Lsd Failure Thread

[TurfBurn]

welding went good... looks good I'll try to post pictures tonight if I can. I'll post the "how" of what he did when I put up the pics. It cost me around 160... but was done at a GT2 Porsche racing shop... so everything costs a little more when done that way.

as far as the quaife... I've helped on an install of that... the "modification" is really just filing down the top of the shifting gate/guide so that the bolts that hold the ring gear on dont' hit it. Not anything difficult, and it can be done with a dremel tool or a hand file for all it matters.. Also, the quaife does not come with it's own ring gear... so you need to drill out the studs on your stock diff to get the ring gear off and then put it on the quaife. That, or buy the gear... but it's not cheap at all. Other than that, the install and everything else is the same as it is/would be for the MSP diff.

 

[enry]

Same s*** here but they can't prove your abuse, its all hearsay.

I know people who bought the whole "car abuse" and paid for it. Always ask for everything in writing, INCLUDING an explanation HOW they determined it to be car abuse ('it looks like car abuse' is an opinion not a fact), otherwise see you in small claims court.

 

[TurfBurn]

Good job, you'll wish you spent the extra money for a Quaife instead. With the amount of $ you spent on your car I would have.

By putting the MSP lsd in, you might as well have put a Phantom Grip in it.

Having been exposed to an MSP with the MSP LSD (obviously) and an MP3 with a quaife... and soon an MP3 with an MSP LSD.... there doesn't appear to be anything obviously different in the feel between them. The quaife is certainly louder... I have not gotten to drive the quaife equipped MP3.... and it may be a while before I do.... but I can say that the MSP LSD is very effective and is a far cry from just being a "phantom grip." I can also say that my total cost for the LSD itself with welding ran me about 610 dollars.... All told with the extra seals and new bearings etc... it'll be around 700 bucks... that's still a far cry from the quaife which doesn't even come with a ring gear (so you either need to buy one of those things... or salvage it off your current diff...resulting in more downtime). So in all honesty I can go through 2 MSP LSD's in the life of the car and still be about even with having done a Quaife... yes in theory the quaife is better... and in my racing application it may have been even more so... but at this point just based off of the value of the situation and the money I have on hand and the negligible noticeable difference that I've seen to date (doesn't mean that I won't ever see a major difference betweent he two... just haven't as of yet... too limited of overall exposure and driving gimte)... I just dont' see a point in buying the quaife (for me that is... for a race application or sever stresses or just simply for wanting the best.. then the quaife is probably the way to go). We've seen what... 6 out of how many MSP LSD's that have broken? So if there are 2,000 LSD's out there.. and say 1,000 MSP members on this board... and we know of 6 of these ... we are talking about a failure rate of under 1%... Yep.. that's "terrible" isn't it . LOL.. and for something that can be "fixed" with a 100-200 dollar weld job... I don't see it as a major issue at all.

My .02

(Obvious estimation on the numbers for the failure rate... but you should see my point hopefully)

EDIT: Smiley added for clarity of joke being made amidst statements (quaife makes a "tone" during a hard turn... nothing else... sounds cool actually...) Also clarified statements to make it clear that I didn't mean that the quaife was not worth while... just not for buying a good LSD if you don't need the highest end of things.

And my overall point here was that the MSP LSD is not equivalent to a phantom grip.. it's not a quaife by any means... but it is a real LSD. responding to the above quote...

 

[TurfBurn]

And back to the facts. The LSDs that have failed broke in the same place each time. We already know reinforcing the part with TIG welds will make it stronger but it still does not outrule it's a weak bad unit from the factory and the welds could hinder the performance adding unbalanced weight to the drive gear.
If it was already stout we wouldn't have these failures.

The weakest link will always break first. It could also be intentionally designed to break where it does/did. That is common proper engineering practice to design a piece of machinery to break at a certain point when overloaded. Additionally, when welds are subjected to shock loading they will develop cracks and those cracks will propagate over time until ultimate failure is reached. So the fact that it is breaking where it does is not surprising especially if the user is routinely "grabbing" gears, allowing wheel hop, punching the gas instead of rolling on, and any number of other "aggressive" but improper driving actions.

