Recently,I had the opportunity to have my Fiesta ST reprogrammed by long time Ford-platform tuner Randy Robles of Mountune's USA
division (who as many of you know, daily drives a Fiesta ST). Excited by the prospect of having a familiar and trusted name in the industry massage the ECU mapping of my already very enjoyable car, we started out with the usual: a Mountune-concocted baseline, over-the-shelf tune that is shipped with each COBB Tuning V3 AccessPort
they sell as a COBB dealer as well as their mTuner. The COBB over-the-shelf v102 Stage 1 93 octane programming was already installed, so at this point, I'd sampled both the car stock, as well as with COBB's OTS mapping.
Though my focus of this review isn't on the Mountune OTS map (configured for 93 octane), I'll give some brief thoughts. For one, I think that the changes to the overall map are a little more aggressive, and a little more dialed in on the Mountune file over COBB. I haven't tried any of the v2xx maps, but at the time, the shift-assist disable was a big hit for me, as it reduced rev-hang up noticeably, allowing for much crisper and quicker downshifts. This helps a lot when you consider that the dual-mass flywheel on the stock clutch blunts both shifts and throttle response. Speaking of, throttle response felt like it was a little sharper, the engine's resolve to pull me out ofa corner honed to a finer point. Another key difference is that the Mountune programming allowed me to specify a 4,000 rpm fuel-cut launch control logic. Let's just say I discovered why getting a stiffer roll resistor for your engine is a good idea.
Then,Randy asked me for data logs from my AP so that we could go ahead and start making adjustments specific for my car, and to see what could be squeezed out of it. I'd never had a remote-tune over emails done before, yet even so, it was a breeze. Unfortunately, some outside circumstances (a fender bender for which we weren't at fault)resulted in my fiancee and I being without our FiST for two months. Nonetheless, Randy let me know we could get started once I had the vehicle back in my hands and was ready to collect more data, which at the time, indicated that the Shell V Power I was running was well,less than stellar. And this is where I need to reiterate what kind of a professional Randy is, not just his understanding that I would have to come back to this at some unknown date, but also his specific questions, and specific disclosures about what was being altered in each revision of the tune.
When I did get the car back, we addressed the bad fuel in my car which was hampering our efforts. I switched fuel brands (Exxon-Mobil to the rescue!) and started anew. Once Randy saw my data and knew he could safely dial in more aggressive parameters, the car changed dramatically. I actually laughed aloud when I checked my phone to find one of his emails stating my new fuel was 'crazy good': we were on the right track, and things were getting very exciting. A lot of peoples' first observation when going from stock to COBB's Stage 1 tune is that the car is much more aggressive in lower gears due to the removal of torque limits; it adds another dimension to the behavior of the car and its character. Well, think of the difference between the programming I was running before, and the tune which was evolving, custom-tailored for my car like another level, another peel of the onion deeper.
The process would go something like this, for the unfamiliar with a remote tune. Randy would email me a ptm file to try out (and there were several) and I would drive it around a bit, and when the opportunity presented itself, I collected data for each revision with hard acceleration pulls, logging the parameters he needed in order to see what was transpiring in my engine. I'd take perhaps three solid runs, and unload the logs from my AP with the APManager software and send them back to him. We repeated this process a few times. With the fuel situation sorted, each successive revision moved in a forward direction. Conditions were great for collecting data: I had a nice variation of late-summer into early fall weather to work with, and aside from the final session of logging, it never got too cold.
The final product I received was a three-slot ECU calibration which transformed the car. All calibrations were made for 93 octane. Allow me to get down to the details. Peak boost is generally around 23psi (I've hit a max observed peak of about 23.6 psi, but this owes more to cold temperatures than anything), and my AF/R at wide-open throttle pulls have been about 11.2-11.4 and 12.5 on the lean end. At one point, before calibration was complete, I was nearly maxing out on timing advance; the car liked the fuel that much. In any event, now I'm hovering around a maximum of +1.20 of correction and a nice, happy -1.0 OAR-L. These don't really speak to the results though…
I haven't dyno'd the car yet, so I don't have a sheet I can point to and say, 'well, this is what I make now on the tune'. And in a way,that would only tell part of the story. I can tell you that from adig, the tires are nearly useless. The torque simply overwhelms the OEM 205-segment Potenzas' compound. If it's chilly out, like it has been the last couple of days, launching requires care, even with TCS on. The way the boost kicks in on the standard car is viscerally exaggerated, even from a roll at highway speeds; the pick-up in any gear is much quicker, much harder than you'd expect from a car with aturbo as small as this one. I'm actually somewhat in awe. I want to make note that even with the COBB OTS maps, I never hit nominal boost targets (the closest I got was 19.8 psi). Not once.