2014 CBR1000RR Aftermarket Exhaust and Dyno Tuning

I'm the owner of a 2014 CBR1000RR (non SP) and I've recorded my experiences here with installing an aftermarket slip on exhaust and subsequent dyno tuning. Many thanks to Julian for giving me access to his treasure trove of dyno chart data.


The post 2008 CBR1000RR comes with a really neatly faired in exhaust canister embodying Honda's "mass centralization" dictum that mandated a move away from undertail exhausts.

However, like all modern motorcycles, the OEM exhaust is forced to compromise performance with meeting emissions regulations. It has two valves in its construction. One is opened by an ECU controlled servo motor to meet low rpm noise regulations. When this valve opens there is a noticeable change in engine performance. The other spring loaded valve is opened when there is a sufficient pressure differential between two internal chambers. Only when exhaust gas pressure builds up to overcome spring tension does the resistance to gas flow drop. Both of these valves are welded into the canister and cannot be removed.

This exhaust is beautifully constructed in stainless steel. Its complicated three dimensional shape packs its mass tightly near the centre of mass of the motorcycle. And no doubt it's gas flow properties were carefully designed and tuned by the genius engineers at Honda. However, to meet EU regulations it ended up being massive (6kgs) and restrictive to gas flow, resulting in sub-optimal volumetric efficiency.

It has to be said that the stock ECU fueling with the stock OEM exhaust is pretty good and throttle responsiveness is generally excellent. Nevertheless, within its "closed loop" area it will be fuelled to meet emissions regulations and be very lean. 

This closed loop area is where fueling is changed in response to the signal from the oxygen sensing exhaust Lambda sensor, generally attempting to keep the air fuel ratios (AFRs) close to stoichiometric (AFR=14.7) to minimize emissions. Note that the intention of closed loop fuelling is reduced emissions, not enhancing performance. On the Fireblade the closed loop area is 0 to 20% throttle opening and 0 to 5500 rpm. Outside of these conditions (so called "open loop" area) is where your real performance lies and here the ECU does fuel more generously.

(Lambda sensors measure exhaust oxygen partial pressures from which AFRs are indirectly calculated.) 

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My main reason for removing the stock exhaust and replacing it with a slip on was to reduce resistance to gas flow, and hence improve volumetric efficiency. Weight loss was an added benefit. I did not replace it so that my bike would make more noise. To me noise is a drawback of a pipe that breathes better.

From 2014 onwards the catalytic converter is no longer in the silencer, it has now become a fixed part of the headers. The only way to remove it is to replace the entire exhaust system. Also from 2014, and because of the catalytic converter, the link pipe for a slip on has increased to 60mm, making older slip ons incompatible (the USA bikes are different).

When choosing a slip on for the Fireblade there are a few choices. The link pipe can either be a convoluted "S" shape or it can be short and direct. The silencer can can either be compact and low to preserve what Honda was trying to do with mass centralization, or it can be bigger and protrude further and higher. Silencers that were not specifically designed for the Blade are often like this.

And then there is a choice of materials. Stainless Steel, Carbon Fibre reinforced plastic, or Titanium.

Stainless Steel is heavy and ages disgracefully. Where it gets really hot it discolours, looking like controlled rust. It is also prone to stress cracking.

Carbon fibre reinforced plastic has the virtue of being light. However, plastic is adversely affected by heat and carbon fibres will burn if heated enough. You will not find this material being used on a MotoGP bike exhaust despite its appealing lightness. No OEM exhausts are made of this material either. It doesn't tolerate localised stress points so the can is usually suspended by an unsightly encircling band. CF tipped exhausts are a cosmetic touch only.

Titanium is the perfect exhaust material.

Lighter and stronger than steel, rustless, attractive colour changes on heating, single piece construction possible without external springs and clamps. Material of choice for the hot end of jet engines since they were invented.

And then there is the actual dynamic design of the silencer and link pipe. Some aftermarket slip on exhausts are little more than a standard silencer can mated with a suitable link pipe to attach it to the headers. Others have been made specifically for the Fireblade on a flow bench and improved performance is confirmed with dyno testing.

