Hi guys, i was having issues related performance (like max. Speed) and i took my car to dyno earlier today. Peak torque is 230NM @3100 and peak power is only 128.5hp @ 5080RPM. It's 110 @ wheels.

Now when dynoing it, at about 3500-4000RPM huge black smoke came outta exhaust and engine popped. Other than that, i checked the engine, nothing is really wrong. I just changed spark plugs, oil, all filters.

So everyone saying it's turbo related? Any other guess? Where should i check if it's the turbo? Thanks.

 

^ sounds like you're misfiring? don't know why though

 

Shouldn't misfire give me a check engine light?

 

No necessarily as I've been getting misfiring occasionally with no codes at all. Once I had huge power loss of the freeway that sounded like multiple misfires and still no codes. You know our engines hp wise would be right at about the hp you're getting without a turbo, I say it's the turbo as well!

A stock Cooper non-turbo is rated for 118 hp, so maybe it's time to pull your turbo and have a look at it! What's your mileage? Turbo seals are most likely the cause of the huge black smoke (oil leaking in turbo) and might be why your turbo is not producing the power is should be.

 

any oil consumption?

 

Yes, there is a minor oil consumption. I'd say quart per 500kms.

There is another problem that might be linked to this. My obc's average consumption says 6.5l/100km but in real life it burns something like 8-8.5 per 100km.

Oil leak to turbo? What should i change to fix that? Turbo pipes?

 

This is the video of dyno, you can see black smoke after 1:40. It happened 2 times coz they tried 2 passes.

 

Did you mean 5000 km (3000 miles)? Because I'd consider 1 qt per 500 km (or 300 miles) is excessive to say the least.

 

Sry, quart per 1000 or, oil change per 4000-5000kms. It surely depends on my driving behaviour but generally i am not really aggresive when driving.

 

I was watching the video and the car makes a strange sound when the black smoke comes out of the exhaust system. Do you know if the sound was coming from the engine or the exhaust? Also what are your EGT temps (bank 1 sensor 2) when the cart is under full boost pressure?

 

I don't really know both of em. But isn't that sound just overrun coming from exhaust?

 

oh sry, i was wrong about quarts, i thought that is quarter so it's 5000kms between full dipstick to min dipstick. sorry about that.

and i also have the dyno sheet now, there are some information but considering it's not a MINI related service, what bothers me is gear ratios. They tried it at 6th and it says, gear ratio of 6 is 1.88 for first pass (which has more torque somehow, but they didn't finished it and stopped it about 4000rpm) and 1.8 for second pass. Is it true? Does it matters?

Either way, I can't take my car to the authorised MINI dealer, they're incredibly pricey, they asked 150 liras (which is about 80 bucks) just for software update last week (i asked for it because of that fuel consumption menu failure i talked about). Considering that, they'll probably ask half of my salary just for diagnosing the problem.

So, I should focus turbo now (i was considering carbon cleaning), but the car is just @ 50k miles and i hope and i believe, problem is not the turbo itself. Where should i focus more? Pipes? Turbo sensors (i really dunno how many i got)?

Oh and there was a problem when I was changing spark plugs, at the closest plug to the chain, there was some oil leaking. Can it be related with this somehow?

 

NO, The noise only seems to happen when the black smoke comes out of the exhaust and not any other time during the pull/s.

The reason I am asking is because most of the time when the car runs rich and blows black smoke out the exhaust there is no noise. I think that there is something else going on that is causing the black smoke. To me it kind of looks like the black smoke or soot that comes out of a Diesel exhaust when the fuel (or fuel oil) is not completely burnt.


Does your car have a catalytic converter? This almost seems like it could be a pre-catalytic converter post turbocharger back pressure issue. The reason I am saying this is because when the black smoke comes out it sounds like something is in the exhaust system and the noise is made as it is sprayed out. If the catalytic converter is clogged it will push oil out the front of the turbocharger and this oil will migrate into the engine when the car is under full boost pressure. And if the oil is making it in to the combustion chamber in liquid form it might be coming out the turbocharger in black vapor like on a diesel engine and the catalytic converter may not be able to burn it all.


On Mini Coopers this starts to happen around 15k klm or miles. The reason has to do to the location of the catalytic converter, since it is so close to the turbocharger it damages the internal turbocharger components. It is the way all turbochargers fail on mini coopers and they usually start to fail around 15k klm or miles. Most of the time the turbochargers that we refurbish have less than 50k klm or miles on them. If you want a more detailed explanation on what causes them to fail and how to prevent it let me know I can add it to the thread.


It is easy to test for back pressure in the exhaust system all that you need is a Snap-on exhaust back pressure gauge. You remove the first O2 sensor and install the gauge than run the car at full boost pressure. If the gauge shows any pressure the catalytic converter and turbocharger will need to be replaced. As little as ½ psi will cause oil to leak out the back of the turbocharger and 5psi will push a large quantity of oil out of the front of the compressor housing and into the inter-cooler.


