E

> I would prefer 2-3 Torsens and no EDL<p>That may not work out as well as you think. Having the entire drivetrain directly<br>coupled could pose a big problem with driving dynamics, feel and safety. A<br>rear Torsen (or quaife) MAY not be bad though depending on it's bias ratio and<br>preload.<p>There is something to say about a Torsen system with open diffs for high speed<br>driving, and an EDL supplemental system for low-speed traction.<p>BTW, from what I have read, the Porsche system or Haldex system is tops.<br> I have not driven one yet though.<p>E<br>86 4KS<br>96 A4QM<br>(and countless other Audi quattros..)<p><p>

Todd W

3 open diffs is just fine. I would prefer to have a couple of Torsens, but that won't happen for a while. Locking the diffs makes it more fun in the snow, but I've never gotten stuck to where I had to lock them to get out (except for when I parked in a snowbank on a steep hill, which I would not have done if I couldn't lock the diffs).<p>I also rarely drive under 25mph :-) Having moved from NY to TX I no longer have to deal with the bad weather, but I still appreciate having quattro!<p>Todd W<p>P.S. This isn't the A4 discussion, don't assume that quattro means quattro IV.

Todd W

I wouldn't do that to my daily driver, but it could make the UrQ a whole lot of fun!!! There is someone with 3 Torsens in their UrQ in the northern midwest. I hear it improves cornering speeds significantly. I know another guy with a rear Torsen in his 4KTQ, he says that it is quite tail-happy. I would probably try front & center Torsens first, and add a rear Torsen after I saved some money ( I could never afford to do all three at once).<p>I grant you that it will change the chassis dynamics a lot, but I don't think that it will be in a bad way for what I want to accomplish. The Porsche system is ideal for what they are trying to accomplish, but the Haldex is just a packaging constraint. The FWD TT already handles wonderfully from what I have heard and the Haldex only helps when launching. I would get the Haldex system in the North over FWD, but I have yet to see it's usefullness on the track. I guess we'll just have to wait a year and see.<p>I am skeptical about the Haldex because it is FWD with computer engaged 4WD. It is <bold>not</bold> AWD. It has no center diff or non-computer-activated mechanical link between the axles. The programming also seems to disengage the rear axle under braking from what I have read. I would be happily surprised if the Haldex system were better than the system in the V8, but I will have to drive it to see for myself. If it were so, I might buy a TT.<p>Todd W<br>86 5KTQ (USS Quattro)<br>83 UrQ (little green track monster)

Joe Lucchio

According the article in Race Car Engineering magazine which had an indepth study of the new Haldex system, the system is programmable for whatever "bias" you want, be it fwd or rwd or awd. Audi/VW has choosen to program it at a 50/50 awd split with up to 95% of the drive being able to be shifted to the rear wheels. The ECU of the Haldex is connected to the electronic throttle controls, abs system, and ESP yaw sensors and the EDL system. It can react in 100 milliseconds and withstand up to 2000nm of torque. The Haldex is considered an "active" centere differential as compared to the "passive" nature of the torsen system. I don't know which one is "better" but the Haldex system appears to have many advantages over the torsen system.

Todd W

Sounds like a bunch of electronic goodies - not AWD. Well, it does have ESP sensors :-)<p>Todd W

E

> I know another guy with a rear Torsen in his 4KTQ, he says that it is quite<br>> tail-happy. I would probably try front & center Torsens first, and add a rear <br>> Torsen after I saved some money ( I could never afford to do all three at once).<p>I've driven 85-87 4KQ's with a Torsen center-rear and a Torsen center-quaife rear.<br>This setup is preferable to a Torsen center-quaife up front. I still assert that<br>3 Torsens all around is not the best way to go. And, in a daily driver - forget it.<p>From what I have read the Haldex system is superior to a Torsen or quaife<br>(or locking diffs ;-)). VW's and Audi's (Golf and TT) specific tuning of the LSC<br>may be questioned.<p>The Porsche system is highly regarded. Have not driven one, yet ;-)<p>E<p>

Dave

><br>I wouldn't do that to my daily driver, but it could make the UrQ a whole lot of fun!!! There is<br>someone with 3 Torsens in their UrQ in the northern midwest. I hear it improves cornering<br>speeds significantly. I know another guy with a rear Torsen in his 4KTQ, he says that it is <br>quite tail-happy. I would probably try front & center Torsens first, and add a rear Torsen <br>after I saved some money ( I could never afford to do all three at once).<br>><br>Audi never produced an quattro car with a front torsen differential, so I don't see how<br>someone with an ur-q has a torsen mounted up front. I hear there is a quaiff differential<br>which can be made to fit the 016 tranny, but have not heard of anyone installing one.<br>Any more details you can provide?<br>-<br>Dave Lawson<br>90 200 TQ Avant, black<br>83 ur-q, lhasa green<br>

E

> 3 open diffs is just fine.<p>For racing, I agree. Actually, having 3 open diffs may be better than having 3 Torsens<br>or quaifes. One center Torsen and 2 open diffs may be optimal, from my<br>experience.<p>> P.S. This isn't the A4 discussion, don't assume that quattro means quattro IV.<br>I did not assume an A4 discussion nor a quattro IV discussion. I've driven many<br>quattro setups since 85, including the UrQ. YOU are the one who asked about EDL <br>and quattro IV. <p>Regards,<br>E <br>

Todd W

. . . is that someone might come out with a chip for it :-)<p>A Porsche with a Haldex on the front wheels would be getting back towards the 959. I could see how it could augment the performance of the TT, but the programming does not seem to take full advantage.<p>Todd W

Todd W

The rear Torsen out of a V8 should fit in the front with minor mods. The internals of the front and rear diffs are apparently the same. Also, it is easier to put a Torsen in the rear if you use the 90Q casing (removeable arms).<p>email me<p>Todd W<br>86 5KTQ Pearl/tan<br>83 UrQ Lhasa green (original color)