[stratos_335]

Originally Posted by Continue5

Sorry to hear OP, at this point it does make much more sense to just grab a used n54 and call it a day. If you are doing the replacement yourself it shouldn't be too painful. Also pistons are not forged as once thought but cast hypereutectic. Here is an engine that might work : http://www.ebay.com/itm/BMW-E71-X6-X...01bfd6&vxp=mtr.
Good luck with everything

Thank you for the input. I'll contact him for some more details, although from the description there are few things that need to be clarified

Originally Posted by Rob@RBTurbo

Sorry about your misfortune stratos. As I said via email feel free to send the RBs back in if you'd like them rebuilt for good measure (highly recommended). Especially now that you have some time available to get it done while your working on the engine remedy.



Please take a pic of the underside of the piston. No forged piston has ever been documented for the N54 so it would be interesting to see this portion. Based on the pics provided it appears to be just like the other cast N54 pistons I have seen. Based on the failure also leads me to believe it is cast. Nothing wrong with Cast pistons, in fact they have proven to be able to withstand quite the load- just want to clear up the "yes they are forged" before it spreads like wild fire.

Rob

Hello Rob.

First of all thank you for all the help you have provided to me all this time and all this communication. Although you are at the other side of the globe, your help is so much that only a few people can provide.

Will send you e-mail about the turbo rebuilding.

As for the forged pistons I don't want to make haste. There are two types of forged pistons (please confirm). First, pistons manufactured from a forged billet aluminum piece, machined to a piston. Second, pistons forged from hot liquid aluminum inside a metal mold with high pressure. This can leave marks from forging underneath the piston. I'll grab a picture tomorrow.

Originally Posted by onesuperboi

Are you sure the failure is caused by a faulty injector?

There was another thread with a engine fire and that have been caused by a faulty injector. I can't imagine why a faulty injector would cause a fire in one situation, and an internal failure in another.

No, I'm not that sure to be honest. Maybe the compression ring stuck, then it bended upwards causing the piston cracking and then a lean burn condition made the piston melt.

If you watch the picture closely, there is a fragmented part and then a molten part. It is really weird

Originally Posted by Mike@N54Tuning.com

Sucks it broke but at those power levels it's somewhat inevitable. I wonder if a single turbo setup would actually be more reliable than RB turbos despite making 100-200hp more due to the reduced exhaust back pressure?

On the damage it looks like typical N54 knock damage to me. Perhaps it was tuned a bit too aggressively or you just got unlucky on meth flow or fuel octane for a moment. It only takes a moment to blow up.

Mike

Hi Mike,

don't forget that the single turbo setup makes lower torque than the upgraded twins setup, with less boost. It makes approx 80 whp more on 18psi than the twins setup.

I have a Nissan Navara for my work on gasoline. I fill it up from the same gas station. If the quality of the gasoline is poor, my Nissan is very prominent to knocking and you can hear it from the engine.

Of course, this cannot prove that the gas I use is of supreme quality. Logging knock detection and timing drops, the curve was optimal topping around 11 degrees at redline.

Originally Posted by 135Pats

Here’s the thing though, if meth were to suddenly cease flow
1. One would hope the failsafe could anticipate and react quickly enough. OP what meth system were you running?
2. Were meth to stop spraying and the failsafe didn’t work, why would just cyl 2 get too hot? Would think all the cylinders would starve. Cyl 2 usually gets pretty decent meth flow too.
Odd stuff. Right as I’m about to jump to RBs and meth, I see this thread and get cold feet. Lame.

I use the very first Vishnu meth system, upgraded with AEM failsafe as the Labonte one crapped out 2 years ago. It is a beat slower than the pwm but it sprays meth before it boosts over 10 psi or so. M10 nozzle used and 80-20 meth mixture.

If meth spray stopped, why would only cyl 2 suffer from knocking?



A lot of people run RBs and meth without problems. You can use this setup with 17-18 max boost and get enough power. You don't need to squeeze every last hp from your car to be fast.