The slip on I chose was this 1.3kgs of titanium made specifically for the 2014 Fireblade by Akrapovič.

It is obviously extremely light (saves nearly 5kgs) and is a single piece construction. No external springs or encircling clamps. It respects Honda's mass centralization dictum.

I was warned that this exhaust would damage my bike's midrange because the link pipe was too short and that it should have an "S" bend link pipe.

Akrapovič have validated the design of this pipe on the dynamometer and publish the following graph:

Akrapovič is more likely to know and understand the performance of this pipe than the critics I was hearing, so I ignored the "need" to have a long, S shaped piece of plumbing under my bike reminiscent of what you find under the bathroom basin.

After fitting a less flow restrictive exhaust to your Fireblade you will hopefully have improved its volumetric efficiency. Fitting a less flow restrictive aftermarket air filter will add to this effect, so I also installed a BMC air filter.

However, unless the bike's fuelling is now altered to match this improved air flow through the engine, the air fuel ratios are going to be hopelessly lean and this will attenuate any likely performance improvement.

Unless you intend changing your bike's fuelling, you are not maximising the benefits that improved gas flow can bring. Personally, I wouldn't go to the expense of fitting an aftermarket exhaust without also improving the fuelling. If your goal was simply to make more noise then none of this is necessary.

After fitting my new Akrapovič slip on there was no doubt that the bike was a lot rougher. There was some performance improvement but it was slight. The very impressive stock fueling with the stock exhaust had gone. I missed the smoothness.

Honda's ECUs cannot be flash programmed so the fueling map in the ECU cannot be changed and is the one designed years ago in Japan, optimised for your stock exhaust and reaching the compromises required to meet stringent emissions regulations.

So the next step was the installation of a Power Commander (PC) fuelling module. This device merely plugs into your bike's wiring between the ECU and the primary fuel injectors. No wire cutting is necessary and no permanent changes are made to your bike's wiring loom. If you later wish to remove it, it simply unplugs and the ECU is again solely in charge of fueling.

The Power Commander reads the fuel injector signal from the ECU and modifies this according to its own map, before then controlling the duty cycle of the primary injectors. (Injectors are digital devices and are either on or off. The percentage of time that they are on is called the duty cycle.)

Unlike the ECU, the Power Commander is user programmable, simply requiring a laptop and a USB cable. Pre-existing fuel maps can be loaded onto it or custom maps can be created using the Dynojet software and dynomometer.

Pre-existing fuel maps, supposedly optimised for a particular aftermarket exhaust, can be downloaded or shared from other Fireblade owners. These maps cannot hope to be right for the unique charactetistics each bike has.

The best possible fuel map for any particular bike is one that has been custom created by a tuner skilled in the operation of a brake dynamometer. This is a tedious process that requires creating a new setting at every different throttle position (2, 5, 10, 20, 40, 60, 80, 100%), for every rev range in 250rpm increments, in every gear. These values are either a plus or minus number, adding or removing fuel from what the ECU would have provided. A "zero map" is thus stock fuelling.

(The bike did over 100kms and used about 10l of fuel on the dyno)

Here is a sample fuel map, for a single gear:

(Generated on Excel from data downloaded from the Power Commander's custom map.)

So I took my bike to Julian who owns Superbike Solutions and the only person I know who has done his 10'000hrs on a brake dynomometer. His ability to optimise motorcycle fuelling and extract extra power is legendary.

However, before he can start he has do do two things (that I know of). The first is to inactivate the native lambda sensor, replacing it with a resistor that produces a flat reading. Otherwise the signal from the Lambda sensor will prevent the PC from taking over control of the AFRs. The second is to inactivate the whole Pulsed Secondary Air Injection system (PAIR). This system bleeds air from the air filter box into the exhaust ports in the cyclinder head, ECU controlled by a rapidly switching solenoid valve. The intention of this system is to introduce extra oxygen into the exhaust gases to ensure complete oxidation of carbon, nitrogen, sulphur, and unburnt hydrocarbon; providing the extra oxygen for the catalytic converter to achieve these goals. Quite obviously, extra oxygen added to the exhaust gasses is going to screw with the tuner's measurements of AFRs. 

