Start and drive
01-25-2015, 03:24 AM
#1
Instructor
Thread Starter
Start and drive
Does anyone know why 991 gt3 manual recommends that once the car is started it should immediately be driven. why can't it idle for a bit. i'm pretty sure this is recommended for all 911s and there is a great reason. I would love to know why!
thanks
thanks
01-25-2015, 04:55 AM
#2
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I don't know why, but one plausible explanation is that you can never warm-up the engine adequately just by a few minutes of idling (I am sure there are other reasons). As far as I recall this has been a recommendations for most if not all Porsche cars (I don't know about hybrids or 356's, 904's), and not exclusive to 991 GT3.
01-25-2015, 07:40 AM
#3
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This is valid for All cars not just for Porsche
most drivers ignore that having a warm engine and cold trasmission is mech not good
so in any car start and drive warming engine And trasmission very gentle
most drivers ignore that having a warm engine and cold trasmission is mech not good
so in any car start and drive warming engine And trasmission very gentle
01-25-2015, 10:30 AM
#6
Three Wheelin'
Idle does not fully oil all surfaces I believe.
01-25-2015, 10:51 AM
#7
I was always under the opinion that engines like loading (not revs when cold). This start and go with low RPM but loading where possible used to prevent "cylinder glazing". In my younger days as a diesel mechanic when we built a new (refurbished) engine and put it on the dyno to run in, we loaded the engine with low rpm right from the get go to prevent glazing. This is the way I have driven all my cars, my thoughts might be misplaced with the new engine standards and oil etc, happy to be corrected
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01-25-2015, 11:37 AM
#8
I was always under the opinion that engines like loading (not revs when cold). This start and go with low RPM but loading where possible used to prevent "cylinder glazing". In my younger days as a diesel mechanic when we built a new (refurbished) engine and put it on the dyno to run in, we loaded the engine with low rpm right from the get go to prevent glazing. This is the way I have driven all my cars, my thoughts might be misplaced with the new engine standards and oil etc, happy to be corrected
Really can't warm an engine by idling only...needs load on it
My routine: Idle for ~30 sec (close garage door, belts, mirrors, etc.), drive slowly through neighborhood putting car under load. Drive at moderate rpm until engine is FULLY warm (i.e. oil temp 180+). To me, worst thing one can do is hammer a cold engine.
Bill
01-25-2015, 01:37 PM
#9
+1
Really can't warm an engine by idling only...needs load on it
My routine: Idle for ~30 sec (close garage door, belts, mirrors, etc.), drive slowly through neighborhood putting car under load. Drive at moderate rpm until engine is FULLY warm (i.e. oil temp 180+). To me, worst thing one can do is hammer a cold engine.
Bill
Really can't warm an engine by idling only...needs load on it
My routine: Idle for ~30 sec (close garage door, belts, mirrors, etc.), drive slowly through neighborhood putting car under load. Drive at moderate rpm until engine is FULLY warm (i.e. oil temp 180+). To me, worst thing one can do is hammer a cold engine.
Bill
01-25-2015, 01:48 PM
#10
I've been surprised at how quickly the 991 GT3's oil and water temps come up. Even on cold mornings (+/- 34 F), after gentle warm-up driving, my temps are up in between 5 to 10 minutes. The 997 TTS seemed to take much longer.
01-25-2015, 01:53 PM
#11
Rennlist Member
Usually need 10-15 second idling to pump the oil through the system, then drive.
I remember from my Honda accord manual back in 1990s. It asked to drive the car right after the start to get the engine temperature up quickly and decrease fuel consumption. The latter was the main reason given by the Honda manual.
I remember from my Honda accord manual back in 1990s. It asked to drive the car right after the start to get the engine temperature up quickly and decrease fuel consumption. The latter was the main reason given by the Honda manual.
01-25-2015, 02:49 PM
#13
It's actually illegal in Germany to start your car and let it sit to warm up. So the manual may just reflect this. I think it's illegal in CO now, don't know of any other states.
01-25-2015, 07:04 PM
#14
Instructor
I think that it's also emissions related. The catalytic converter is not as effective when cold. Driving, with some load, warms it up more quickly. I'm pretty sure that reduces the total emissions. The manufacturers used to run a very rich mixture to heat the converters more quickly. I expect CAFE make that less prevalent.
Scott
Scott