25-12-2012, 10:50 PM
Right before I strap my knee up and get under the car, I want to pose a few questions about what could have popped this time with the motor.
What basically happened was I was pulling onto the motorway in 3rd from 2krpm up to about 4.5-5krpm, as if I was doing a 30-70 run. As it hit the higher end of the rev range I heard a bang/pop noise, like a blown boost hose, and black smoke billowed out everywhere to the point I couldn't see outside the car.
Pulled over, engine was still idling, so I knew it wasn't a rod being spat or a lack of compression. There was reek up the rear bumper and oil in the exhaust, and a puddle of oil forming below the back of the block. The oil feed looked ok, was dry, and the top half of the turbo looks clean.
The underside, it's hard to tell, but the back of the block and the underside of the turbo are oily. The engine lost enough oil to go from the max line to under the min line but there's still just enough in the sump to register on the dip stick.
When the engine idles, you can see oil dripping from somewhere at the back of the block but iirc no real amount of smoke, no more than cold veg startup anyway, the occasional white puff.
My thoughts are either oil seals on the hotside of the blower or oil return line blowing off/splitting.
Reasoning?
Inlet pipes are clean so the coldside is fine, from my experience if one seal goes that badly, the impeller shaft is knackered and takes the other side out too. No oil in cold side.
If hotside seals go, oil comes pouring out the exhaust. The exhaust IS oily, but I wouldn't say drenched. If turbo oil pressure was that high it destroyed the seals, the whole thing would have been flooded as an engine can be emptied of several litres in seconds with the oil pressure.
Oil is down the back of the block and the underside of the turbo. In my head, if i'd got the oil return wrong, pressure could have built up and blown the oil return pipe. I didn't measure the pipe diameter scientifically but it was definitely a bigger bore than the T2 line. The layout seems to be unrestrictive too and i'd have expected smoke before a blowout of all the oil if it was restrictive and caused a buildup of oil.
I'm just wondering if excessive boost has blown the turbo, but I can't explain why oil is both on the outside of the turbo/engine, and down the exhaust and under the rear bumper. Unless travelling at 70mph*ish has caused oil to be dragged along under the car with the airflow.
Suggestions?
I'm hoping it's not another turbo as from my setup, the only thing I could think would be excessive pressure but it peaked at just over 30psi and the turbo was in good nick before fitting, i'd hope it would last longer than 10 seconds at high psi, even at that pressure.
FYI, it was being run de-wg with no actuator while I was waiting on a billet actuator being fitted. This was the first run I had it over 20psi as i'd been cautious on its few outings with it being wet and SO MUCH TORKZ. y0.
Sorry, /essay. Need to figure out what went wrong and why though.
What basically happened was I was pulling onto the motorway in 3rd from 2krpm up to about 4.5-5krpm, as if I was doing a 30-70 run. As it hit the higher end of the rev range I heard a bang/pop noise, like a blown boost hose, and black smoke billowed out everywhere to the point I couldn't see outside the car.
Pulled over, engine was still idling, so I knew it wasn't a rod being spat or a lack of compression. There was reek up the rear bumper and oil in the exhaust, and a puddle of oil forming below the back of the block. The oil feed looked ok, was dry, and the top half of the turbo looks clean.
The underside, it's hard to tell, but the back of the block and the underside of the turbo are oily. The engine lost enough oil to go from the max line to under the min line but there's still just enough in the sump to register on the dip stick.
When the engine idles, you can see oil dripping from somewhere at the back of the block but iirc no real amount of smoke, no more than cold veg startup anyway, the occasional white puff.
My thoughts are either oil seals on the hotside of the blower or oil return line blowing off/splitting.
Reasoning?
Inlet pipes are clean so the coldside is fine, from my experience if one seal goes that badly, the impeller shaft is knackered and takes the other side out too. No oil in cold side.
If hotside seals go, oil comes pouring out the exhaust. The exhaust IS oily, but I wouldn't say drenched. If turbo oil pressure was that high it destroyed the seals, the whole thing would have been flooded as an engine can be emptied of several litres in seconds with the oil pressure.
Oil is down the back of the block and the underside of the turbo. In my head, if i'd got the oil return wrong, pressure could have built up and blown the oil return pipe. I didn't measure the pipe diameter scientifically but it was definitely a bigger bore than the T2 line. The layout seems to be unrestrictive too and i'd have expected smoke before a blowout of all the oil if it was restrictive and caused a buildup of oil.
I'm just wondering if excessive boost has blown the turbo, but I can't explain why oil is both on the outside of the turbo/engine, and down the exhaust and under the rear bumper. Unless travelling at 70mph*ish has caused oil to be dragged along under the car with the airflow.
Suggestions?
I'm hoping it's not another turbo as from my setup, the only thing I could think would be excessive pressure but it peaked at just over 30psi and the turbo was in good nick before fitting, i'd hope it would last longer than 10 seconds at high psi, even at that pressure.
FYI, it was being run de-wg with no actuator while I was waiting on a billet actuator being fitted. This was the first run I had it over 20psi as i'd been cautious on its few outings with it being wet and SO MUCH TORKZ. y0.
Sorry, /essay. Need to figure out what went wrong and why though.
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