Getting it TIG welded only eliminates the first weak link in the chain... there is another weak link that WILL come up at some point. But it may be FAR higher than this original "weak" link. No matter what part you have, no matter how strong it is, it can be made to break. I thought I saw something (maybe it was in this thread) about quaife's shearing as well... so nobody is immune

The TIG welds will add only a nominal imbalance if any. TIG welding uses very little filler metal in the first place, and with the welds all the way around and so near to the center of rotation, the imablance effects are extremely small... especially considering that it is your final drive so the RPM's are pretty much the same as your wheels, and thus even at 100 mph is only around 1,000 rpm's... which allows for a fair bit of imbalance to be present without causing problems.

As far as if it was stout we wouldn't have these failures... well people have been complaining about the shift forks in MP3's that have broken and so forth... I just saw a picture of one of the failures for the first time yesterday and it clears up the mystery of the why... User created failure. Doesn't mean that the shift fork isn't a weak point, obviously it is since it failed... but that doesn't mean the failure is the fault of the part. Which may be the case as well with the LSD's.... they may have a weak point that can and has failed, but it doesn't mean it's a fault of the part... it could easily be a fault of the driver and of the use... You can drive a car hard and have fun with it and enjoy the performance.. but plenty of people think they are doing that and actually doing nothing more than abusing their car while doing little to actually "drive" the car.

 

[70]

The weakest link will always break first. It could also be intentionally designed to break where it does/did. That is common proper engineering practice to design a piece of machinery to break at a certain point when overloaded. Additionally, when welds are subjected to shock loading they will develop cracks and those cracks will propagate over time until ultimate failure is reached. So the fact that it is breaking where it does is not surprising especially if the user is routinely "grabbing" gears, allowing wheel hop, punching the gas instead of rolling on, and any number of other "aggressive" but improper driving actions.

Getting it TIG welded only eliminates the first weak link in the chain... there is another weak link that WILL come up at some point. But it may be FAR higher than this original "weak" link. No matter what part you have, no matter how strong it is, it can be made to break. I thought I saw something (maybe it was in this thread) about quaife's shearing as well... so nobody is immune

The TIG welds will add only a nominal imbalance if any. TIG welding uses very little filler metal in the first place, and with the welds all the way around and so near to the center of rotation, the imablance effects are extremely small... especially considering that it is your final drive so the RPM's are pretty much the same as your wheels, and thus even at 100 mph is only around 1,000 rpm's... which allows for a fair bit of imbalance to be present without causing problems.

As far as if it was stout we wouldn't have these failures... well people have been complaining about the shift forks in MP3's that have broken and so forth... I just saw a picture of one of the failures for the first time yesterday and it clears up the mystery of the why... User created failure. Doesn't mean that the shift fork isn't a weak point, obviously it is since it failed... but that doesn't mean the failure is the fault of the part. Which may be the case as well with the LSD's.... they may have a weak point that can and has failed, but it doesn't mean it's a fault of the part... it could easily be a fault of the driver and of the use... You can drive a car hard and have fun with it and enjoy the performance.. but plenty of people think they are doing that and actually doing nothing more than abusing their car while doing little to actually "drive" the car.

UH OH...Now he's gonna jump all over you too.

As for my dyno pulls JDM Sam, go do a serach., they have been posted several times. Jack ass. Maybe if you actually did something other thna b****, you would know that.

You can stand by your opinion that it sucks. Just like people who stand by their opinion that the tranny sucks becuase they abused the crap out of it and it broke.

Everyone wants to b**** when somethign breaks, but no one is willing to do anything about it.

Was you differential replaced under warranty? The way you act here, I figure probably not. And if you acted the way you do here at the dealership, I wouldn't have replaced cracp under warranty for you either.

You attack anyone who even hints at slight abuse, which tellls me your over-reaction to that comment is bordering on truth. I really don't care one or another about how you drive. But be honest with yourself and us. If you only dragged once or twice, or whatever, be honest and don't flip out anytime someone had=s a differing opinion.

You call me a magazine racer, what are you? You know less than I do about your own f-ing car and I don't even own one. I'm not jealous of an MSP. I came to this thread to see why differentials were breaking. Added some questions and got attacked by you, a b****y cry baby...

