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Ill be getting a 991 in a couple months (either a 991.1 carerra (either base or s) and a 991.2 base) and currently carpool to NYC with my neighbor that lives about one mile away.
As a result, the 991 will be getting a cold start, driven for a mile, parked all day, then driven home a mile a few times a week (the days he drives).
Do you have any objective or anecdotal evidence that these short trips will pose a problem for the 3.4L/3.8L/3.0 turbo engines in any of these cars? Wondering if perhaps the N/A options would be better for this type of commute.
I am not aware of any objective studies, but dogma is that it takes about 10 min of driving to get the oil temps up and shorter trips are harmful to the engine. However, this cannot be true, for everytime you warm the engine, you have to go through the first mile or so, when the temps are not up and thus theoretically you are harming the engine.!
My advise would be to not rev the engine above 4000 rpm, you should be ok otherwise.
I do the type of driving you are describing a couple times per week. I primarily work from home and some days its just a quick trip to the coffee shop and back. So far no issues (991.1S) but I do drive the car quite hard on the weekends to help offset the quick trips around town.
IMO, the NA motors need to be opened up fairly often for the best continued performance and longevity. I can't prove it but I believe a lot of the "stumble" type issues owners report are due to them not pushing the cars enough.
Yeah, you can do lots better in high end bicycles--or get something equivalent for less. Bikes with prestige brand logos stuck on them are like mediocre cars with clothing designer branding--purely image, and usually snickered at by those who know bikes (or cars).
Where are you going to park this car before getting into the carpool? What are you going to do in the winter? How about just leaving the 911 home and buying a used Subaru for this daily 2mi trip?
I am not an engineer (but sure worked with many, and play at amateur auto mechanic at home). What I understand about frequent, short trips:
1. Much (maybe most) physical engine wear happens right after cold starts. So 1000 miles in a single drive causes much less wear than 100 ten mile trips (or in your case, 1000 one mile trips).
2. Engines that do not fully warm up tend to leave condensation of water and other compounds in the exhaust, and also in the engine oil. This leads to degraded oil sooner, and maybe accelerated corrosion in the exhaust.
I am not an engineer (but sure worked with many, and play at amateur auto mechanic at home). What I understand about frequent, short trips:
1. Much (maybe most) physical engine wear happens right after cold starts. So 1000 miles in a single drive causes much less wear than 100 ten mile trips (or in your case, 1000 one mile trips).
2. Engines that do not fully warm up tend to leave condensation of water and other compounds in the exhaust, and also in the engine oil. This leads to degraded oil sooner, and maybe accelerated corrosion in the exhaust.
Others can weigh in.
Also, not reaching operating temps for the engine contributes to fuel dilution in oil.
Thanks guys. I appreciate the input. Keeping it under 4K rpm seems like a good idea.
Sorry if it's a pathetic question haha, I've seen several threads in this board where people will be describing and issue and say "I always let my 911 warm up fully before driving etc etc." -
I currently dd a mk7 gti - and could keep it - but really the only reason to keep it would be for this small little commute and the perhaps 5 snowy days a year here.
Re: walking and biking comments sounds good in practice, but his house is basically straight uphill from mine and I have to wear a suit every day so that's not really a viable solution.
I tend to agree that it’s probably the worst thing you can do in terms of accelerated wear and internal corrosion, turbo or not.
Appears to be an ideal use case for a cheap electric car!
[anecdote]I bought a car many years ago, one careful lady owner, etc. (actually true) and within six months it had broken down. On disassembly, there was rust in various places inside the engine including the crank, half the oilways were obstructed and the end result was a cracked block and a write-off. Found out later that each mile on the odometer equated to two journeys from a cold start...[/anecdote]
I tend to agree that it’s probably the worst thing you can do in terms of accelerated wear and internal corrosion, turbo or not.
Appears to be an ideal use case for a cheap electric car!
[anecdote]I bought a car many years ago, one careful lady owner, etc. (actually true) and within six months it had broken down. On disassembly, there was rust in various places inside the engine including the crank, half the oilways were obstructed and the end result was a cracked block and a write-off. Found out later that each mile on the odometer equated to two journeys from a cold start...[/anecdote]
Only driven on Sundays, and only a quarter of a mile at a time!
My advise would be to not rev the engine above 4000 rpm, you should be ok otherwise.
Good advice - but incomplete.
You want to avoid stressing the engine in general, so that means no lugging at very low RPMs and generally using very little throttle. I'd rather have a cold engine at 5000 RPM light throttle than 2000 RPM with a lot of throttle.
I like to keep it between 2 and three grand with very gently throttle use, keeps the loads on the components nice and low. It does mean using the PDK in manual as the eco-minded TCU software likes to shift ridiculously low.
08-18-2017, 06:25 PM
Daily Driver - very short trips bad for engine?
