I'm driving a 2018 Prius Prime (plug-in). What do you want to know about it?

[MetroMPG]

Yeah, my gen 2 Prius had a grabby transition. I know that feeling. The regen/friction transition in this car is much better.


I'm talking about something else here -- the grabbiness I'm experiencing is during friction braking at extremely slow creeping speeds (speeds well below the transition).


I think ProDigit nailed it: it's the "initial bite", and it's super sensitive. Too sensitive.

[ProDigit]

Try out organic brake pads.
A set is pretty cheap online (like $~20 or so for a pair), and swap the front ones out.
See if it improved the situation somewhat.
If it did, you can also change the rears.

If any way possible, try if the car still brakes ok, when the regenerative braking isn't working well (eg: fresh off the charger, a 60MPH quick stop).

New pads sometimes don't brake very well, and need a break in period. Do take that in account as well.

[vskid3]

Originally Posted by MetroMPG

I can't find any info about that. Can you share a link? What I am reading is the ICE powers the wheels directly at 70+ MPH, but only if it was already running (eg. the EV range was depleted and the generator/ICE was on). EG: link, link, link. In charge-sustaining mode, the generator/ICE "cheats" via a clutch that connects it to the transmission/wheels above 70 MPH.


As far as I know, as long as the battery is above "empty", both generations of the Volt will run up to top speed solely on electric power.

That has been my experience with my 2013 Volt; if the ICE is running due to the battery being empty or holding the charge level, it'll stay on at high speeds (I think it even stays on going downhill or high regen, until the speed gets to 60-65ish). It has full performance and capabilities in EV. You could yank the engine and not notice a difference until you find yourself stranded.

Have you driven it on gas? While the Volt shines as an EV, it's kind of lacking when it comes to hybrid efficiency.

[ksa8907]

Originally Posted by MetroMPG

Yeah, my gen 2 Prius had a grabby transition. I know that feeling. The regen/friction transition in this car is much better.


I'm talking about something else -- the grabbiness I'm experiencing is during friction braking at extremely slow creeping speeds (speeds well below the transition).


I think ProDigit nailed it: it's the "initial bite", and it's super sensitive. Too sensitive.

Probably not the same thing, but.... years ago I learned to drive in a 1975 chevy pickup and a 1993 dodge 15 passenger van. Then I drove my mom's new 2004 Pontiac vibe/toyota matrix. The first brake event just about sent my dad and I through the windshield!!

[redpoint5]

I went from driving a stick for months/years, to jumping into an automatic. One day I instinctively went to press the clutch and jammed on the brakes. My mom was riding shotgun and asked what that was about. Just a brain fart, trying to shift an automatic car.

Automatics have an extra wide brake pedal that approach the area that would be occupied by a clutch.

[jcp123]

Maybe a Chevy Bolt-style paddle for regent would be well-advised. If integrated with a brake light, I would think you might have marginally more controllable braking plus the regen.

[MetroMPG]

Originally Posted by ProDigit

New pads sometimes don't brake very well, and need a break in period. Do take that in account as well.

Could be that. The car only has about 3k km on it, and the friction brakes have considerably less use on them than a non-hybrid.


I played with it a bit more last night, and I'm pretty sure this is a software brake-by-wire issue. The pedal pressure difference from "creeping along at a snail's pace" to "bite too hard" is a couple of millimeters of pedal travel. That's not how normal hydraulic brakes behave.

[oil pan 4]

My leaf does the same thing.

[Vman455]

I wonder if the Prime has a different brake pad compound because of its increased weight compared to the standard Prius?

[MetroMPG]

You can definitely feel the increased weight in the back over bumps.

I'm not surprised they deleted the center rear seating position. You'd be bottoming out for sure with 3 adults back there.


But I still think it's a calibration/programming issue that could be refined with some code changes.