I don't know if you can get Snap-on tools in Europe so here is a list of symptoms of back pressure. In the mean time I would not recommend driving the car until you test for back pressure in the exhaust system the oil that leaks out of the turbocharger can end up in your combustion chamber and cause engine damage.


Excessive heat in the exhaust system, usually above 1500f.
Exhaust leaks, noise or smell in the cab of the car when the vents are on.
Liquid oil in the inter-cooler.
Erratic map sensor function
Problems with the operation of the throttle plate
unusually large amount of oil consumption
Knock or reduced power due to the timing being retarded because of oil in the engine.
Blue smoke out the exhaust when a catalytic converter test pipe is installed.
Turbocharger failure
Oil on the outside of the turbocharger compressor housing
liquid oil in the intake lines.
Excessive oil coking on the valves.


I might be wrong here but there is no reason for black smoke to make noise, it just doesn’t make sense unless liquid oil is making is way in to the exhaust system.

 

We would all like to know how to prevent what causes the turbochargers to fail on Mini Coopers, much appreciated!

 

I'm having couple of that symptoms. but before that, my car is stock, so it has catalytic converter right?

gasoline or sometimes exhaust smell in the cabin after driving the car hardly.
there is reduced power, but sometimes there are big knocks without any cel, car just pauses for a while, then, a sound comes from exhaust like something just breaks and falls out in there (it happened 3-4 times this year, but it can't be the same thing what happened in dyno 'coz, there is no pause at the sheet), then back to normal. also tc failure (because of the dyno, i wasn't really aware of that), and some oil consumption.

now, i dunno where is that turbocharger compressor housing, but overall, when i'm looking at the engine, there are no oil leaks visible, it's just clean. also nothing dropping to the ground.

either way, it's gonna be pricey eh? what happens if i keep driving the car like this? i'm asking this because it's probably been more than 15k miles since car started to behave down on power.

 

Lets just say it isn't going to be cheap! Why you have been driving it so long is beyond me, I would have taken it in right way when your problems started! Don't drive it, get it looked at!

Just because you don't see oil dripping doesn't mean you're not leaking oil internally inside the turbo.

 

let's say, i wasn't sure about the performance loss, i thought (and my technician) i was just getting used to the car's performance. now, after dyno, i can see what's really happening.

 

The prevention is easy just, idle your car until the EGTs get below 900deg F (about 5 to 10 min) before you turn off your car. Since the catalytic converter is so close to the turbocharger the heat from the catalytic converter soaks into the turbocharger and damages it. Read on for a details description of how and what happens to your engine and turbocharger.


As you may have read or heard people say that the N14 engine is a weak engine due to the pistons cracking. This is actually not the case, the problem and reason for this actually has to due with the new emissions standards. To meet the new emissions standards the catalytic converter was moved about 6” away from the turbocharger. Since the catalytic converter was moved so close to the turbocharger it uses the turbocharger as a heat sink and dissipates heat in excess of 1400f in to it. The catalytic converter can hold the heat for up to 30min after the engine is turned off. This excessive heat cooks the oil in the turbocharger once the oil and coolant stops flowing when the engine is turned off (oil burns at 200f). Mini cooper does turn on an axillary pump to prevent the oil from burning but it only runs for 5min after turning off the engine. 5mins is just not enough since the catalytic converter will still be over 1000deg F.


In the exhaust side of the turbine assembly there is a pressure seal (what people call an oil seal which is a miss-understanding there are no oil seals in a turbocharger just a cavity that allows the oil to flow out faster than it flows in). This seal fills a gap on the turbine shaft that holds a c-clip that when inserted into the turbo bearing housing is compressed into a groove in the turbine shaft. It doesn't touch the turbine shaft once in position it just fills the area in the shaft to prevent exhaust gasses from getting into the engine through the turbocharger.


If the turbocharger is exposed to heat (after the engine is off) oil will burn on the turbine shaft. Over time the burnt oil builds up in the turbine pressure seal C-clip groove and eventually locks the C-clip in place on the shaft. Once this happens the C-clip will start spinning with the shaft and as it spins the shaft will wobble. This wobbling motion will compress the C-clip into the turbine shaft opening up the back of the turbine assembly to the exhaust. This allows exhaust to get into the engine via the turbo when the car is under full boost. Pressure builds in the engine as the exhaust enters through the turbo. When you let off the throttle the pressure in the exhaust decreases and the pressure in the engine escapes through the turbocharger back in to the exhaust carrying large quantity’s of oil with it which burns on the catalytic converter.


When oil enters the catalytic converter it blocks the air flow due to all the particles in the oil and creates back pressure. This “back pressure” pushes the turbine shaft into the thrust bearing causing excessive wear, pushes more oil into the exhaust, and/or into the intake piping. Eventually due to the thrust Bering wear the compressor touches the compressor housing which stops the turbine from spinning or worse completely breaks the turbine shaft.


