What is LSD?

[Apeximprt2nr]

What is LSD, in detail?
-thanks

 

[DG-FNR]

http://autocross.dsm.org/diffs.html

DG

 

[jtmcinder]

That page on Dennis' site is useful, but it describes clutchpacks (at best) incompletely and doesn't explain how a Torsen works. The following are a bit more detailed:

http://dsmtuners.com/forums/showthread.php?t=177117

http://dsmtuners.com/forums/showthread.php?t=177206

It's the second one that you are asking for, but it's better to read them in the order given.

- Jtoby

 

[xpr626]

Lysergic acid diethylamide













Ok, im not funny. Sorry.

 

[DSM PERFORMANCE]

Those 'following' are good Jtoby.

If I undestand well the best set-up would be a Quaife at front and a Kaaz + 4 spyder gear at center (anyway Quaife at center is Hazardous) ?

Eric

 

[glish_dreams]

http://auto.howstuffworks.com/differential.htm

all u need to know basicly
its where i get all my info from

 

[jtmcinder]

If I undestand well the best set-up would be a Quaife at front and a Kaaz + 4 spyder gear at center (anyway Quaife at center is Hazardous) ?

Drag racing or turning?

There is not enough data available on the Cusco 35/65 center, but I'd be looking at it closely if you're serious. Just be ready to replace rear axles if you make any real power.

Also: you cannot combine a 4 spider with a Kaaz in the center. The Kaaz completely replaces the center. Your only "options" with a Kaaz center is whether to keep the VC.

- Jtoby

 

[DSM PERFORMANCE]

Thank's Jtoby.

It's for turning, I don't really care about drag. For the Cusco, I've talked with Mike (RRE), it's sems that Cusco has the same problem then Quaife at center. To play safe I think hte only two option are : Quaife at front + Kaaz at center or : Quaife at front + 4 spyder gear.
What do you think about that ? (Daily driven car).

 

[jtmcinder]

Well, there is some disagreement, but most people say that you should do the front before the center if you're only doing one. (In about five minutes you'll hear the opposite, so be patient.) I agree completely on Quaife front, not Kaaz. And if you make enough power, then you might as well put a 4-spider in while you're in the area. I assume you plan to leave the stock VC on the center, too.

Then you can wait a while and see if Quaife redesigns their center and/or more positive reports come out on the Cusco. ACM has a Cusco center and has done a few ProSolos with it and all he did was prove that our rear axles can be as weak as the fronts. The center, itself, was not the weak link.

- Jtoby

 

[DSM PERFORMANCE]

Thank's again, what do you think of that : Quaife at front and Kaaz at center ?

 

[jtmcinder]

I think a Kaaz center will cause too much power-on understeer. Remember: a Kaaz locks as a function of transmitted torque, regardless of whether any locking is currently needed. This means that it can lock way below the limits of your grip and induce understeer compared to a car with an open or VC'd center. I would not put a Kaaz in the center of an autocrosser. It's not a crazy to me as putting a Kaaz in the front of an autocrosser, but I'd still save the money for a Quaife or Cusco.

- Jtoby

 

[MrAWD]

For right now, I would keep the stock unit with the VC and the 4 spider conversion at the Speed Design. Unless you can fit that ACD unit from the EVO...


Fedja

 

[DSM PERFORMANCE]

Ok thank's, so a 4 spyder gear at center, not Quaife (my first choice) because Shepherd told me he would waranty his tranny if I put that (same thing for TRE).

I have 2 more questions, is it really worth it to put a Quaife at front on a AWD ? will a see a significant difference in RR ?

And here in winter we have a lot of ice/snow, will it be an advantage to have a Quaife (because it can act as an open diff) or a disavantage ?

Thank's

 

[KlowdDragon]

http://www.nida.nih.gov/Infofacts/LSD.html

all the info you need

 

[MrAWD]

I have 2 more questions, is it really worth it to put a Quaife at front on a AWD ? will a see a significant difference in RR ?

Well, this is a subject heavily discussed all over the different forums and I am sure that you will find a lot of versions for answers. Basically things come down to two cases. One is that Quaife will help put more power down during the exit phase of the corner. The other one is that it will create some oversteer at the corner entry and it will take a bit longer to settle the car for that oncoming corner.

Interestingly enough, while racing in SM with over 350 HP even with the open front diff I had never had any issues with putting the power down. Some other people had problems and swear to it.

I believe that it all comes down to the driving style that each driver is going to execute. More smoothness will keep all four wheels longer on the ground for sure and you will be able to use them without any help from diffs. But, on less then perfect grip (wet, asphalt,…) such a diff would show its benefits.

And here in winter we have a lot of ice/snow, will it be an advantage to have a Quaife (because it can act as an open diff) or a disavantage ?

Even though, when unloaded (meaning zero traction on that side) Quaife is just an open diff, driving in snow still offers some grip which is greater then zero. You will surely benefit more from it in those conditions compared to the high grip of concrete!


Fedja

 

[DG-FNR]

Heh.

The interesting thing about driving style is that you and I have driven the same car at the same event with the datalogger running (that Nationals when you broke your hub) so I actually have data about how our driving styles (back then - things are undoubtably different now) differed.

In a nutshell, you were better at getting into corners than I was, but I was better at getting out. I was consistantly on the throttle earlier and harder than you were.

Given that it was your first time in the car (first time in a car with a Quaife even?) I think you just weren't aware of just how early & hard the Quaife lets you get back on the power. And for what its worth, I wasn't aware of how much deeper into the corner I could go - no doubt because I didn't trust the back end of the car to not come around on me.

It never ceases to amaze me at how well people can adapt to the weird little quirks of their cars, to the point where it becomes an unconcious action. I bet you never encountered much front wheelspin because you were driving around the problem, adapting, and just never used enough throttle (unconciously-on-purpose) to encounter it.

DG

 

[MrAWD]

It would help a lot to see things better if you would tell us what where the speeds at each of the turn phase, and cornering Gs during such a different driving styles…

Fedja
Ps. Yes, that was the first time for me to drive a car with the Quaife front diff

 

[DG-FNR]

I don't have that data right in front of me, but I do have some more information.

My data system has a differential time function. One can overlay two runs, and the software will draw a trace that indicates how much faster or slower in terms of elapsed time one run is compared to the other. It shows, graphically, where I lost time to you, you lost time to me, and by how much.

On almost every corner, that trace rises (where "up" is me losing time to you) going into the corner, and then falls coming out. And then you look at the throttle position trace, and you see that I beat you to the throttle, both in terms of absolute time (I got there first) and in amount (I used more of it, quicker)

The *net* time through the corner was usually a wash though. Sometimes I beat you, other times you beat me. Neither one of us was clearly superior.

Incidently, I took this as evidence that I was overslowing going into corners, worked on that, and got faster as a result.

DG