I just replaced the V&H short shots on my 2011 1200C with Screamin Eagle slip on's. I purchased the bike with 500 miles on it, the original owner had the short shots, the Screamin Eagle air cleaner and the TTS tuner installed at the dealer when he took delivery. I have the TTS tuner module but no cables.

Do y'all think I will need to reflash because I went from the short shots to the Screamin eagle slip on's ? I went for a short test ride, the bike stumbled once around 1500 RPM from a stop but seemed to get better as I rode. Does the TTS tuner adjust on the fly like my Thundermax on the Road King or does it just work off a set of tables like the old power commanders ?

 

Wow 1 day, 90 views and not one suggestion or comment ? Seems like no one has the TTS Mastertune or has any idea ? Surprising !

 

Exhaust systems are one of the big, big factors that affect air flow through a motor. Exhaust "A" will pull at one rpm and push back at another, exhaust "B" will push back at the first rpm and pull at the the other. This is why torque curves aren't flat. It's the nature of exhaust systems to behave this way, because they primarily work on pressure waves traveling up and down the pipes.

Anyway, where a carb can, to a point, deal with changes in airflow in a passive way, an EFI bike has to be told how much air is flowing through the motor at every rpm and throttle position.

So if your bike is mapped properly for one pipe, and you change the pipe, it's no longer mapped properly. And it's not like an air cleaner change, where the air flow will largely just go up or down and you can make a global change. A pipe change scrambles your airflow map (commonly referred to as VE tables, which stands for "volumetric efficiency").

Now is it going to be far enough off to hurt anything? Without the actual data, nobody here can answer that question. All we can really say is that it won't be right.

With respect to on-the-fly adjustments, the ECM can do a limited amount of that, but it doesn't have much to do with the TTS tuner.

Here's how it works: As mentioned, the ECM has a pair of VE tables, one for the front cyl and one for the rear, and the contents of these tables model the air flow through the motor. Well, there's another table as well that contains the target air/fuel ratio (afr). You get to specify, for every combination of rpm and manifold pressure, what you'd like the afr to be. The ECM looks at the air flow through the motor, and looks at what you want for the air/fuel ratio, and calculates how much fuel to inject.

Well, it turns out that if you put the value "14.6" into any particular cell in that target afr table, the ECM operates in "closed loop" mode. What that means is that it'll read what it's oxygen sensors are telling it and it'll use those for the fuel calculation, to try to achieve 14.6:1. If the table cell has anything other than 14.6 in it, the ECM ignores the oxygen sensors.

14.6:1 afr is pretty lean. It's fine for light throttle, low rpm cruising, and will deliver the best gas mileage, but if you're putting a load on the motor and/or winding it up, you want more fuel than that (a smaller number). So the closed loop area of the map is typically restricted to the low rpm, low load areas.

So sure, for any cell you've got a 14.6 in, the ECM is adjusting for your new pipe and you're probably fine. The other areas of the map, however, you really need to get the air flow model right.

Like all the flash type tuners on the market, the TTS gives you access to these internal tables, VE, afr, spark advance, and several others. But it doesn't actually fill them in for you, it's up to you to figure out what goes in them.

The VE tables are the big ones that matter. The TTS has some tools to help you figure out what goes in them. It's called "Datamaster" and "Vtune" in TTS world. Basically the process involves putting the entire afr map into closed loop mode and riding the bike with a laptop in your backpack while the TTS software logs how much the ECM is having to tweak the fuel delivery. The idea is to hit as many cells as you can and gather the data. Then you take that logged data and using some tools they have, you apply changes to the VE tables based on it. Put your afr map back to where it should be, load up the new VE tables, and you're golden.

You can immediately see the issue with this: you're going to be visiting high load/high rpm cells with the afr set very lean. To keep the heat down and minimize risk to your motor, it's a good idea to pull timing out when you're logging.

The Screamin Beagle stuff works much the same way, in fact the two systems have a common lineage, as the TTS was the original SERT system (Screamin Eagle Race Tuner). However the new SE stuff has the ability to store logged data in the little communications box that comes with the system, so you don't have to lug a laptop around as you log.

The best system however is the Dynojet Powervision. It takes this whole logging process and automates it into a very simple push-button affair on it's little display unit. It automatically modifies the afr table, takes out timing, flashes the ECM, then while you're logging it shows a little table that indicates which cells you've hit and which you haven't, then when you're all done it's just a couple of keystrokes and it applies the logged data and restores the timing and afr targets and presto, you have a new tune. It's the slickest little device you've ever seen. It also has a wideband kit available that does an even better job and doesn't require that you do the process at 14.6:1 or with reduced timing.