If you think you spent good money on the MSP and expect it not to break, you are an idiot. Stuff breaks, regardless of horsepower, regardless of cost. You could have bought two Kias, and would have to have bought two Kias. One tor drive while the other is in the shop...

Keep bitching since that is all you are good at doing. Keep on crying instead of actually trying to figure why and how your differential broke and what can be done to prevent it. We all know crying and bitching will accomplish nothing.

 

[TurfBurn]

UH OH...Now he's gonna jump all over you too.

Well I'm not calling names, swearing repeatedly, or belittling or flaming anyone... so I'll hope/assume that I won't.

Tone of response goes a long way toward what comes back in return. It's hard to communicate tone with words on a screen.... so being obliging and non-argumentative is the best way to get across what you are trying to say.

I think everyone so far to some extent has had a valid point. That's getting lost amidst the tempers and the back and forth.

 

[70]

Well I'm not calling names, swearing repeatedly, or belittling or flaming anyone... so I'll hope/assume that I won't.

Tone of response goes a long way toward what comes back in return. It's hard to communicate tone with words on a screen.... so being obliging and non-argumentative is the best way to get across what you are trying to say.

I think everyone so far to some extent has had a valid point. That's getting lost amidst the tempers and the back and forth.

I see what you are saying. I re-read my first post. I suppose some of my questions asking for clarification of JDM Sam's opinion on why Mazda makes crappy cars could be seen as bating.

However, my opinion and suggestion about the differential was not.

After that everything went down hill.

 

[TurfBurn]

It takes two to fight is one of those mom adages isn't it? (Just razzing ya both in good humor )

The thread has gone downhill but is still informative.. there is a lot of information mixed in here amongst everything.

 

[ddogg777]

Wow, this thread is sooo good, and bad! It is like a professor teaching then at the end of his lesson, "Did you get that, dumb@$$es?"

Can't wait to see your pics Turf, well done!

 

[TurfBurn]

LOL... NICE ddogg ... I had professors that stopped just short of saying that.... they'd give you the look though..

But anyway... I'll definitely get pics up tonight. If I had a camera here at work I'd put them up right now... hmm.. maybe I can find one .. but yeah the welds look good... the guy can DEFINITELY weld...

 

[TurfBurn]

Damn it.. forgot my lug key today and I'm getting new tires put on today... so I have to run home... so I'll take pics on my run home and post them... so you'll see them in an hour.

Later.

Steve

 

[ddogg777]

I am sorry but... I feel happy for you forgetting!!! yay!

 

[Little Beavis]

The Quaife for those that want to see it. And yes the modifications needed to install it are super minor. A couple of minutes with a dremel and you're done.

 

[TurfBurn]

Careful now. . .the quaife has a higher torque bias, allowing you to transfer way more power! Also no clutch packs and springs and such.

yes but the quaife as far as I know doesn't have a torque offset. It has a greater torque bias but if one tire has 0 traction the other will get nothing as well.. SOME torque has to be applied to the ground for the a pure torsen gear differential to transfer power. the TSF has an offset that allows it to always transfer some power regardless of conditions. Doesn't mean it is necessarily superior, but is a difference between them. No it can't send as much power ot the other wheel, but at the same time how much power can one wheel reall handle before it begins to slip as well and you now have less grip than before?

EDIT: the quaife is not a Torsen diff... it has the ability to never completely rob a single wheel of all power... so all wheels should be able to be driven regardless... I'm not sure at all though what happens when one wheel is completely off the ground and the other not which is a problem if you have a Torsen brand differential.

Quaife is certainly louder. Where the @#$% did that come from? Could you hear it? Did you know it was the Quaife and not the tires or the maybe the loose bolt you left on the car? How about the hum of the inline pump, the buzz of the AWR mounts, the nice exhaust leak I had when you got a ride in it? Don't state things you don't know so that others perceive them as fact.

I have never heard the LSD in any turn whatesoever on the MSP... there is a distinct tone from the quaife, nothing bad or obnoxious and no you dont' hear it during any kind of straight line operation. I was also just simply making a joke and trying to keep this thread already full of too many people being uptight slightly lighter.

When did you experience the Phantom Grip? Just curious how it can be said that the TSF is far superior.