However before the turbo is damage by the back pressure the back pressure pushes oil into the intake system through the compressor side of the turbo causing other issues. In vapor form it can cause pre-ignition or detonation, and which can and does break the pistons on a turbocharged car. But when liquid oil makes its way into your engine it will enter the chamber increasing the compression ratio or prevent the piston from reaching TDC and it does cause pistons to crack.


I suspect this oil is entering the engine and making the strange noise as it is forced through the catalytic converter. This could be causing the reduced power or the piston could be damaged already. It is hard to say and we wont know until you run the car with a test pipe (test for back pressure or do a compression check)since the catalytic converters do such a good job burning oil in the exhaust system. Sometimes a customer calls thinking that the turbo oil seal is damaged because the car is smoking so badly after a new turbo installation (usually after they get rid of the catalytic converter). Only to find out that the reason or the smoke is the piston is cracked.

I am not saying that this is the cause for the reduce power just check the car out before you do get enough oil to crack a piston.

 

Yes all mini coopers do.


If you can smell gasoline or exhaust in the cab than it is highly likely that you have a back pressure issue. The fact that you can smell gas means that the O2 sensor is sensing a lot of oxygen in the fuel mixture so it will increase the fuel to try to get the mixture right. However do to the extra oil in the system it can not adjust properly and is probably the reason for the knock (since oil doesn't have octane it will lower the flash point of the fuel).


The intake and exhaust system are sealed very well so you usually don't see oil leaking outside of the turbocharger. So most of the time there is no visible sign of back pressure.


Yes it will cost a lot to fix especially since you have to replace the catalytic converter with the turbocharger. If you don't you risk damaging the new turbocharger usually in as little as 2000miles however we have seen some fail instantaneously due to excessive back pressure.

 

Black smoke in small amounts like that is unburned fuel. Could be related to the injector spray pattern, meaning you might have carbon buildup. That could also explain the power loss, although the peak HP you quote seems severely degraded. If you've lost that much power, you should be getting error codes, did you check for codes? Could be related to a failed O2 sensor.

Have you looked at the plugs? Run a compression test?

You're not going to find the cause until you do more diagnostics on that engine.

 

^^nope, no error codes whatsoever, even at the secret menus, nothing. i just changed the plugs like i said before, they are ngk's platinum, so i don't think they are faulty either.

i always thought it was carbon buildup too, considering the quality of the gasoline i'm using, there is definitely carbon buildup. but there is nowhere in turkey can do that walnut shell thingy, they're just doing carbon cleaning, which if what i read is true, is useless on gdi engines. so i don't really have that much option there.

but after what JM Turbo Coopers' said, i'll definitely do every test i can get it done in Ankara. i stopped driving the car today and i'll take it to my technician tomorrow morning, hopefully he can figure it out (i don't think he can though). but it seems like i have to take it to the MINI service after all.

and god help me, if there is cracked piston.

 

did they actually dyno your car in 6th gear?

 

i dunno, it says (on the sheet) 6th gear 1.8 ratio? i'm really not experienced about this topic, so i'm just asking everything i have in my hands.

here is the sheet http://s11.postimg.org/5a9zcwckz/Foto.jpg

now, i don't trust them, they definitely done wrong things, but there is definitely something wrong with the car, i done a top speed run before dyno, and all i can reach was 205kph indicated, considering i reached 240 indicated (middle speedo) 2 years ago, it's obvious.

0-60mph is at 8.3-8.4 seconds btw.

 

The first thing I would do is perform a cylinder leak down test to try to determine the condition of the engine. How many kilometers are on it? Do you allow the turbo and engine to cool off a bit before shutting off the ignition?

While watching your video I noticed the driver was blipping the throttle quite a bit prior to the "black smoke" incident and it is possible that excess fuel built up in the exhaust system and ignited in the exhaust which could explain the noise as well as the black smoke. Although it is not as common for this to happen on today's ultra computer controlled vehicles, if the engine is not healthy and sealed properly internally, then this situation could occur which is why I suggested the CLT.

Good luck with your diagnosis and remedy.

 

it's on 80k kms. allowing the turbo cooling off is a bit complicated topic though, i bought this car when it's 30k, i dunno how it's first owner used it, i always let it cool off for at least 20 secs (i dunno if its enough), then my dad used it for a while, he never does things like that, he just stops the car after parking, that's it.

but the thing about both of us, we never drive the **** out of this car, and then just shut it off, we always drive calmly, it doesn't even passes 2000 rpm that often, even after an aggressive drive, our house is somewhere you have to reach slowly (tight roads, blind junctions, parallel park) so i always thought that last bit of our drive lets the turbo to cool off. i might be wrong about that though, i'm just assuming.