I had previously inactivated the air inlet duct flap valves.

As Julian points out, the only way you are going to get more power is to burn more fuel. Having created better gas flow through the engine with aftermarket air filter and exhaust, you have the opportunity to burn more fuel, but only if you decrease the AFRs to an optimum for power production.

To satisfy stringent EU and other emissions regulations, the closed loop area of operation aims for an AFR close to stoichiometric (14.7). From the tuner's point of view this is far too lean for maximum power production. This occurs at AFRs in the 13.0 to 13.6 range. Exactly what AFR produces the most power at any given point on the fuel map is part of the dark art of dyno tuning.

My bike first went onto the dyno in February. Note that AFRs cannot be measured with the stock exhaust.

A good six months later it went back on the dyno with the Akrapovič exhaust fitted, but not yet dyno tuned. And then finally after dyno tuning. Blue is stock, Red is after fitting the Akrapovič and Green is after dyno tuning.

Note that this graph is generated in fifth gear at 100% throttle opening.

At first glance those increments appear small. But it would be entirely wrong to just look at the peak figure and decide that this exercise was largely futile. Also pay careful attention to the AFRs, depicted in the third line. Note how incredibly lean the Akrapovič made the AFRs especially between 4k and 8k rpm. This is exactly the intention of fitting the pipe. There is now the opportunity to add more fuel for more power. The Green AFR line is the result of Julian's tuned fuelling.

This particular graph is just one gear at 100% throttle opening. It doesn't tell you anything about how responsive the bike is to smaller throttle openings in lower gears, or how responsive the throttle is in general. Indeed, the difference when actually riding the bike is very obvious. After the dyno tuning it is far more responsive, smooth, and it accelerates a lot harder. The next graph attempts to illustrate this.

This is an acceleration graph. It is really important to note that the units on the horizontal axis here are seconds and not revs (it looks just like revs). This graph illustrates how many horsepower are available to you seconds after pinning the throttle. Note that after just two seconds the bike now has about 15Newton metres of torque extra. After five seconds you have 13Nm and 21 horsepower more than before the tuning. Not surprisingly, this is very readily felt when riding the bike, and noticed by my friend on his S1000RR.


The next graph is a comparison of my plain 2014 with my pal's 2014 SP. (See here.)

His SP has an Arrow titanium can and a stainless steel "S" link pipe.

The SP was on the dyno in March and mine in August but these two engines have an essentially identical torque and power generation. There is perhaps a slight advantage to my bike, so the predictions I was getting that my minimalist pipe was going to rob it of midrange are demonstrably false.

The next graph is a comparison of my bike and the undisputed 2015 Superbike horsepower king, the new S1000RR. This 2015 S1000RR was admittedly stock. 

Note the truly massive advantage my bike has at 4k and 8k rpm. Up until 11.5k rpm my bike is making significantly more power everywhere. After 11.5k rpm the S1000RR takes over, and enjoys a higher rpm redline as well, enabling him to hang onto the gear for longer than I can. You choose what you would like from your road bike. In fairness I have to point out that the S1000RR responds well to Julian's tuning as well. 

(The S1000RR has variable length, servo driven velocity stacks which are responsible for some of the glitches in the torque curve, especially the one near the top.)

The next graph is a comparison of my pal's SP (as above) and his 2013 ZX10R,  both fully tuned.

Here note that up to 11k rpm the Fireblade holds an advantage but after that the ZX10 makes greater peak power and would use this to advantage on a racetrack. Again, choose what you would prefer from a roadbike.

Thanks to Julian's meticulous tuning, my bike is more responsive, feels smoother, accelerates harder and feels much more like the precision instrument it should be. Highly recommended. There's a lot behind the new sticker on my lower fairing:

Keep it safe!

