7milesout

I wanted to point out one quick thing, maybe you folks have noticed, but I had not. And I also want to mention something I'm noticing, and see if I'm the only one.

One Quick Thing:
When I turn on the cruise, and it defaults to Radar Ready, I find myself not wanting to set it in the default following distance. Which is the farthest distance from the car ahead. I noticed that before I set the speed, I can push the following distance button and set the distance I want, before setting the speed. I found that handy.

Something I've noticed:
When my vehicle has caught up to traffic ahead and has slowed to keep a fairly consistent gap, I believe that at times the brakes are being activited at the same time it is throttling. Unlike how one drives when only using their right foot for the gas or brake (one at a time). It has a "feeling" like it's being restrained, and it sounds like it is making power. And when I look at the tach, even though it is at a low rpm, it does not appear to be idling ... I find it at like 1,400 rpm when I'm noticing this feeling that the brakes and throttle are being used at the same time.

While I find that it is likely doing precisely that (gas & brake at the same time) I don't find it dangerous. It is doing it's job to hold a consistent gap to the car ahead. But what bothers me is that a) it should not be necessary to have them both working, and b) it wastes both brakes and gas when it activates both the brake and throttle. This is yet another reason I do not prefer to use the Radar Cruise Control. I frequently find myself pushing the lever forward into normal cruise control.


QUESTION: Am I the only one who notices this is happening?


7milesout

jamodeo

iTrader: (1)

I usually set my speed and hit the distance button twice for it to change to one bar. I guess you can do it before or after you set the speed, and I agree its annoying but haven't found a way to default it to one bar.

I believe what you are feeling is it downshifting. Do you notice the little picture of the car in the dash break lights lighting up when you feel that?

-Joe

7milesout

It's definitly NOT downshifting. What I'm feeling happens at a steady speed. And when I notice this, it goes on and on just about the entire time it's trailing a car at LESS than my set speed. It's almost as if the car's little devil on it's left shoulder is (lightly) pushing the accelerator to accelerate back to its set speed, while the car's little angel on its right shoulder is holding the brake to prevent the car from getting closer to the car in front.

I haven't noticed the dash picture shows brake lights. I will watch it. I have noticed the car in front shows up, when the radar detects it. But have not noticed it showing lit brake lights. Interesting.



7milesout

Nospinzone

I've been using my system regularly for almost 8 years now and have never experienced that sensation. The system is either accelerating, coasting or braking, but none of those things at the same time.

When the car does have to apply the brakes, the brake lights on the car icon on the dash actually light up red. I always thought that was pretty neat.

I don't know if you have a malfunction or if it just seems that way to you. When you have it set for say 65 mph and are only going 40 mph and then have a clear road, do you feel the accelerator pedal move?

Tee

Yes you can set the distance before engaging the set speed, I prefer one bar (100 ft) as well vs the default at 160 & 130 ft. I have not notice the push-pull effect you described, the brake lights that come on the virtual LS when braking is cool also when the system detects a possible collision and shuts off the frame of the display will flash bright yellow and sound a beeping alarm. Here is a pic of the brake lights on the virtual LS in the display.

14LSSport

Love mine, One bar.

I can push the cruise froward to deactivate radar cruise? I'll have to try that

7milesout

Once you've activated Radar Cruise, pushing forward does nothing. The push forward only works when you first turn on the cruise system. If you've already set Radar Cruise, just cycle it off and back on, then push forward. This brake and throttle feeling is totally absent when I use Normal Cruise.

And again, when in Radar Cruise and no car in front, it doesn't do this. It's only when my set speed cannot be maintained due to traffic ahead, and therefore the speed of the car is less than the original set speed. During those times.


7milesout

7milesout

OK guys - I have more now. I used this feature a bit more. I did notice the brake lights come on the dash LS rear facia display. This is kind of cool ... a waste, but kind of cool.

However - THERE IS SOMETHING going on with this cruise feature that is helping to slow the car down. I'm not saying it's a bad thing, or that it's a problem. But SOMETHING is going on.

Here is what I feel, the best I can describe it.

I was on a 45 mph road. The traffic flows about 50-ish, and slows for various turns, etc. What I did was I set my cruise for 55 mph.

