Smart Car of America Forum banner
1 - 20 of 33 Posts

·
Registered
Joined
·
101 Posts
Discussion Starter · #1 ·
So this morning, while commuting on the freeway, with my cruise control and maxed out speed of 78, another 451 Smart flew by me, at least 7-10 mph faster than I was going. How is this possible?? I thought the computer limited us to 80mph? I've never gotten above 78 by the way. I have a 2016 Smart Fortwo ED.
 

·
Super Moderator
Joined
·
17,738 Posts
Petrol 451s: The limiter is supposed to kick in at 90 mph, though on a few occasions with my pedal to the floor I blasted past the limiter and pegged the speedometer at 100... verified by a GPS and the police officer that pulled me over! He was more amazed it could go that fast and let me off with a giggly warning.

*My speedo actually reads accurately because of my chunky tyres.

Petrol 453s will go 100 all day long. I think their limiters try to stop you at 95 mph.

Petrol 450s will top 85 and their limiters are really aggressive about making you stick to that speed.
 

·
Registered
Joined
·
101 Posts
Discussion Starter · #11 ·
With an EV car, all that will do is add to the rotating mass and you will go slower... :shrug:

So the limiter doesn't use the "speed" from the speedometer?



When I am at top (limited) speed, the analog speedometer gauge on my car reads about 83mph, but my true speed using GPS is 78mph. My car tires are standard size. It would seem to me that if I used slightly larger tires, with a bigger tire radius, I would go faster. That 78mph would increase somewhat, and be closer to the 83mph on the speedometer.


Is my thinking not correct?
 

·
Registered
Joined
·
383 Posts
Your thinking is correct. You would lose acceleration with bigger tires that's all.
451s are known for having about 5 mph optimistic speedo.
With an EV car, all that will do is add to the rotating mass and you will go slower...

So the limiter doesn't use the "speed" from the speedometer?



When I am at top (limited) speed, the analog speedometer gauge on my car reads about 83mph, but my true speed using GPS is 78mph. My car tires are standard size. It would seem to me that if I used slightly larger tires, with a bigger tire radius, I would go faster. That 78mph would increase somewhat, and be closer to the 83mph on the speedometer.


Is my thinking not correct?
 

·
Super Moderator
Joined
·
17,738 Posts
Your thinking is correct. You would lose acceleration with bigger tires that's all.
451s are known for having about 5 mph optimistic speedo.
Lose acceleration, but you will make that speedometer much more accurate. 185/60/15 on all four has my speedo absolutely dead on. :D
 

·
Registered
Joined
·
151 Posts
@Smart car. I just looked at your garage photos. You have done very creative mods and the car really looks good.
Thank you,
All the Aero Kit was my own design, I modeled it in SolidWorks, ran tool paths with CamWorks and used my home garage CNC Mill to cut it out.

I wanted the "Bolt on" looks so all the Aero kit has bolts showing as well as the flare kit.
The H&R Lowering spring sure helped the front "Tuck"
It also took me 17x8 rims, 20mm adapters and 15mm spacers to get the rims out 1.75" past the body panels.
 

Attachments

·
Registered
Joined
·
5 Posts
I've got a 2015 (453) Passion ICE and I never take it faster than 75. The steering feels too light and crosswinds move the car significantly. I've been a speed demon with heavier cars in the past. Are you folks doing something to improve your suspension, aerodynamics, road stickiness, etc?
 
1 - 20 of 33 Posts
Top