My tuning methodology

I thought I'd take an opportunity to explain a bit about my approach to tuning; what I think is important and how I achieve the results I want. This is going to be a little long, but I think you'll find it enlightening.

To start, I think it's a good idea to establish what engine tuning is, and what it can and cannot do. Think of an engine as an air pump. The more efficiently it can pump air, the less losses that are drained through friction, restricted air flow, etc, the more efficient the engine will be. This efficiency will result in better fuel economy AND better power, if done properly. Engine tuning is basically optimizing the performance of the hard parts selected that make up the engine, including the intake and exhaust components. At it's core, tuning is controlling cylinder pressures and heat at the highest level possible without overloading the octane value of the fuel selected. Over running the fuels ability to resist self ignition (gas knock or it's variants) is devastating to power, economy, and engine longevity. Good engine tuning will capitalize on capturing as much air / fuel mix as possible and turn it into usable energy to move the vehicle.

What tuning CANNOT do is to “create” power. It's not like adding an extra cylinder to the engine, so there is a finite amount of power that can be extracted from the fuel. Once that has been reached, that's it for the given engine / fuel combination. That's why folks add things like larger exhaust systems, larger throttle bodies, etc... because once the limits of the original combination is reached, it will take a change of the hard parts to be able to get more power from the engine. It must be remembered that engine power is actually measured as torque, and horsepower is a mathematical derivative of that. I don't want to go to far with that now because it's another subject altogether, but suffice it to say that to make significantly more horsepower from a given displacement naturally aspirated engine will require an increase in peak RPM. With higher RPM comes more momentum of the engines' reciprocating mass, and the closer the engine brushes up against the load limits of the parts and eventual self destruction. All of this must be considered from a mature tuner's point of view. When is enough enough? To me a good tuner “listens” to what the engine is telling him and gets the gains available without driving the engine into self destruction.

Almost 40 years ago when I first started building and tuning engines, I read a book that I still have, titled “The Design and Tuning of Competition Engines” . In that book a philosophy of tuning was laid out; basically it said that tuning was like climbing a mountain in that you never know when you've reached the summit until you start to go down the other side. That made a lot of sense to me, and I then adopted that philosophy to my tuning. What that means in action is that I'll continue to “climb the mountain” as I am changing tuning parameters, not knowing what the ultimate “peak tune” will be until I've passed it and start losing power, economy, or whatever I was searching for. I can then back up to the “peak” and be sure that it really is “the peak”. I understand what the engine is telling me, and follow the path it sends me. This is a very tedious process, but at least it insures no stone was left unturned.

I am a conservative tuner. The first thing I want to do is be sure my tune is SAFE, because pushing any tuning parameters to the point of potential engine damage is a foolish thing to do. To that end I tune the concours with 89 (mid grade) octane, although I advise all who use my flash to use premium octane fuels. I use manifacturers minimum octane requirements on my other flashes. The reason I do this is so that there will always be an extra level of protection from gas knock, regardless of ambient conditions. If I sacrifice a couple HP so be it, it beats turning your engine into an expensive chuck of busted up metal. I have only used fresh Texaco mid grade with 10% ethanol... ethanol blend because this is representative of common fuels any c-14 owner will likely encounter. I also do not feel exhausting the very last high rpm potential is a good idea. Bad things happen when all that reciprocating mass gets whipping around inside the engine at high RPM's. In particular the Variable Valve Timing  (VVT) module, that weighs 1.5 pounds and is a reciprocating weight no other comparable street bike has. VVT is great for spreading the torque curve on the c-14, but it's there to help the bike be exactly what it is - a sport tourer, not a supersport bike. If you want a supersport, buy one... but your c-14 is not a supersport and trying to turn a 700 pound shaft drive bike into a supersport isn't really a wise thing to do, in my opinion. I also don't throw a lot of “bells and whistles” into my tunes... changes that sound cool, but really have no effect on how the bike runs or improving your experience on the bike. I'm conservative, pragmatic, and thorough.