BMW R 1200 GS LC (Liquid Cooled) Tuning

In 2004 BMW released the R 1200 GS, after having had great success in the world market with its predecessor, the R 1150 GS.  Sales of BMW's dual sport range accelerated after Ewen McGregor and Charley Boorman  did “The Long Way Around” traveling across the US and Russia. They later followed this up with "The Long Way Down", where they traveled through Africa.

In 2013 BMW introduced the R 1200 GS LC, their first liquid cooled version of this odd motor configuration since its initial introduction in 1923.

In this article we will cover the fuel tuning of the R 1200 GS LC (Liquid Cooled). 

After tuning many of the previous models, I was quite keen to see what BMW had done in terms of Air Fuel Ratios (AFRs) as the predecessors were pretty lean throughout the rev range up to eighty percent throttle opening. My first impression of the LC was that it was a lot smoother, and that it had a lot more horsepower and torque. As you can see in the graph below, it also gained an extra 500 RPM.

Graph showing the older, air/oil cooled motor in Blue, and the newer liquid cooled motor in Red

I must mention that this LC is a huge improvement on the older bike. The new bike is equipped with ride by wire throttle which also enables different riding modes. In addition, the LC has a quick shifter which in my opinion is really not necessary on a bike like this, a quick shifter lends itself more to sporty machines which this bike is not. However the bike does make quite a nice, self satisfying burble while using the shifter.

After doing the first pull on the dyno, I was quite surprised to see that the AFRs were almost identical to the older models. I was expecting to see a richer mixture in the high load areas. Due to strict emissions regulations, manufacturers have to comply with the usual, agreed “stoichiometric” air fuel ratios (14.7) in all currently manufactured vehicles. Being water cooled, I was surprised to see this AFR carried into the high load areas.

We then fitted a Dynojet Power Commander V (PCV) in order to take control of the fuel injectors' duty cycles, and to correct the factory Air Fuel Ratios. I must add that although this bike is simple in design, it does make a Power Commander installation somewhat challenging if it is neatness you are looking for. All the injector and throttle position plugs are exposed, it could look unsightly if the installation is not done correctly and with neatness in mind.

Once the PCV was installed, we could now start mapping the bike. Because it is a Boxer motor, we always choose to map the cylinders individually. With fitting a Power Commander, the oxygen sensors are eliminated and this allows me access into the exhaust via the standard lambda fittings. This is important as it enables me to get an accurate AFR footprint straight from the bike.

We started mapping Cylinder 1 which is on the left, and targeted an AFR of 13.5 in the low load area, and enriched up to 13.1 - 13.0 AFR in the high load area.

BMW seem to carry a 14.7 AFR all the way up to 80% throttle position (TP). Even with the ECU now being in 'open loop' (oxygen sensors disconnected), the factory map was still lean. The richest I saw from the stock map was a 13.6 AFR.

You will notice from the above map (Cyl 1) 2% to 15% TP and up to 5250 RPM (Low load) requires less fuel, and from 20% to 80% TP up to the rev limiter (High load) requires a substantially larger amount of fuel to be added. Only at 100% TP will you notice that I was required to remove some fuel in order to get to the desired AFR.

On Cylinder 2 the story is somewhat different. At 0% TP I had to remove a considerable amount of fuel to correct the AFR at idle. On this cylinder, the entire fuel map was richer than the left. This can be seen by the negative values in the (Low load) as well as smaller corrections in the (High load).

As the AFR was being corrected, you could literally feel the bike getting smoother and smoother, and another thing I noted was that the water temperature dropped by +/- 5 degrees. 

The graphs below are before and after the mapping session, Blue = Before and Red = After. Unfortunately I have not attached every throttle position for the sake of time.

The first graph is a stepped run in increments of 250 RPM at 5% TP and to make things a bit clearer, following the graph is the raw data.

Graph at 5% throttle position, Blue being before, Red being after.

Raw date at TP of 5%

At the above TP we are targeting 13.5 AFR up to 5500 RPM.

The graph below is at 40% TP and unlike the run at 5% TP it is not a step test but rather a loaded roll on with 10% load and here we are targeting a 13.0 AFR.

Graph at 40% throttle position, Blue being before, Red being after.

