Engineering the right fuel solution … less can be more

In light of recent questions I have been receiving, just wanted to discuss the design choices behind our recently released Xtra fuel system.

First of all, when talking about fuel delivery more is not always better. You want to have as much fuel as you need with a little bit of headroom but you don’t want an under-utilized fuel system. The reason for this is that too much actually hurts driveability and performance.

The biggest reason for this is resolution and the fact that injectors are actually mechanical pieces with defined opening and closing times. Injectors are actuated electronically but inside them there are small needles that lift when the ECU turns them on to spray and this is called the injector PW. There is a delay time for them to lift and for fuel flow to stabilize. Usually this delay for port injection injectors is 0.8-1.2 milliseconds (ms). Within this time, the injector is not spraying or the spray is not well atomized. This can cause very uneven delivery from stroke to stroke and air/fuel ratio fluctuations. You can see this kind of phenomenon in older school high horsepower builds where the cars idle very rich and high. These problems are addressed with staged injection system and this is exactly what this Xtra Fuel System is.

Attached is the injector flow data from the injectors used in our kit. I highlighted in red the area where the injectors are opening – you don’t want to operate them in this region! I highlighted in red the flow region in which we are operating at 30psi of boost and 80psi of fuel line pressure.

With the injectors we have chosen the minimum pulsewidth we are running them at is at 1.6ms. The maximum PW we run them at to cover 30% of our total fuelling at 415whp on our shop car is 3ms. This means that any more injectors or any bigger injectors will be difficult to control in terms of pulsewidth eventually not being able to open reliably. Remember that this system has to blend with the OEM DI system in a smooth and predictable manner.

The next question is – are these two injectors big enough for your needs? At 3ms opening time, the two injectors are ran at a whopping 35% duty cycle cycle at 8000 RPM. This is while the aux fuel system covers 125whp worth of fuel. To get to 600whp we need to cover 600-375 = 225whp with the aux system. Let’s take some more stress off the OEM system and we are looking at covering 250whp worth of fuel. At that rate we will need 70% duty cycle from the aux injectors. There is still headroom in the system even at that power level with an 80-90psi rail pressure.

One more thing to keep in mind. Always use as much of the DI system as possible for your power needs. The entire control system in the Focus is built around an efficient DI system so use it to its full potential. This means that the aux system should only be used at WOT and only used as much as there is need. Otherwise, again, driveability, economy, and poor running will result.

These kind of design decisions and A LOT of on-vehicle testing have guided the design of this system and the choice of components used. It’s easy to fall into the trap of “overbuilding.” The best way to maximize performance is building to YOUR power needs. A little headroom is nice. A lot of headroom hurts a lot more and really doesn’t help.

While the big power builds on the Focus are just starting to happen, we have plenty of experience with a similar but slightly older platform and these aux fuel systems. Here’s the result of a two injector throttle body aux injector system we tuned on a MazdaSpeed3 with a GTX3071 turbo making 500whp.

And yes, reliability is there. The proof is in this datalog where the car is driven at WOT to the top of 6th gear (on a closed course)!

If you have questions regarding whether this system is right for your build and power level don’t hesitate to contact one of us on the Stratified team and we are more than willing to answer any questions.

The MazdaSpeed Synapse BPV/BOV

The OEM MazdaSpeed Bypass Valve/BPV  is well suited for up to 18-20psi of boost. Past this point it starts to leak air and torque drops off even if boost is maintained above 20psi. All big turbo cars should upgrade their BPVs. On some cars even the stock K04 turbo is hindered by a leaking OEM valve. The Synapse Valve is the fastest BPV on the market and you can run it as a BOV as well using our Guardian Angel. For this reason we started to carry it right here in our store.
This Synapse valve won’t leak even up to 60psi of boost and the fast response means excellent driveability as well as fast spool and excellent re-spool between shifts. Our BPV of choice for the MazdaSpeed.
If you want more information on why an upgraded BPV is important read our tech article here.

How to determine a WMI Failure on your MazdaSpeed

These days Water-Methanol Injection (WMI) is a vital part of many high horsepower builds on which the cooling effects, increased octane, and added fueling are essential for the motors performance and reliability. Because of this a WMI failure can be catastrophic for a lot of our customers, luckily, if you drive a MazdaSpeed it’s very easy to know if your WMI system is spraying or not. As you can see from the image below when the WMI system on your MazdaSpeed is spraying your boosted air temps (BATs) will experience a sharp drop soon after letting off the throttle. You don’t need to do a full gear run, being under boost for a second or two is enough to create this effect. However this method does not tell you if you have a partial failure in the system or just how much water/methanol is delivered.

A graphical comparison of the conditions present with and without WMI spraying.

Failures of your WMI system can be quite hard to prevent as they are often caused by unforeseen circumstances such as a clogged nozzle, bust line, empty tank, or even a leaking connection. Many of the most popular WMI controller manufacturers (AEM, CoolingMist, AquaMist, Snow Performance) on the market have fail-safe options which will detect failures such as this and warn the driver. Often by the time you have been warned, and responded to the warning, the damage has been done.

Pairing one of these fail-safe enhanced devices with a Stratified Guardian Angel will give you the utmost in safety. Any WMI fail-safe with an output can be very easily configured to trigger your GA. The Guardian Angel reacts to triggers instantly – in less than a tenth of a second. The reaction speed is what is essential here; by the time you have recognized the warning on your dashboard your Guardian Angel will already be venting boost pressure and saving your motor.

Here is an overview of how easily you can connect your Guardian Angel to an AEM WMI fail-safe gauge.

Schematic representation showing how to connect the AEM WMI failsafe guage 12v trigger to the Stratified Guardian Angel.

COBB Accessport V3 with Stratified S-OTS+ Tune for Focus ST


Ford Focus ST Plus Stratified S-OTS+

We are excited to announce that Stratified Automotive is now selling the COBB Accessport V3 packaged with a Stratified S-OTS+ tune modified to maximize your vehicles performance and driveability.

The COBB AP V3 is by far the best tool available to increase the torque, horsepower, and response of your Ford Focus ST. However, as powerful as this tuning tool is, it can be very easy to become overwhelmed when attempting to tune your own vehicle. This is why we created the Stratified S-OTS+ maps which take advantage of our years of experience and engineering background to offer you the easiest, most sophisticated, tuning package on the market.

The Stratified S-OTS+ maps for the Focus ST are modified to accommodate for different types of gasoline fuels available in your area (91 or 93 octane), different launch control settings, flat foot shifting, and we can even include a low boost tune for winter driving or if high quality fuel is not available. Switching between tunes (for different flat foot or launch control settings, and high/low boost map) is extremely easy thanks to the COBB Accessport’s map switching feature (see the youtube link below).

Follow the link below to take advantage of this offer and get your first taste of being Stratified Tuned!

COBB AP V3 and S-OTS+ Package


The Stratified Mazda Shifter Extension and Knob

The MazdaSpeed3/Mazda3 MPS is a very exciting and potent vehicle. One of the few criticisms it has received has to do with shift feel and precision. Missing a gear can be frustrating or can make the difference between a loss and a win on the track.

At Stratified we strive to improve the driving experience of your Mazda. Our engine tuning is second to none and we are now releasing an addition for your shifter that will significantly improve the smoothness, precision, and ease of shifting of your Mazda’s gears!

Check out our new shift knob and extension for your Mazda here!

Happy shifting, The Stratified Team