XutvJet

So I'm still looking at these cars. I drove a 2008 ISF two years ago and inadvertently left it in normal mode because I didn't know better. The car drove really docile and reminded me very much of my 2003 G35 automatic in terms of feel, response, etc. If I get one of these cars, I will likely drive it in Sport all the time. I've done a lot of research, including reading a couple ISF transmission tech articles regarding Sport mode, but information is constantly conflicting both on this site and in automotive articles. I know shifting in Manual Mode while in Sport Mode is awesome and the torque converter (TC) stays locked in all gears but 1st. I have no questions about that operation. I get it. My questions are as follows:

1) Based on my research, it appears that the TC does not stay locked while shifting automatically in Sport. Can the group confirm?

2) I know that while in Sport, the transmission is smarter and will downshift on braking, increase the shift points, and shift firmer, but how's it's responsiveness to throttle inputs? Specifically, is it a lot quicker to downshift depending on throttle input compared to Drive? For example, my G35's automatic was quite responsive and I'd know just how much throttle to get a one gear downshift, a two gear downshift, and of course the full throttle downshift. Is this more of less the same behavior in Sport Mode in the ISF?

3) When in Sport, but not Manual Mode, how are the manual shifts when the paddles are used? Is it laggy/mushy since the TC is still involved?


Thanks everyone.

Tokenblkgy

Xutvjet

Got a question for you man. What are you looking for in the IS-F? Or for any matter in your next car?

I dont think any of the peeps who drive these cars have even the slightest care what the car does in manual or auto mode with shift points, locking tq converters, and flux capacitors lol.. I think we just get in and drive the **** out of it when we want to or we enjoy the tame ride when we also want to. Thats what i like about it.

I have owned it 6 weeks and i "Fawking Love" this car. I cant say I have owned a car that can do so much and is comfortable. And this is coming from a guy who said i would never buy an automatic car, I have driven manual cars for the last 20 years( it got old fast)

What i love most about this car is this. My wife is 8 months preganant to day was baby errand day so we drove the F. I left it in normal drive mode and i loved how we carried on conversation, laughed and enjoyed the day and the ride was smooth, shift points were precise and she didn't complain one time about the ride or the harsh shifting or the neck breaking acceleration..

Now when its just me in the car, i NEVER drive in auto mode or what ever you want to call it. I haven't since i got the car because the manual "sport mode" paddle sifter ( to me) is the only way this car should be driven (when not entertaining others in the car). From a few ISF owners i have run into they all tell me Paddle when alone normal with wife or family. lol

I'm telling you man just go out there get one and drive the hell out of it. Your above post will make no sense to you once you get behind the wheel of one and get out there. Who cares when it shifts and what locks up and this and that. buy one, enjoy it, and try not to get any tickets because these cars will get you caught up..

but to quasi answer your questions, shifting is crisp, not laggy and just all out a blast to drive. If you want milliseconds shifting response go buy a Ferrari.. The ISF is doing a fine job at it so far..

Token

H1_OFICR

I couldn't have said it better.. Seriously jump in a isf and all these specifics will become irrelevant because the transmission is truly a masterpiece.. I think it's the fastest shift single clutch transmission out there. Shifting in 1/10th of a second. In normal mode the car shifts (up and down) smootg and gentle. In manual mode it's ferocious.. And gets me "excited" everytime I blip the throttle and hear the burble from the exhaust.

To answer one of your questions.. The tourney lock-up happens in manual mode.. You can feel and and hear it engage when downshifting into first. It's quite the mechanical orgy. *go's and gets keys and takes car for a spin*

PatrickISF

Just wanted to point out your comment about the single clutch transmission. This transmission doesn't have a clutch, just a torque converter that locks up when in sport/manual mode.

H1_OFICR

Whoops.. Got ahead of myself.. I think it's (still) the fastest non dual clutch transmission..
Yea.. It's a direct drive.. My bbbbbb, good catch.. I got a Lil excited.

Eedo123

Here is a good read that gives you a good amount of information on our transmission:

"The Lexus IS F 8-Speed Sport Direct Shift Transmission: Conquering a Stereotype

Conventional wisdom has long held that a good manual transmission is always faster and more fun than an automatic transmission: Faster because it directly transfers power without the typical power loss of a torque converter, and more fun because it responds exactly to the driver’s commands with no delay. Fast, direct, fully controllable and predictable – exactly the desired qualities in any “driver’s car.” Moreover, precisely the qualities that describe the new Lexus IS F’s 8-Speed Sport Direct Shift transmission.

