Warm up time

[GeorgeBeirut]

Found this on the e46 m3 FB group

[mrgizmo04]

It does not warm up enough from no-load rotation to really make any difference. Even the engine oil takes forever to warm up while idling.

Yes it'll take hours, like I said, fun side note.

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[Pavlo]

Side note for fun, tranny input shaft is spinning and warming up as the engine idles, so the only thing that is not getting warmed up is the diff without driving.

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It does not warm up enough from no-load rotation to really make any difference. Even the engine oil takes forever to warm up while idling.

[mrgizmo04]

Of course. Back when this forum started IIRC in 2003, the general consensus was to do what I described and it made perfect sense to me. I treated it as gospel and still do...original bearings and all (well, besides the two SA replacements).

Yeah I used to watch the oil dot like you described, but then used the tool to get the lights more in sync. The lights are there to tell me that it's good to start ripping, so seemed off that the dot below didn't reach the desired temp yet.

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[Jimbo's M]

Water and glycol transmit heat faster and better than oil, so "coolant" warms up faster. There is a way to manually adjust the degrees at which each of the orange segment lights goes off via Martyn's tool.

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Of course. Back when this forum started IIRC in 2003, the general consensus was to do what I described and it made perfect sense to me. I treated it as gospel and still do...original bearings and all (well, besides the two SA replacements).

[mrgizmo04]

They are. I personally don't get on it til the oil temp reaches the first dot which is considerably longer than all the lights going out..

Water and glycol transmit heat faster and better than oil, so "coolant" warms up faster. There is a way to manually adjust the degrees at which each of the orange segment lights goes off via Martyn's tool.

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[mrgizmo04]

The procedure that most people here follow is the best one from my understanding. The reason for it is that the sooner the engine comes to operating temp, the better its off.
On a cold idle, the AFR are pretty rich and a lot of unburned fuel ends up making it into your oil, reducing its life (and the life of your engine). So start it up and casually begin your drive.

Another consideration with warming the car up is that your gearbox and differential are still cold, so light driving helps with getting everything up to temp together and not just the engine.

Side note for fun, tranny input shaft is spinning and warming up as the engine idles, so the only thing that is not getting warmed up is the diff without driving.

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[Jimbo's M]

Thought I read the warm up lights are tied to water temp and not oil temp...I've always used oil temp as the primary guideline.

They are. I personally don't get on it til the oil temp reaches the first dot which is considerably longer than all the lights going out..

[Pavlo]

The procedure that most people here follow is the best one from my understanding. The reason for it is that the sooner the engine comes to operating temp, the better its off.
On a cold idle, the AFR are pretty rich and a lot of unburned fuel ends up making it into your oil, reducing its life (and the life of your engine). So start it up and casually begin your drive.

Another consideration with warming the car up is that your gearbox and differential are still cold, so light driving helps with getting everything up to temp together and not just the engine.

[ELEM3NT]

Thought I read the warm up lights are tied to water temp and not oil temp...I've always used oil temp as the primary guideline.

[Flat-Six]

I don't/never let it sit and idle. I crank it up and drive off, and don't exceed 4500, usually 4K in the M3, until I have full oil temp (170-180). If I am in a position where I am waiting on something/someone after starting cold, then I take it up to 2K immediately and hold until I am ready to drive off. Engines like to warm up quick...

[mrgizmo04]

The factory S54 oil pump has a regulated pressure of 4 bar (58 psi). On cold start idle oil pressure will be 4 bar (58 psi) and when warm driving at higher rpm the oil pressure will also be 4 bar (58psi).

Dan, I don't think that at idle the pressure will be that high. At idle the pressure will probably be closer to 10 or 20 psi, and drop a little as the oil warms up and viscosity drops. Given that the oil pump is mechanically driven, it can't have max flow at idle, there is just not enough oil volume being pumped through the fixed size/area oil tubes/pipes/galleys/etc to create that much pressure. Above 3k rpm, I can see it building to the max.

It's similar to washing a car with a hose and holding your finger over the end of the hose to constrict the flow to reach farther away. That's what pressure is, flow through a restriction. But there has to be enough volume flow, otherwise if you put your finger over the hose, you will stop the flow completely, and you will have to go back to the faucet valve and open it more.

So starting the car from cold and idling will see a bit higher pressure than idling a warm engine because cold oil will have higher viscosity and therefore run at slightly higher pressure. After the car warms up and oil thins, running it at higher rpm gets you to the proper pressure.

I think that is why these cars require such thick oil, to protect the engine somewhat running it cold, but also that the pump doesn't really put out that much pressure (60psi is not a lot) when hot and running it to 8k redline, so having ticker oil helps keep the surfaces protected with subpar oil pressure from the mechanical pump.

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[erickhoyos]

Damn, everyone here is taking that extra step to make sure the engine is lubricated well on cold starts meanwhile I’m here like “if I’m not ready, neither is my car” LOL.

[Tbonem3]

Rasp comes on full bodied at 2.2-2.5k with oem Uros and scza, beautiful tone and loud for my setup . Those first few hundred feet when cold I adore.

Oh that early? I'll have to pay attention next time, I thought it was above 3k. Come to think of it, I think there are two spots in the powerband where rasp is pronounced.

[FBloggs]

I wait 30 secs, then drive.
The gearbox is baulky until it warms up so there's little point in hurrying.