Braking "B" mode around town... kind of a different animal. Thoughts?
03-18-16, 12:35 PM
#1
Lexus Test Driver
Thread Starter
Braking "B" mode around town... kind of a different animal. Thoughts?
I know what braking mode does. It uses the engine in conjunction with the electric motor to slow the car down. I've used it on steep grades in my 2015 Prius before to ease duty off the brakes.
But what I didn't realize until today is that "B" mode keeps the engine running even at idle/low speeds below 40mph. So this means for any spirited driving (autocross/canyon) you can keep the engine on for better response when you have to hit the gas again instead of waiting for the slight delay for the engine to kick on. In a situation where you're driving in such a way where your engine is constantly turning off and on (like in a spirited manner) "B" mode might be the way to go. Was driving around in "B" mode today and the instant response of the always-on engine plus 650V electric mode in "sport" made the car feel very different.
However, while highway cruising, you might add unnecessary stress (albeit small) to the drivetrain and waste gas as you would be slowing down too much. Though I do want to try this theory out.
I haven't tried idling that long but from my brief tests, the engine stays on in "B" mode at long stop lights. As soon as I shift it back into "D" the engine shuts off. Kind of cool! It's almost like a hidden sport mode in itself. Plus the revs stay higher which aids response I would think.
So for spirited driving on a closed track/race course, one could certainly try the following combination for best results:
1) Sport mode
2) "B" mode
3) Trac off
The benefits:
1) Engine always on (for spirited driving)
2) Engine revs stay higher for when you get on the gas again
3) Response improved
Possible down sides:
1) Fuel economy (of course)
2) Possible inverter/electric motor generator strain (shouldn't overheat)
What do you guys think?
I don't know much about this car yet, does "Trac off" completely disable stability control? Or is it a "soft off" where it simply tones it down? With my BMWs, you can shut it completely off. You spin, you're ****ed.
I don't condone driving around public roads with stability control off by the way. I love the technology. But for track or autocross purposes which I may want to try in my CT one day, turning it off would be best and most fun.
Of course this isn't a track car but it is a car that handles well enough for occasional fun driving =)
But what I didn't realize until today is that "B" mode keeps the engine running even at idle/low speeds below 40mph. So this means for any spirited driving (autocross/canyon) you can keep the engine on for better response when you have to hit the gas again instead of waiting for the slight delay for the engine to kick on. In a situation where you're driving in such a way where your engine is constantly turning off and on (like in a spirited manner) "B" mode might be the way to go. Was driving around in "B" mode today and the instant response of the always-on engine plus 650V electric mode in "sport" made the car feel very different.
However, while highway cruising, you might add unnecessary stress (albeit small) to the drivetrain and waste gas as you would be slowing down too much. Though I do want to try this theory out.
I haven't tried idling that long but from my brief tests, the engine stays on in "B" mode at long stop lights. As soon as I shift it back into "D" the engine shuts off. Kind of cool! It's almost like a hidden sport mode in itself. Plus the revs stay higher which aids response I would think.
So for spirited driving on a closed track/race course, one could certainly try the following combination for best results:
1) Sport mode
2) "B" mode
3) Trac off
The benefits:
1) Engine always on (for spirited driving)
2) Engine revs stay higher for when you get on the gas again
3) Response improved
Possible down sides:
1) Fuel economy (of course)
2) Possible inverter/electric motor generator strain (shouldn't overheat)
What do you guys think?
I don't know much about this car yet, does "Trac off" completely disable stability control? Or is it a "soft off" where it simply tones it down? With my BMWs, you can shut it completely off. You spin, you're ****ed.
I don't condone driving around public roads with stability control off by the way. I love the technology. But for track or autocross purposes which I may want to try in my CT one day, turning it off would be best and most fun.
Of course this isn't a track car but it is a car that handles well enough for occasional fun driving =)
Last edited by E46CT; 03-18-16 at 12:38 PM.
03-18-16, 02:24 PM
#2
Driver
Interesting writeup!
I love driving in 'b' mode while in sport, however I always feel guilty because I know I'm ruining my fuel economy. If I did it all the time I would only be at about 39-41mpg.
My favourite thing to do is to floor the accelerator for just one second while slowing down in 'b', and it kind of mimics gearing down in a standard... With my custom exhaust and air intake it sounds really good too.
I love driving in 'b' mode while in sport, however I always feel guilty because I know I'm ruining my fuel economy. If I did it all the time I would only be at about 39-41mpg.
My favourite thing to do is to floor the accelerator for just one second while slowing down in 'b', and it kind of mimics gearing down in a standard... With my custom exhaust and air intake it sounds really good too.
03-20-16, 06:18 AM
#4
Sounds reasonable
Yep, I've often thought that if I ever have the opportunity to autocross my CT, I'd do exactly what you're saying. B mode and sport mode would make the car most responsive and easier to drive smoothly. My '13 doesn't have the ability to turn off traction control, but that wouldn't matter to me since the goal of performance driving is to be smooth. So smooth that the traction/skid control should never kick in in the first place. Dammit, now you got me wanting to autocross again!
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