[greasypeanut]

So others have said that it's more a n54 problem not a n55 issue. But is that just because the n54 is older? What has changed between the two?

[//M]

Originally Posted by look585

OK sir you're the genius. I'm not going to argue with you.
What proof do you need? You know everything 1000%

Well your wrong so there's that.

Most race engines are not direct injection and the ones that are don't have to recycle the oil Vapors the same way we do that's why they don't have build up. Nothing from tracking your car will prevent carbon buildup on the intake valves on a BMW N series or newer S Series engine. Period.

[KevM2]

Originally Posted by greasypeanut

So others have said that it's more a n54 problem not a n55 issue. But is that just because the n54 is older? What has changed between the two?

Originally Posted by greasypeanut

So others have said that it's more a n54 problem not a n55 issue. But is that just because the n54 is older? What has changed between the two?

That's a very question to which nobody seems to have a good answer... the n55 has been around in other cars for about 9-10 years...guys at Burgertuning tested the n55 in the M2 with catch cans and didn't find any accumulation... that may be just one factor... but I suspect that as the n55 gets older then it becomes more of an issue but still much less than the n54

[look585]

Originally Posted by tifosielia

Well your wrong so there's that.

Most race engines are not direct injection and the ones that are don't have to recycle the oil Vapors the same way we do that's why they don't have build up. Nothing from tracking your car will prevent carbon buildup on the intake valves on a BMW N series or newer S Series engine. Period.

[KevM2]

Did CRC valve cleaning as per instructions by spraying into the hole where the manifold absolute pressure sensor sits close to the throttle body… after 1 hour heat soak, took it for the 10 min highway drive and went into limp mode with a bunch of knock and super knock errors….

I suspect my spray may have accumulated into the charge pipe away from where throttle body sits…. Will try to see if I can suck out anything from the charge pipe… but the CRC fluid should evaporate over a day or so anyways…

Anyone have any insights about this?

[F87source]

Originally Posted by KevM2

Did CRC valve cleaning as per instructions by spraying into the hole where the manifold absolute pressure sensor sits close to the throttle body… after 1 hour heat soak, took it for the 10 min highway drive and went into limp mode with a bunch of knock and super knock errors….

I suspect my spray may have accumulated into the charge pipe away from where throttle body sits…. Will try to see if I can suck out anything from the charge pipe… but the CRC fluid should evaporate over a day or so anyways…

Anyone have any insights about this?

I probably wouldn't have done that if I were you because even if the procedure did work alot of carbon could've fallen directly into the cylinders which is never good for the combustion chamber as the pistons would grind against that. Super knock is also extremely detrimental to the pistons and the rod bearings, especially under high load.


Anyways, all said and done, I would probably pull the charge pipe off over night to let the fluid evaporate. Then I would drive the car for an hour to ensure enough air flows through the induction system to fully dry everything up. Then it's time for an oil change to prevent oil contamination, because there's a chance the CRC could've went into the combustion chamber and slipped past the piston rings and entered the oil supply. Or contaminated the oil film in the combustion chamber and that eventually ends up in the oil.

[KevM2]

Originally Posted by F87source

I probably wouldn't have done that if I were you because even if the procedure did work alot of carbon could've fallen directly into the cylinders which is never good for the combustion chamber as the pistons would grind against that. Super knock is also extremely detrimental to the pistons and the rod bearings, especially under high load.


Anyways, all said and done, I would probably pull the charge pipe off over night to let the fluid evaporate. Then I would drive the car for an hour to ensure enough air flows through the induction system to fully dry everything up. Then it's time for an oil change to prevent oil contamination, because there's a chance the CRC could've went into the combustion chamber and slipped past the piston rings and entered the oil supply. Or contaminated the oil film in the combustion chamber and that eventually ends up in the oil.

Yeah I hear you. I'm pretty bummed out by it. Hoping nothing got damaged. The absolute boost pressure sensor was soaked in that CRC stuff when I removed it so that maybe have also caused the super knock I'm guessing.

[F87source]

Originally Posted by KevM2

Yeah I hear you. I'm pretty bummed out by it. Hoping nothing got damaged. The absolute boost pressure sensor was soaked in that CRC stuff when I removed it so that maybe have also caused the super knock I'm guessing.

Yeah I hope your car is ok too.

I doubt the TMAP being soaked in CRC caused the super knock because lets say the wet sensor could not read boost properly, the car would likely limp out with boost pressure implausibility (WGDC being very high, but boost being super load, and fuel trims and afrs being all off) long before it caused damage. However what I think happened was the CRC got into the combustion chamber and ignited before the gasoline did under the heat and compression, and this caused the super knock - and this is really really really bad for the engine (can crack pistons and spin bearings) particularly under load.


So I guess my next question was were you under high load and high rpm? If not then you should be ok. If you were under high load then it is a bigger risk of engine damage, but I would not jump to conclusions because bmw engines are quite stout.