Yes, sometimes I saw 21 psi of overboost, tappering to 18 at redline. But all logs were superfine, especially ignition timing.

[Tzu]

IMO looks like a material or casting defect, or possibly fatigue but not likely given how many other engines are subject to worse torture on this forum. If you'd like some fractography, send the piston to my lab and I'll let them have a gander.

[turb0mik3]

Welcome to the club...

[135Pats]

I just hope we can figure whether meth caused this. You just don’t see N54 pistons exploding like that often, and sadly meth seems to be involved in most of these blown motor threads. To be clear- I am NOT suggesting a causal relationship here, just pointing out what appears to be a common link. If it was an injector that suddenly stopped flowing, you’d think the DME would shut down the cylinder right away. But it only takes a second for things to go wrong in this scenario.

There are dozens and dozens of people running RBs for several years now, I’ve never gotten the sense that the turbo design could cause excessive EGT or backpressure, leading to block damage. Anyone can blow up a motor if they get the tuning wrong, but it doesn’t sound like OP’s tuning was particularly aggressive or unique. Either way, have a tough time believing the turbos are to blame.

Man this thread is a bummer….IDK.

[boom]

If the injector stopped flowing, there wouldn't be fuel in the cylinder. No fuel = no combustion = no detonation. If the injector stuck open, the cylinder would hydrolock or at least run pig rich. Either way it would have shown up in the DME as an error with the mixture.
Weird incident. Good luck.

[enrita]

Thats what happens when u run aggressive with meth. Its always either cyl 2 or 5. Injector is NOT the issue.

[cn555ic]

That for sure doesnt look like a melted piston. What were the circumstances that lead to the smoke.. Were you doing a run or driving spirited minutes prior to the first sign of the exhaust smoking?

[Tzu]

What map were you running? Were you using the backend flash?

[ChuckD05]

motor blow, nothing to worry about, n54 crowd is VERY lucky overall

[N8N]

Interested to see results of testing injectors too... seems that when they go bad they leak, not stop flowing - that's what happened to me. and no, no codes then either, just a rough idle and black spark plug.

[135Pats]

Originally Posted by ChuckD05

motor blow, nothing to worry about, n54 crowd is VERY lucky overall

We are lucky that the motor is very stout overall…but blown motor = nothing to worry about? Wha?

[ChuckD05]

Yes, random user X blew his motor, maybe a few others but overall its less than 5% of the RB n54s out there that have had an engine failure.

If you are tuned properly and take precautions this guys motor should not worry you in the slightest.

[Tiago@VRSF]

Just goes to show that you should absolutely run a custom map on any upgraded turbo as well as have some sort of AFR monitoring to prevent this from happening.

[135Pats]

I would generally agree with that, but it’s still important we get to the bottom of what caused this. If there was a meth flow issue that caused this, it’s a valuable piece of information for those who are still on the fence with regards to using it. Especially since OP was using it with pump gas, so there was no other source of in-cylinder cooling or octane to prevent knock. I’ve said from the start I find it hard to believe the turbos are directly or at all responsible.

[Jeff@TopGearSolutions]

Originally Posted by enrita

Thats what happens when u run aggressive with meth. Its always either cyl 2 or 5. Injector is NOT the issue.

Are you leading us to believe that meth distribution may be the issue?

**

Stratos, very sorry for your loss. I know you put a lot of money, time and effort into your car. If there is anything you need let me know.

[boost junkie]

Originally Posted by Jeff@TopGearSolutions

Are you leading us to believe that meth distribution may be the issue?

If you're not doing port meth injection then how could you be sure? I certainly wouldn't trust the intake manifold to evenly distribute it accurately.

[BavarianBullet]

Sorry to see the engine blew.

It's just a cracked piston crown like a lot of the failures. Could be a lot of things but at that performance level, things can and will happen.

The piston looks like it does because you drove on it for a while. It won't take long for combustion gas from a big crack like that to melt the piston and rings.

