HSV Dyno day Oct SRR
Discussion
Agree with stevieturbo and wormus ref the turbo possiblity....I'd be looking carefully at the turbo oil drain setup too.
If it is gravity drain, the pipes need to be vertical from the turbo's and if they enter the sump horizontally
then the 90 deg bend radius be nice and large, also the entry point be above the oil level in the sump.
The turbine seals are not actually seals, more like little piston rings, gapped or if you are lucky step gapped.
IMHO is about the differential pressure either side of the rings which stop the oil leaking past, relative positive
pressure on the exhaust side compared to the turbine side. Positive crankcase pressure (if engine cannot breath...)
can upset the balance.
Experience with the turbo setup on the LC's has shown that positive crank case pressure will make oil leak past
the seals and burn in the down pipes, but, curiously with the LC this happens mostly at tick over. It's been
found that creating even a very small amount of vacuum in the sump has eliminated completely the smoking at idle.
Not saying this is your problem, but something to consider........
If it is gravity drain, the pipes need to be vertical from the turbo's and if they enter the sump horizontally
then the 90 deg bend radius be nice and large, also the entry point be above the oil level in the sump.
The turbine seals are not actually seals, more like little piston rings, gapped or if you are lucky step gapped.
IMHO is about the differential pressure either side of the rings which stop the oil leaking past, relative positive
pressure on the exhaust side compared to the turbine side. Positive crankcase pressure (if engine cannot breath...)
can upset the balance.
Experience with the turbo setup on the LC's has shown that positive crank case pressure will make oil leak past
the seals and burn in the down pipes, but, curiously with the LC this happens mostly at tick over. It's been
found that creating even a very small amount of vacuum in the sump has eliminated completely the smoking at idle.
Not saying this is your problem, but something to consider........
rich24v said:
Agree with stevieturbo and wormus ref the turbo possiblity....I'd be looking carefully at the turbo oil drain setup too.
If it is gravity drain, the pipes need to be vertical from the turbo's and if they enter the sump horizontally
then the 90 deg bend radius be nice and large, also the entry point be above the oil level in the sump.
The turbine seals are not actually seals, more like little piston rings, gapped or if you are lucky step gapped.
IMHO is about the differential pressure either side of the rings which stop the oil leaking past, relative positive
pressure on the exhaust side compared to the turbine side. Positive crankcase pressure (if engine cannot breath...)
can upset the balance.
Experience with the turbo setup on the LC's has shown that positive crank case pressure will make oil leak past
the seals and burn in the down pipes, but, curiously with the LC this happens mostly at tick over. It's been
found that creating even a very small amount of vacuum in the sump has eliminated completely the smoking at idle.
Not saying this is your problem, but something to consider........
As above, the piston rings are more to prevent turbine or compressor pressure entering the centre housing, than to prevent oil escaping.If it is gravity drain, the pipes need to be vertical from the turbo's and if they enter the sump horizontally
then the 90 deg bend radius be nice and large, also the entry point be above the oil level in the sump.
The turbine seals are not actually seals, more like little piston rings, gapped or if you are lucky step gapped.
IMHO is about the differential pressure either side of the rings which stop the oil leaking past, relative positive
pressure on the exhaust side compared to the turbine side. Positive crankcase pressure (if engine cannot breath...)
can upset the balance.
Experience with the turbo setup on the LC's has shown that positive crank case pressure will make oil leak past
the seals and burn in the down pipes, but, curiously with the LC this happens mostly at tick over. It's been
found that creating even a very small amount of vacuum in the sump has eliminated completely the smoking at idle.
Not saying this is your problem, but something to consider........
The oil setup should never see oil get to the piston ring in the first place.
stevieturbo said:
rich24v said:
Agree with stevieturbo and wormus ref the turbo possiblity....I'd be looking carefully at the turbo oil drain setup too.
If it is gravity drain, the pipes need to be vertical from the turbo's and if they enter the sump horizontally
then the 90 deg bend radius be nice and large, also the entry point be above the oil level in the sump.
The turbine seals are not actually seals, more like little piston rings, gapped or if you are lucky step gapped.
IMHO is about the differential pressure either side of the rings which stop the oil leaking past, relative positive
pressure on the exhaust side compared to the turbine side. Positive crankcase pressure (if engine cannot breath...)
can upset the balance.
Experience with the turbo setup on the LC's has shown that positive crank case pressure will make oil leak past
the seals and burn in the down pipes, but, curiously with the LC this happens mostly at tick over. It's been
found that creating even a very small amount of vacuum in the sump has eliminated completely the smoking at idle.
Not saying this is your problem, but something to consider........
As above, the piston rings are more to prevent turbine or compressor pressure entering the centre housing, than to prevent oil escaping.If it is gravity drain, the pipes need to be vertical from the turbo's and if they enter the sump horizontally
then the 90 deg bend radius be nice and large, also the entry point be above the oil level in the sump.
The turbine seals are not actually seals, more like little piston rings, gapped or if you are lucky step gapped.
IMHO is about the differential pressure either side of the rings which stop the oil leaking past, relative positive
pressure on the exhaust side compared to the turbine side. Positive crankcase pressure (if engine cannot breath...)
can upset the balance.
Experience with the turbo setup on the LC's has shown that positive crank case pressure will make oil leak past
the seals and burn in the down pipes, but, curiously with the LC this happens mostly at tick over. It's been
found that creating even a very small amount of vacuum in the sump has eliminated completely the smoking at idle.
Not saying this is your problem, but something to consider........
The oil setup should never see oil get to the piston ring in the first place.
monkfish1 said:
Vixpy1 said:
Don't think its turbo seals as it would show on boost, it was only at idle and on overrun.
Thanks to everyone who came, hope your all enjoyed our new premises.
Also zero crankcase pressure under full boost. Checked and checked again. Thanks to everyone who came, hope your all enjoyed our new premises.
monkfish1 said:
GaryNoGrip said:
Roger said it was -9 as he had it on his laptop, filled up at texaco instead of shell this week, most likely culprit so project empty fuel today
-9 degrees knock retard on top of the 2 or so lost due to high IAT. Cars are tuned for a specific octane mate. Thats why they all recommend a specific rating.
9 degrees is a lot. FI on stock NA compression isnt a good recipe, its a compromise which more people are realising. This illustrates nicely the concept of being knock limited.
All FI setups on stock engines are knock limited. Even with no knock registered power gains are limited by the fact that timing is reduced to avoid knock.
Therefore timing moves further and further away from Mean Best Timing (MBT)
Running hightest octane possible will help a bit, but it cant fix a fundamentally limited configuration.
9 degrees is a lot. FI on stock NA compression isnt a good recipe, its a compromise which more people are realising. This illustrates nicely the concept of being knock limited.
All FI setups on stock engines are knock limited. Even with no knock registered power gains are limited by the fact that timing is reduced to avoid knock.
Therefore timing moves further and further away from Mean Best Timing (MBT)
Running hightest octane possible will help a bit, but it cant fix a fundamentally limited configuration.
MadMaxHSV said:
monkfish1 said:
Vixpy1 said:
Don't think its turbo seals as it would show on boost, it was only at idle and on overrun.
Thanks to everyone who came, hope your all enjoyed our new premises.
Also zero crankcase pressure under full boost. Checked and checked again. Thanks to everyone who came, hope your all enjoyed our new premises.
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