bclexus

When you are in a gear that causes the engine to turn higher RPM due to the transmission having downshifted (while at the same time the gear is causing the engine to brake the car's speed because throttle is not being applied) you must actually press further into the gas pedal to (1) first overcome the engine braking, and then (2) get back to either maintaining a constant ground speed or increasing the car's speed. If you are not used to this effect with its results - it can actually surprise you how much pedal travel is needed to get back to the speed you were once at just before the downshift and consequential engine braking slowed you down.

To blow things out of proportion a bit to help understand the phenomenon, put the car in Manual 1st Gear (M1) and get the car up to [say] 25 mph, which will be about 4,000 RPM with a 6-speed transmission. Now take your foot off the gas pedal so the engine brakes the car's ground speed for just one second of time. Now, get back on the gas. This is what you will find. When you get back on the gas as the engine is braking or slowing the car's ground speed and the engine's RPMs are dropping - (a) you will find that a goodly amount of gas pedal travel will be needed just to prevent the speed from decreasing further (now down to lets say 15 mph), and (b) to get back up to where you once were at 25 mph speed takes even more gas pedal travel...and (c) if you want to go faster than the original 25 mph then it will take even that much more pedal travel still. And keep in mind that these engine RPM speeds in my example are pretty close to the engine's peak torque and horsepower, so lack of torque and horsepower is not a problem.

It is not a matter of the engine not making its expected torque or horsepower, but instead it is the driver's unfamiliarity with dealing with a car in which it automatically downshifts from an already reasonably high RPM. This downshifting in Sport mode (even from an already fairly high RPM upon using the brakes) is designed on purpose so when the driver goes into a curve/turn the declining high RPM of the engine helps slow or brake the car's speed and helps the driver 'set' or load the car's chassis/suspension dynamically going into the curve/turn so he can apply engine torque and horsepower at the earliest part of the turn's exiting apex so he builds speed as he comes out of the turn. Trust me, when an experienced driver gets back on the throttle at the curve's apex he will have to push the gas pedal down a significant amount of travel to prevent the engine from continuing to brake the car's speed. And, then he will send the gas pedal to the floorboard steadily and quickly to to accelerate and increase his speed...and get up to his next upshift RPM point.

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Take a look at this race car driver's footwork on a road course - notice first that he rev-matches his downshifts going into a turn - but pay particular attention to how much he must get 'into' the throttle (e.g. gas pedal travel) to prevent any further slowing down of his speed from the engine braking at the curve's apex...and then he gives it full throttle as he comes out of a turn, and then upshifts. I realize that looking at a video you cannot sense when the car's speed is slowing down, or maintaining a speed, or accelerating, but maybe you can get an understanding of the necessity of having to give the gas pedal a lot of travel toward the floorboard to overcome the engine's braking momentum when the engine's RPMs are mid-range or higher. The higher the engine's RPMs the more you need to get into the throttle - the lower the engine's RPMs the less you need to push on the gas pedal to start accelerating.

rijc99

I wouldn't expect it to happen if I were under manual mode. I'd expect it to stay in the gear I chose unless I were seriously bogging the engine or over revving. Then I can understand if the computer decided to override manual mode. But under D with S/S+... I'd expect the computer logic to handle gear selection for optimum engine braking and rpm to help me slow down or get out of corners.

PirelliRC

what does OP mean

bclexus

Original Poster

dseag2

I can understand the OP's concerns. When I had my GS F Sport I also thought it kept the revs way too high in Sport/Sport +. It also took quite a while for the revs to come down.

The answer for me was to only use it in areas where I was planning on driving aggressively or around turns. On the open freeway with traffic flowing I never saw the need to use it. Only in stop-and-go traffic when I needed to change lanes. Since he lives in CA, stop-and-go may be the only freeway traffic he is in.

Shrtstp757

I recently purchased the 2015 GS-350 F AWD. I was on the interstate in Drive mode (not manual) and put the car in S+ on a straight stretch of highway. I applied the brakes to slow the car down as I was approaching traffic and the car got stuck at 4000 RPMs and would not come down. I had to lift my foot off the accelerator and it eventually the RPMs decelerated. This happened twice in the same day. Is this normal? Should I have pushed the gas pedal? What should I do in these instances? Also, is it ok to switch from Drive to M while actively driving and should i have done this when the engine got stuck in the RPMs?

np20412

This is normal behavior as indicated in this thread.

If you want the revs to come down, just hit the + paddle shifter and the transmission will shift up a gear, lowering your revs. You can be in D and still do this. In your scenario, this would have solved your issue and brought the revs down immediately.

You can switch from D to M and back again anytime and with any frequency, even while actively driving or accelerating

Shrtstp757

Thank you so much and you answered all of my questions! I did read the threads below however, I did not see the answer my particular issues or... if it was addressed it, I did not quite understand what the heck they were saying lol. Ready to ride again!