Cold start question

[Porsche]

Originally Posted by mitosis

I guess I am a bit strange though...

No need to apologize for your cool new tools and for your enthusiasm in putting them to good use.


You've reminded me of a quote I always liked:

"All the world 'tis strange.
All excepting thee and me, of course...
But even thou art just a little bit strange."

I got an alarm with remote start, so i usually start my car about 5 minutes before i leave (on cold start at least), and then drive with restraint until it's at normal operating temperature. Especially in the winter, at which point i also leave my heater on .

This is how i was taught to maintain my vehicles and so this is how i do it. From what i understand also is that the remote start, perfectly starts the car every time so its also easier on the starter.

I think it is basically all subjective, and just comes down to personal preference.

[Moss]

Imho....the proper way is to wait until the idle calms down, that will be 30 to 40 secs (1 or 2 mins thats long time), Then slowly take off, but wait another 1 or 2 mins before you really gun it........then and only then.....when the "Happy hour" starts.

[Moss]

Even if Zombies were after you.....close the window lock the door and stiill do follow that...its alright ... i go for Pizza pls... thanks

[Kwisak]

Looks like the answer is almost Pizza lol

[Muaddib]

I keep it under 2k till coolant reaches operating temp ( usually takes 5km). Cause pizza.

[mitosis]

Originally Posted by Porsche

I note that the coolant temperature typically begins far higher than ambient temperature. I assume that's not residual heat remaining from the previous drive, so I'm guessing it's because the engine has been on and idling before you drive off. The graphs seem to begin when you drive off, not(?) when you first start the engine.

Most of the graphs actually start within less than 30 seconds of engine start, so make of it what you will. The only graph that has a late start was the one from Oct 4th, because I had to restart the car twice before the bluetooth would connect so you're actually looking at a third "start engine and wait for revs to drop" in a row there (I know, terrible for the engine... ugh). In every other graph you can see the vehicle speed starting out at zero for about 15 to 30 seconds which is me waiting for the revs to drop and we all know that that usually takes about 30 to 45 seconds.

Once the revs drop I almost immediately head out because I don't wanna be late for work and I know I'm gonna have to granny it on the way out so every second counts. So, knowing that the zero-speed section at the beginning represents me waiting for the rev drop one can come up with an approximate timeline of how far after engine start any given graph starts. I can't conclusively say that it's NOT residual heat, but I also think that maybe the water in this car gets hot SUPER FAST.

Originally Posted by Porsche

Do I guess correctly that you live within about 2 minutes drive of the Interstate?

On these graphs, you're accelerating briskly up to 75 mph within less than 3 minutes from first driving off.

Yep, very close.

That load measurement is wacky, I'm actually REALLY babying the car even on the onramp, like never more than 20% throttle (if that) until I get to the offramp for my work. This car just holds the corners so tight that I'm able to carry the momentum from the surface streets all the way through the loop so I hit the straight part of the ramp at 45 MPH or more. Even while grannying it this car is (relatively) quick, very often smooth driving will get you out of a turn just as fast (or faster) than brute force.

Originally Posted by Porsche

I wonder if the time to bring the oil to proper operating temperature would be extended were one to spend the first 10-15 minutes just gently driving around town at no more than, say, 40 mph? My guess is that it would not take significantly longer to bring the oil up to temp. But, I don't know.

Perhaps you'd care to log that and share that, too. (It is interesting what you can do with that tool.)

So, I take the freeway route because I feel that it is a gentler warm up than going through town. If I take the surface streets all the way to work it's actually a lot faster (only 8 minutes) but it is all stopsigns and stoplights on the way... so it would just be a long series of "launch car, get to second, bump into third, oops time to stop" and the car would barely even spend any time in third gear. The blocks in my town are VERY short so all that repetitive stop and go would not be very nice to the car.

There have been a few days where I was gonna be late to work if I took the freeway route since that takes about 15 minutes but the town route only takes 8. I didn't have the logs running but I unscientifically concluded that the car gets up to temp just as fast if not faster based on how quickly the needle hits that second mark where it always settles and how quickly the heater starts blowing hot air. I mean, it makes sense that all those repetitive launches would put quite a load on the engine considering Newton's first law.

I will get a log of that alternate route ASAP, probably Monday if I remember.

Originally Posted by Porsche

As you noted, the Engine Load % is interesting. I wonder what parameters they're measuring? Do you suppose the software may regard very low rpm + large throttle opening as lugging and show that as high load percent? Just guessing, trying to account for what you've seen as odd graph lines for that measure.

Yeah I have kinda come to the same conclusion... but I never lug it so I dunno. My best guess is that it has very little to do with ACTUAL engine load, but instead is some super-complicated mathy formula that the ECU is doing based on vehicle speed, engine RPM, MAF readings, etc and it's using this here "engine load" number as an input to another formula for determining timings and AFR and whatnot. I don't log timing or AFR but I do have live graphs of them running on Torque and they both seem to have a very close relationship to engine load. Keep in mind that I only log data points every 5 seconds as well, so there could be some hysteresis induced errors in the readings and we might be completely missing the whole picture that we might see if I could log 10 times a second or something.

