IS3FIDDY

My question is (1) whether anyone knows--definitively--what the difference is between driving in "D" mode vs driving in "S" mode and leaving it in 6th gear; and (2) whether it hurts the tranny to drive in "S" mode in 6th gear? Please try to limit the speculation, as I'm sure others will also benefit from the factual knowledge that frequently surfaces in this awesome forum.

Both modes shift gears automatically, and both seem to shift similarly (to my untrained eye). So, I wonder what the difference is, if any?

Personally, I like to leave my shifter in "S" mode in 6th gear...this gives me the flexibility to gun it if I ever want to by just blipping down the paddle to upshift. I feel like this gives me the best of both worlds in terms of being able to control the gearing when I want and just plain being lazy at other times (i.e. traffic).

I was reading my manual and it recommended to use "D" mode when driving normally. "S" mode is to 'limit the upper range of the gear...' (paraphrasing).

It also says on p.100 that "AI-SHIFT" mode only works when the shifter is in "D", but then how does it know how to shift automatically when in 6th gear in "S" mode?

Thanks,

Ed

inecstaz

i dont get it then... why would we have shifter paddles if we're not suppose to be shifting to the different gears. does the car shift automatically when in S mode? I've always shifted using the paddles and such. And what's Al-Shift? I read that in the manual too... didnt understand it.

t0e

iTrader: (1)

Artificial intelligence shifting

IS3FIDDY

Well, one can only speculate on this one...

I *think* it's because Sequential Shifting is a more recent phenomenon...everyone and their brother HAS to offer it now to keep up with the Jones' (i.e. BMW, MB, Ferrari, Lambo, etc.). Thus, Lexus offers it, but does so in a "safe" fashion such that one will not be able to mess up the transmission, because in essence this is what they are enabling the driver to do...over rev the engine, 5K RPM upshift swings, etc. If you ever drive an M5, check out the SMG...it's MUCH more sporty and "manual' than the Lexus. That's because them Germans care more about building a racing machine than a family sports sedan with a little oomph. In short, I just don't think Lexus wants to deal with all the service issues of offering a truly manual type of sequential shift...

So in answer to your question, yes, leaving it in 6th gear *appears* to make it shift like a normal automatic (the gear display below the multifunction gear display shows the highest gear that the car will automatically shfit down to without downshifting further). But then my question is, why isn't "AI-SHIFT" enabled while in 6th gear S-mode?

I mainly don't want to shorten the life of my vehicle by driving it like an automatic in S-mode.

Some Lexus engineers, please help us ouuuaaat....

vlkcheng

The paddle shift on the IS is not the real semi-auto like the ones on Ferrari, Maserati, Alfa or DSG of the VW/Audi. The car's ECU still decide which gear to select. So say if you floor the padel and you decide to change from 2nd to 3rd, the ECU may decide to stay 2nd until redline.

loftus112

iTrader: (2)

Nice Superlexy, this is definitely a great idea you discovered. Best of both worlds alright but now we just need someone knowledgable enough to confirm the safety of your theory.

cdeslandes

Driving in "S" in 6th gear is the exactly same as driving in "D", except you have the paddles to force a downshift.
To vary shift points, use the ECT switch: "PWR" mode to downshift early/upshift late and make the throttle more sensitive, "SNOW" to downshift late/upshift early and make the throttle less sensitive.

IS3FIDDY

Hmmm...I'm not sure I totally agree here...

The manual actually states that "AI-SHIFT" is turned off when switching to "S" mode (from "D" mode). What AI-SHIFT actually does is still a mystery...

The manual also recommends to drive in "D" mode unless you want to use the paddles or shifter to manually shift.

These clues lead me to believe that it's not exactly the same driving in "D" and "S" modes, even if the gears automatically shift in "S" mode if you leave it in 6th gear...

Trust me, I would love to just leave it in "S" mode, but I want to know if it's safe. I wish there was an engineer on this forum who could tell us if it's safe or not...

monkeyfarm

Safe? Are you kidding? Do you actually think Lexus would design a car with a mode of operation they considered unsafe? Oi vei...

The only difference between S mode and D mode is exactly what the manual states... in S mode, AI-SHIFT is turned off. That means it's left up to the driver to downshift when they want to (although obviously the car will still downshift when you're coming to a stop or if you hammer the throttle). Where as in D mode in ECT PWR, downshift will occur under heavy breaking when the computer has decided some engine braking would be a good idea.

It's incredibly easy for you to see this on your own. Go out for a drive. Put the car in D mode with ECT PWR on. Floor it until you hit reasonble speed, then hammer the brakes. As you slow, the car will downshift at noticeably higher rpm that it would without ECT PWR on to provide engine braking and to select the correct gear for a potential corner you might be about to enter.

If you then switch to S mode and leave ECT PWR on and do the same thing, the car won't downshift. AI SHIFT has been disabled... i.e. it's up to you to downshift if you want to.

That's it... those are the only differences. Now stop sweating over something that isn't a concern.

Nextourer

hmm.. that was what came to mind when I read "AI-Shift". It won't upshift/downshift for you. It'll upshift until said gear then stay there. It'll downshift to 1st at a stop but won't downshift any other time.

jlin101

You can't leave the gear selector in S and 6th gear. As soon as the car comes to a stop, the transmission automatically shifts down to 1st, then you have to upshift with the paddles. To me, it's a drag to drive around in S mode on a regular basis; just leave it in D, PWR mode and the transmission ought to downshift with just a tap of the gas pedal.

IS3FIDDY

Uhh...what in the world? Does your IS really work like this?

I've been driving around in 6th gear since I owned the vehicle for 3 weeks now. I don't think anyone else experiences what you've experienced, either...I would go check that out, if I were you...

IS-Jim

Mine is the same way as jlin101.. that is how they all are. Maybe you just don't realize that it is shifting into a lower gear event thought the Gear Display shows you are in 6th on the digital read out.

IS3FIDDY

Ok this is weird. Let's clarify the situation...

If I put the shifter in "S" mode and leave the gear in 6th, then my IS shifts automatically all day and twice on tuesday. It's as if I am driving in "D" mode. I do not have to touch the paddle shifters ever to shift. The car will downshift when I slow down to a stop. But when I accelerate, the gears will shift automatically.

However, if I leave the gear in--say 4th gear--then the transmission will shift up and down automatically from 1st to 4th, but then stay in 4th until I downshift manually.

Is this not how it's working for everyone? What the freak? Can we at least clear this portion up?

IS-Jim

OK. this is a run down on how the S mode works:

If you have the tranny in "S" it allows you to select what gear you want to be in 1-6.

If you keep it in 6th then the tranny will automatically use gears 1-6 ( same thing as "D" mode)

if you keep it in 5th gear then the tranny will automaically use gears 1-5 and will hit the rev imiter at the end of gear 5 instead of shifting past it.

If you keep it in 4th gear then the tranny will automatically use gears 1-4 and will hit the rev limiter at the end of gear 4 instead of shifting past it

If you keep it in 3rd gear then the tranny will automatically use gears 1-3 and will hit the rev limiter at the end of gear 3 instead of shifting past it

If you keep it in 2nd gear then the tranny will automatically use gears 1-2 and will hit the rev limiter at the end of gear 2 instead of shifting past it

If you keep it in 1st gear then the tranny will only stay in first gear....


So.. that is why having it in "S" mode and 6th gear is the same as having it in "D"-- it is using all 6 gears automatically.

So why have it in "S" and 6th,,, that way you can shift down quicker than having to move the gear lever over and then shifting...

I hope that helps you some.. So really to answer you question is is ok to drive in "s" mode and 6th gear.