The transmission is an arrow through the heart of conventional wisdom.

But why go to the trouble of creating an automatic transmission that performs better and faster than a manual? After all, the simple yet effective manual transmission is held in high esteem by driving enthusiasts everywhere.

Engineers love a challenge and when the IS F Chief Engineer dared his staff to build a paradigm-changing high-performance car, the conventional automatic transmission was a ripe target. Why? The IS F would not meet their lofty goals with anything less than a complete re-think of the gearbox. Goals that included scintillating track performance.

You may not care much about the detail and might feel that driving is the only proof you need. If so, you’re encouraged to get some IS F seat time at your earliest opportunity. But if you would like to know how Lexus built the world’s fastest shifting automatic transmission, read on.

Moving from Weakness to Strength

In the process of creating a maximum performance car, Lexus has done nothing less than turn what is typically thought to be a weakness into a solid advantage. To illustrate the point, let’s get right to the qualities that make it so:

· The among the world’s fastest shift time for street legal production cars. At 0.1 second, it’s faster than you.

· Full manual shift control that can be instantly accessed by moving the console-mounted shift lever to “M” and then using either the steering wheel-mounted paddle shifters or the shift lever. In manual mode, it shifts only when you tell it to.

· A direct feel unrivaled by conventional automatics, made possible via clutch lockup (yes, like a manual) employed in second through eighth gears

· Ultra-quick throttle blipping downshifts match engine and gear speed to avoid sudden engine braking—an advantage during performance driving, on the track or on the road

· First gear torque multiplication for maximum off-the-line acceleration

· Smooth, yet quick and drama free automatic shifting, if that is what you desire

These qualities add up to create a track-worthy ultra-high performance transmission that works for you, not against you, by responding to your demands the moment you want or need it to. And unlike other transmissions built for high performance duty, there is no pain required for your gain.
Speed is EssentialThe most important quality in the development of the new gearbox was shift speed. Incredibly, the team looked at the world’s fastest shifting transmissions for reference and inspiration: Formula One. A typical F1 transmission shift time is approx. 0.05 seconds, with virtually imperceptible lag. The IS F shifts occur in approximately 1/10th of a second. The charts below put the remarkable shift speed of the IS F’s transmission in perspective.

Begin with a Robust Design…


The transmission team started with a new 8-speed automatic transmission design from the LS 460. This may sound like physical overkill but IS F would have notably more power than the LS and certainly be driven more aggressively, so a robust design was required.

The cleverly designed gearbox is relatively light and uses a special planetary gear set that allows a more compact design. The whole unit weighs only 96.3 kg yet has more than enough torque capacity for the IS F’s 5.0-liter engine.



…and Relentlessly Pursue Efficiency

The team that designed and developed the transmission knew that they had to think without boundaries to achieve the type of performance on both road and track that skilled drivers demand. The surprising results are rooted in two key areas: Shift/lockup clutch operation and shift control. It also doesn’t hurt to have eight speeds in the g‘box.

The so-called lockup clutch is not new to automatic transmissions, but the control strategy is. Traditional automatics have used the lockup clutch to make them more efficient by creating a direct power path between the engine and transmission. This is normally done in the upper gears and in low load operations to preserve smoothness while gaining fuel economy.

The IS F turns this idea on its head by employing lockup in all gears except first when in manual mode. This eliminates any power loss from torque converter from 2nd through 8th gear while preserving desirable torque multiplication in first gear for stunning launch acceleration. The result is a direct feel unlike any other automatic, and right now response to the throttle.

This lockup scenario surely creates excessive shift shock, you say? The intentional result is much more in the “useful feedback” category than shock. And remember we’re still in manual mode; Shifts are quite smooth and quick in auto mode but manual is so addicting, you may never look back.

Add Strategic Control…

In order to create the virtually instant upshifts (in manual mode), Lexus engineers developed new methods to control the hydraulic pressure that actuates the transmission clutches. A high flow-rate linear solenoid is one of the key elements that work together with special computer programming to provide quick and precise control in concert with engine torque. Ultra quick shifts—when you want them—are the outcome.