Obviously it was going to slow for the traffic ahead. On the areas where traffic was flowing somewhat smoothly, I still get this feeling. When the car ahead of me speeds up a bit, the LS responds in kind. However, sometimes it catches up a bit aggressively. I watched the icon on the dash and the brakes would not come one ... but the car did something to slow itself down. This is the times when I have the feeling. I previously described this feeling that it felt like it was braking and throttling at the same time (but not heavy throttle).

But now, what I wonder, is the computer doing something in the transmission? Is it locking up the torque converter while slowing, so that the transmission directly transmits engine braking to the driveshaft? You know ... like a manual transmission. And that is what I'm feeling?

I can only explain it like this. If you were driving a manual transmission in a very appropriate gear for the speed. Say 5th gear at 50 mph.

In order to make that manual transmission most similar to an automatic, you would engage the clutch everytime you push the throttle for acceleration or cruising. But every time you left off the throttle, you would push the clutch. That's how a manual transmission car would have to be driven to mimic the way an automatic transmission works.

A manual transmission car however, experiences engine braking when you let off the gas (without pushing the clutch). But an automatic does not experience engine braking.

But ... maybe this is what I'm feeling. I'm thinking that in certain conditions while cruising with the Radar cruise control managing the speed, the computer is locking the torque converter to provide some level of braking, without actually activating the brakes / brake lights.

That's my theory anyway. And I think there would be several advantages to doing this, advantages that I think Toyota would have considered, and decided to take advantage of. Like:

• Locking the converter to slow the car would reduce the frequency of the brake lights activating and annoying drivers behind.
• With the torque converter locked and the vehicle trying to deccelerate to a set speed, the computer can inject 0 fuel. This would save fuel, and the engine would not stall because the driveshaft and transmission would continue to spin it.
• Doing this would converve brake pad and rotor wear.

I'm sticking with this theory because I know I feel something going on. It's not perfectly smooth, and it being transmission related would explain it. And lastly, I noticed that during these times it seemed to be doing this (t/c locking - engine braking), my "MPG since last fill" did jump up quickly. And it would tend to climb quickly if it were injecting 0 fuel.

On late model engines with manual transmissions, when the throttle is at 0%, and the engine rpm is above idle, they will inject 0 fuel. Because the drivetrain will drive the engine to keep it from stalling, and this saves fuel. Automatic transmissions have to inject some fuel at this same condition, otherwise the engine will stall.


7milesout

LordBowral

The feelings you describe are correct and does feel a little unnatural at first as if the system is working against itself.
You have to remember that Lexus has spent God knows how much money developing the system and that don't often Create things that don't work superbly. They also wouldn't have a system that has any potential to fail, especially one that is essentially driving the car .... as they would be sued for squillions of dollars .
Deactivating radar is just daft and you make as well go and buy an old car if you don't embrace new technology and all the safety that goes with it
It is so much more relaxing and vastly safer than sitting there as you go barreling up behind another car and have to brake yourself . Every time I drive an older car with regular cruise I can't believe how scary they are compared to radar systems .
BTW Mercedes and BMW systems work exactly the same with the same feel . It's not wearing out your brakes and its reaction time should an accident occur will save your life . That's what it's designed to do . Turning it off is just plain crazy

7milesout

It's only just plain crazy or daft ... if you drive with your head in the clouds or up the rectum. That reply is so absurd. It is only applicable to those who just ride in their cars instead of actually driving their car.

I'm not saying it doesn't work ok, but I will say I can control my car's speed, smoothness, efficiency and wear and tear better than the Radar cruise can. I use my eyes, and I watch what traffic is doing and I anticipate. I will say that 90% if not more, other drivers anticipate nothing. I will see ahead that traffic is slowing and I begin to coast or lightly apply the brakes (depending). And most of the time I have SUV's, and BMW's go flying by me accelerating INTO the upcoming slow down or stop. Those are the same people who complain about poor mpg, worn out and warped brakes, and scary cruise controls.

