Engine Warm-up???
Newbie
Joined: Nov 2003
Posts: 7
Likes: 0
From: NH
<<Oh for GOD sakes, Toughen up, Kids will live . >>
No reason for them to live with fewer fingers due to frostbite.
<<Throw a jacket and gloves on them for crying out loud. >>
First thing they do when they get in the car is take hat and gloves off.
<<your the reqason for canceling school too when it gets cold but lets the kids go to the mall instead waaaahhhhhhh GODD>>
There ya go making an ASSumption. My kids are 1 and 3, so they aren't actually IN school yet.
And for the record, while your parents were making you 'tough', they made you stupid:
It's 'you're' not 'your', 'reason' not 'reqason' and 'GOD' not 'GODD'.
My point, which you missed, was that there are other reasons to let the engine warm up. Glad you were able to add to the discussion.
No reason for them to live with fewer fingers due to frostbite.
<<Throw a jacket and gloves on them for crying out loud. >>
First thing they do when they get in the car is take hat and gloves off.
<<your the reqason for canceling school too when it gets cold but lets the kids go to the mall instead waaaahhhhhhh GODD>>
There ya go making an ASSumption. My kids are 1 and 3, so they aren't actually IN school yet.
And for the record, while your parents were making you 'tough', they made you stupid:
It's 'you're' not 'your', 'reason' not 'reqason' and 'GOD' not 'GODD'.
My point, which you missed, was that there are other reasons to let the engine warm up. Glad you were able to add to the discussion.
The bearings will not wear prematurely by keeping it under 3000 RPMS or so. It's not that big a deal to drive the car to warm up. Bearing wear is a function of speed and load. This function is also non-linear and goes up substantially when the loads and speeds increase. The difference between 1300-1500 RPM warm-up idle and and driving it at below 3000 RPMS will make a negligible difference. The loads experienced when driving it like this will also be much lower than normal driving. You probably don't use more than 10hp driving it this way.
What everyone is saying is that driving it ever so softly while warming it up is hardly any different from idling to warm up. However, when you warm-up by driving, you warm up up everything at the same time and you don't foul stuff up by idling.
Don't play off soot build up as no big deal; that stuff cakes up on there (piston tops, valves and the head) and it's really hard to get off. You can't just blast it all out with WOT. When it builds up, it increases your compression ratio, bringing you closer to detonation. It also reduces heat transfer as its not a very good conductor, forming hot spots in the cylinder, thus increasing chances of detonation more. Not to mention the contamination of the oil which affects the whole engine, including the bearings you are trying so hard to protect.
I wouldn't feel all that bad about idling it too long once in awhile, but I wouldn't make a habit of doing it. It's widely accepted that extended idling is not good.
Hypothetically speaking, let's leave out the harmful effects of idling, and just discuss the wear differences between warm up idling and gentle warm up driving. First off, you got to get where you are going anyways, so a car that does 100,000 miles with idle warm ups will see more wear than a car with 100,000 miles that warms up by driving gently, simply because it saw more idle time. A lot more. Just because you idle your car, doesn't mean you have to drive any less farther. While you were sitting in your car warming up the other car is already on it's way. Just by idling all that time and not going anywhere, in those 100,000 miles you probably did 2000-5000 miles of extra wear just sitting there depending on how long your commutes are. Seriously, if you compare the hours spent driving vs. hours spent idling, it will probably amount to that much.
Furthermore, since the engine speeds and loads are still very low with gentle driving the difference is hardly noticeable. The loads are nowhere near the spec'd loads that the bearing can tolerate. However, there is a difference. FACT: 3000 RPMS is faster than 900-1500 RPMS. FACT: Idling is less load than driving. So maybe there will be a little bit more wear during that TIME when the motor is warming up while driving, but since you are spending all that TIME warming up going nowhere, you are seeing more wear if you idle. If I were to guess how much more wear you would see in the time of warm up while gentle driving vs idling, I would say less than 10% for sure, but more like 5% or less.