One thing to watch out for is that the piston parts probably exited out the exhaust valve and likely hit the turbine on the turbo on that cylinder. I'd definitely send at least that one back to RB or pull the CHRA out of the exhaust manifold and look at it real close. A dinged turbine will be unbalanced and could toast when you reinstall it. Better safe than sorry.

[Jeff@TopGearSolutions]

Originally Posted by boost junkie

If you're not doing port meth injection then how could you be sure? I certainly wouldn't trust the intake manifold to evenly distribute it accurately.

I'm not necessarily disagreeing.
Even port meth injection has it's failure points though I.E. Clogged nozzle

That's why methanol will always be a band aid for power and fueling. I dont want to count the chickens before they hatch though.

[Dave W.]

Originally Posted by boost junkie

If you're not doing port meth injection then how could you be sure? I certainly wouldn't trust the intake manifold to evenly distribute it accurately.

It's difficult to know the meth distribution for sure, but we do know that there are many users running meth injection with nozzles in the charge pipe and there are very few engine failures due to meth, so we can assume the distribution is adequate for the majority of users, unless this kit had the nozzle mounted too close to the throttle body.


Which makes me wonder if there were other factors that contributed to this engine failure? Maybe it wasn't one cause, but a few that wouldn't break an engine by itself but if they happened together it might be enough. I find it odd that the failure point is alongside the pin. Usually a piston comes apart at the intake or exhaust side. Was the engine overheated? Any trouble with the water pump?

[buster84]

Originally Posted by Dave W.

It's difficult to know the meth distribution for sure, but we do know that there are many users running meth injection with nozzles in the charge pipe and there are very few engine failures due to meth, so we can assume the distribution is adequate for the majority of users, unless this kit had the nozzle mounted too close to the throttle body.


Which makes me wonder if there were other factors that contributed to this engine failure? Maybe it wasn't one cause, but a few that wouldn't break an engine by itself but if they happened together it might be enough. I find it odd that the failure point is alongside the pin. Usually a piston comes apart at the intake or exhaust side. Was the engine overheated? Any trouble with the water pump?

Just thought i'd also toss out the idea that this could be a simple manufacturing defect that started out small, but overtime wore down and the increased load didnt help. It could also be meth, but with most engine failures its really hard to say what happened unless its a broken rod, broken heads ect...

Honestly, If your running meth your chances of having your engine catch on fire is probably much higher than your engine blowing (at least on stock turbos, but running lean can blow anything). I'd be worried more about the car catching on fire before anything else. Thats why i wont touch meth. I don't care if its in the trunk; It's a fire hazard no matter how you look at it. You wouldn't stick a giant propane container 1-5 feet from your house would you? Although totally different concept it still falls under the category of a fire hazard. And YES I do realize that a trunk mount kit is very unlikely to catch fire, but that still doesn't change the fact that whats inside that container is a fire hazard.

Sorry OP about your engine failure, but why buy a replacement? Why not take this opportunity to Bore it to fix those cylinder wall scrapes and install new forged pistons and rods to match the bore? I know our crank is forged, but not sure about the rods?

[stratos_335]

Originally Posted by Tzu

IMO looks like a material or casting defect, or possibly fatigue but not likely given how many other engines are subject to worse torture on this forum. If you'd like some fractography, send the piston to my lab and I'll let them have a gander.

Hi Tzu,

I've studied advanced fracture mechanics and if you can help me with some fractography and SEM photos then we could determine if it is a material failure or caused from something else.

Once I'll have my engine running, I'll let you know.

Originally Posted by turb0mike

Welcome to the club...

Honestly, I never read engine failure threads. I thought it would never happen to me.

Originally Posted by 135Pats

I just hope we can figure whether meth caused this. You just don’t see N54 pistons exploding like that often, and sadly meth seems to be involved in most of these blown motor threads. To be clear- I am NOT suggesting a causal relationship here, just pointing out what appears to be a common link. If it was an injector that suddenly stopped flowing, you’d think the DME would shut down the cylinder right away. But it only takes a second for things to go wrong in this scenario.