From what I've read it applies a load on the gears at all times, I can't see how that is good for them in the first place. Secondly, it's an insert for something that isn't designed to have it in there... that's typically not the best of routes either. Third, people on the mini forums have had issues with them I believe if you talk to Jim. So although I have not experienced one that is plenty enough information to work from in my opinion to say that the TSF should be superior, not necessarily far superior or anything else.. and there is the cost thing as well... but the TSF is actually a LSD... the phantom grip is plates stuffed into an open diff to simulate an LSD... makes me nervous.

The Quaife for those that want to see it. And yes the modifications needed to install it are super minor. A couple of minutes with a dremel and you're done.

 

[TurfBurn]

Anyway.... moving along..

here are the pics...

 

[TurfBurn]

I am sorry but... I feel happy for you forgetting!!! yay!

I'm glad it's of value. Hope it was worth the wait and helps someone out.

 

[JustMe]

From pics the MSP LSD seems to be just like the Quaife one, where is the difference exactly?


And TurfBurn, thanks for the pics!

 

[Little Beavis]

From pics the MSP LSD seems to be just like the Quaife one, where is the difference exactly?

Look a little closer, one is all gears. One is a clutchpack and very similar in design to an open differential.

 

[TurfBurn]

first of all I am no expert and never claimed to be. If I posted something wrong please point it out and I'll remove anything erroneous from my posts...

but in support of what I put up already:

Well I looked around and I haven't found a torque preset for the quaife.

Also as far as I know the quaife is a purely mechanical gear based Torsen differential:




The Torsen differential* is a purely mechanical device; it has no electronics, clutches or viscous fluids.

The Torsen (from Torque Sensing) works as an open differential when the amount of torque going to each wheel is equal. As soon as one wheel starts to lose traction, the difference in torque causes the gears in the Torsen differential to bind together. The design of the gears in the differential determines the torque bias ratio. For instance, if a particular Torsen differential is designed with a 5:1 bias ratio, it is capable of applying up to five times more torque to the wheel that has good traction.

<TABLE cellSpacing=0 cellPadding=3 width=200 align=right bgColor=lightyellow border=1><TBODY><TR><TD><CENTER>Hummer!</CENTER>[size=-1]The HMMVV, or Hummer, uses Torsen differentials on the front and rear axles. The owner's manual for the Hummer proposes a novel solution to the problem of one wheel coming off the ground: Apply the brakes. By applying the brakes, torque is applied to the wheel that is in the air, and then five times that torque can go to the wheel with good traction.[/size]






</TD></TR></TBODY></TABLE>These devices are often used in high-performance all-wheel-drive vehicles. Like the viscous coupling, they are often used to transfer power between the front and rear wheels. In this application, the Torsen is superior to the viscous coupling because it transfers torque to the stable wheels before the actual slipping occurs. However, if one set of wheels loses traction completely, the Torsen differential will be unable to supply any torque to the other set of wheels. The bias ratio determines how much torque can be transferred, and five times zero is zero.









A wheel can only support so much power to it...


Who has heard an MSP make any noise? Shawn from mazdaformance has said repeatedly on the phone and I wouldn't be surprised if he has said on the forum that he hears the quaife. You've heard it in your car too. So I don't understand the issue there.

As far as the MSP diff...
Here's it's specs:
Super LSD by Tochigi Fuji Sangyo KK, conical ring torque sensing type Torque Bias Ratio: 2.0 / Preset Torque 49 Nm
From:
http://www.avantemazda.com/www2/mazdaspeed.html

Showing the preset torque that I'm talking about that gets it around the 0 Torque condition. The TFS is neither a clutch nor pure gear LSD. It's a mixture of the two.

From phantom grips own website:
Phantom Grip serves two distinctive functions in your street or race vehicle. First, it functions as a disc-type limited slip in cornering and braking. Disc plates exert pressure against spider gears using spring pressure to regulate the amount of slippage at the wheels. Helping to accelerate earlier, while exiting corners at a higher speed

And looking at the construction you can see that it is two metal plates with sprinsg in them forcing out on the spider gears...

So I question where the point of friction is out of all of this?

 

[LinuxRacr]

Good info going around guys. Glad we are starting to get back on track. I will keep an eye out.