goldstonj

I have a 2012 FX4 Eco with 8200 miles. I've noticed that I have way less acceleration when it gets below 0 outside...even after I've been driving for a while and given the fluids and drivetrain plenty of time to warm up. The difference in available power is significant otherwise I wouldn't care enough to make a big deal out of it. The only mod I've done to the truck is the CAI that I added in May. Any ideas on the power loss? Is that normal at subzero temps?

BoostedFx

The coldest I have had my ecoboost in is 8 degrees while up in Breckenridge Colorado this past February. I didn't notice any real loss in power plus I was at 10,000ft. The cold causes my MPG to go down which seems to be the case for everyone with the Eco engine, but power stays the same. I have a 2011 Fx2 eco.

byoungblood

If anything, the power should be better. Cooler air is denser, more air equals more fuel, therefore more power.

It is possible that the winter blend gas in your area is particularly bad.

Black 10

There's a problem.....cold air is dense air which makes more power.

jes

Cold air makes more power. I would definitely take it in. Winter blend fuel does cause less MPG though.

Where the hell are you that it is 0 degrees out already?

Franchi Motorsports

iTrader: (9)

I've noticed a slight increase in power, not a drop. But it's only been down to about 20 degrees couple times here, haven't hit 0 yet.

goldstonj

Haha...I'm just outside of Fairbanks, Alaska. We've been getting temps in the negative teens a lot lately and it's only gonna get worse!

engineermike

Guys, drive-by-wire systems work completely different than cable throttles of years past. When you give it throttle, the ECU interprets it as a "torque command", not a "throttle valve command". In other words, they could be reducing the actual throttle valve open % in colder climates to achieve a target torque response.

It blew my mind when I first saw the complexity and methodology behind a typical DBW system.

SA73

That's crazy, who would have thought, now I want to know more about this and how it works. Because you can be sure that this type of system is here to stay.
Understanding it may also explain why it behaves the way it does sometimes.

engineermike

I wish I knew more, myself. Everything I thought I knew about throttle control went out the window and I only saw a glimpse.

Some of what was explained was also that your foot is only one input (vote) into the equation. There are lots of algorithms and requirements that also have input, such as noise, emissions, stability control, driveline torque limits, etc... that output a throttle opening that's sent to the TB. It gives you a % of available torque. It also calculates "available torque" based on another set of inputs.

When I first got my truck and scanned it, I noticed that at low rpm and full throttle, the blade was only opening ~50%. With the SCT and 5Star tunes, it goes to 100%. When I asked an expert why on earth the factory programming doesn't give me true WOT at low rpm, he responded, "did you notice more intake noise with the tune?". I had noticed that. It opened my eyes to all the things (other than power) that the throttle valve can control.