What is the real difference between Aquamist and ...
Nov 10, 2009, 04:41 AM
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What is the real difference between Aquamist and ...
The differences between an
Aquamist PWM -V system (Pulse Width Modulated - Valve)
and
PPS system (Progressive Pump Speed).
Delivery method:
- PPS system: controls flow by changing pump speed.
- PWM-V system: controls flow by pulsing an inline valve (same principle as the OE fuel injection system)
Atomisation:
- PPS system: low flow = low pressure = poor atomisation (video)
- PWM-V system: constant pressure at any flow = constant good atomisation. (video)
Consequences:
Poor atomisation results in large droplets resulting in uneven fluid entering each cylinder.
Modern manifolds are not designed for transporting fluid loaded air.
Response time:
- PPS system: slow response due to rotational inertia of the pump. typically between 0.1 to 0.5 second.
- PWM-V system: Fast response time. typically within 0.003 second.
Consequences:
In consistency in Air-fuel ratio under transient load due to the pump's inability to change speed.
A rotating mass has ample inertia resulting in after-spray dribble. (video)
Dynamic range:
- PPS system: only produce 2x between 50-200 psi. (A typical PPS system operating pressure range)
- PWM-V system: comfortably manages x10 minimum flow range between 0-100% duty cycle
Consequences:
Without the dynamic range, PPS system can only operate in a narrow power range of 2x. Not really ideal for Daily Driver.
Linearity:
- PPS system: A linear "pressure" increase does not produce a linear "flow" through an atomisation nozzle. Error can be as much as 120%+.
- PWM-V system: Flow linearity is in the region of 5%, can be improved by a custom designed valve on request.
Consequences:
Wacky AFR under different load and engine speed is common - nightmare to tune.
Cost considerations:
- PPS system: It is basically a motor speed controller, design cost is low. Regardless of how many gizmos are included.
- PWM-V system: Each PWM valve individually calibrated by technicians to ensure flow consistency under harsh engine bay environments. Cost is high.
Consequences:
PWM-V system production cost is high. PPS systems are normally 30% lower to produce. But overall performance is 5x poorer.
I will be undating more links and videos to support the above statements - may not be immediate but it will be done.
Last edited by Richard L; Nov 10, 2009 at 01:30 PM.
Nov 10, 2009, 04:42 AM
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Delivery Llnearity comparision of the two systems
Image below is an ideal chart that all progressive delivery system should follow.
Aquamist will track the dotted line within ~5%. We are working to improve this further in the coming years.
As the voltage increase along the horizontal scale (0-5V), you will see a linear flow increase on the vertical scale. A M5 (500cc/min at 250psi) is used for this example. At 2.5V, the flow is exactly at 250cc/min. At 5% error, the flow will deviate by 12.5cc/min on either side of the dotted line. This is what aquamist has achieved to date, with no droplet size increase at the low end due to constant line pressure.
Image below is a PPS (progressive pump speed) system at work. This is not just a
theoretical plot, it is confirmed in real life tests. Immediately you can see the delivery line is far from straight.
At 20% or 50psi, the flow has almost reached 50% of the M5’s maximum flow capacity. The error continues all the way to 100% or 250psi.
According to the above chart, when this system is delivering fluid based on boost pressure or MAF, the error will cause great problem of AFR if the fluid contains high percentage of methanol. It the fluid is water, it will cause overcool and slow down the flame speed too much. This only one of the many problems of PPS system which I will discuss later.
You should have noticed why a PPS is marketed in such as way that the fundamental flaws are covered up with slick, gizmo-orientated presentations.
Image below is a PPS (progressive pump speed) system at work.
Here is recap of the performance of the two systems side-by-side, notice the big difference?
I will continue to reveal the “real difference” of the a PWM-V system against the PPS.
Last edited by Richard L; Nov 10, 2009 at 02:46 PM.
Nov 10, 2009, 04:43 AM
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We are slowly changing the push-in fitting to the new compression type.
Below is a picture of the HFS-6 photographed recently, see the new fittings and new in-tank filter (soon):
Last edited by Richard L; Nov 14, 2009 at 12:49 PM.
