2013 Light Duty Challenge

itguy08 wrote:

ib516 wrote:
I wonder what would have happened if they wouldn't have "power braked" before all of the acceleration tests (which to me seems like a blatant way to show favor the EcoBoost). Power braking before starting to move is unlikely to happen in the real world - something the tests are supposed to simulate, and would do nothing to help the non-turbo competitors. As I have a turbo-charged vehicle as my daily driver, I'm going to say not power braking the trucks would have seriously lengthened (due to turbo lag) the acceleration numbers for the EcoBoost F150. Thumbs down.

I don't think it would have made much difference. The turbos on the Ecoboost are small and really only made to service an under 2.0 Liter engine. They are designed to spool fast and are heavily managed by the ECU.

In the car application of the 3.5 Ecoboost it has been found to not really matter if you brake-torque it or not.

Edmunds SHO Comparison

"The SHO didn't respond (good or bad) to brake-torque, so best launch was at 2,000 rpm."

My guess is the stall speed of the Ecoboost Torque converters is set so that it is close to when boost is starting and that's why brake torquing has no effect.

Bottom line is the EB has the advantages of Diesel (flat torque and lots of it) with few of the drawbacks (service cost, expense, weight).

When I was test driving the Ecoboost F-150 (towing 6,500 lbs.) I noticed that if you went WOT, there was no turbo lag. Only if you were driving around 1,000 RPM would you find any lag, and it's impossible to keep the engine at 1,000 RPM at WOT, brake torquing or not.