Max speed of Prius

[Sun__Tzu]

Originally posted by MarinJohn
On a recent trip I wanted to see if the digital readout on the speedo went to three digits so I got my '04 up to 103mph, driving with one hand while taking pictures of the display with the other.  Pictures did not come out, but I can verify we have a three place digital readout!

Hahaha. That seems like a comically dangerous thing to have done. I wonder how you would've explained it to a police officer if he happened to see you pulling that stunt? : )

"What? Oh, I was taking a picture of the spedometer."
"Huh? Well, I wanted to see if it would show a 3rd digit."
"Yeah! It sure did! 103mpg easy!"
"What? Its a 35mpg zone?"
"And yeah, that's an open beer, an unregistered firearm and a box of illegal fireworks in my back seat. What's your point?"

Kinda seems like something Kramer would've tried on Seinfeld : )

[Frank Hudon]

Prius Classic 152 KPH MG2 5500 RPM ICE 4500 RPM MG1 1900 RPM

[HTMLSpinnr]

Originally posted by mdacmeis
This may be correct, however there is another possible reason for the 106 mph speed limit - tire ratings.  106 matches the speed rated certification for the tires used.

Actually, S rated tires, which our cars have are rated to 112mph, which is where you'd find the speed limiter in most cars.

According to the NCF guide, the top speed is actually rated at 103mph.

In the case of our car, it really is the maximum speed of the powertrain. You'll need to recall that the Prius has only one fixed driveline ratio, and that only torque can be directed through the planetary gears of the PSD. The speed of each component in the PSD is directly relative to each other. In the case of the Prius, we'd reach maximum speed for one of three reasons:

1. Speed limiter for tires - while I'm not discounting this theory completely, it's a bit conservative for S rated tires.
2. The ICE and MG1 have both reached their maximum speeds - 5000, and 10000 rpm respectively - simultaneously. This could be possible, but I don't have the brain-power to compute this scenario.
3. MG2 has reached it's maximum speed of 6000 rpm (trying to confirm this number). This is most likely true after looking at below.

Other info for people who wnat to do the math for gear ratios and max speeds:
Planetary gear teeth count (same on '03):
Ring Gear: 78
Pinion Gear: 23 (there are 4, but that doesn't matter for conversion)
Sun Gear: 30

Chain Drive:
Links: 72 ('03 had 74)
Drive Sprocket Teeth: 36 ('03 had 39)
Driven Sprocket Teeth: 35 ('03 had 36)

Counter Gear Teeth ('03 has same count):
Drive Gear: 30
Driven Gear: 44

Final Gear Teeth ('03 has same count):
Drive Gear (on counter's driven shaft): 26
Driven Gear: 75

Final Gear ratio (per specs): 4.113 ('03 was 3.905)

I believe the difference in gear ratio comes from the change in teeth count at the chain drive between MG2 annd the counter gears.

But now, back to the point. Knowing that our P185/65-15 tires revolve at about 849 revs per mile or about 849 rpm at 60mph, we can then derive how many MPH is possible at 6000rpm with MG2, which is about 103mph.

Using (((MG2 RPM / Final Drive) * 60 minutes) / Tire revs per mile) = Max MPH

(((6000 / 4.113) * 60) / 849) = 103.09 mph - just shy of 166 Km/h

Now if some could exceed that by just a bit, we may be looking at some "tolerance" for MG2's max RPM, or a possible different revs per mile figure for the 16" wheels (and a recalibrated spedo to match).

Ok - looks like I've got way too much time on my hands... LOL - hope this helps iron it out.

-Rick

[Ray Moore]

I've done 95 in mine and was pulled over doing 81. I didn't get a ticket. I really think he just wanted to check out the car. I enjoyed telling my 13 year old stepson about that one as he jokes about us being flipped off by passing snails when I drive for mileage. He's just used to his mother's driving. At 95 the car seems very smooth with plenty more to give and oddly quiet for that speed in any vehicle.

[n3ok318]

I guess it's not 85MPH. Someone told me that Prius can only go up to 85MPH. I guess 106MPH is the most out of 1.5L. It's pretty decent.

[jimvitz]

Originally posted by bookrats
With or without the optional JATO unit attached to the back?  

I definitely think "Mythbusters" should re-do their JATO show with a Prius just to see! :wink:

[8AA]

According to this model, the 2004 could theoretically go 129 MPH:

Planetary Gear System of Prius

However, this would assume that MG1 has a maximum speed of 7500 RPM, which does seem high. I tend to agree with Rick, that MG1 is limited to 6000 RPM, and therefore the 2004 is powertrain limited to 103 MPH.

[victor]

Translated from the German Technical docs.

"The MG1 and MG2 are located in the hybrid transaxle and both are light, high efficiency AC syncron motors with permanent magnets. There is no special maintenance required.

MG2 is permanently connected to the front wheels and therefore drives the wheels directly. During regenerative breaking, MG2 is used as a generator to provide power to recharge the HV battery. MG2 also provided the drive in reverse by reversing its direction.

MG1 loads the HV battery and, driven by the petrol motor, provides power for MG2. MG1 is also the starter motor for the petrol motor.

Service data MG1
Voltage 500V AC
Max output power 37.8kW @ 9500 rpm
Max torque 45Nm @ 0 - 6000 rpm
Max rpm 10,000 rpm
Function Power generation
Starter motor

Service data MG2
Voltage 500V AC
Max output power 50kW @ 1200 - 1540 rpm
Max torque 400Nm @ 0 - 1200 rpm
Function Power to wheels
Generator for regenerative breaks "

[HTMLSpinnr]

I think vapor_pearl meant that MG2's max is 6000 rpm.

I too have only found a solid number for MG1 being 10000 rpm - and the US docs didn't specify torque figures for it either. While it can power the car in the hypotetical heuretical mode (overdrive), it's not documented that it does so.

Now the debate goes on that the max speed is much less if the battery is discharged, however :-) (see other threads)

[8AA]

Sorry, I did mean the motor that is directly connected to the front wheels. Maybe now that I have been embarassed here, ops: I will remember that MG2 is connected to the ring gear and MG1 is connected to the sun gear.