Dyno-Tested - 2013 Ford Focus ST Long-Term Road Test
ADVERTISEMENT

2013 Ford Focus ST Long-Term Road Test

2013 Ford Focus ST: Dyno-Tested

October 31, 2013

2013 Ford Focus ST

Our long-term 2013 Ford Focus ST is now gone, but just before it left I managed to squeak in a dyno test at MD Automotive's Dynojet chassis dyno.

You can see the results and read the details here. The surprising bit was how inconsistent and increasingly knock-prone it was on the dyno. This characteristic was in stark contrast to the uncannily robust Fiesta ST that I dyno'd immediately prior. If I had to guess (and I do) I would say that the two cars' powertrains were integrated and calibrated by completely different groups.

Jason Kavanagh, Engineering Editor


Comments

  • formerly formerly Posts:

    I thought someone suggested that the difference was probably due to your ST being an early build.

  • socal_eric socal_eric Posts:

    The calibration ID appears to be the same across all the cars so likely not a difference in the tune. Also since they bought off the lot in SoCal (well after I purchased on out here as well), the car really wasn't and "early" model either since for some reason other areas out east started getting production cars on the dealer lots about a couple months before us. .-------------- As commented in another thread, the variations are likely due to cooling and airflow across the intercooler and a small stock turbo that is being pushed up against its normal operating range efficiency limits. The larger for the family but still small BorgWarner K03 turbo produces pretty high discharge temps coming off the compressor.-------------- When the car is on a dyno, even the biggest shop fans can't replicate the real-world air flow the frontal area of the car will see at speed out on the street. So the intercooler heat soaks, the various T-MAP (temperature and manifold absolute pressure sensors, three of which used on the 2.0L EcoBoost at various points in the intake tract) show hotter, less dense air and pressure and the Bosch torque-based engine controller tries to keep engine output power the same by increasing boost further. Charge temps climb too high for the fuel octane and ignition timing, even with direct injection allow for cooler combustion temps and you still get knock/detonation and the controller pulling back on timing and altering boost downwards. .-------------- Other owners have seen similar things on the dyno although this particular dynamometer used by Edmunds does show a little more variation between pulls. Running some higher octane fuel and longer cool down periods between pulls might verify that it is a charge temp issue although data logging would tell for sure. Also since it wasn't mentioned, the dyno operator could have did the pull in fourth gear because they think it will give better torque readings from how it loads the engine, but the longer time to accelerate in the gear creates too much combustion heat. With a good dyno able to correct and measure correctly in a lower gear anyways, I would have tested the car in third gear to see if it was more consistent if they did do all the pulls in fourth.

  • bassrockerx bassrockerx Posts:

    i think its just easyer to get 250 horsepower out of a turbo 2litre engine so shortcuts were made but for the smaller fiesta the engineers had to pull all of the stops to get the performance they wanted. considering this engine is offered in the explorer, the taurus, and the fusion im not sure what if any changes were made to the engine in the focus.

  • greenpony greenpony Posts:

    So then it seems the solution would be (1) increasing air flow to the intercooler or (2) changing to an intercooler with higher cooling capacity.

  • hybris hybris Posts:

    May I ask why post something like this after you have sold the car and it is no longer a part of the LT fleet? I realize that you guys take a few weeks/months to remove old cars but I don't see why we needed this post at this point in time.

Leave a Comment
ADVERTISEMENT
ADVERTISEMENT
ADVERTISEMENT

Past Long-Term Road Tests

ADVERTISEMENT
Have a question? We're here to help!
Chat*
Chat online with us
Email
Email us at help@edmunds.com
*Available daily 8AM-5PM Pacific
Phone*
Call us at 855-782-4711
SMS*
Text us at ED411