Out 100,000 miles, a car that drives gently to warm up, probably sees 8000 miles or so of warm up time. So 5% extra wear of 8000 miles is 400 miles. Not much. Hardly worth bothering about.
These numbers are my best guess, but if anyone has more solid numbers, then feel free to take a stab. I am a mechanical engineer, but I don't memorize text books and data charts. I don't think I'm way off, but who knows. But I feel the logic is strong.
I hope this makes sense.
Remember, you still have to get to where you are going. The engine WILL wear no matter what you do. But to warm up 5 mins for a 10 min drive, is 15 min of wear vs. 10 mins (+30 sec maybe) wear without the idling. You are doing more harm than good in this case.
What everyone is saying is that driving it ever so softly while warming it up is hardly any different from idling to warm up. However, when you warm-up by driving, you warm up up everything at the same time and you don't foul stuff up by idling.
Don't play off soot build up as no big deal; that stuff cakes up on there (piston tops, valves and the head) and it's really hard to get off. You can't just blast it all out with WOT. When it builds up, it increases your compression ratio, bringing you closer to detonation. It also reduces heat transfer as its not a very good conductor, forming hot spots in the cylinder, thus increasing chances of detonation more. Not to mention the contamination of the oil which affects the whole engine, including the bearings you are trying so hard to protect.
I wouldn't feel all that bad about idling it too long once in awhile, but I wouldn't make a habit of doing it. It's widely accepted that extended idling is not good.
Hypothetically speaking, let's leave out the harmful effects of idling, and just discuss the wear differences between warm up idling and gentle warm up driving. First off, you got to get where you are going anyways, so a car that does 100,000 miles with idle warm ups will see more wear than a car with 100,000 miles that warms up by driving gently, simply because it saw more idle time. A lot more. Just because you idle your car, doesn't mean you have to drive any less farther. While you were sitting in your car warming up the other car is already on it's way. Just by idling all that time and not going anywhere, in those 100,000 miles you probably did 2000-5000 miles of extra wear just sitting there depending on how long your commutes are. Seriously, if you compare the hours spent driving vs. hours spent idling, it will probably amount to that much.
Furthermore, since the engine speeds and loads are still very low with gentle driving the difference is hardly noticeable. The loads are nowhere near the spec'd loads that the bearing can tolerate. However, there is a difference. FACT: 3000 RPMS is faster than 900-1500 RPMS. FACT: Idling is less load than driving. So maybe there will be a little bit more wear during that TIME when the motor is warming up while driving, but since you are spending all that TIME warming up going nowhere, you are seeing more wear if you idle. If I were to guess how much more wear you would see in the time of warm up while gentle driving vs idling, I would say less than 10% for sure, but more like 5% or less.
Out 100,000 miles, a car that drives gently to warm up, probably sees 8000 miles or so of warm up time. So 5% extra wear of 8000 miles is 400 miles. Not much. Hardly worth bothering about.
These numbers are my best guess, but if anyone has more solid numbers, then feel free to take a stab. I am a mechanical engineer, but I don't memorize text books and data charts. I don't think I'm way off, but who knows. But I feel the logic is strong.
I hope this makes sense.
Remember, you still have to get to where you are going. The engine WILL wear no matter what you do. But to warm up 5 mins for a 10 min drive, is 15 min of wear vs. 10 mins (+30 sec maybe) wear without the idling. You are doing more harm than good in this case.
In my opinion, a turbo engine with 100,000 miles that has never been warmed up properly before driving will have MORE wear than a engine that idled for 30-60 seconds before driving off. This is what most turbo engine manufactures recommend doing (Mitsubishi included).
Last edited by sonicnofadz; Mar 1, 2007 at 11:14 AM.
Yes excessive idling will cause black soot to stick to the walls of everything. The first time you hit WOT afterwards, all of these deposits get thrown out into your exhaust. Would you rather get your exhaust black and sooty or wear out all your engine bearings? What are you recommending is absolutely ludicrous, and goes against every serious engine builders & engineers practices. People don't listen to this crap. Think for yourself do some research, and decide for yourself. There is only one real fact here, metal expands under heat. Do you want your engine driven under load without all the tolerances properly expanded yet? Ummm...no. Thats why letting your engine warm up is a good idea.
