LSD question

[assassin10000]

NoHachi Wrote:One thing I can say immediately: if you are braking in a straight line, and the rear wheels are locked, any resistance to a change in the rear wheel speed differential (aka diff-action) will result in understeer. The rear of the car will just plow straight on and resist rotation.

Also your examples of how diffs work are wrong..its the stuff you see a lot on the internet but its just not how the little buggers operate. Read the stuff in the links I posted earlier, they explain things a lot better then I can with an hangover.

My take on the 1.5/2-way diffs: They lock the wheels together untill they are overpowered. While they lock (during braking and no- or little steering) they stabilise the rear of the car preventing the car from making sidesteps on small steering imperfections. This allows you to setup the car comfortably towards the turn-in. Once you turn in, the torque diffential across the rear wheels breaks the clutches loose and the rear starts to turn (and also, you usually reduce braking effort towards turn in, so the diff is engaged less severly). So diffs would really benefit a clean driving style. Dunno...difficult stuff it be...

If I'm wrong I'm wrong, but I don't think I totally am.

Perhaps it's just based on my experience driving a cusco 2-way which has ramp angles which allow the rear to rotate out when partially off throttle. And I'm used to driving it which allows me to make the car rotate into corners and follow the lines I want.

I just didn't want to get into ramp angles and all that fun stuff. My 'observations' would be on what I would call 'properly' setup diffs. You're thinking of it like a 1.5/2-way setup very harsh and almost acting like a welded diff/spool.

Which it can be, but most of the time it isn't because the manufacturer of these knows not to have too much angle which causes the understeering type of LSD setup your talking about. 1-way, 1.5way and 2-way aren't quite true of the amount of lock they are providing. They are just giving you a description of the basic operation of the LSD you are being provided.

The information I provided above is what I think of as 'good enough' for the average not so mechanically inclined driver looking to purchase an already setup LSD. NOT the type of info someone who is mechanically inclined and wanting to do a complete racecar setup where they control all the variables.

I agree an almost fully locked lsd/welded diff would cause under steer on decel until you make it to the point too much weight has shifted to the front or you let off the throttle too fast 'shocking' the drivetrain and causing the tires to slip or just plain overpowering.



Found some bookmarked info that I saved on another forum since you guys like this stuff.

FWD/AWD related stuff - not LSD related

FWD: http://whiteline.com.au/docs/articles/AS...1_0202.pdf

AWD: http://whiteline.com.au/docs/articles/AS...1_0202.pdf

A BUNCH of good reading.

Quote:Whiteline has a ton of past technical/how-to and why it works articles here (some vehicle specific, some not): http://whiteline.com.au/dir.asp

I'd recommend at least checking these out, all have helped my understanding of suspension/tuning/set-up:

http://whiteline.com.au/docs/articles/AS...3_0228.PDF

http://www.whiteline.com.au/articles/WL_So...e_Antisquat.pdf
http://whiteline.com.au/images/articles/04...iftAlign_01.jpg
http://whiteline.com.au/images/articles/04...iftAlign_02.jpg
http://whiteline.com.au/images/articles/04...iftAlign_03.jpg
http://whiteline.com.au/images/articles/04...iftAlign_04.jpg
http://whiteline.com.au/images/articles/06...ktherapy_01.jpg
http://whiteline.com.au/images/articles/06...ktherapy_02.jpg
http://whiteline.com.au/images/articles/06...ktherapy_03.jpg
http://whiteline.com.au/images/articles/06...ktherapy_04.jpg
http://whiteline.com.au/images/articles/F4...d_v_power_1.jpg
http://whiteline.com.au/images/articles/F4...d_v_power_2.jpg
http://whiteline.com.au/images/articles/F4...d_v_power_3.jpg
http://whiteline.com.au/images/articles/F4...d_v_power_4.jpg
http://whiteline.com.au/images/articles/F4...d_v_power_5.jpg
http://whiteline.com.au/images/articles/Ge...er_2000an_a.jpg
http://whiteline.com.au/images/articles/Ge...er_2000an_b.jpg
http://whiteline.com.au/images/articles/Ge...er_2000an_c.jpg
http://whiteline.com.au/images/articles/Ge...er_2000an_d.jpg
http://whiteline.com.au/images/articles/Ge...er_2000an_e.jpg
http://whiteline.com.au/images/articles/..._Y98_a.jpg
http://whiteline.com.au/images/articles/..._Y98_b.jpg
http://whiteline.com.au/images/articles/..._Y98_c.jpg

http://whiteline.com.au/images/articles/...0498_a.jpg
http://whiteline.com.au/images/articles/...0498_b.jpg

http://whiteline.com.au/images/articles/...0798_a.jpg
http://whiteline.com.au/images/articles/...0798_b.jpg

http://whiteline.com.au/images/articles/...1098_a.jpg
http://whiteline.com.au/images/articles/...1098_b.jpg

http://whiteline.com.au/images/articles/...1198_a.jpg
http://whiteline.com.au/images/articles/...1198_b.jpg

Plenty of info for beginners and even advanced suspension tuners to help with how to set up or alter settings.

Andrew