burned pistons

[rs200]

hy people..
well my friend had big problem with his engine.
the engine is 1.8 20V TURBO.
he bought this engine with pistons and H rods, and put it into golf 2, use standalone ECU(MS2 pcb 3.0), he drive around 10 000km on base map , and everithing was fine. than they finaly decide to done remap, on 1.8 bar overboost , and they done remap , all was fine, but 4 days after when he kick pedal to the metal, few times, engine die.
and here is result:













it is 1.8 20v , pistons and H rods,
simens deka 660ccm
4bar fpr
Gareett GT30R
BOSCH 044
stock cams
external wastegate with 3" downpipe
what can cause this?
something wrong in part , or the guy who remap the engine done something wrong.
please help me , and my friend , because there is lot of money in game. we have to find who is guilty.
please, please.
your opinion is very important to us.
tnx

[driftin jo]

The person who mapped it is at fault, that's been detonating like mad and or going very lean.

[rs200]

thnx for quick answare!

[a4kquattro]

combination of high EGT and detonation from the look of it.

[Carfreak]

Reasons: Bad tune with to high egt, faulty fuelsystem with loss in pressure, detonation..

The tuner should have noticed any that stuff..

In my opinion the tuner should compensate for this screw up! Next time - let prj or some other guy tune it!

[JP]

Not detonation.

That's pre-ignition through running lean. Where cylinder temperatures are getting too hot and mixture is pre igniting. Detonation comes from advance timing which is gauranteed to be mappers fault.

Pre ignition however can come from various issues. First you have to ensure there is no air leaks between maf and engine. All the boost hoses need checking and all the vacuum and breather hoses. If these are 100% then it is a fueling issue. You need to check fuel pressure regulator is working and fuel pump is good enough for hp target and receiving 14v when running.

If all these are fine then it is issue with the mapper running mixture lean.

Looking at pictures which brand pistons are those as they look factory stock. Stock factory pistons I have never seen reliably last very long beyond 380hp as a sidenote.

Hth

[rs200]

friend got stock audi 4bar fpr , brand new 044 fuel pump bought in BOSCH shop. there is no MAF sensor because it is standalone ECU. injectors was taken from same tuned engine and owner need bigger injector and sell tis one to him, so injector was running perfect before on same type of engine, for many miles.
there was not boost leak because he get 1.6 bar without any problem, and 1.8 was overboost.
I will post his pictures of engine bay and you will see that job was done perfect with motorsport parts.

tnx for all your answers, I said the same to friend, but we want to heard the opinion from more people, to be sure that mapper is guilty for this.
so here is one more case how can wrong person in 5 minute destroy 1 year of hard work .

[a4kquattro]

Not detonation.

That's pre-ignition through running lean.

hard to say. once the piston melts as has happened here it obscures the telltale pitting from det damage. I can still see some pitting on the crowns, but bottom line the major fault/failure appears to be meltdown from high EGT, which can be caused by as you note lean mixture or ignition timing problems.

[driftin jo]

Unfortunately it is impossible to PROVE that the tuner is at fault , however likely it is,
many things could have caused this, simple things, such as the manifold pressure ref hose to the FPR coming off or spit for example.
Using the wrong heat range plugs may also have caused this and even if the same plugs were used when it was tuned they may not have caused an issue until prolonged WOT.
Detonation can also lead to pre ignition as prolonged detonation can over heat the plugs until they are hot enough to cause pre ignition.
Bad fuel (lower octane ) than the car was tuned on could also be a cause, especially as this is after market ECU with none of the safeguards of motronic if you get bad fuel.

We really don't have enough to go on, was it tuned on a dyno, were there AFR logs done etc ?

What plugs were used and what do they look like out of interest ?

[rs200]

http://tinypic.com/view.php?pic=119s4du&s=6

[Jamo]

You can't Prove it was the tuner especially if the car had been running for 10k on a basemap
The 1st damage could have been done then

[UrS4boy]

Pre ignition however can come from various issues. First you have to ensure there is no air leaks between maf and engine. All the boost hoses need checking and all the vacuum and breather hoses. If these are 100% then it is a fueling issue.

I am confused as to how a boost leak between the MAF and the engine can cause pre-ignition. If less air shows up at the engine than the MAF told the ECU was coming, the result will be the engine will run rich = no pre-ignition but often an O2 sensor adaptation limit reached MIL/CEL code.

[driftin jo]

I am confused as to how a boost leak between the MAF and the engine can cause pre-ignition. If less air shows up at the engine than the MAF told the ECU was coming, the result will be the engine will run rich = no pre-ignition but often an O2 sensor adaptation limit reached MIL/CEL code.

I think he meant an air leak between the MAF and the turbo, hence unmetered air in and lean condition.

All irrelevant anyway as running no MAF in this case.

[rs200]

Unfortunately it is impossible to PROVE that the tuner is at fault , however likely it is,
many things could have caused this, simple things, such as the manifold pressure ref hose to the FPR coming off or spit for example.
Using the wrong heat range plugs may also have caused this and even if the same plugs were used when it was tuned they may not have caused an issue until prolonged WOT.
Detonation can also lead to pre ignition as prolonged detonation can over heat the plugs until they are hot enough to cause pre ignition.
Bad fuel (lower octane ) than the car was tuned on could also be a cause, especially as this is after market ECU with none of the safeguards of motronic if you get bad fuel.

We really don't have enough to go on, was it tuned on a dyno, were there AFR logs done etc ?

What plugs were used and what do they look like out of interest ?

friende use NGK spark plugs BCPR7ES

[prj]

Don't use ECU without knock detection capability... monitor EGT...

You don't know what happened - maybe just the fueling went lean from fuel pressure dropping for some reason.

Or maybe it was mapped bad, but anyway - no knock control is bad.
The fact that it's in all cylinders pretty much means that it was too advanced timing or too lean, which led to very high temps.

You really have to try to melt an engine like that.