Sounds like many have lost diffs this year. We lost ours at the Blytheville Pro, but it has survived 4 long/full seasons of auto-x with co-drivers. I feel the OEM diff is pretty strong, but is the extra power of the STR cars making a difference or the change in suspension (as previously mentioned)?

-Marc

 

The spacers go between the axles and the stub axle. Think of them as prices of aluminum that push the stub axles in, or if you prefer, take up the distance that they try to pull them out. They do not go between the diff and the stub axles.

That said, I like not having to spend money on a mod that's not necessary for fun, competition, or the health-development of this class.

I know that people have spent money on diffs, but that's not a good reason to keep them legal. I also don't think that we should have the STX brake allowance for the same reasons.

With these rules we should be asking the following: how do they allow for a fun, competitive, diverse, and sustainable field of cars for 5-10 yrs

 

That's a shame. The ability to run a clutch-diff was one of the main reasons I'd consider STR. It'd make a better dual purpose time trial car.

 

Wait! You lost your diff too?

 

At this rate, we could leave the rule as-is and people will end up not running the OS anyway because of imminent failure. I have to admit, I was probably going to install one next season.

 

Yeah, Mere lost her's first. Then I think Des and Annie in the same weekend. I'm kinda regretting buying my diff now. No problems or anything but I am just afraid to launch it now. I was going to pick up a co-driver for Nationals but now I won't because I don't want more wear on my diff.

 

It's strange though, I thought the OSGiken was the diff to have, and was built for all kinds of abuse... what's breaking? Is it failing in the same fashion as the stock differentials?

 

I installed mine a week before Annie did, and mine failed a week before hers (at the Tour rather than the Pro). Whatever we're doing doesn't really seem related to "wear" in any traditional sense. Neither of ours had more than 50 or 60 runs.

It's not related to power. My car has an intake and exhaust, and Annie's CR eats it alive. And not related to install, either. Three different installers. And not to axle stress; mine had spacers (at Mere's recommend).

If it matters (and it doesn't, now), the diff was magic.

 

So what failed on yours Des? I'm waiting to hear from Annie once she gets it torn down. I know Mere's seemed related to the stub axles pulling out of the diff. That is what I was worried about as well.

 

Don't know yet. The dealer asked us to look at the housing and end caps first to make sure nothing was amiss, and nothing was. We took the pumpkin back to the install guy. I wouldn't really know what I was looking at but will update here when he cracks it open.

I think the failure was exactly the same as Brian and Mere's car, despite the spacers. We changed the fluid once the car started to make "the noise" and found a couple of 1mm or so metal bits on the drain plug.

So the progression was:
-- Peace and bliss for three events, usually two drivers.
-- At event four, car starts to bind a little more in very low speed turns, and the chuffing sound of the diff is interrupted every few feet by a clank. Car is still very driveable, and the Internetz say this is normal sound.
-- Next event, diff "surprises" me on course -- I think it locked/unlocked/locked again during middle of a corner, compete with a big clank. I DNF and park the car, noticing that it's difficult to maneuver in the pits because the rear is locked all the time.
-- This is where we changed the fluid (believing warmer weather and two drivers had thinned it out. Giken fluid is 80w 250!). We do figure 8s until we barf. It doesn't sound any worse. We decide if it's broken, it's broken. Let's run it at the NT.
-- We were wrong. "Broken" isn't an open diff, it's complete inability to move under any kind of load. The car shudders and clunks every few feet, and there is terrific clutch rattle (again, something I'm told is normal but didn't appear until self-destruction had begun).

Annie's is making the same sounds.