And they have plenty of systems on Lexus and all other cars that have PLENTY of potential to fail. I pay high attention when I'm driving. I don't have to wait until cars ahead me come close enough to my vehicle to activate radar reaction. I can see it and react before the radar cruise would. I personally do not see Radar cruise as any kind of safety feature. Although others who are just riding along in their cars daydreaming of other things might not agree, and may actually see it as a safety measure. I know those drivers exist. I managed one time to prevent a rear end collision by moving my car forward before an *&^^%^ ran into me. That person eventually locked up their brakes and I managed to move forward and avoid it by inches. I think all drivers should be that aware ... but unfortunately they certainly are not.

LordBowral

Well your obviously very alert with better ,quicker reflexes than a computer ... Lol ...

7milesout

I'm not better or quicker. But the computer cannot see what's transpiring ahead. It only reacts to what has happened or is already happening. The radar cruise control cannot anticipate. A human can.

I will add though that even if I'm driving along at peak attention, and for whatever reason a car crosses the yellow line at the last second and is careening toward me, the radar cruise may out perform me. It is those unexpected head on where the radar cruise may help. I say may because I don't actually KNOW if the system would slam the brakes or not. I would hope it would ... and tense the seatbelts.

But if things happen in front of the car i'm trailing, I'm going to notice it and react before the radar cruise does.

About 20 years ago I had a rear end crash with a car and I was on a motorcycle. I WAS alert, but I was changing I to the left faster moving lane, and I glanced in my mirror then turned my head to look back to make sure no one was in my blind spot. During that time the cars ahead of ne in that left lane pani stopped because when I looked back up, it was too late. I was too close, and moving at probably close to 55 mph and they were stopped. Something innate took over. I don't know how but I dumped the bike and push my body to the left and wound up sliding on the pavement past the car my bike hit and past the car in front of that. I stood up like a runner stealing 2nd and walked back in shock past the cars I slid past. They looked at me like I was an alien the just pooped up on the road from underground becasue they had not seen me sliding past. I was really close to the left side tires.

When I got to the rearmost car, I found my bike wedged under the car I hit with the car's rear tires off the ground. It was a pivotal moment. From that point on, I don't follow closely. It's a lot less stressful to have a big gap, and I can enjoy the view better and not have to focus on just one car to make sure I don't rearend it. Leaving a big gap has HUGE advantages. But this is not the thread for it, and most people would just find it boring to not have their right foot planted firmly to the floor.

caha14

This is all very interesting. Radar cruise is relatively new to me, and I have not experienced it in a 460. However, based on what I've actually experienced, your description of what is taking places seems very reasonable. Even the 460 (as well as other Lexus) without radar will "engine brake" to maintain a set speed if you happen to be going downhill, etc.

On the 600, I also experience lighter engine braking with no brake lights on display (though in this case, it's less engine braking and more regenerative braking), potentially followed by heavier braking (with brake lights on display). On a separate note, I originally thought the virtual LS with the brake lights was only so in the 2010-2012 600h gauge cluster, and it was cool to find out that all LS cars with radar get it.

My own experience has been that the system works reasonably well except in situations when I'm changing lanes and/or the road is a bit windy. I've never been about to crash or anything remotely like it, but there have been times when the acceleration has indeed been aggressive, followed by braking, and I've wondered about why the radar is seemingly pointing at air, even if for just a short time, instead of to a vehicle that I, the driver, can most definitely see.

The coolest thing is to turn radar and LKA on. As long as there is some load from the driver's hand on the steering wheel, the LS will slightly steer itself and follow the lanes on the road.

Ascari_2

7mile, I have been using this system quite often and for very long distances (my daily commute includes about a 50-mile expressway stint each way). I think I know what you are feeling, and I don't think its the brakes engaging. Instead, as mentioned below you are feeling "engine braking" which actually saves your brakes rather than waste them.

7milesout

When I drove this car back from CA to GA, I wondered if it had LKA and Radar cruise, if I fell asleep in Arizona, I might wake up in Arkansas on the side of the road out of gas. Just think, the LKA would keep you in your lane and the Radar cruise would prevent you from running into the car ahead! Now that would be cool if it could really do that and be safe. I could have sat my alarm for a few minutes prior to my exit for gas and had a long nap. It could have also followed my Navigation route. That would be smooth. I could have climbed into the rear seat, turned on the massager and been out like a light. I realize it won't do that. But I think the day is coming. I do think it would be cool.


7milesout