Next, I fit the exhaust with a wideband oxygen sensor (WB02) in the header, in front of the catalytic converters (pre-cat) to measure the engine's air / fuel ratio. It's important to know that ratio, and getting the reading post-cat is subject to be incorrect because the catalytic converter will have changed the gases exiting the pipe. Consistency is the key here.

Another little trick I use is that I calibrate my throttle with an indicator on the kill switch housing and throttle tube. I set these marks so that in a quick glance I can see 0-10-15-25-50-100% throttle. This really helps when trying to corroborate how much throttle it takes to achieve a steady cruise speed, or how much throttle a medium acceleration takes, depending on gear. I also can quickly compare rpm / speed / throttle position/ fuel economy (with the “current” readout ) while riding. This is just a quick reference guide, but it definitely helps me when I review the datalog recordings of that part of the ride and see what the ECU was seeing at that time. I use any information I can to my benefit.

As I just alluded to, I also fit the bike with a datalogger. Basically this is a data recorder that will record and play back a ride for me in the data the ECU is seeing. Things like ambient and engine temps, ambient and intake pressures, throttle position, timing, secondary position, and air / fuel ratio are capable of being stored and reviewed after the ride.

Of course I also make sure the bike is in a good state of tune with a good clean stock air filter, spark plugs, properly adjusted valves and tires properly inflated. Then it's time to start riding and datalogging.I have also been fortunate to have friends with c-14's, and during the riding portion we have done many roll ons for acceleration comparisons. It's important here that only one bike is changed and the other left alone for accurate, real world data.

When I ride and datalog, I can really only pick one thing per ride that I'm targeting, and concentrate on that. Sometimes it may be light throttle fuel economy, other times it might be full wide open throttle performance. Sometimes I'm looking to check air fuel ratios, other times it might be to get a particular “feel” from the throttle reaction to certain inputs or situations. I then return to the shop, download the file, and start to analyze the data.

Often I will slow the data down to really pick up on what the ecu is reacting to and how long the reaction takes. It was in this manner, at 1/10th speed, that I found that TPS sensors are all over the place as to when they notify the ECU that the throttle is being lifted off a closed throttle idle. This is the information that led to my unique method of setting throttle cables to minimize lag time. Without the ability to slow the datalog, this information would not have been exposed for me to find.

After carefully studying the datalog, I make whatever changes I think necessary to the file, and flash it into my ECU. I then go out for another ride and again, analyze the data, make whatever adjustments I deem necessary, and flash my ecu – again. I repeat this until I feel I have exhausted whatever gains I was looking for in whatever part of the tune I was working in. My ECU has been flashed over 130 times. I also have autotune capabilities and use it depending on the situation. Often times I'm manually inputting fueling corrections, and then analyzing the results on the next datalog. I use different air / fuel ratios depending on the engine load. In this manner the same tune can deliver incredible fuel economy AND power, depending on the throttle position, which of course is dictated by load.

You may have noticed that I haven't said much about using the dyno. I have a Dynojet dyno, fitted with the newest dynojet program, Winpep 8RT and Wideband A/F  meter. But using the dyno comes later on in the process for me, after I have datalogged and adjusted to real world riding conditions.

Once I feel my tune is probably about done THEN I put the bike on the dyno. Because of the significant time I've spent riding and datalogging, I've insured the engine and drive train is well broken in, and we won't be comparing results from a new motorcycle that has high frictional losses to one that's fully broken in and producing 6-8 hp more than it did when new. In this way my horsepower gains don't look inflated, or better than reality. I have 2 ECUs that work on my bike, one that I have been flashing, and one that is stock. I also have a KDS (Kawasaki Diagnostic System) unit, and can switch out the ECUs in a couple minutes, because I have keyed both of them into my bike with the KDS unit. At this point I can measure the bike in stock tune and then with my tune, or with stock exhaust or different slipons, in a pretty short period of time. This matters because trying to get good weather for the dyno runs is important, and consistency of ambient conditions matters. I am within 50 ft of sea level. This helps greatly when building on base, uncorrected maps. Even though the dyno has mathematical correction factors built in to the weather station information, it's still within a slight range of deviation, so again, consistency is the key. While on the dyno, I can try changing timing, or see what the effects of air / fuel ratio changes or secondary opening rates would be. When it comes to high rpm settings, I have always deferred to what the real world datalog results are, rather than the dyno results. This is because I have actually datalogged with the appropriate road force and wind load on the bike. Higher speeds done with a larger windshield such as my Cee Bailey shield will create a load a dyno cannot create, and I want that real world load when it comes time to build a SAFE timing map.

