Why did my piston melt?

[Audivotee]

When the car was remapped the boost was upped to 1.8 bar dropping to 1.3 bar ( I think that’s what I was told!)

As for fuel that was most probably Shell optimax (98ish ron)

The N75 is less than a year old but suppose they could go at anytime? How would I know? Oh yes and while I’m asking how do I check the injectors?

Again thanks for any advice

Dave

[EspenW]

When the car was remapped the boost was upped to 1.8 bar dropping to 1.3 bar ( I think that’s what I was told!)

As for fuel that was most probably Shell optimax (98ish ron)

The N75 is less than a year old but suppose they could go at anytime? How would I know? Oh yes and while I’m asking how do I check the injectors?

Again thanks for any advice

Dave

Fuel should have been fine, then. The Banbury based boys definitely know their stuff, so the remap should have caused no problems.

Three ways to check injectors:
Pull fuel rail and crank engine (pretty worthless)
Rig up test stand with compressed air (I did this, pretty easy)
Send out for testing and cleaning (note that some will claim that commercial injector cleaning with ultrasonic cleaning while cycling the injectors will kill injectors).
N75's can go at any time. I have one that leaks at pressures above 1.5bar. Makes the boost skyrocket to 2.5 bar...
Replaced it with a ceramic ball equipped Turbotech boost controller

[aronmatic2]

Easy: Too much torque delivered by the RS2 turboed ADU, get forged pistons

As others have said, probably pre ignition. Remember, though, that detonation can cause pre ignition due to the heat buildup. Overheated spark plug tip, burnt exhaust valve, but most commonly, carbon buildup causing hot spots are the typical causes.
what grade of fuel were you running? How much boost?
Would not surprise me if this was yet another engine blown due to N75 failure.
Check injectors and install A/F gauge and KnockLite.

i dont think is too much torque. i am using garbage N/A (10v) pistons in my rallye car, on almost 600nm. they like it soo much. asking for more. my lambda is 0.72 on boost.

[EspenW]

i dont think is too much torque. i am using garbage N/A (10v) pistons in my rallye car, on almost 600nm. they like it soo much. asking for more. my lambda is 0.72 on boost.

That was a joke, actually
AFR of 10.6 is pretty rich...

[aronmatic2]

That was a joke, actually
AFR of 10.6 is pretty rich...

yes. needs to be rich with those pistons.
stil working good.

[gnutz2]

std pistons are forged.

Without a doubt this engine sufferd from pre-ignition, this could have been induced by detonation but forged pistons wont stop them from melting.

Get that engine decoked

[gnutz2]

Or maybe colder plugs

[Audivotee]

Thanks to everyone and your advice, lots of checking, fitting etc to do!

Really really useful forum

Dave