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Interesting info about the IFS!

6583 Views 9 Replies 7 Participants Last post by  henry zzzz
The following info is quoted from motive magazine...

Unlike the somewhat predictable engine mods, the reprogramming of the LS's eight-speed automatic is unexpected and groundbreaking. The so-called 8-speed Sport Direct Shift gearbox has two modes: In D, the torque converter is engaged throughout all gear changes to smooth them out (and sap power and time), just as in a conventional automatic. But in manual M mode - controlled by either the gear lever or two blade-like paddles attached to the steering wheel - the converter only twists in first gear, multiplying torque for a fast launch; in gears two through eight the gearbox functions like a two-pedal manual, the torque converter's lock-up clutch providing a direct connection between throttle input and rear-wheel power. In this mode, the IS-F is the fastest-shifting manumatic on the road. It swaps cogs in 0.1 sec, faster than the F1 gearbox in the Ferrari F430, without much bucking or torque interruption - the thing even blips the throttle on downshifts. The ratios between gears three and eight are incredibly tightly spaced and short - to the extent that you question why, in a car with 371 lb-ft of flat torque, you should run through the middle ratios so quickly - but it's the small, stiff gears in this transmission that make such lightning-quick, unmassaged shifts possible. (Also, the Mercedes gearbox only has seven speeds.)

Lexus didn't neglect the IS chassis either, even if the changes here aren't as extensive as those implemented by the F's German competition. The front A-arm suspension has 90 percent stiffer springs and shocks than the IS350, with revised geometry to help mitigate brake dive. In back, the damping and springing rates are up 50 percent, but the rear toe-link bushings are more compliant than the 350's for better toe variation when cornering. Huge 14.2-inch drilled and vented Brembos with six pistons sit under the front wheels, with two-piston 13.6-inchers under the rears.

The sensors in those brakes enable a wide range of functions, bundled together in what Lexus calls Vehicle Dynamics Integrated Management (VDIM), which has three modes.
1. Normal keeps traction- and stability-control on at all times.
2. Sport ups the heft of the electronic power steering, raises transmission shift points, speeds throttle response, and relaxes the linear and lateral slip thresholds of the traction and stability systems.
3. You can also turn the whole thing off - press the button with the sliding car icon once to kill traction control, hold it down for three seconds to snuff out stability control. In all modes, ABS and the electronically controlled brake LSD are always engaged.


ISF Mercury metallic
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Some additional quotes from the same Magazine....

Speaking of weight, the ton of it up front means that you need to be patient with the car on turn-in - not Mustang patient, mind you, but the bow needs to be planted if you want to make your line and not understeer wide of it. If you go into a turn well set up but just a little too hot, however, VDIM helps. Its transitions between traction and stability control are invisible and its Sport mode does a superb job of allowing some slip angle while keeping you out of the gravel. On the track, VDIM is less satisfying in Normal mode, even though interventions are subtle, too. In Everything Off mode (also know as Holy Crap! mode), well, it's like driving on ice - a wide neutral phase soon becomes a large amount of oversteer. Even with everything off, the LSD does still help out a bit, providing some braking to a slipping wheel, and the coolest thing about this limited slip is that it can feed in brake and throttle at the same time.

The fact that this car is so capable, so fast, and so unflappable is a testament to the seriousness with which it was developed. It was shot like an arrow into one of the most competitive segments in autodom, and it can hang there. No, its chassis wasn't completely reengineered like an M car or even the new C63, but because the IS shares its architecture with the larger, V8-bearing GS, it gets away with it. Feelwise, the IS-F splits the difference between the bipolar M3 and the other parenthesis of the category, the C63, which is the very model of supersedan stoicism. It strikes its own elegant balance of the aggressive and the balletic, the stout and the playful. This car is better than it has any right to be when you consider it's within spitting distance, dynamically, of the race-bred giants in its segment. Moreover, this Lexus has the attention of all the Evo and STI drivers who, up until this car, have had no true Japanese supersedan into which to graduate. Add in that its price will undercut the M3 at an estimated $59,000, and you have a car that adheres to another precept of the Toyota way: "Be Late, But Be Great."
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Very nice.
well put oldparts!!!!

i tradedin my moded wrx for my isf and never looked back . wrx is great for what it is but the isf is simply in a diffrent class i almost bought the new evo until i drove the isf . with the other cars there were compmises none wth the isf! except i need to buy a 3rd car for winter and to leave at train station. i commute to nyc
No comparison with between WRXs and the F. I still track the Subie but the F is for the street...but one day it'll probably be out there too!
"except i need to buy a 3rd car for winter and to leave at train station. i commute to nyc"

Buy an old (1975) VW Beetle, nobody will touch it in NYC. LOL
Maybe some thieves like classics??? haha
your more likely to get run over by a bently then get ure car stolen nyc is totaly diff city now!!!!! i have a 5000 buget for my 3rd im thinking svx or 2.5 rs or legacy
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