Using Engine "B"rake as Slowing Method

Just drove home our '08 Prius Pkg. 4 last weekend. Salesman told us the 'B' in shift lever is for the rare occassion that battery needs to be 'charged up' (he had asked service man who told him a person may only need to use it twice in the life of the car; same thing as down shifting). When he mentioned 'down shifting' I figured I would use this method when wanting to slow from, say, 40 mph to 30 mph rather than brake. Is this hard on the engine or even what the 'B' on shift lever is for??? Definitely a newbie!

It's not hard on the engine, but its purpose is not to charge the battery. It means "engine braking", and should be reserved for use only on extended downgrades (like a mountainside) where you wouldn't normally want to ride your brakes. For the sake of your "newbie-ness," I won't take time to explain why, but to use it in everyday driving will cost you fuel mileage and is totally unnecessary.

If you want more background on its use, you can search the PC forums. Lots of threads available.

Welcome to PriusChat!

As a former Saint Paulite, offhand I can't think of any place in Minnesota where you would need to use B. Leave it in D and use the brakes. Salesanimals will say anything rather than admit that they don't know something.

Some people find that B gives them better control of the car on slippery surfaces at low speed, but try it without first.

Thanks, Richard and Jim! I will save the 'B' for the Rockies when I return to visit my roots. You guys helped without making me feel idiotic. Any other pointers I should keep in mind before wasting trial and error? I will check out threads on engine braking, as well.

Here's a lengthy explanation of B-Mode.
:hail:Hobbit has lengthy explanations of lots of things, actually.

Thanks to PriusChat . . .

... I'm not using the "B" mode anymore either! :clap2:

Been driving our Mag Gris for only 3 days, but I've using the "B" as though it were a downshift/lower gear in a manual car. I thought it was great - - except that I kept forgetting to take it out of "B" when I started accelerating again (duh!)

Our salesman made it sound like a good thing to use - and I didn't question him about it then - too many new things! - later I consulted the manual, but didn't find much, then thought to check here, luckily before ruining my gas mileage and maybe the engine brake system!

I LOVE these forums! :wub:

OMG, other dealers crack me up!!!:frusty:

The Rockies, definitely :_> Nobody is born knowing this stuff so we should always be gentle, at least the first time.

Other pointers? If the last pip on the gas gauge ever starts flashing, buy gas immediately. Don't overfill. Consider using 42/40 PSI in the tires front/rear for better fuel economy (but a harder ride). Follow the scheduled maintenance guide and do only what it says; don't waste money on a dealer's prix fixe menu of services.

:first:Mag gris, Have you been listening to the rest of these comments? I am also very happy to have found this site! It is going to help me much more than I ever thought would be possible. Terrific! Let's keep reading!

Welcome to PriusChat, LEILANI. Remember that your Prius is mostly computer controlled, with you telling the computer what you want.

The computer runs the Internal Combustion Engine for lowest emissions, which means good fuel economy, and it's hard for you to actually control it. When you select a "gear" like D or R, you're flipping a switch to tell the computer the direction you want to go, and it's smart enough to know that P or R is a bad idea when you're whizzing down the freeway, so it will ignore a selection like that. When you step on the GO pedal, you're telling the computer you want to go in the direction you selected and how urgently, but the computer balances the use of the electric motor and the ICE to give you what you want while trying to minimize emissions. When you press on the STOP pedal, you tell the computer you want to reduce your speed and how urgently, but the computer decides how much energy to pull out of the generator, and how fast, to slow you down or to use the friction brakes.

Other computers track how fast wheels are spinning and keep them at the same speed. A computer senses if the car is not going in the direction of the front wheels and corrects it. And there's a computer for the display and radio. There's a computer to make sure the high voltage battery is optimally charged. And the computers all talk with each other over three different networks. A Prius is a rolling data center!

And the best part is, you don't have to worry about any of it. Just step on the pedal and go! Happy driving! :car:

Welcome Leilani. I have not used my B at all...I have 5K miles right now. I was told that the B may be used to slow down the vehicle without using the brake. That is all I know about it...but one thing you should not do is to accidentally shift from D to B while travelling above 50 or 60 mpg...This will probably be a little hard on the engine. I would agree that using the B often will decrease your mpg results.

Hey, N3FOL, "shifting" to B at any time won't stress the engine. You're just telling the computer to waste energy. The computers take care of the Prius.

Tony, I did something like this one time in a Ford van. It was with the brakes, so brake lights were showing, but the results were somewhat different than expected. We were driving down the highway at 70 when some jerk came up from behind and started riding our rear end. I couldn't imagine why he didn't just go around us; the road was clear with two open lanes. I decided to slow down and make him go around. When I tapped the brakes he banged into the back of us, then swerved back and forth across all three lanes. After that he fell way back for a while, during which time I called him in to the police. A bit later he flew by, mostly on the grass off the right side of the road, narrowly missing signs and bridge abutments. After about 20 minutes, three police cruisers moved and and did a rolling road block and pulled him over. He had a blood alcohol content that would power most flex fuel vehicles. Fortunately no damage was done and no one was hurt.

Tom

I went to Alex Tech College... graduated in 99
I lived in your area for a total of 14 years... 12 out South of Kensington.

okay, thanks for the memories... :focus:

Oh, you DO like to live dangerously, don't you?
One day, you'll do that, and the idiot on the cellphone behind you won't catch on, until they ruin the back bumper of Priapus!!