I mean, there's no way that a less than 20% throttle slow climb to 30 MPH could actually represent "75% engine load" (look at about the one minute mark on most of the charts to see the particular moment I'm referring to). If THAT was 75% engine load then what am I doing when the car is hot and I hard launch, chirp the tires, and am at 30 in the blink of an eye... 250%?

Originally Posted by Porsche

Finally, is there anything I might do for you in return for your kindness? Anything about our wonderful cars or about driving, perhaps, that I could share with you? Any questions at all about, oh, handbrake starts on hills, or heel-and-toe, etc? (I don't know your age or experience. Me? I'm old and may have learned a useful thing or two over the years. )

Awe thank you so much, you're too kind. The truth of the matter is that I have SOOOOOOOO much fun geeking out over all this stuff that no thanks is necessary at all. I'm an EE and doing R&D stuff is my hobby, hence why I was already logging all these things and really just needed to click a few buttons in Excel to get those graphs made up... no problem at all, pure fun! The fact OTHER people would even be interested in my results is the best reward of all!

Haha, I'm self-described as old but physically I'm not. Married, graduated, career'd, shaking fist at hooligan teens, etc... I check all the boxes for being "old" despite still looking like a kid to most people twice my age. Go buy some cool dude a beer and chew his ear off about car stuff and we'll call it even

[FRSBRZGT86FAN]

Just a force of habit, in a non frs/brz vehicle, after a cold night before school or work in the morning, I just turn the car on 10 min before I leave just to get the heat going, gets all the fluids going too. I also know that catalytic converters work better when warm anyway so you are slightly helping emissions But general idea is "baby" it till normal temps then do what you want, common sense tells you engines warm up better under a light load than just idling for a couple minutes.

[dem00n]

Unless it's Italian, i'll wait for the idle to settle and i'll drive off.

[TJ3000]

I let it warm up by letting the revs drop. It usually drops twice so when it drops the second time is when I'll start driving. But if I'm in a hurry I'll start it up and drive off. BUT, I'll drive it slow not reving high. Eventually it will warm up before I hit the freeway.

[gzpermadi]

I always warm up the car for 2-3 mins until the temp needle reaches the 1st bar.
After that I will drive but still below 3-4K RPM maybe around 15-20 mins. That is basically how long it takes to reach my office, so my car rarely see 7k RPM. So sometimes I take the car for long night drive just to rev the car high.

[Trettiosjuan]

Hi guys/gals,

I live in Sweden and am an automotive engineer, so perhaps I am qualified to answer. So here is how I do it and why.

- Drive off immediatly if possible (clear windows), you need *some* load and oil pressure to both warm the engine and keep it protected from wear.
- At first use a very light throttle to keep torque and load low, BUT drive in one gear LOWER the you usually would when taking it easy! So roughly 3000rpm instead of 2000rpm. Why? For the same power (torque x revs), you torque and load will be (much) lower (less wear), while at the same time higher oil pressure will give more protection (less wear). Also many imagine it is combustion that warms the oil, when in fact it is primarily friction in the oil itself, especially at startup. The higher revs and higher oil pressure combined with very low load thus make the oil warm much faster in a safe manner than if you would "baby" it (not) by keeping revs very low.
-Roughly, the oil reaches temperature in twice the time of the coolant. Instead of suddenly going WOT because you now think the oil is warm, a safer and quicker strategy is to progressively increase load (thats is, throttle) over 5-10min once you have some temperature in your coolant. Progression is a good thing as progressive more load will introduce more heat and accelerate the warming without any thermal shock that may cause wear. Let the ramp up of load reach its peak at about twice twice the time it took for the coolant to reach its steady operating temperature.

With the above method, you will heat the engine quicker, have less wear and use less fuel once it is warm, than driving along in very low revs and then suddenly pinning it while not being quite sure if the oil is hot enough. In fact, good chance is that the oil never gets really hot that way and you will give your engine a thermal shock by suddenly going WOT to the redline...

How fast this goes of course depends on many factors, data is nice but the good thing with this one is that with this method is fairly foolproof without the need of hard data.

So in summary.
Drive off asap, very light throttle and choose one gear lower than usual, build load progressively once coolant needle gets moving, build progressively so that the time for full load equals twice the time the coolant reached its operating temperature.

The very fact that you care and want to warm the engine will make the biggest difference...

[Clembo]

^^^Exactly how I've driven for the last 50 years or so^^^

[stevo_12v]

I usually let the car idle for at least 4 minutes. Or sit in the car while playing a whole single song 4-5mins. Ever since I've bough the P3cars vent though I just let the car idle, until the oil temp gets up to 50deg C, then drive off slowly. I usually try to stay to one gear whenever possible(better for a cold tranny) and not go past 3krpm. Once the oil hits 70deg C, I just drive like normal.