Cold weather performance.

[Bill in MN]

This is for those who are more mathmatically and techno savy than I.

Not everyone runs their turbo motors in cold temps. and I do. I've had it out in -25 ambient temps (not much need for an intercooler here) and while the seat of the pants meter tells me there is a huuuuge difference I don't push it. I want to keep the motor in one piece. I've smoked enough sled motors at 20 below to know you've got to be careful.

At 0 or below, how much more power can a turbo motor produce and at what point does it get dangerous? At what point do fuel maps no longer provide proper information to keep from lean situations? I am not running MS yet but there has to be a point where even programmable maps are in uncharted territory.

Someone inform me. Is it possible itdoesn't really matter? That an ECU compensates regardless of temp. ?

[Duke]

Yes, there is more power due to - Colder IAT temp which equals denser air and denser air will blend with more fuel to make more power.

You Motronic ECU has input from a IAT sensor and will compensate for colder air and add more fuel.

This will not be damaging to the engine due to the waste gate. Your car will not over boost due to this. It will spool up faster and stronger due to the colder air.

No worries, keep it floored.

Now traction is another story.

[russc]

One thing to watch for is the WG. If you using it mechanicaly, it will change from temp, mine does. On the dyno, the WG was under-boosting by ~2psi. Out on the road, where theres more air flow and lower underhood temps, it then over-boosted with the new dyno adjustment. If your running a boost controller, it wont matter as much.

I don't believe theres an issue, except the IC will cool much better, and give better efficiency. That can change the fuel delivery needed, but not enough to be deadly, I believe. The lower temps will allow you to run more boost, if you set it to do that, but will need to be changed back for higher ambients.

RussC

[T_C_D]

Bill,

You need to retune the fmu for such cold temps. The Motronic IAT adj is almost worthless at your HP level.

It's always been my experience that the wastegate will give you 1 or 2 psi more in the winter.

Todd

[Craig -535i- Seattle]

My biggest problem is cold weather is traction- even with all seasons traction is nearly hopeless.
I gotta wonder what your tires are like (rocks?) at 25 below.

[Bill in MN]

The tires eventually warm up but the cabin does not. I drove my old 528 for 4 winters and froze my ass off when it hit -20 or colder.

[a]

The tires eventually warm up but the cabin does not. I drove my old 528 for 4 winters and froze my ass off when it hit -20 or colder.

never had it that cold around here, coldest temps my eta has seen was -14. But if I had heat problems, there's this old school trick of blocking off the radiator with a piece of card board. ....