Anyways my advice would be pull the CP and let the CRC evaporate, drive the car for a bit to force air through the induction tract to remove any residual crc. Then do an oil change, I would do spark plugs too if your super knock occurred during high loads because that can crack plugs. If it wasn't under high load your plugs should be ok.

[///MPhatic]

Originally Posted by KevM2

Did CRC valve cleaning as per instructions by spraying into the hole where the manifold absolute pressure sensor sits close to the throttle body… after 1 hour heat soak, took it for the 10 min highway drive and went into limp mode with a bunch of knock and super knock errors….

I suspect my spray may have accumulated into the charge pipe away from where throttle body sits…. Will try to see if I can suck out anything from the charge pipe… but the CRC fluid should evaporate over a day or so anyways…

Why did you do this? Were you having issues of some sort? What's your mileage?

[KevM2]

Originally Posted by ///MPhatic

Why did you do this? Were you having issues of some sort? What's your mileage?

Only have about 15k miles but I've been hearing of people doing this as part of maintenance to prevent any carbon buildup.

Originally Posted by F87source

So I guess my next question was were you under high load and high rpm? If not then you should be ok. If you were under high load then it is a bigger risk of engine damage, but I would not jump to conclusions because bmw engines are quite stout.

Yeah unfortunately I was at highway speeds in 4th gear just under 3000rpm

[KevM2]

I think this CRC spray has potential to keep the valves clean as long as possible however, the videos on YouTube that show spraying this stuff with an extension tubing are not proper way to do it because it changes the droplets in the spray into liquid and you end up with the liquid pooling down in the charge pipe…. The only way to do this properly is to spray directly into throttle body using the can's own nozzle which is nearly impossible on the N55 if one uses the hole for the MAP

[F87source]

Originally Posted by KevM2

I think this CRC spray has potential to keep the valves clean as long as possible however, the videos on YouTube that show spraying this stuff with an extension tubing are not proper way to do it because it changes the droplets in the spray into liquid and you end up with the liquid pooling down in the charge pipe…. The only way to do this properly is to spray directly into throttle body using the can's own nozzle which is nearly impossible on the N55 if one uses the hole for the MAP

Well I looked up the CRC valve cleaner and it indeed should be a working product because it uses PEA, which is well known for being a very good fuel system cleaner and can clean the carbon deposits on the pistons extremely well. This also affirms my suspicions that you probably should do an oil change after the use of this product as you would with fuel system cleaners, because the PEAs can damage the oil.


However, I still would not use this product, imo I don't think it is a good idea to use this at all, you risk pooling of this liquid in the combustion chamber if it is not fully atomized going in, then you can get super knock events like what you experienced. IMO just leave the car as is, if carbon does build up then the best and safest solution is walnut blasting. If you are really insistent on trying to prevent this issue get an oil catch can, this will take some of the edge off this issue. Also use good quality oil with a low NOACK rating, this will also help.


If you are really worried about this issue then plug your head ports and vent to atmosphere. You can use vent caps and occ's here to prevent the oil smell.

[3LiterBeater]

Coming from experience with Audi and VW products that see many carbon buildup issues, avoid any of the "spray" type cleaners.

They won't breakdown the carbon any noticeable amount. Wait until 80k or so and have it walnut blasted.

As for the "race engines don't need carbon cleaned", I've worked closely with teams who run DFI cars. They all have the same buildup.

[KevM2]

Originally Posted by F87source

Well I looked up the CRC valve cleaner and it indeed should be a working product because it uses PEA, which is well known for being a very good fuel system cleaner and can clean the carbon deposits on the pistons extremely well. This also affirms my suspicions that you probably should do an oil change after the use of this product as you would with fuel system cleaners, because the PEAs can damage the oil.


However, I still would not use this product, imo I don't think it is a good idea to use this at all, you risk pooling of this liquid in the combustion chamber if it is not fully atomized going in, then you can get super knock events like what you experienced. IMO just leave the car as is, if carbon does build up then the best and safest solution is walnut blasting. If you are really insistent on trying to prevent this issue get an oil catch can, this will take some of the edge off this issue. Also use good quality oil with a low NOACK rating, this will also help.


If you are really worried about this issue then plug your head ports and vent to atmosphere. You can use vent caps and occ's here to prevent the oil smell.

So I've cleaned/dried up all the excess CRC fluid from my charge pipe. I pulled out my spark plugs and did a quick Boroscope to check the piston heads.

Just curious as to what you think in terms of some of the fresh looking oil I found on the pistons:

https://www.bimmerpost.com/forums/sh...php?p=29049788

[F87source]

Originally Posted by KevM2

So I've cleaned/dried up all the excess CRC fluid from my charge pipe. I pulled out my spark plugs and did a quick Boroscope to check the piston heads.

Just curious as to what you think in terms of some of the fresh looking oil I found on the pistons:

https://www.bimmerpost.com/forums/sh...php?p=29049788

Carbon build up looks normal, no real signs of concern.

There really shouldn't be oil pooling on the pistons in any quantity, but it's hard to say if it should be a concern without knowing things like compression testing results and oil consumption.