Sure plenty of updates. But, until now they have all been for the 133hp E85 powered Focus (The Explorer is next). Since I figured, you would rather hear about the Explorer, updates had to wait. I finally got to hit the dyno yesterday and do a baseline, 87 tune and, some tweaking time. Over $250 in dyno charges (ouch), but later runs will be far cheaper since there won't be any data logging going on at the same time. There were dozens of questions as to why certain things are done certain ways, and why it's a good idea not to follow some other groups/ideas.
So, we start with what to bring:
Laptop, spare battery (or DC-DC convertor!), LiveLink 4.17 (or better), USB cable, camera, soft drink(s), pen/pencil, notebook, tuning manuals/reference material, common hand tools, MAF cleaner, rags and a game plan.
Prestaging:
A good tune up is recommended, no oil or fluid leaks, no smoke, no mechanical issues. If you have any of these issues, you are really wasting your time and money. I recommend cleaned, regapped plugs and a MAF cleaning the week before. A clean (or cleaned/reoiled) air filter is a good idea too.
What to watch for:
The ABS light on most vehicles will come on since the rear wheels are turning and not the front, this is normal, and the light will go out a few minutes after leaving the dyno.
Make plans well in advance, I actually scheduled for last Saturday, two weeks prior. Just so happens we got 4" of snow last Saturday, following massive flooding the week before. So, Friday I called to verify and then again on Saturday. Showing up early was well worthwhile as I got to see a twin-turbo Z05 Corvette... sweet.
I had the X3 loaded with a modified stock profile (no limiters), an 87 profile and a 93. This allows for a quick transfer of files and a minimum amount of wasted time while strapped to the roller - that gets costly! Now, the vast majority of my dyno experience has been lowered Rangers, Explorers and Focii with "Z" series tires, so the standard procedure is to SLOWLY row the stick through the first 4 gears (all 5 speed O/D), then stab the throttle at the lowest RPM you can get without lugging the engine. On an auto, I have a special profile that locks the TC and trans in 4th gear, deselect the O/D, and set the IAC up a bit to keep it from stalling on the dyno. Rev the engine to just over a grand in neutral and drop the selector in to "D". With the extra IAC air and the RPM's, it is enough to get the roller moving (preventing an embarrassing stall!) and your off in high gear with minimal losses and no silly 4,800 RPM "flare" from the TC.
But, this is the first time I'm testing a lifted truck with 32" mudders. These are "S" rated tires which were recently balanced. This puts them at approximately 112mph, and the Focus (with 3.8:1 gears and 24" tires) hit 119mph, easily. We know most Ford trucks have a speed limiter at 87-95 mph (with factory tires), and that should be over 100mph with the 32's. So, since I'm doing a dyno article for another forum, I figured I'd go Barney-style; deselect O/D, drop it in "D" and stab the throttle.
Here is the ugliness:
What do we get out of this spaghetti bowl? Well, we can see that first gear is completely useless, the time is too short to glean any useable data. Second gear is nice, starts reasonably low and gets well over the magical 5252 (TQ/HP crossover) and shows until HP tails off. Third gear is a little weak, it starts late (just before the 5252 convergence) and ends normally. Fourth is by far the sweetest gear for real numbers - unless you have a stock limiter. The limiter, in this instance, hit at 105mph, and at 4,860RPM's - much too soon. The reason for the 105mph speed limit? Start with 1 divide it by the 28” tire, times a 32” tire = 1.14 x the 92mph limit = 104.88mph - coincidence? Not! Notice the rapid drop in HP/TQ numbers? They correspond with the rapid increase in the AFR (18:1) since the PCM pulls injector dwell time to limit speed and rpm’s. Major problems for nitrous and forced induction folks - this would be blown head gaskets for sure.
The other obvious signs are the radical spikes (increase) in HP/TQ at each shift. These are not only unsightly, but they fool the dyno computer in to thinking they are the peak HP/TQ numbers. The readouts stated that my peak numbers were 200.1HP and 221.23TQ,
completely wrong. The true numbers were 181HP and 188TQ. I plugged these in to the “Rogue Dyno” and got 181HP and 18
9TQ - Hmmmmmm…..
Remember, these are "unlearned" bone stock PCM numbers, the torque numbers are low, but I attribute this to the lack of learning.
What's the verdict, what did we learn?
-Safety first: 2nd gear only runs for any non-speed tires. I still prefer 4th gear for better data, but 2nd is perfect for mudders.
-Rev/speed limiters are pretty evil, annoying and unsightly.
-The Excell dyno works dead-on if the factory torque limits are untouched.
...more to follow...