Having Had The TTS & Race Tune…. Certainty

This is a follow-up to my blog entry from this morning entitled, “Taking the H-D in for TTS Master Tune & Dyno Race Tune Today…. Ambivalence

I should have probably mentioned that “taking the bike in” today was actually a pretty neat deal.  You see, Earl Small’s provides free pick-up and delivery… of you or your bike!  Yup, they’ll come and pick the bike up from your home with a truck & trailer, or they’ll give you a lift to work after dropping off the bike, and then come back to get you when it’s done.  I opted for the latter, since I only work about 1.6 miles from Earl Small’s.

Anyway, after Bobby got my bike checked-in around 8:30 a.m. and I met Orie — the tech who I’d asked to do the Race Tune on our Harley — as he was coming into the shop.  Our bike was first up in his queue since we’d made the appointment a week earlier.  Reco gave me a lift back to the plant: what a neat guy!  Shortly after noon we got the call that the bike was ready to go and Reco came by and gave me a lift back to Earl Small’s about 15 minutes later. Nice!

The total damage ended up being 8 Benjamin’s once the tax was factored-in… yikes!  Oh well, I look at is a front-loaded preventative maintenance plan / insurance premium in that it will be amortized on every ride and enhance the long-term reliability of the motor.

Getting back to the bike…  Even though it was a short ride back to the plant, the change in the engine was clearly apparent.  The most noticeable difference was the very smooth delivery of power all the way through the power band. It was somewhat deceptive on the butt dyno at first, but I’ve had similar experiences on my sport bikes after having them tuned… where the smooth delivery can make the bike feel like it’s not as peppy when it really is pulling stronger. The minor popping on decel is gone and it feels good.

Bottom Line: The motor felt much more refined, and that’s goodness in my book.

As for the numbers, both horsepower and torque values increased by ~9.1% but are still ho-hum, bearing in mind that our ’98 Honda CBR1100 made about 150 hp. That said, I must confess that there’s something about how well the torquey Harley’s launch and accelerate that just puts a huge smile on your face…
However, it was the Air Fuel Ratio (AFR) where I discovered the big change I was hoping to see.   Keep in mind that the higher the number, the more lean (and more hot) the engine runs. In fact, Harley typically uses a 14.6:1 AFR to meet EPA emission standards which is pretty lean to begin with.  Adding the full exhaust system and Harley-Davidson Screaming Eagle (SE) Stage 1 breather would be expected to cause an even higher lean condition in the motor. It was that lean condition and the associated engine heat that I really wanted to address with the work that I was having done.  So, here were the all-important results:
– On the baseline run, AFR held at a very lean ~15.0 in the 2,400 – 3,500 RPM range that decayed to ~13.5 at 5,500 RPM and then ~13.0 at 6,200 RPM.
– After the tune, it’s a solid ~13.5 all the way across the board, +/-.1

In terms of the value-proposition, the cost for the TTS Master Tune module was is a bit more than the cost of the performance chips I’ve put in my sport bike ECUs.  However, the TTS Master Tune is a one-time cost (so long as you don’t lose or damage the TTS module), and the labor for the time spent on the dyno is what it is. So at the end of the day and adjusted for inflation, today’s TTS Master Tune + the Dyno Time / Race Tune labor by Orie was a little bit more than what it has cost to have a speed shop do performance tunes on my ECU-controlled sport bikes that also had induction & exhaust system upgrades… and with similar results.

Again, the big value to me was seeing the AFR numbers come down, given that I was looking to address the lean / high engine heat condition that could eventually lead to long-term reliability issues. The smoother running motor is icing on the cake. The difference in power is negligible for all practical purposes: Wide Open Throttle (WOT)  on the Harley is not going to pull the handlebars out of my hands the way our ’98 CBR1100 did, anymore than going WOT on my BMW R1100S will: they just ain’t got the juice!

Thankfully, I no longer feel the need to have that much juice on tap with a quick twist of the wrist and having the Harley tuned has simply made it an even more enjoyable cruiser… which is why we got the thing in the first place!!


About TG

I've been around a bit and done a few things, have a couple kids and a few grandkids. I tend to be curmudgeonly, matter-of-fact and not predisposed to self-serving chit-chat. Thankfully, my wife's as nice as can be otherwise we'd have no friends. My interests are somewhat eclectic, but whose aren't?
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