996T x50 questions
Discussion
I drove a reputed 550 bhp 996T X50 yesterday and was Very impressed, typical Porsche no fuss does what it says on the tin!
Car certainly went well. I have a couple of questions and would appreciate any knowledgeable replies.
On cold start up, the left bank exhaust omitted a small amount of oil smoke, possibly the turbo bearing seal?
On hot start a small amount of black smoke, as if overly rich on the same side only.
When I drove it the Max boost on the gauge was 1.0 bar, is this about right?
I am quite tall and could do with the seat back another 1/2”or so from max, anyone else managed to do this with the standard seats?
Very nice car, strangely enough though, I am not sure I might get bored with it as I have sold my Mk 2 Escort rally car retiring from rallying again! But want a car I can still compete in hillclimbs etc, the Porsche would be Very good I am sure, maybe more fun with the front diff removed
cheers
Car certainly went well. I have a couple of questions and would appreciate any knowledgeable replies.
On cold start up, the left bank exhaust omitted a small amount of oil smoke, possibly the turbo bearing seal?
On hot start a small amount of black smoke, as if overly rich on the same side only.
When I drove it the Max boost on the gauge was 1.0 bar, is this about right?
I am quite tall and could do with the seat back another 1/2”or so from max, anyone else managed to do this with the standard seats?
Very nice car, strangely enough though, I am not sure I might get bored with it as I have sold my Mk 2 Escort rally car retiring from rallying again! But want a car I can still compete in hillclimbs etc, the Porsche would be Very good I am sure, maybe more fun with the front diff removed
cheers
White smoke is fiarly normal on start up, so long as it's only for a few seconds and isn't on every single start up. You might get it once a week, depending on usage? You get oil settling in the cylinders and / or Turbo's, this burns off on start up.
Black smoke from a hot start, I've never had in 5 years. So that's a new one to me, it could possibly point to a tired Turbo. I had my Turbo's replaced 2 years ago and they weren't smoking on start up, just full boost..........Could point to a few other things as well?
The boost sounds is a little high. I'd expect this to be 0.8, maybe .9 on a standard car. 1 Bar could point to a remap or it may have just been atmospheric and driving conditions at the time. The car will adjust boost to suit conditions.
But 1 bar from standard doesn't sound quite right
Black smoke from a hot start, I've never had in 5 years. So that's a new one to me, it could possibly point to a tired Turbo. I had my Turbo's replaced 2 years ago and they weren't smoking on start up, just full boost..........Could point to a few other things as well?
The boost sounds is a little high. I'd expect this to be 0.8, maybe .9 on a standard car. 1 Bar could point to a remap or it may have just been atmospheric and driving conditions at the time. The car will adjust boost to suit conditions.
But 1 bar from standard doesn't sound quite right
Factory HP for the 996 Turbo S is 450hp. Factory boost level is 0.8 bar. If the engine is indeed putting out 550hp it is a tuned engine. And this would explain then the 1.0 max boost you saw on the boost gage.
A bit of oil smoke at cold start is normal. My 03 Turbo emits some once in a while, a great while.
I am in the car and can't observe the exhaust so I can't say if one side emits more or less smoke than the other.
It could. The oil comes from oil vapor that makes it past/through the AOS and the AOS generally has one connection to the intake and this one connection "favors" one cylinder bank with any oil. Thus upon cold start one or more cylinders of this bank will burn some oil and smoke and of course the smoke will appear from just that bank's exhaust.
However the smoke could be from a turbo seal. IIRC the proper check is to inspect the intake for the presence of oil and to examine the turbo compressor turbine for oil. Oil at this point is a good sign the turbo seal or seals are failing.
Black smoke at startup I have not seen. Generally these engines (all modern engines) are quite well fueled even at cold start and soot from an overly rich mixture is just not seen. To see this from a hot engine at start up is a bit troubling.
However, with a tuned engine who knows?
Generally I recommend a longish road test of the car first as a passenger then as a driver. The route should be around 15 miles in length and give the driver then you a chance to drive the car as you intend to use it, within reason of course. I doubt you'll get a hill climb test drive.