Nov 10, 2009, 07:49 AM
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I thought you had already done a thread like this. Yeah but like the man said Aquamist is the only way to go when adding meth to your setup. Especially when you have a big turbo and stock motor.
Nov 10, 2009, 01:23 PM
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I have done it one but not in such details. I get asked this PPS/PWM-V question repeatedly so it would be easlier to put it down on a thread, with references to real life situations.
Last edited by Richard L; Nov 12, 2009 at 01:06 AM.
Nov 11, 2009, 02:58 PM
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i recently worked with an aquamist system and was wondering what the purpose of the accumulator was? i've done some off topic testing with positive displacement pumps like the shurflo and aquatec and turbine type flow sensors. these types of setups are very very "pulsey" if you will so perhaps the accumulator is used to dampen the output from the pump? otherwise the output from the flow sensor could be very noisy.
it seems like you can only use an accumulator if you have a valve or solenoid of some kind because the bleed down is incredible. so perhaps it has to do with stabilizing line pressure during initial openings of the valve?
just wondering...
it seems like you can only use an accumulator if you have a valve or solenoid of some kind because the bleed down is incredible. so perhaps it has to do with stabilizing line pressure during initial openings of the valve?
just wondering...
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Nov 11, 2009, 09:06 PM
#8
^^^ Yes you are correct, pressure drops ever so slightly in the line and at the valve as the pump cycles. The accumulator makes up for that slight drop (150psi down to 85psi~) keeping pressure consistent and stable at the valve allowing for faster response better atomization and consistency. Another reason Aquamist sets the bar higher. 
Evan Smith
Evan Smith
Nov 12, 2009, 03:23 AM
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^^^ Yes you are correct, pressure drops ever so slightly in the line and at the valve as the pump cycles. The accumulator makes up for that slight drop (150psi down to 85psi~) keeping pressure consistent and stable at the valve allowing for faster response better atomization and consistency. Another reason Aquamist sets the bar higher.
Evan Smith
Evan Smith
Nov 12, 2009, 09:42 AM
#10
Not only do they set the bar higher but there customer service is second to none. My employer got a phone car at 6:30pm eastern standard time in regards to purchasing some more kits and possible getting a banner in his showroom. Now I used to love in London and I know the time jump. This woman and Aquamist are so dedicated that making a phone call across the pond at 11:30pm their time is no problem I was shocked and suprised at how good they treat their vendors. AQUAMIST FTW again and again
Ok ok, I see your 6:30 eastern and I raise you 6:00PM Pacific coast time! lol Richards dedication is beyond anything I have seen as far any industry! The man doesn't sleep! We talked for an hour and a half just to see what things we can do to make Aquamist better, and how just now competitors are attempting to coping their engineering... Just 8 years to late lol
I'll explain Aquamist's PWM -V system vs everyone else's PPS system;
A water/meth injection system is considered a secondary fuel source correct? (it either adds fuel ie meth, or allows you to use less ie H20)
How does the factory fuel system control its volume and flow of fuel into the motor? (well it obviously doesn't "pulse" or change the voltage to the fuel pump?)
A factory fuel system controls volume and flow characteristics by opening and closing a valve for different lengths of time depending on the engines fuel demand. This is know as a "injector"
So, if the the factory fuel system doesnt control flow or volume of fuel given to the motor by altering voltage or "pulsing" the on off switch a bunch of times to the fuel pump... why therefore should your secondary fuel system do it that way?!
Thankfully for the past 8 years Aquamist with their HSV(High Speed Valve) and their new FAV (Fast Acting Valve) Engineered the solution. Allowing for a perfect H20 to Fuel ratio, and precision that of OEM! PWM-V FTW
Thanks
Evan Smith
Nov 12, 2009, 02:53 PM
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^^^ Yes you are correct, pressure drops ever so slightly in the line and at the valve as the pump cycles. The accumulator makes up for that slight drop (150psi down to 85psi~) keeping pressure consistent and stable at the valve allowing for faster response better atomization and consistency. Another reason Aquamist sets the bar higher.
Evan Smith
Evan Smith
Nov 14, 2009, 10:27 AM
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Can someone pm me the best places to buy an HSF-6 or even 5 for that matter? I'm running out of time and it's really surprising how hard it is to find them for sale.
