Slows2k

This is a stock pinion gear from removed from a turbo s2k. It's using a 60-1 hi-fi, making 440hp on pump gas, and 525hp on c16 race gas. The car is making 300ftlbs from 6k to 9k on pump gas.

The differential's pinion preload was well off spec, and suspect that it was not set up correctly when a ATS carbon diff was installed. The pinion turned very easily, with no preload on the bearings. The backlash on disaasembly was .012. Over double the spec. (.0035-.0043) The car is also equipped with a Comptech reinforced housing.

There are cracks at the base of every tooth on the pinion gear.

fperra

Good thing you caught it before it came apart and destroyed your ATS LSD. What made you suspect there was something wrong? Good pictures by the way.

Slows2k

The diff was making nasty noises on the dyno. It had seen 1 track day and some street driving before the dyno time. It's not my car, I'm rebuilding the diff for the owner. The owner bought another diff and finished out his 2nd day of dyno time. (he had to fly a tuner in for it)

Squeezer

looks like my pinion gear, except the teeth did break on mine. but the ones that didn't break are cracked exactly the same.

Slows2k

Squeezer, any drivetrain mods to your car?

Squeezer

no, my s2000 is completely stock. its exactly as it came off the dealer's showroom 4.5 years ago. no mods at all. i think the repeated clutch drops to get moving at auto-x's did it by putting too much strain on the pinion gear.

Ludedude

That's the classic failure mode for these. Krazik posted some pics of his lunched diff, normally aspirated car, pinion broke the same way.

https://www.s2ki.com/forums/index.ph...f=123&t=179658

Slows2k

Just wanted to share the before the gear made little pieces.

bigpurp

Ludedude

Yep

Interesting "before" pics.