Raw data at TP 40%

Finally the graph at 100% TP showing peak gains, Blue being before, and Red being after. 

In my opinion, every motorcycle engine that has to comply with emissions legislation needs some sort of fuel tuning module like a Power Commander (my choice), and this is particularly true for BMW's Boxer engines.

Thanks for reading,
Julian

Superbike Solutions

Dyno Tuning

Dynamometers, or "dynos" have become an integral part of reputable workshops and tune shops, and help the dyno operator diagnose and tune bikes and cars to their full potential.

Dynos are more typically used to improve performance on bikes, cars, trucks etc., but for the purpose of this article we will stick to bikes. Using a dyno to tune and diagnose most problems, be they chassis, electronic, engine or fuel, will require the use of a load controlled or brake dyno, the most common being the
Eddy Current Load Absorption Unit.

Without being able to apply the correct load to a certain rev range and/or throttle position (TP), it is almost impossible to simulate road conditions in order to identify problems.  Simple inertia dynos are great for providing horsepower and torque data, but leave little available for use as a tuning tool.

Dynojet’s model 200i

Modern motorcycles incorporate an ever growing list of technologies. It is important to understand what engine management and electronic systems a particular bike uses. For example, ride by wire, traction control, rider modes etc. Using a load controlled dyno enables the operator to quickly diagnose problems and perfectly tune such high tech motorcycles.

Dynojet’s Model 250i

Understanding the motorcycle before tuning.

There are a couple of things about the bike  you have to know and understand before tuning. Its general  condition,  current state of tune and whether the bike has a problem or not. I have  seen dyno operators spend hours trying to tune a bike when a problem existed that they were not aware of, either on the bike itself or a problem  with the equipment used.

Nowadays there are many tuning modules and methods that can be used to tune fuel injection systems, some more preferred than others. In this article we will discuss fuel injection adjustment units (Power Commander™) and ECU tuning (flashing).

 Before tuning you should have a firm grasp of Volumetric Efficiency (VE).  VE is the efficiency with which air (actually air plus fuel or charge) is moved into and out of cylinders.  This is dependent on various things, such as barometric pressure (density of the air), air filter resistance and air box volume, velocity stacks, forced induction or naturally aspirated, camshaft profile, exhaust system etc. Keeping this in mind is extremely important as it will have an effect on the end result, again lots of time can be lost and damage done to the bike as well as your equipment.

Now that we have some of that out of the way we can actually talk about tuning a bike. We will start with Power Commander™ which is my personal preference as it offers the best balance between ease of use, money spent and results achieved. Power Commander first came onto the market in the late nineties and was very high tech at the time, looking back now the first version  seems a bit archaic. Power Commander II worked on the basis of sensor offset, very similar to the GSXR 750WW stock FI system. Sensor offset, in short, affects the voltage seen by the ECU from the various sensors. From this "picture"  the ECU will calculate and output data to the injectors.

The current Power Commander V (PCV),  is however a really nice piece of kit which is almost infinitely  upgradable. This unit uses direct driver technology, in other words the PCV plugs in line with the injectors and modifies the signal from the ECU to the injectors giving the tuner full control of the injector duty cycle.  Also worth mentioning is that the PCV uses original equipment connectors so no cutting or splicing of the wiring harness is required. Installation is usually straightforward  and removal is simple, returning the bike to factory spec immediately.

Now that you understand how a Power Commander works, I am going to explain how a bike should be tuned. In order to do this job properly you have to have the right equipment (as discussed earlier), knowledge and experience.

Installation of a PCV is pretty simple on most bikes (unless it is a Ducati, some of them take around three hours to install). Knowing what air/fuel ratio (AFR) targets certain bikes will require makes the job easier, but also comes with some experience. In my opinion there is only one way to map a bike kitted with a Power Commander and that is on a dyno using Dynojet’s “Tuning Link” software.

The software takes control of the dyno and the Power Commander at the same time allowing REAL TIME tuning. It is up to the tuner to determine and choose the correct dyno load in order to get  the desired AFR, and this can only be learned with experience. Too much or too little load will result in a badly tuned bike which is either going to be too rich or too lean or a combination of both.