Of course excessive idling is bad for the engine. But not letting the motor warm up at all is a *very* bad idea for a turbo engine. Keeping the rpms under 3000 rpms might cut it for a low power NA engine, but depending how how "easy" the driver is on the throttle there will still be a considerable amount of load at 3000 rpms which is NOT good for a cold turbo engine. Many of your numbers seem like conjecture, there is no way to tell if wear will be greater while idling for 5 minutes or just driving while the engine is cold. Alot of this depends on how "softly" the driver chooses to drive the car while driving. How long would you personally recommend to idle before driving off? For the most part I agree with what you have said, however the question is, how long should one wait while idling? 2 seconds? 30 seconds? 60 seconds? 5 minutes? Perhaps it depends on the temperature?
In my opinion, a turbo engine with 100,000 miles that has never been warmed up properly before driving will have MORE wear than a engine that idled for 30-60 seconds before driving off. This is what most turbo engine manufactures recommend doing (Mitsubishi included).
In my opinion, a turbo engine with 100,000 miles that has never been warmed up properly before driving will have MORE wear than a engine that idled for 30-60 seconds before driving off. This is what most turbo engine manufactures recommend doing (Mitsubishi included).
Dude, I think we should wrap up this thread here. It went completely off topic here for the last 8 pages. First few were fine. Than it just becamse who's smarter and who's not. Many people that read this thread now have no idea what's going on, and what we have talked about for couple last pages. Just let it die out and be done with it.
Someone who will need all the info can look into first couple pages....
I'm done here
Someone who will need all the info can look into first couple pages....
I'm done here
Dude, I think we should wrap up this thread here. It went completely off topic here for the last 8 pages. First few were fine. Than it just becamse who's smarter and who's not. Many people that read this thread now have no idea what's going on, and what we have talked about for couple last pages. Just let it die out and be done with it.
Someone who will need all the info can look into first couple pages....
I'm done here
Someone who will need all the info can look into first couple pages....
I'm done here
I remember reading that too except it wasn't from the manual, but from something Mitsu sent me in the mail. At first I thought it was a piece of junk mail until I opened it up, I remember it had some "tips" to keep the car running well along with some coupons for services from any Mitsu dealership, but nontheless it was from Mitsu.
Of course excessive idling is bad for the engine. But not letting the motor warm up at all is a *very* bad idea for a turbo engine. Keeping the rpms under 3000 rpms might cut it for a low power NA engine, but depending how how "easy" the driver is on the throttle there will still be a considerable amount of load at 3000 rpms which is NOT good for a cold turbo engine. Many of your numbers seem like conjecture, there is no way to tell if wear will be greater while idling for 5 minutes or just driving while the engine is cold. Alot of this depends on how "softly" the driver chooses to drive the car while driving. How long would you personally recommend to idle before driving off? For the most part I agree with what you have said, however the question is, how long should one wait while idling? 2 seconds? 30 seconds? 60 seconds? 5 minutes? Perhaps it depends on the temperature?
In my opinion, a turbo engine with 100,000 miles that has never been warmed up properly before driving will have MORE wear than a engine that idled for 30-60 seconds before driving off. This is what most turbo engine manufactures recommend doing (Mitsubishi included).
In my opinion, a turbo engine with 100,000 miles that has never been warmed up properly before driving will have MORE wear than a engine that idled for 30-60 seconds before driving off. This is what most turbo engine manufactures recommend doing (Mitsubishi included).
The point is, driving gently and staying out of boost will have a negligible effect on bearings and contact surfaces when compared to idling. Furthermore, excessive idling simply adds more hours of operation to the engine, which negates any wear minimization you were attempting by idling the engine to operating temps.