There are dozens and dozens of people running RBs for several years now, I’ve never gotten the sense that the turbo design could cause excessive EGT or backpressure, leading to block damage. Anyone can blow up a motor if they get the tuning wrong, but it doesn’t sound like OP’s tuning was particularly aggressive or unique. Either way, have a tough time believing the turbos are to blame.

Man this thread is a bummer….IDK.

Originally Posted by boom

If the injector stopped flowing, there wouldn't be fuel in the cylinder. No fuel = no combustion = no detonation. If the injector stuck open, the cylinder would hydrolock or at least run pig rich. Either way it would have shown up in the DME as an error with the mixture.
Weird incident. Good luck.

Thanks. I'll have my injectors checked once I finish with the repair.

Originally Posted by enrita

Thats what happens when u run aggressive with meth. Its always either cyl 2 or 5. Injector is NOT the issue.

Hi enrita. Please define why cyl 2 and 5 are more prominent to failure. Thanks

Originally Posted by cn555ic

That for sure doesnt look like a melted piston. What were the circumstances that lead to the smoke.. Were you doing a run or driving spirited minutes prior to the first sign of the exhaust smoking?

No, I was cruising when the failure occurred. I was always pre-heating engine and oil before boosting hard. It just started smoking like a train and then on a short low boost acceleration the piston failed.

Originally Posted by Tzu

What map were you running? Were you using the backend flash?

I was running procede Rev. 3 aggressive maps for upgraded turbos for the last 9000 km when new turbos were installed. I didn't use backend flash although I wanted to. I was ready for a custom reflashing but the engine failed.

Originally Posted by N8N

Interested to see results of testing injectors too... seems that when they go bad they leak, not stop flowing - that's what happened to me. and no, no codes then either, just a rough idle and black spark plug.

Hopefully, you noticed it soon. No DME codes whatsoever?

Originally Posted by Tiago@VRSF

Just goes to show that you should absolutely run a custom map on any upgraded turbo as well as have some sort of AFR monitoring to prevent this from happening.

As soon as I get the car back on the road, I'll have my DME custom reflashed and use some wideband gauges for monitoring the AFR

Originally Posted by Jeff@TopGearSolutions

Are you leading us to believe that meth distribution may be the issue?

**

Stratos, very sorry for your loss. I know you put a lot of money, time and effort into your car. If there is anything you need let me know.

Thanks Jeff. You've helped me a lot tunning my car. I have invested a lot of money but tunning an engine so hard may lead to such a failure.

If I need anything, I'll contact you the soonest possible.



As for the poster asking why not rebuilding my engine.... cyl 2 sleeve is damaged. There are to ways repairing it. Machining and honing and then use 84.5 mm lower compression pistons and forged rods.

The other option is removing the sleeve, order and install a new sleeve and then use OEM pistons or forged aftermarket pistons.

Either way, I will have an unreliable engine. This is my daily driven car. If I could have this car for racing use only, I would go with repairing it.

I'll try the low mileage used engine option, although it costs as much as rebuilding the old engine. Same engine, lower boost, more OEM and secure feeling.



Something else. N54 is an open-deck engine. I am an owner of a machine shop and I manufacture every day new parts for heavy industry, so I have equipment for measuring dimensions accurately.


I measured all the cylinder bores. At the middle of the cylinder, all bores were 84.00 mm. At the bottom all cylinders were 84.01 mm dia. At the top of the cylinder, all were 84.02 except of one cyl which was 84.03 mm dia.

Hell, all cylinders were expanded and had an oval or egg shape at the top. This is an open deck engine. All cylinder walls are so thin and the sleeves inside them are much thiner.

Maybe this engine is not designed for that power. Expansion of all cylinders? Come on.

For these power levels, this should have been a closed deck engine or built it as such. Maybe heat dispersion would be more difficult, but pushing and boosting this engine so hard made the cylinders expand.

Alpina uses lower compression pistons, 9.4:1 i think.

[stratos_335]

Something else. I was using NGK spark plugs gapped to 0.022" or 0.55 mm. Lowering the gap, it is more possible detonation to occur. Do you think spark plugs were involved to this failure?