Do you let your 135 idle?

[Dackelone]

Originally Posted by LeifW

Well that's good enough for me. Also, Mike Miller (Bimmer magazine and Roundel) also recommends letting a turbo engined BMW idle.

Leif W.

[ejm3]

Originally Posted by Bob Z.

With the top up or down?

This is CT in the winter so my top will be up for another few months.

My previous high was 110 several times both with the top up and top down. As you might expect, even with the windscreen its pretty noisy with the top down.

So this weekend I was doing about 100 for some reason and the road opened up and it was down an incline so I figured I could safely get to 120 and beat my old record. Well maybe it was because I going down hill but I blew through 120 up to about an indicated 130.

It was only for a few seconds as I was catching up to traffic pretty quickly but the car seemed to handle fine (was a straighaway however).

[ErvGotti]

The best practices for the N54/55 engine that's recommended from the numerous threads and advice floating around is this.

1. No need to let the engine idle warming up, but do not romp on it ie go WOT till the oil has time to warm up. That's why we have an oil temp gauge.

2. If you been driving it really hard the best practice is to drive around normally off boost to help cool the turbo's down that way you don't have to wait for it to cool down just idling. Now if you've been driving normally or casually then it's ok to shut the car off after getting to your destination.

3. Yes the car will continue to circulate coolant if the turbo's are hot, but it will not circulate oil. As Dakel has said these turbo's are oil and water cooled. To me if you've been driving hard and the turbo's are red hot I wouldn't want the oil to just be sitting there. Circulating coolant probably helps but that's not a chance I'm willing to take.

I've owned my car since new for 5 years now and 35k miles and these are rules I try to follow. Besides plugs and injectors knock on wood I've not had turbo problems nor waste gate rattle.

[Rowdy]

So much misinformation out there. Plain and simple.. if you want those turbos to last.. make sure there is a cool down period after spirited driving. It doesnt matter that we run synthetic motor oils, those simply dont break down under the excessive heat and lubricate a bit better.. they DO NOT stop glowing hot oil cooled turbo center sections from baking the oil (which is now not being circulated with the engine off). The fact that the turbos are watercooled is also not a saving grace. This simply helps extend bearing life by keeping temps consistent. The electric water pump cycling after the car is shut off helps a tiny bit, but whats really needed is an electric auxillary oil pump to keep those fluids flowing through so they dont sit, stagnant, and Bake in the turbos center section!

I'll reiterate what a few of the knowledgeable others have said here..

1) Let your car come up to temp before going into boost or above 4k..

2) allow for a cool down (best while driving) after being on the freeway or beating on it and failing that, a couple minutes at idle before you shut it off!

From the man who HAS had turbo seals go south after an ex decided she'd stand on it with a cold car (-3C outside temps).

*haha looks like ervgotti and I were typing at the same time!

[RiefferD]

From my Suby days, I always let my car idle until the exhaust note changes, and then I drive conservatively until the engine warms....and if I've been driving hard, I always drive normal for a bit before shutting her down.

[bradleyland]

IMO, idle (in any scenario) isn't the best thing. You car is designed to work best on the move. For example, cars designed to sit stationary for extended periods (like police cruisers) typically come with larger cooling systems. The effectiveness of your oil cooler and radiator are much better at 25-30 MPH than they are sitting stationary because the air moving over them is fresh, and you're generating minimal power/heat. Also, the engine actually gets a cooling effect (compared to WOT operation) by the air moving through it during normal operation.

Remember that Otto cycle engines convert heat in to motion. The more motion you want, the more heat you need. The less motion you want, the less heat you need. During low-power operation, the engine is circulating and cooling fluids, but isn't producing as much heat.

Driving casually is the best way to cool an engine off after hard usage.

[dan_brooks]

For me, if the car's been sitting overnight, I let it idle for about 20 seconds on startup (until the revs drop to 1k) to let oil circulate to the head, as some may have drained a little.

IMO if BMW wanted you to let the car idle after driving it, they would've made it so the oil pump stays on along side the coolant pump. Coming from a 500hp Supra, I didn't have a turbo timer on the car, and just drove conservatively for the last few minutes of the journey. Sure, if you boost the crap out of the car then park it immediately then let it idle for a minute, but as a street car I don't think this is necessary.

[VMRWheels]

As everyone said, just for peace of mind keep it on for 1-5 minutes before shutting her down. If you go around your car after going on a long drive, the car is relatively cool. Let it sit for 10 minutes and your car/garage will feel a lot warmer.