Everything about a tune is of extreme importance and requires accuracy and finesse. For example, at what point in the exhaust the AFR is measured and how many litres of air per min is sampled by the vacuum pump for small opening throttle position areas. Many tuners and riders are too concerned with peak horsepower and torque figures, but in the real world it is all about feel and rideablilty. In other words, connectivity between the throttle and the rear wheel. This is not to say that peak horsepower is not important, but concentrating on only that takes your focus off your goal.

A Dynojet dynamometer, “Tuning Link” and  Power Commander are, in my opinion,  the ingredients for a perfect tune. I know this is starting to sound like a Dynojet advert, but I'm afraid this is a fact.  Over the last eighteen years I have used many tuning modules but they have always fallen short in some way or other. 

Another brilliant product is the Autotune for PCV, this thing fitted to your bike is like dragging me and my dyno behind your bike, constantly keeping the AFR in check.

What I am going to say next  is where lots of people in the industry will disagree with me. (Again!)
In  my opinion, an  Autotune works best and most accurately with a custom map specifically mapped and configured for a specific bike on the dyno. Using a zero or downloaded (canned) fuel map and then waiting for the Autotune to correct each offset would take forever for it to become perfect. Let's imagine a line (pictured below) which is your target AFR at thirteen parts of air to one part of fuel (13.0 AFR).  On the first peak the bike's current AFR is 14.5 and the first valley it's 11.8 and this is all happening at say 15% TP throughout the RPM range. The Autotune now has to work within wide parameters in order to get that TP and RPM range to the correct AFR.

Let's also just throw in some more factors which must be considered. Let’s say on the first day of riding the conditions are 1029 Mbar air pressure, humidity of 40% and temperature  22°C and you have ridden the bike for a hundred kilometres. Lets also say on day one the bike was ridden pretty aggressively (heavier load) with X fuel quality (and we all know the variants of fuel we get in S.A).

On the next day of riding which could be a week later, the conditions are 1005 Mbar air pressure (which relates back to volumetric efficiency being less because of lower barometric pressure), humidity of 23%, temperature 30°C, and the bike is ridden more sedately with Y fuel quality of a different brand. Now the Autotune has to work with these very different parameters and as you can imagine it would take quite some time and kilometres to build a decent  map.

Imagine now that the bike is mapped on the dyno and all the target air fuel AFR’s are perfect. On the road, in real world conditions, this perfect map could be out by a small percentage. Look at the lower  line at 13.0, on the first shorter peak the AFR is closer at 13.2 and the first shallower  valley at 12.8. this means the Autotune has to work within a much smaller range to keep the AFR in check.

ECU tuning (flashing).

With technology growing by the hour and more becoming available to tuning shops, ECU tuning (flashing or reprogramming) has become very popular. In 2007 I got my grubby paws on an interface and software which gave me access to Suzuki ECUs and was beaming with excitement, anticipating that I had everything the factory had put into this thing at my disposal for editing the ECU default settings. I could now turn off the factory limiters, disable lambda sensors and PAIR valves, enable quick shifters and so on. This was great until I got to the tuning bit, I soon realised that this was not going to be easy and was going to take lots of hours if not days.

For example, a K7/8 GSXR1000 has 1150 fuelling cells in the throttle position (TP) table that need to be adjusted if necessary, and I have found that most of the time they do need adjusting. In the inlet air pressure (IAP) table there are 1000 fuelling cells that have to be looked at as well. Now you can imagine how long this would take an experienced tuner, and we haven’t even looked at ignition timing maps yet.

Because the tuning is not happening in real time it means it is less accurate and it takes a patient and knowledgeable tuner to get a perfect tune. Products like Woolich are brilliant for ECU editing and functionality adjustments and I believe that if it is your choice, it has to be used with a logger. A logger will collect AFR data as you are riding and the AFR trims have to then be written to the ECU, much like an Autotune. Again, you have to consider that it will take some time for the map to be perfected.

I trust this has been helpful and informative.

Julian Neethling.