the 2is doesnt have LSD !! why is that??

 

i think the vdim acts as an electronic lsd... not sure~

 

The 2IS does have a LSD option if you have a 250 automatic. None of the rest do. They have "pre-torque" which is a fancy way of saying they put a conical washer behind the pinion gear to preload it. The rest of the LSD function is up to the VSC and/or VDIM.

 

Why is the slowest, least powerful powertrain the only one with an LSD option?

 

LSD......No......... But my 350 drives like it's on PCP and Meth all the time.....

 

My sentiments exactly. I've been extremely happy with the Torsen in my Supra, and one of my friends commented (when I mentioned I was thinking about the IS), "I bet they didn't even put a limited slip in it!" He's a pretty fast driver (4th and 6th in One Lap '02 & '03) so he actually has a clue. And of course, he was right. Damn the bad luck!

That said, I would like to see the performance comparison between the "electronic" LSD we got and a genuine LSD spool. I know I've used the parking brake technique a few times when I had wheel slip problems, and it does work well. It may just be a matter of speed of reaction, I'm not sure. It would be interesting to know for sure.

 

That is weird. The slusho-magic transmission'ed 250 is the one model least likely to be driven hard, too. Toyota probably had a stockpile of LSDs sitting in stock somewhere, inventory manager got tired of them taking up space, and told the engineers to "get rid of them somehow".

The best part is of this, is that the traction/stability control is so intrusive, that it's hard to imagine the LSD ever being utilized. It's like having a set of extremely strong legs, but being paralyzed from the weight down.

 

I believe that the 3-Series also lacks the LSD unless you get the //M3. Think I read that last week. So it's not as insane to me why they didn't include one.

 

Correct. Although it's not so much the fact that the other IS' didn't get one. It's the fact that the IS 250 slushotippymagictronic did.

 

It's not automatically in the car, it's optional. And looking at the drawings in the New Car Features, it seems pretty unlikely it was laying around collecting dust. Possible, just really unlikely. Maybe it's a Tacoma part like the manual gearbox?

BTW, there is no way you could swap any of the 250 differential pieces into the 350. The entire rear subframe is different, the mounting points are different, and the internal dimensions on the 350's shell are different. Damn the bad luck, but it's typical Toyota.

 

so can someone explain the difference between and electronic and mechanical lsd....

i mean with the vdim.. it limits slip ... so what's the difference...

 

The traction control system (VSC or VDIM electronic system) transfers torque by applying the brake to the spinning wheel and reducing engine power. The mechanical one simply transfers torque to the one that isn't spinning.

 

In the simplest terms, VDIM (and the like) limit slip by applying the brakes and reducing engine power. Mechanical LSD limits slip by forcing both wheels (within its own abilities) to spin at the same speed, and does so by sending torque to the wheel that isn't spinning as fast.

Why is mechanical LSD better? Simple: the electronic "LSD" kills performance.

 

So the manual gearbox in the IS 250 is in fact from the Tacoma, I've been trying to figure out where it was from?

 

I highly doubt they took a tacoma trans and put in the new is, this is not ford we're talking about here, the driving characteristics are total opposite for both vehicles and so are the enigine, very unlikely it's just a swap.