So I was on the track + my oil got up to 260+* Here are pics of the carnage




This is the apex seal that broke. I'm surprised that just the corner broke off + not somewhere in the middle. I guess this is why 3 piece are extinct now.



Rotor. This gouge is a lot smaller than it looks in the picture. I was also wondering if I could blend this out. Is there a certain depth to where I shouldn't do this anymore? I was going to stay away from the apex seal area also.



Gouge in the housing by the spark plug hole. This isn't so bad



But these ones are pretty deep. So the housing is trashed. Luckily the side irons are still in good shape + weren't harmed by this.



So, what exactly went wrong? What can I do next build to prevent this?

 

were u boosting? pump fuel? timing? ecu? more info might help

 

Damnit, totally forgot that

S5 jspec swap, FMIC, stock turbo, boosting at 15psi ish, intake, exhaust, pump gas, stock everything else.

 

stock turbo @ 15psi + 260 oil? you detonated. Not crazy, but obviously enough to crack the seal. TOO HOT!

 

that corner of the seal is the weakest part. @15psi on the stock ecu, you are too lean, and 260F oil temp is too hot.

the engine can handle either being a little lean or a little hot, but both together is bad. if it makes you feel any better lean and hot on a piston engine would detonate too.

 

Pictures aren't even required. That's a timebomb. Anything over 10lb on stock injectors is asking for it...be glad you only toasted one rotor/housing.

 

 

Remember that oil is used to cool the rotor. According to Mazda engineers there is a relationship between rotor temperature, ignition timing, and knock.



Even if you were getting enough fuel the stock ECU's timing maps are not optimized for the amount of airflow you are getting at those high boost levels. Combine that with the oil temps and boom.

 

I believe his lean condition contributed to high oil temps. Lean=higher combustion temps=higher oil temps.

 

how big was the fmic. Was it big enough to block the oil cooler?
When you go to rebuild the engine and put it back in, you should figure out a way to divert air to the oil cooler and radiator when you have a fmic.
15psi on stock injectors and ecu is a holy crap moment there lol

When my apex seals went from detonation, it was total carnage inside the housing...

 

15 is the highest I've ever hit. Most of the time it will either be at 6 or 9. I still have the stock **** wastegate so it's pretty uncontrolled at best.

The FMIC is rather large. I would need to divert air better.

I've never seen my wideband gauge go lean. It's always either rich or right around 14:1

But yeah, that would make sense that too hot = boom.

 

i hope that 14:1 is not in boost...?!