3 Runs 15psi = Dead Clutch
 

Saturday night I made three runs, one of my buddies pointed out the passenger tire was spinning its ass off, while the driver side just hung out. This normally doesn't happen, even with my open diff, but the car was running pretty good. The second run was beastly, but once I hit 80 things got a little weird, and an odd smell started. Third run, and the car just sat for a second as it just reved as if the clutch was still in, I never got it over 40 mph. I parked the car for an hour, and drove home, as if nothing had ever happen.

Its pretty clear the clutch lost its ability to hold anything, but I'm wondering how long do I have before the car isn't driveable. I was thinking about doing a clutch upgrade after Christmas, but now I'm wondering if the car will leave me stranded if I wait that long. Does anyone have any ideas how long it might last after this sort of failure? And if the weak clutch is maybe saving the diff?

it probly is if i where you i would drive it conservativly until you get a better clutch man.

what sorta rear end?

It sounds like you just overheated the clutch. It could last a long time as long as you don't keep overheating it. That protecting the diff crap is some sorry rationalization though. If you're going to drag race a miata, you better have a spare diff in the truck, but that's still no excuse to run a sorry clutch. I'm running a street ACT at 18+ psi with no problems. It feels stock to me and the price is pretty low.

The clutch thing is not an excuse, I was asking if the stock clutch might be the reason I haven't killed the stock rear end yet. I want to replace both, the current plan being to replace the 1.6 diff with a 1.8 open, and later to swap in a RX-7 LSD diff. I'm not trying to use the stock clutch as a safety, just asking why it didn't die yet if the clutch is losing it.

Dude, just buy my 1.8 open setup. I even have a good used 1.6 ACT Extreme I need to pull from my car.

I am using a used 1.6L ACT Xtreme...and it's friggin' bullet proof. I got a deal on it too, barely cost more than the XTD puck bullshit.

I'm actually debating if I should use the Extreme from my 1.6 or this 1.8 HD I had in my other Miata, less weight but just as strong.

So you are using a stock clutch with 15psi?

The stock clutch is an organic design. And when organics get overheated they don't always glaze over completely. So if you let it cool, which it sounds like you did after the 3rd run, there's a good chance it would keep going.

Did this all the time with my spec clutch if I did a hard launch (some clutch slip to lower tire slip). It would just spin free when I hit boost. I'd just drive it out of boost for 5 minutes, and then it'd be fine till the next time I slipped it too much. I believe a leaky rear main seal did not help however.

I let it sit for nearly an hour afterwards, and it felt fine on the drive home, but I haven't driven the car since Saturday night. I'll give it a go again on the morning. I guess a new clutch that will hold up to 250 tq will be my next purchase for my car.

You have a PM.