This gives you a chance to experience the car in a variety of scenarios to verify the car, the engine, behave. The Turbo engine should idle without drama, or scary noises, should pull like a freight train on meth up to redline and resume its pulling upon an upshift and then afterwards return to a nice idle like nothing happened. 2nd gear (any gear) should not pop out.
At cold engine start the CEL should come on but go out when the engine fires. This is to confirm the CEL bulb works. Then during and after the test ride/drive the CEL should remain dark because at the DME constantly checked it found nothing amiss.
Now a complication is if the engine is tuned, it probably has an aftermarket DME program present and this may bypass some checks.
It can also raise the RPM's and as a result DME overrev counters can have a scary high number of over revs and these can be in the higher ranges.
Some owners remove the front diff to save weight in the belief its absence will result in an improved track time, or to address the car's feel on the track (or street), or to avoid an expensive replacement should the thing go bad, or because voices in their head told them to.
I haven't done any research to know if there is anything to be truly gained from removing the front diff, but it is removal. GT2 front spindles can be used as part of this process.
Oh, I forgot to mention: After your test ride/drive then you give the car a thorough used car check out. This is followed then by a PPI by someone very familiar with these cars. Among other things this looks for leaks. These can be at the RMS, the water pump, the transmission seals (including the selector shaft seals on the side of the tranny), the rear and front diff axle flange seals, the cardan shaft is not wobbly, the spoiler hydraulics are dry, and about a zillion other checks.
A bit of oil smoke at cold start is normal. My 03 Turbo emits some once in a while, a great while.
I am in the car and can't observe the exhaust so I can't say if one side emits more or less smoke than the other.
It could. The oil comes from oil vapor that makes it past/through the AOS and the AOS generally has one connection to the intake and this one connection "favors" one cylinder bank with any oil. Thus upon cold start one or more cylinders of this bank will burn some oil and smoke and of course the smoke will appear from just that bank's exhaust.
However the smoke could be from a turbo seal. IIRC the proper check is to inspect the intake for the presence of oil and to examine the turbo compressor turbine for oil. Oil at this point is a good sign the turbo seal or seals are failing.
Black smoke at startup I have not seen. Generally these engines (all modern engines) are quite well fueled even at cold start and soot from an overly rich mixture is just not seen. To see this from a hot engine at start up is a bit troubling.
However, with a tuned engine who knows?
Generally I recommend a longish road test of the car first as a passenger then as a driver. The route should be around 15 miles in length and give the driver then you a chance to drive the car as you intend to use it, within reason of course. I doubt you'll get a hill climb test drive.
This gives you a chance to experience the car in a variety of scenarios to verify the car, the engine, behave. The Turbo engine should idle without drama, or scary noises, should pull like a freight train on meth up to redline and resume its pulling upon an upshift and then afterwards return to a nice idle like nothing happened. 2nd gear (any gear) should not pop out.
At cold engine start the CEL should come on but go out when the engine fires. This is to confirm the CEL bulb works. Then during and after the test ride/drive the CEL should remain dark because at the DME constantly checked it found nothing amiss.
Now a complication is if the engine is tuned, it probably has an aftermarket DME program present and this may bypass some checks.
It can also raise the RPM's and as a result DME overrev counters can have a scary high number of over revs and these can be in the higher ranges.
Some owners remove the front diff to save weight in the belief its absence will result in an improved track time, or to address the car's feel on the track (or street), or to avoid an expensive replacement should the thing go bad, or because voices in their head told them to.
I haven't done any research to know if there is anything to be truly gained from removing the front diff, but it is removal. GT2 front spindles can be used as part of this process.
Oh, I forgot to mention: After your test ride/drive then you give the car a thorough used car check out. This is followed then by a PPI by someone very familiar with these cars. Among other things this looks for leaks. These can be at the RMS, the water pump, the transmission seals (including the selector shaft seals on the side of the tranny), the rear and front diff axle flange seals, the cardan shaft is not wobbly, the spoiler hydraulics are dry, and about a zillion other checks.
Edited by Rockster on Thursday 6th November 16:58
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