The ability of the transmission to respond only to your commands yields a manual mode that is true to its name. It shifts only when you ask it to, and not when it thinks it should.

In addition, a modified manual mode is readily accessible without even touching the shift lever. When driving in “D,” one only needs to tap the downshift paddle once to move into the modified manual mode. In this mode, one can shift manually as desired; the system returns to automatic when the vehicle is stopped or driven at a constant speed for a time.

…and Performance without Pain is AssuredThe IS F Sport Direct Shift transmission manages to be both an amazingly effective manual and a refined automatic. One stereotype…conquered."

http://pressroom.lexus.com/article_p...rticle_id=1519

XutvJet

The problem is there are none of these to test drive in Kansas City, so I have to drive hundreds of miles to go drive one. I'd just really like to know how this thing drives in Sport Mode while shifting on it's own. Is it responsive to throttle inputs or is it laggy and confused given the shear number of gears? I know Sport Manual Mode rocks, but I'm not going to be driving like that all the time plus the shift speed of Sport Manual Mode is dependent on rpm. The lower the rpm, the more laggy it becomes, likely because of line pressure. I want to know that when in Sport Mode and automatic shifting, the transmission is smart enough to find the right gear nearly immediately. I'd hope so because more autos on the market can do that. If I doesn't, that's going to be an annoyance to me. I know standard Drive mode will be Lexus slushy and will seek the highest gear possible.

INTMD8

I find that in automatic/sport mode upshifting from a stop is fast and on point. Downshifting when it senses lateral g's (coming fast into a corner) feels laggy to me, as does downshifting in general under 40mph or so.

Auto downshifting on the highway, 60mph or so is nearly instant.

Another oddity is under 40mph, I feel like it doesn't automatically downshift fast enough at WOT, but once it does, even if you lift off the gas to maintain speed it will hold a low gear and say 5000rpm for a while before it decides to upshift again.

Really it's my only criticism. And I think it's just overly safe/goofy programming, not mechanical limitations, which strikes me as odd as I felt the trans in my old LS430 was telepathic.

SubOrbital

The gear holding around that speed and RPM is weird, I agree. This is no run of the mill automatic gearbox though, that I can attest to. It's certainly fast, but the occasional laggy downshift is to be expected.

fearnight

I'm sure most everybody knows this, but for the quickest WOT downshifts in D mode, you have to depress "the button". There is quite literally a button under the accelerator that you must press to get the quickest downshifts. At 70mph on the highway, it will shift from 8th down to 3rd at full throttle within 1-1.5 seconds as long as you press the button. Way faster than you can blip all the way down with paddles, or even downshift rev-match in a true manual.

Once you get good, you can use throttle in D mode to downshift for you, then swap over to M mode and be in the ideal gear. It's very quick.

RSXiMUS

iTrader: (7)

Like someone already stated in here, I don't think it's a mechanical limitation since we know the IS-F can crack off some of the fastest shifts in Manual Mode.

In Auto mode, sport or normal, the programming is plain goofy as hell. I swear the transmission in my old IS350 behaves better in Auto.

The IS-F seems very reluctant to downshift in auto at anything less than 8/10ths throttle it seems. It always wants to stay in the highest gear possible, maybe to try and save fuel? It's cool if it was in normal mode, but I would like it to behave sportier in...you know...SPORT MODE?

It also does strange things sometimes like hanging onto a certain gear for too long in Sport. Shifts also have a definite "pause" when in auto mode, sport or normal.

I find myself always pushing the SPORT button then shifting to M, it is second nature to me now and I never leave it in auto except for long extended freeway trips.

XutvJet

Are you saying there's a detent in the throttle pedal unit similar to what the Germans and Mazda use in their cars? Well I learned something today. I had no idea.

RSXiMUS

iTrader: (7)

Yes there is a pretty stiff "downshift" button under the gas pedal, you floor it, then push harder and you will feel the button click. Same feel as my 335i. If you search, there were some people who actually modded this button and made the spring a little less stiff for easier activation.

INTMD8

I'm aware of the button but even if you curb stomp it american history x style there is still a substantial delay in downshift at times.

Tokenblkgy

Wait I'm not following. You depress the gas pedal to the floor to click a button to get faster downshifting??? Not computing......