So here we are, comparing the results of a real world tune on the dyno. At this point there are places I might be able to slightly improve power, or other places that if I accepted the dyno's results I could LOSE power on the road. For instance, I have datalogged at 160 mph if 5th gear, and also compared those results to datalogs from 5th gear runs on the dyno. The difference in air intake pressures (from ram air) is significant. What that means is that fueling developed on a dyno run would be lean at real road speed, because it would have been adjusted for less oxygen. And remember that any mathematical correction of ram air in the ECU is still not as correct as tuning to real world data.

Many times, folks think the dyno is the be-all and end-all in tuning. I personally disagree. A dyno is like a yardstick; it's a method of measurement, hopefully consistent. But there are things you cannot quantify on a dyno, things like “feel”. Maybe this is the reason the stock tune is so bad. Perhaps it was developed on a dyno, with little or no input from actual riding. Think of it this way... if you were drag racing, would you prefer to run a bike you tuned and peaked out on the track, or on a dyno? The track tuned bike, of course. Because you have proven it's validity in real world conditions. You might start with a dyno tune, but if the track runs indicate changes are needed to improve the performance, you must follow that path. That's what I've done in building my flashes... real world performance and data wins out over strictly dyno tuning.

Recently I released my newest flash, the Mountain Runner Flash. I started with the Evolution flash as my base starting point, because it's really a great flash. What I was looking for in Mountain Runner was better engine braking on deceleration, and a less linear and seamless power delivery in the first few degrees of throttle input. All of the work was done from 10% throttle down to closed throttle. It took me 35 different flashes to get where I wanted to be – each one a flash / ride / datalog / change / flash / ride , and then repeating the process many more times. During this process I never used the dyno, because the dyno could not give me the feedback I wanted. Think about it... how can you “feel” a deceleration on a dyno and know it has the qualities you want? Impossible. So is a dyno useful? Yes. But I do not consider it THE tool for building a flash... I think datalogging and riding is much more suited if you learn how to do it well... but it's slow, tedious and time consuming. It's also accurate and precise. The results speak for themselves.

To date, I have released 5 Concours 14 flashes. Each a different approach, with a different result. All are smooth, fast, and economical. Each flash is designed to best the previous flash in some targeted way. Constantly improving and innovating. This isn't easy to do, and it means I need some inspiration... and often that comes from the guys who are riding on my flashes. I have found that listening to feedback is the best way to improve, and in fact the Mountain Runner Flash – which is my absolute flagship flash – was not built just to my exacting standards, but to the standards of several beta testers positioned around the country. These beta testers would ride on beta flashes and give their input. That input, along with my own observations would send me back to work until the “ mountain was climbed and the summit was proven”. This insures that you are getting the best mix of smoothness, economy, slick shifting, power, engine braking and rideability from 0 to 100% throttle in ALL riding conditions.

I hope this helps you understand the method and effort that goes into building the premier flashes for the c-14, the Shoodaben Engineering flashes. As one of us, a dedicated 12 year COG member, c-14 owner , and sport touring rider, I know what we want, and my flashes have proven to deliver it for years now. Constant attention to improvement and detail and a “never say can't” attitude drive me to produce the very best.

Thanks for your time, and I hope you have gained some insight into why you would want to choose Shoodaben Engineering flash tuning for your Concours 14.


Steve S,
Dec 27, 2017, 5:48 AM