34 replies to this topic

[Ron Alan]

Did you clean the underside of your car with a tooth brush?

 

The break is usually caused by a bump crash or just plain hard impact from behind.  The diff housing is scored there to shear.  Have a shop weld it up and you are good to go to the next race. 

Just for my clarification, is it legal to weld/add reinforcement to these? 

 

Schabi....it is my guess the owner of this site will ship a new(used) carrier right to your door!!

[davew]

Since we're talking about diffs, let me post a picture what happened to mine the first time I went racing.  This is not the best pic, but you can see the diff arm broke in half.  I have to read on the diffs, because I have no idea what caused this.  The bolt that holds the diff from the bottom of the diff through the long membrame did come out,  and I missed few gears, but I'm not sure if that would cause this. 

The only good news is it happened after the checkered flag and I was able to roll down to the garage. 

 

 

 

This is a smooth case 1.6 housing, for the effort you obviously put into the build, why not upgrade to a Torsen???

 

The type of breakage is most often caused by crash drafting or hard rear corner inpacts. But if a bolt fell out anything can happen.

 

Why is there a non-factory fitting on the diff housing? Nothing except the factory vent is allowed

 

Dave

[Mike Collins]

This is a smooth case 1.6 housing, for the effort you obviously put into the build, why not upgrade to a Torsen???

 

The type of breakage is most often caused by crash drafting or hard rear corner inpacts. But if a bolt fell out anything can happen.

 

Why is there a non-factory fitting on the diff housing? Nothing except the factory vent is allowed

 

Dave

 

That particular fitting is used to run a hose up into the trunk which allows you to run additional fluid in the diff, thus keeping it a little cooler....

[davew]

That particular fitting is used to run a hose up into the trunk which allows you to run additional fluid in the diff, thus keeping it a little cooler....

 

I really do know what the fitting is for. I also know it is not legal.

[George Munson]

Main question is it legal to brace the diff housing to prevent breakage on impact?

[john mueller]

I got nailed during a 3hr enduro and busted a Torsen case, got it fixed.

I run a lot of enduros and get run into often, I want this insurance...  But I'm not sure if it's 100% SM legal but it's not gonna break again.

Personally, I don't see this sort of bracing as providing an advantage as the diff case probably doesn't flex, that's what the bushings allow.

 

[Bench Racer]

As long as the ruel book allows this ^ your golden. If not your, you can figure out the rest.

[Caveman-kwebb99]

Probly not legal but should be made legal...

Puzzy protest imo

[Cy Peake]

We didn't go as crazy as John ^above^ but my teammates and I have had a bunch of diff covers repaired after they broke where they were designed to break.

[AW33COM]

I bought the vent with the diff.  There was that hose you're talking about, but I removed it, as I'm not using any liquids to cool it from the trunk.  I simply never bothered to buy the proper breader.  For now I just want to fix it for the next event.

 

Someone said it broke where it's suppose to, but I'm not so sure about that.  I removed it, and it looks like someone cut it on purpose and did a louse job doing so.  You can see it on the pictures below.  It does not look like "scoring".  I have a feeling the smooth housing and the other types of housing are interchangable, so that I can swap it, without the welding. 

 

The car was sold to me with an LSD, but from the outside it does not look like one.  I would have to open it up I think. 

 

 

 

 

 

 

Anybody with the housing and that spacer for sale please PM me, especiallay if you can ship it for Thursday to 07095.

 

Will upgrade to Torsen eventually, as I just figured out what is needed. 

[Bench Racer]

Here are some pictures that will help you identify without opening.

http://www.miata.net/garage/diffguide/

Picture 7 shows the shaft flange ears of a VLSD, (Viscous limited slip differential)

Picture 9 shows the shaft flange ears of an open differential.

Picture 6 with the cross pin shows that the differential is an open diff for sure.

A Mazda Comp LSD uses the open differential shafts.

My Mazda comp LSD shaft flanges are square, I bought the diff assembled and don't have a clue where the square flanges come from.

Hope this helps.

[AW33COM]

Another great read on Miata differentials (Torsen): http://www.miata.net/garage/vlsd.html

Unfortunalty, reading this link, the link posted above, and Dave's explanation does not show me, which differential I have.  Mine is a collection of parts put together.  From the outside it is an open diff, but once I removed the axel stubs, I can see through the differential.  It might be the Mazda Comp LSD, but I did not read anywhere that you can see through that one. 

 

Bench Racer, do you know if you can see through in yours? 

[Bench Racer]

Yes, you can see through a MazdaComp limited slip differential and you will see one spline diameter with a smaller center hole.

When you look through the OEM Viscus limited slip differential you can see through EXCEPT, you will see two different diameter splines. I presume the shaft flanges eliminated this posibility.

[makus0025]

 

does this hold true for the open and torsen diff's on miatas?

[AW33COM]

^ Yes it does, but there are different types (type 1 and type 2) of Torsen diffs in the Miatas.