[Olympiadis]

Aside from all the valuable uses I have for this sort of function, I'll stay on topic for now and post results of a CTS tricker on my 2003 Ford Focus project. I'll make a separate post about this car as a project when I have more time.

Before:
First morning cold-start & commute -first leg only.
Average ambient temp over 8 data points = 77.1*F (beginning of leg)
Average coolant temp over 8 data points = 150.8*F (end of leg)
Average MPG at end of first leg = 34.7 (8 data points)

After:
Activated CTS tricker 10 seconds after start-up. Set to 225*F.
Average ambient temp over 1 data point = 65*F (beginning of leg)
Average coolant temp over 1 data point = 146*F (end of leg)
Average MPG at end of first leg = 37.5 (1 data points)

*Notes: I had wired this car for a CTS tricker, but not using one - was planning to run other tests first. I have kept complete mileage logs of this car since August 2007, and recently collected a great amount of baseline data in preparation for testing several new modifications. After seeing this thread, I decided to throw in one of my old CTS trickers for some testing, so I could contribute recent data. I have piles of test data from years past, but every vehicle type responds a little differently due to differences in the control algorithms and calibrations. A switchable CTS tricker combined with a Scangauge2 make this testing relatively easy.

*This 2003 Ford Focus has always been able to go into closed-loop operation very quickly, even with low coolant temperature, due to having a heated O2 sensor located very near the exhaust port, and having thermo-tech insulating wrap around the exhaust header/manifold. By quick, I mean less than 30 seconds, and sometimes as quick as 15 seconds after a cold start from 70*F. Most cars out there (especially older ones) aren't that quick at reaching threshold for closed-loop, and so tend to remain in warm-up enrichment longer. Clearly a quicker closed-loop was not a significant factor in this particular test.

*What I have noticed and logged about this Focus is that even in closed-loop, the coolant correction factors add considerably to fuel usage after a cold start due to the increased idle speed and throttle-follower settings for the IAC. This is a big factor with me and this car because I do engine-on coasting. I have not as yet taken the time to go into the PCM calibration and adjust the idle speed and throttle-follower settings on this vehicle.

Any AE - Acceleration Enrichment (or pseudo AE) used is also increased due to coolant temp factor. TCC (torque converter clutch) operation also has a coolant temp threshold, and this is just one more factor where a low coolant temp can cost you mileage.

This morning (02-Aug-2010) was my one "After" data point. I thought this would be good because it was unusually cool here for august at 12* cooler than the previous 8 data points average. 75*F was the coolest morning out of those previous 8 points.

My MPG consistently follows the ambient temperature, and especially so on the first leg of my commute, which includes the cold start. Higher starting temps have shown higher MPG, and vice-versa. This, I think was a very good reason to start the CTS-tricker testing today. It's starting out at a disadvantage compared to the previous 8 data points, but has potential to make a bigger difference. The first leg of my commute is only a 10 minute drive which drops about 100 feet elevation, and so has a lot of coasting right after the cold-start. This is why my actual engine coolant temp stays pretty low during the first leg of my commute. It's a perfect opportunity to show what a simple CTS-tricker can do in a situation like this.

Here are the before & after engine-on coasting numbers.

Before: Starting temp = 75*Fwt
.RPM...--GPH-- (gallons per hour - fuel usage per Scangauge2)
.1400.... 0.73
.1350.... 0.67
.1325.... 0.64
.1300.... 0.61
.1250.... 0.61
.1200.... 0.57
.1200.... 0.55
.1150.... 0.52
.1100.... 0.50
.1100.... 0.48
.1050.... 0.47 (stopped in neutral)
.1050.... 0.41 (stopped in neutral)
.950...... 0.38 (stopped in neutral)

After: Starting temp = 65*Fwt
.RPM...--GPH-- (gallons per hour - fuel usage per Scangauge2)
.980..... 0.44
.900..... 0.40
.850..... 0.40
.825..... 0.33 (stopped in neutral)
.800..... 0.29 (stopped in neutral)

I will of course collect a few more data points with the CTS in operation before I move on to testing something else. I will update my original post with the new data averages for a few days.