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Old 08-01-2015, 02:10 PM
Richard L Richard L is offline
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Join Date: Oct 2003
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Default Aquamist system in details - no others can offer


List below... unique to Aquamist, not offered by other systems

1. Fittings: ..........Compression tube fittings.
2. Spray jet: .......... All designed and manufactured in house machine shop.
3. Fluid pressure: .......... Constant pressure setting through out the injection cycle. (deadhead at 160psi)
4. Turbine based flow monitoring/failsafe: .......... Sensor is designed from ground up and manufactured in house.
5. IDC based: .......... Aquamist reads fuel flow to ensure it matches engine load in all gears accurately.
6. Delivery method: .......... PWM-valve, controlling flow similar to the OEM fuel injection system
7. True linearity: .......... Only PWM-valve system can guarantee true progressive delivery.
8. Only Aquamist: .......... Supply the entire package to guarantee full system integration. No need to add other parts.
9. Wiring diagram: .......... Specific wiring diagram for the ST platform. Fully tested, no guess work.

Please ask if more details are required. The price/performance comparison chart


1. Fittings:..........Compression tube fittings:
We used to offer push-on fittings since 2002, it was cost effect and mechanically simple.

It was fine until a few years later when higher percentage of methanol was added, as much as 100%! It only took a year or so, we received over-whelming reports for these push-fittings started to fail. "low to server" leakage. We responded pretty swiftly and redesigned a family of new compression type fittings. By 2007, we have replaced all these fittings on our systems, failure reports stopped completely. Sadly the rest of the industry still clings on to these types of fittings to date.

There are a few platforms suffer more than just a few leaks. In particular the BMW N54 forum, most users inject 100% methanol. There were a few fires, causes have always been disputed strongly. We pressed on and start manufacturing the compression-type fittings. We are not going to defend passing on some of the cost of low-volume manufacturing onto our systems.

2. Spray jet: .......... All designed and manufactured in house machine shop.
Aquamist has always designed and made their own jet since 1992 where have supplied over 5K pieces to the Ford rally program over 2 months, Over 12K pieces in total for the next fours years. A few years later, Chrysler. We also supplied bespoke wmi parts to every works WRC rally teams, except the French. The jet has been under a constant improvement since.

The atomisation effect is produced by a small insert behind the opening. We call them spinner. It a few swallow spiral grooves, directing the water under high pressure in a spiral path before existing the jet. Our latest jet uses a 5-groove spinner instead of 2 in the 1990s. This improved the evenness and atomisation to no end. Again manufactures in our own in-house CNC machine shop.

Since 2011, we offered a large range of jet designs, some with inbuilt 15psi checkvalve. The latest CV range has inbuilt 100 micron stainless disc filter.

3. Fluid pressure: .......... Constant pressure setting through out the injection cycle. (deadhead at 160psi)
Aquamist is the only system on the wmi market runs on constant line pressure. This setup can guarantees great atomisation from a few cc to several hundred cc/min. It will of course require an inline Fast Acting Valve (FAV) to complete the task. The response time is only a few thousandth of a second from a PWM signal from the controller. This allows highly accurate flow control. Identical to the standard OE fuel injection system. The dynamic range (very low to full spray) is vast and linear.

A 160psi constant pressure system is always primed and stored on the upstream side of the FAV. This eliminates any ramp up time compared to the pump speed systems, regardless of the line length. Dribble is almost none as there is no line decompression period.

4. Turbine based flow monitoring/failsafe: .......... Sensor is designed from ground up and manufactured in house by Aquamist.
In 2001, we started looking into the commercial turbine flow sensor that meets our price criteria. We eventually found and tested one some 12 years ago. It was made by GEM sensors, a plastic body construction, price was quite reasonable. We discarded it soon after a few months of intensive testing. Unfortunately it was just not quite reliable enough for the engine bay environment.

So we set off and designed our own from ground up, metal bodied and low friction stainless spindle. This all-important device can save your engine from flow issues or simply a few large bubbles in the line. Do not under-estimate the importance of this sensor. A few wmi makers started to offer the same sensor for the last few years with numerous unreliability issues. A simple google search will confirm this.

5. IDC based: .......... Why?
Aquamist reads fuel injector signal rather from a single signal from a MAP or MAF sensor. This is because F-IDC% is the result of multiple sensors and thousands of engineer hours. The fuel flow information is the closest signal to represent true engine load.

Some argued MAP or MAF sensor is as good as F-IDC, think again.

Boost without RPM reference is meaningless. MAF signal is not linear by design. (see image below). The modern DI engines work very much like a diesel engine, basically an excess air system. You will be surprised to know when you are cruising for a short period, the ECU will open the throttle fully while adjust fuel to maintain the speed. This is to maximize the efficiency of the inlet tract. ECU will inject more fuel when power is demanded upon overtaking whilst the throttle is still fully opened. So reading the MAF is not accurate at all on modern DI engines.

6. Delivery method: .......... PWM-valve over the pump speed method
Having an accurate engine load signal is pointless if the delivery is not tracking it accurately. We ruled out using Progressive Pump Speed (PPS) method because it is too slow to respond to engine load changes. This is due to the rotor weight of the pump motor and inertia of a rotating mass.

Here is chart of our FAV system with a random input (Magenta), flow (Cyan) is mirroring well except we clipped the signal over 90%. Notice there is a 95ms lag due to the response time of the flow sensor. The actual flow delay is in the regions of 5-10ms.

7. True linearity: ??. How important?
Only PWM-valve system can guarantee true linear delivery. This is why all car manufacturers use this method to control fuel flow.

Apply a variable voltage to a pump motor will indeed give you a linear pressure response. That is where the linearity ends and all the marketing hypes stops from a PPS system makers when this topic is mentioned.

When the controller sends a 50% duty cycle signal to a 500cc/m system, the system is expected to deliver 250cc/m into your engine. A PPS system will deliver over 350cc/m! Why?
Laws of physics rules here: Flow change through a fixed orifice is proportional to the square root of Pressure change (see the true response curve of a PPS system below). Why then are other wmi makers still using this delivery method? Answer is simple: it is cheap to produce and no one knows any better.

8. Only Aquamist: .......... supply the full package
The aquamist systems do not come with a water tank because there isn?t one size fits all. But we do supply all the parts such as level sensor, in-tank filter, compression fitting and tank bulkhead adaptor.

We supply 3 jets (0.8, 0.9 and 1.0mm), a Tee and two adaptors as standard. Covering the power range of 350-850bhp. Other sizes are available if you are ordering online where you can choose any size combinations between 0.4 to 1.2mm.

With aquamist, you don?t need to add extra parts to complete a reliable working system.

Richard L
aquamist technical support
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Old 08-01-2015, 11:06 PM
mrx79 mrx79 is offline
Join Date: Aug 2005
Posts: 33
Default Re: Aquamist system in details - no others can offer

Great post Richard!
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