Rev Limit by Gear in MPH?

[powerbookguy]

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.

[jefferios]

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.

[WhiteNBlack08]

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.

[JPaul]

Is this what you're looking for?

Originally Posted by saronian

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)

[powerbookguy]

perfect, thanks!

[mendo]

Originally Posted by jefferios

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.

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,

[SuperGeek]

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?

[fortow]

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!!!!

[geosynch]

Originally Posted by powerbookguy

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

[mdfortwoguy]

Originally Posted by fortow

- 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.