Open Diff vs. LSD Diff??
 

It is easy to see the logic to havind a LSD 3rd member over a Open Diff 3rd member.

BUT, is there ANY advantage to an Open Diff over a LSD?
More durable perhaps? Maybe less power loss to the wheels otherwise?


Curious why they even have them?

:confused:

cheaper and simpler to manufacture, uses normal gear oil, less worrying handling for incompetents...

Charlie

Well, quite simply in many cars an LSD is not necessary. In local SCCA road racing, an open diff 14" wheel FC was able to lap faster times than a clutch type LSD 15" wheel FC. On a road course, an LSD is not necessary on the naturally aspirated cars because they don't have enough power and corners are likely not tight enough to cause the inside wheel to lift and spin. Autocross may be different however.

In addition, and LSD can promote understeer in a chassis that might be more neutral with and open diff.

How is that? With an LSD both wheels break would free when you apply too much power which would cause oversteer, right?

Open will give you less headaches. CLutch type LSD's wear out over time anyway and with the age and mileage of FC's nowdays they are probably almost dead anyway.

OPen is fine for everyday use. If you are drag racing, just weld your spider gears. Easy :D

Remember, LSD's engage on acceleration as well as DEceleration.

"an LSD is not necessary on the naturally aspirated cars because they don't have enough power and corners are likely not tight enough to cause the inside wheel to lift and spin."

ummmm... no! having an LSD even in a NA car (or any car for that matter) on a road course is a world of difference. I race my car on the big tracks and having an open diff would just be a mess. A diff will totally change how you car feels at its limits. Right as your at the edge of traction, the difference of an LSD will be night and day. what about launches, too? your going to be a one-wheel-wonder with out an LSD.

on super expensive race diffs, you can adjust the ratio of lockup on the throttle vs. off throttle, so you could make it lock up more when your off throttle, causing off throttle oversteer if you wanted.

Im pretty sure that i read somewhere that the turbo LSD's have a better lock up raito then the non turbo LSDs. But an LSD still really helps on a NA car!!!

as you can clearly see, a LSD on any car is going to have a large impact on handling.

You dont have to put in special additives and you can run synthetic oil in the S5 LSD diff. its clutchless viscous type.

Only 2way LSD's do that. Stock FC LSD's are NOT 2way.

isn't 2 way the standard... I'd have assumed it'd require extra engineering etc to get it to only work 1 way.

Charlie

Uh....No?

The clutches are always on so the clutches will engage even on decel.

Unless they make clutch packs that only slip one direction?

The clutches arent always on.



Do a google search for 2way, 1.5way, and 1way clutch LSD's

If you are decelerating while turning, the clutches would engage, no?

Kinda like when you let off the gas on your engine, it bogs down because even though the clutch wasnt intended to work backwards, it does :D

Bah who cares. At any rate a factory LSD will be shot by now anyway.

Not that factory LSD's offer much more positive slip anyway.

I dont think you quite understand how these clutch type LSD's work.

Like I said, do a search on it.



You cant compare a transmission clutch to a LSD clutch. Just because they have the same word, doesnt mean they work the same way.


Secondly, if your engine is bogging when you let off the gas, youve got a problem.

I didnt know having good engine compression and a strong holding clutch causing engine braking on deceleration was a problem?

Not sure what youre trying to say here...but ok.

Like I said, if your car bogs when you let off the gas, youve got problems.

Instead of coming up with these replies, why dont you read up on LSD's?








Now to get back on topic, LSD > Open Diff

Boy.....
 

love it when one of my threads start LIVELY conversations like this.

But, considering how little stress daily driving would put on a clutch LSD, would you really expect them all to be "shot" by now?

Also, I put Royal Purple Synthetic in my S4 LSD. The bottle says LSD additive is already mixed in. Should I look to add additional additive anyway?

Sometimes you just gotta swallow your pride and shut up though :D

100k - 150k miles is a whole lot of miles for an LSD to have been driven.

But yes it depends alot on how the car was driven.

As for more additive: its kinda overkill

I got my t2 bogged coming down off the gutter at an angle the other day :D
it's done about 60'000 miles, and is all in reasonable nick. one of the wheels just lifted slightly off the ground and the fucking thing was stuck spinning in the air. had to get out and push it off...

Charlie

the s5 viscous lsd's suck. they're fine if you are putting around town, or spinning a 180 to turn around in the parking lot every morning like i do, lol. but coming out of tight corners it allows far too much wheel spin. and remember, clutch type lsd's can be rebuilt/repacked. just because it might not work great now doesn't mean you can't throw it on the bench and repack it with new clutches and bam, feel like brand new. here is alink on them from a miata site. http://members.aol.com/solomiata/MiataVLSD.html as posted in the 1st gen section on a kaaz vs cusco lsd thread.

what do u mean your car bogs after you let off the gas. Its called the weight of the engine, or engine braking.

I was told that my IT-7 car has a LSD that's 10x tighter than the standard setting. that's my .02
and all i really wanted to know was whether or not i need to put in an additive in my T2 diff. some of you have suggested using it, and some have said that there are oils that are premixed...but...i didn't find anything in my manual about LSD additive.

Clutch type LSD's...
 

you need an LSD additive for sure if running standard 80-90W Gear Oil.

However, I put Royal Purple Synthetic in mine with no additive as the bottle said additive already mixed in. I also read that a separate additive is needed for Red Line Synthetic.

I've read many posts that Viscious LSD (S5 type) don't need additive.

But, to be sure, I'd go to the Mazdatrix.com web site and read what they have to say. At the least, they have a e-mail link where you can ask them directly.

That help?

viscous lsds are an enclosed unit and do not need additive. they can also not be rebuilt.