Look, there are a lot of myths when it comes to engines, because very few people understand them. However, engineers do understand them and they work for manufacturers. They say drive to warm the engine. When stuff gets warrantied, it (the broken part) goes back to them, and they check it out why it failed. Then they learn. There probably was a time when they said "Idle to warm up", but not anymore. IC engines haven't been around that long and engineers are humans that learn as the technology progresses. This is their job: To learn and apply. This is what they learned: Don't idle to warm up.
Last edited by ITEM9; Mar 2, 2007 at 02:00 PM.
One more thing:
No one is saying don't warm up your engine. Everyone is saying that you should. The argument is about HOW you should do it. Having the car moving and accelerating slowly vs idling and going nowhere in your garage. The consensus is that driving to warm up will hardly affect service life.
Basically, your car is a virgin every time you start her up. You need to be soft and gentle and tell her everything is going to be alright at first. Once she's all warmed up and loosens up a bit, then you nail the crap out of her.
No one is saying don't warm up your engine. Everyone is saying that you should. The argument is about HOW you should do it. Having the car moving and accelerating slowly vs idling and going nowhere in your garage. The consensus is that driving to warm up will hardly affect service life.
Basically, your car is a virgin every time you start her up. You need to be soft and gentle and tell her everything is going to be alright at first. Once she's all warmed up and loosens up a bit, then you nail the crap out of her.
My facts have not changed. "Excessive idling" has a very subjective interpretation. I admit, idling for 40 mins straight might cause enough carbon buildup to have detrimental and permanent effects. But idling for 5 minutes? Who cares, You idle longer than that standing in traffic. EVOgasmIX, do you have any links to any sites that recommend not warming up? How long would you recommend someone warm up, if they lived in extremely cold climate say (20 degrees and colder)? Is there actually any proof out there that states excessive idling is bad?
My facts have not changed. "Excessive idling" has a very subjective interpretation. I admit, idling for 40 mins straight might cause enough carbon buildup to have detrimental and permanent effects. But idling for 5 minutes? Who cares, You idle longer than that standing in traffic. EVOgasmIX, do you have any links to any sites that recommend not warming up? How long would you recommend someone warm up, if they lived in extremely cold climate say (20 degrees and colder)? Is there actually any proof out there that states excessive idling is bad?
I see both sides of the argument. I just tried to lay it out for you to see were our argument is coming from. You have to agree on some of my points. A person who idles to warm to operating temps, still drives the same distance as someone who doesn't. Thus car that idles more will see more operating time than one that drives to warm. Idling still wears the engine.
The only thing we don't agree on is how much wear you save by idling vs. the slightly elevated engine load that happen when you are driving to warm. Agreed?
This how much determines whether the wear caused by gently driving the engine when cold vs. the extra wear caused by more idle time is more or less than the other. Agreed?
Chances are they are probably about the same if you idle for a reasonable amount of time or you drive to warm properly. The difference is when you idle you are going nowhere, wasting fuel. Either way you do it, you probably still will have a build of of carbon regardless, but with more idle time it will happen faster. There is no magical time limit where stuff starts to build up when you idle. It's a gradual process you can't do anything about, but you can minimize it. Idling in traffic; you can't do anything about it, so you have to do it. Stop and go IS hard on a vehicle; we all know that. You want to minimize that kind of operation. Idling is a necessary evil. No way around it.
The only way you can stop wear is by not ever driving your car. Engines wear out. They have a service life. Besides the wear caused by cold operation is a fraction of the wear caused by hard driving. That's where the spec'd loads happen. That's were the wear is. Even worse than that is when you start the car, waiting for oil pressure to come up. Cold parts and cold lube is hundreds of times better than cold parts and no lube.
If you think idling to warm is better for the car and you can sleep better at night about it, in the end that's all that matters. It's probably not a big deal anyways, either way. These cars hold a special place in our hearts that even our females will get jealous of and you have to be the best parent to your car the best way you know how. Hey at least you care.
Last edited by ITEM9; Mar 2, 2007 at 04:45 PM.