Oooh. I like that spread sheet. Can I have a copy?

Aren't the T2 diffs notorious for breaking, at least way more often than T1's? If so, putting a unicorn gear in a weak diff doesn't sound smart...

No. TF diffs are notorious for breaking. T1 and T2 are the same strength.

Then what is the issue to where T1 diffs are preferred? I vaguely remember something about an internal spring on the T2's being the issue?

They behave slightly differently under braking and Accel. It's a driving characteristic difference not issue with one or the other.

Driving the Miata to my Dad's place tonight, going to pull the valve cover off to see about the noise I've been having. After seeing Aidan's issues with his lifters, I'll be checking those, gauging the lifter clearances and overall looking for unusual wear. I'll try to post pics later tonight/

Pulled the VC off and found.... NOTHING. No problems in the top end whatsoever, gaps on 4 of the valve pairs were all below .01 for gaps. I did find a thread that mentioned the grommets between the heater core hoses and the firewall can wear out, and one does move more than the other and there's a hose clamp that I COULD see tapping against the other clamp or the brass against the firewall.. I believe I'm going to replace the valve cover gasket and try driving it again, if I get the buzz I'll ziptie the hoses together to see if that resolves it. Seems to go away with heat when the engine gets hot, so I was thinking bearings buuuut.. the hoses get softer with heat too, which could make it change the vibration pitch? IDK. Will know more tonight.

Got things cleaned up, lost a fairly big rtv chunk into the oil passages. Ran a gallon of mineral spirits through the engine to clear anything out. Poured oil over the cams. Rtv applied and valve cover on, just needs to cure now.

https://cimg8.ibsrv.net/gimg/www.mia...603d05be7f.jpg
https://cimg2.ibsrv.net/gimg/www.mia...351c59a572.jpg
https://cimg6.ibsrv.net/gimg/www.mia...a944a88ad4.jpg

Below .01"? Exhaust should be .111-.133"

I thought the difference in 'strength' was caused by the acceleration and deceleration bias of the respective units. I thought autocross folks preferred the T1's due to driving characteristics, but the T2's were less likely to go kablooey during a launch since they're decel biased.

Source? The construction of the T1 and T2 are very similar. The TF is a totally different diff.

Yeah, I'm not referring to the tofu diffs at all.

Torsen Diff - Spec Miata Garage - Mazda Racers

"Type 2 is a fundamentally more robust design". Don't have an 'official' source for that, but perhaps there was confusion with the T2R unit which was a specialized version of the T2. It's also funny that torsen has a faq saying that the NA/NB torsens are no longer being made as they were last made in 2002 and all the tooling is gone lol.

You didn't finish the quote.

"The Type II is a fundamentally more robust design, but I have not heard of either unit breaking from track use. They seem to last forever."

That still wouldn't negate the fact that its stronger, if that were true. In any event, the issue is the diff case, not the torsen itself right?

Not the case, the gears inside the torsen shatter when they break, then pieces of those gears get into the ring and pinion and destroy that too.

Except for the MSM diff right? I've heard there was a guy that could break anything he set his mind to breaking and he couldn't figure out how to nuke that!

Something like that! I break a few things from time to time in the name of go fast.

You're right, that was entered in a frenzy. Intake was definitely tighter than exhaust and exhaust was above .1.

I'm picking the car up tonight, gonna throw some zipties in the car and see if I can get the buzz to happen.

Precisely why I was looking at a OSG if those 3.3 gears ever ACTUALLY re-materialize. I don't want to spend the $ on 3.6 if the 3.3 are actually happening.....

Noise still extremely prominent between 3250 and 4k, dad's thinking it might be the downpipe (crack/fracture somewhere?), he's getting a lot of noise and vibration off the turbo from the stethoscope and was thinking maybe it was that. Spool and turbo characteristics were OK as of a few days ago (well after the noise started) so I'm leaning to a downpipe crack resulting in harsh harmonics after the turbo and the plywood undertray is acting as a reflector. Is there an easy way to dump exhaust up off the manifold if I pull the turbo off to test the car? Hmmm...

I still have my TSE downpipe so perhaps I'll be giving that a go? Fighting a cold, might be a while before I get to this :(