Does the engine completely shut off automatically while driving just like the prius?

How seamless is the process? Can the driver and passengers be able to hear and feel this happening?

I am trying to figure out between gs350 and gs450h to preorder.

My dealer does not have any GS450h to test drive so any help from you guys is greatly apprreciated.

 

Yes the engine will switch of automatically under certain circumstances, when the engine is warm and the hybrid batteries have charge.

You won’t feel the engine cut in and out if the car is on the move, its seamless, unless you have the engine / hybrid display showing you wont even know its happening, but if your stationary then you may feel a small judder when the engine stops and starts,this is very slight and you won't allways feel it, you won't feel anything when you pull away.

Hope this helps

 

There's a bit of a jolt but it's not bad

 

Also I just watched a video on YouTube about gs450h, at one point in the video he mentions the brake feel as not so smooth because of the regenerative brake transition to mechanical. What do you guys think about this?

Video:

 

Never really noticed any problems, although I tend to avoid heavy braking and to be honest 90% of my driving is less than 40mph.

 

Inital light brake pedal pressure slows the car by regenerative charging of the battery and no use of the wheel brakes. As you increase the pressure you are adding the friction of the brakes + the charging. A panic stop is all about the conventional brakes and maybe even ABS.

If any of you have driven a car with four wheel drum brakes (pre-1970 era) you will recall that the feel and response was quite different than a four wheel disc or mixed disc/drum setup. The change in sensation with our Hybrids is similar and to maximize the MPG you need to learn to love the difference. Pulse and glide!

 

Well I have to say you should really test drive it because the one major thing some people hate is the drone for the CVT. I do understand the GS shift in sport mode, I can't say much on that. The process at first will be noticeable when driving along the roads especially with music off or really low. I can promise you after a while you will not even notice it though, like Hoovey2411 said its a bit of a jolt very small but can be felt. The engine does shut-off like prius and is very quiet. Try a used one in your area if there is any to get a feel, its a beast the instant power feel is different to a regular GS.

 

I was able to test drive a GSh for a long weekend back in February, which really sold me on Lexus Hybrid Drive. I took delivery of my car in May.

As previous posters have noted, the system operation is quite smooth. Lexus Hybrid Drive does a better job of implementing Start/Stop than non-hybrid systems. With non-hybrids, when the engine needs to restart, a high speed starter motor is used to spin up the engine between the time you release the brake and move your foot to the accelerator. It is very quick, but you can often feel some hesitation on initial acceleration. I test drove Start/Stop on a 5-Series BMW, and an E250 (diesel) Mercedes. With Lexus Hybrid Drive, there are two very powerful electric motor generators in the system. With the gas engine stopped, when you step on the accelerator, the electric traction motor gets the car moving while the other electric motor spins up the gas engine. There is absolutely no hesitation off the line. Just the immediate low RPM torque of the electric motor.

With regard to brakes, the transition from regenerative to friction braking is much improved from previous generations of the system, although the feel is different from traditional 4 wheel disc brakes.