must be all that elise driving, heh. :D
 

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I hammer on mine at nearly every shift.
It will hit the rev limit and shift for you faster than you can guess which rpm is the best. Then when it goes again it is in the powerband again.
Me too.

Except I usually try to do the 1-2 manually at ~6k -- quicker, if you let the limiter shift it the rpms "hang" for a second. The rest of the shifts let the ecu do it and rpms drop to torque peak with each upshift for max accel.

Yowch, every shift? Let us know how long that transmission lasts. That's got to be murder on the clutch, no? Even with RPM matching, the clutch still slips a bit when it engages at full power, doesn't it?
Naah, it's fine. Try it a couple times -- no different than a manual shft.
 

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Discussion Starter #14
Me too.

Except I usually try to do the 1-2 manually at ~6k -- quicker, if you let the limiter shift it the rpms "hang" for a second. The rest of the shifts let the ecu do it and rpms drop to torque peak with each upshift for max accel.
can't wait until my motor is broken in.
 

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i see i was pretty close to optimum going by my seat of the pants:



must be all that elise driving, heh. :D
Yep - you were driving it well. It can be pushed a little harder with a little more performance but why bother? - it still isn't much to write home about. The shift speeds you were using would keep you ahead of most traffic anyway.

On another slightly different matter - All of this, of course, is meaningless to those who shift by the auto mode but may encourage some who don't have a tach to try manual shifting. It's possible that many 'auto mode only' drivers have no idea just how smoothly the transmission can be shifted manually - so smooth that a passenger won't be able to tell a shift took place particularly if the paddle shifter is used. That takes an appropriate rpm to shift at and properly timed throttle modulation.
Mentioned before, shifting manually is unbelievably satisfying with this car but shifting by the auto mode is in the opposite sense equally as frustrating and less satisfying.
When manually shifting, you can easily choose the engine speed to shift at, keep it in the most appropriate gear for the situation, choose whatever level of performance is desirable with ease and make shifts absolutely smooth. There's no need to do the throttle dance trying to get the computer to do the right thing but never getting it right. The computer shift programming is like a recalcitrant child that won't respond to correction. It keeps wanting to do it's own inappropriate thing no matter how much you try to correct it.

Some reviews with comments regarding auto shifting; -
What is Smart's automated manual transmission? - Ask.cars.com

2009 Smart fortwo Road Test: Performance, Engine, Transmission, Suspension, Brakes, and Handling

http://www.thetruthaboutcars.com/smart-fortwo-review/

Comments about the transmission in these reviews are typical of virtually all reviews - I do not agree with many of the comments about the car generally and even those regarding the transmission reveal inexperience by the reviewers. It does take some experience to be able to drive this car smoothly. However, they all do speak of the rough, slow, unsuitable shifts of the auto mode of the transmission. Mentioned frequently in reviews is that throttle manipulation can smooth things out a bit and that using manual mode can be a further improvement.
There is also a comment in one review that owners of the car not only excuse the faults but actually find them endearing (my words) - and that is so true.
 

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Discussion Starter #16 (Edited)
thanks.

on shift technique, do you breathe the throttle first and then shift, or shift first and then breathe the throttle? i've experimented with both approaches and am still unsure which is better. i expect this will become clearer once the motor is broken in and i can be more aggressive with rpms. for now it seems that shifting first is faster but that breathing the throttle first is smoother.

:confused:
 

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thanks.

on shift technique, do you breathe the throttle first and then shift, or shift first and then breathe the throttle? i've experimented with both approaches and am still unsure which is better. i expect this will become clearer once the motor is broken in and i can be more aggressive with rpms. for now it seems that shifting first is faster but that breathing the throttle first is smoother.

:confused:
For a smooth shift you need to make the shift first then immediately lift throttle and slowly reapply. The timing is just a matter of experience. It really is quite simple with this transmission.

The reason to shift first is because the computer must declutch before throttle is lifted or you get a lurch at that point. The connection between the engine and drive wheels needs to be broken when the throttle is lifted. The timing of reapplication of throttle must coincide with the reclutching and the amount of throttle lift and reapplication is also a matter of practice.
For normal manual transmissions the same things have to happen. It's just that you are controlling the clutch as well as the throttle. This is generally known as "rev-matching" but actually involves more than just that. With the smart, the computer does the declutching and reclutching as well as some rev matching particularly on the down shift. You do need to manually do the throttle manipulation though.

It sounds more complicated then it really is and I suspect that for most people the process becomes second nature - as easy as walking - but then if you can't walk and chew gum at the same time... :)
 

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Discussion Starter #18
For a smooth shift you need to make the shift first then immediately lift throttle and slowly reapply. The timing is just a matter of experience. It really is quite simple with this transmission.

The reason to shift first is because the computer must declutch before throttle is lifted or you get a lurch at that point. The connection between the engine and drive wheels needs to be broken when the throttle is lifted. The timing of reapplication of throttle must coincide with the reclutching and the amount of throttle lift and reapplication is also a matter of practice.
For normal manual transmissions the same things have to happen. It's just that you are controlling the clutch as well as the throttle. This is generally known as "rev-matching" but actually involves more than just that. With the smart, the computer does the declutching and reclutching as well as some rev matching particularly on the down shift. You do need to manually do the throttle manipulation though.

It sounds more complicated then it really is and I suspect that for most people the process becomes second nature - as easy as walking - but then if you can't walk and chew gum at the same time... :)
thanks, that's very helpful. i will work on my timing and modulation and will even try doing it on downshifts!
 

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- 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.
-Don't use the suggested arrow prompts for shifting manually. If you don't have a tach - get one.
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.

The shift arrows are fine for normal driving on level roads with average acceleration. They will improve MPGs.

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.

Before you tell me I don't know how to shift or drive a manual, I'll just say, you're wrong. :)
 

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thanks, that's very helpful. i will work on my timing and modulation and will even try doing it on downshifts!
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.
 
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