Every year i do a boroscope to check the pistons condition and i found something looks like a white chips on the pistons. please check the pictures any idea whats wrong with them!? is it detonation!!?
my S is 2008 2.0 turbocharged P-Tuning kits 8-10 psi ( engine 100% stock )


piston#2

piston #2

piston #2

piston #3

piston #3

 

Stop lugging the engine. Looks like LSPI.

 

LSPI??

 

Those are areas of melted aluminum from detonation, not really deposits. Check your plugs for any aluminum dingle-berries on the ceramic plug end where the material often lands.

 

The Spark plugs condition.. one of my friends told me that because ur tune is over advanced timimg!

Note: the car is too rich the AFR guage reads 10:1 at WOT. And used once leaded fuel race VP C16 I think the yellowish color because of the leaded.

 

Low Speed Pre-Ignition

 

Learn something new everyday.

I don't drive the S2000 that way but you might nail me for the base engine/model 2002 Tacoma I have.

 

Interesting. So, the cause is running at low rpms? How low?

 

It's lugging the engine that causes this. Low engine speeds leads to poor fuel mixing than at higher RPMs where the piston speed promotes more turbulence and better mixing of air and fuel.

If you run too rich you may have unburnt fuel in the CC, this leads to LSPI as the unburned mix ignites with the subsequent mix and spark. Especially if you lug the engine, ie high throttle opening at low revs.

Don't floor the loud pedal below 4500rpm and it shouldn't be an issue.

 

Keeping in mind the OP has turbocharged a motor that was built and tuned for NA. The conditions in that motor are causing detonation which has pitted the piston tops as molten aluminum is released from the pistons.