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* 2008 335i running on 91octane fuel with Dual Cone Intakes and Cat-back Exhaust System. No other modifications.

PWM Meth Injection Kit (N54)......$795
(Current lead time: Approx 2-3 weeks)
Meth Charge Pipe (Required).......$330
This charge pipe is required for use with the PWM meth kit. 3rd party charge pipes may not physically fit due to tight clearances.

This complete system comes pre-assembled, pre-wired, ready to install and fits under your hood. Plus, it is easily installable and removable (less than an hour each way!) It uses your large capacity (approx 5 quarts) factory windshield washer fluid tank and will even alert you when your water/meth mixture is low. No running lines under your car. No drilling holes. Nothing mounted in your trunk. This is the perfect methanol injection system for those who want more power, lower intake temperatures and better drivability but without any real world hassles.

PWM Methanol PnP Adapter………….FREE
(For Rev3 Procede and Rev3 Harness use only)
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This adapter makes connecting the PWM methanol harness to the Procede as easy as plugging in two connectors. No need for any terminal extraction or wire splicing. Installation doesn't get any easier than this!

More Info on our Procede controlled PWM Methanol System:
Unlike other conventional methanol injection systems for your BMW, ours uses Aquamist's race-proven Fast Acting Valve (FAV), stainless steel flow meter (100% methanol compatible) and dual 1.0mm nozzles that are a perfect match for any n54 making up to 500whp. And because our system relies on a PWM-controlled valve to meter methanol, it keeps a constant line pressure. This means immediate response, seamless integration and perfect atomization throughout its wide dynamic range of operation. No waiting for the methanol pump to build pressure. No dribbling during ramp up or ramp down. And best of all, no wasted methanol! This means you get all the benefits of running race gas and an intercooler for a fraction of the operation costs and none of the inconvenience. Also unique is that this is the first available methanol injection system that is actually controlled by the tuning computer (Procede). This means that it regular injection strategies based upon a wide variety of engine controls data (intake temp, fuel consumption, throttle angle, boost pressure, road speed, etc,.) and NOT just boost like other systems. This integration also allows the Procede to adjust the tune itself based upon monitored methanol flow so you will never be caught running high boost without achieving targeted methanol flow. And unlike most other flow meters which uses a plastic bodied flow tube that isn't compatible with high concentrations of methanol, the stainless steel Aquamist flow tube won't fail on you. Read what a professional race gas driver has to say about it:

"Jeff Westphal here, As some of you may know my 335 has the first public copy of Vishnu's new Progressive Meth kit and i wanted to share some of my thoughts on the kit after the first gas tank with my newfound power.

Let me start by saying the install is GREAT. One of the things that stopped me from running meth in the past is that I have an internal conflict with compromising my street car for usability. To define that, as Shiv has mentioned in earlier posts, I am a professional racecar driver racing and developing everything from Rolex GT cars, Dinan Continental Tire 328i's, 700+whp AWD Unlimited Time Attack Subaru's, and various styles of open wheel formula cars from 300whp carbon fiber Lola F3 cars to F2000's and Indy Lights machines. That said, I am CONSTANTLY looking for ways to make a car turn in, brake, and accelerate better, however I have one rule. My street car must STAY A STREET CAR.

Now like anything in racing, rules are meant to be bent, and what I love about this new Meth Kit Vishnu has created is that I don't feel guilty about running a wire underneath the car from the trunk, not to mention loosing trunk space. I love the fact that when meth is low, i get a low washer fluid level warning. The stock integration to the way the car operates is very classy, no compromise.

The important stuff
smile, how does it feel. The delivery of the meth to the powerband and how it interacts with the turbo spool is so seamless, it actually will lend a hand in being more progressive with throttle making corner exits easier to optimize. To me, it feels like an extension of the turbo charger in that there is no on/off light switch actuation like other meth kits, so there is less of a torque shock which makes keeping traction easier, especially with any wheel in the car exiting a corner.

On boost the car is muuuuch smoother than it was with no meth, even at higher power levels. Living in CA we do have pretty crappy gas to tune with, and my car seems to be very octane sensitive as i have experimented with mixing race gas and or octane boosters in the past when i had only a procede on the car. With Meth active, the power delivery is just what i wanted (smooth), and the meth activates early on in turbo spool (around 5-6psi) which tells me that i WONT have a high threshold moment where meth is starting to flow at high boost and the motor could be vulnerable for a second. This kit seems to cover all bases on ease of use, safety, and pushing the envelope for more power (which all chassis engineers hate, but we all love).

Big thanks to Shiv and Rob at Vishnu for installing such a great product on my car. I am extremely pleased with the results. I will keep the community posted as I get more feedback from the car and drive it some more. Off to test our redesigned Time Attack monster, till next time!"


More Technical Tidbits from our friends at Aquamist:

The differences between a

PWM -V system (same as OE fuel injection system)
PPS system (Progressive Pump Speed).

Who manufactures what?
- Devilsown, Snow, Coolingmist and Labonte make PPS systems.
- Aquamist and FJO are the only manufacturer making the PWM-V system.

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)

- PPS system: low flow = low pressure = poor atomisation. (video)
- PWM-V system: constant pressure at any flow = constant good atomisation. (video)
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.
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
Without the dynamic range, PPS system can only operate in a narrow power range of
2x. Not really ideal for Daily Driver.

- 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.
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 environment. Cost is higher.
PWM-V system production cost is high. PPS systems are normally 30% lower to produce. But overall performance is 5x poorer.

I will be posting in links and videos to support the above statements - may not be immediate but it will be done.


You may have seen this thread before from another forum. It is my attempt of explaining how different type of systems work and its advantage and dis-advantage, based on current systems offered. It is a my view and findings, please do chime in and discuss. I will update it from time to time.

1) Single-stage
2) Two-stage
3) Progressive Pump Speed system (PPS)
4) PWM Valve controlled system
5) System that will integrate well with third party controllers.
6) Direct port


The single stage:
(1st September 2007)

The single stage WAI (water alcohol injection), as the heading implies, is not as basic as most people expects. It some cases, it will out perform a two-dimension progressive system. Please do not underestimate it. I will try to explain briefly why after the next few paragraphs.

Having a single trigger point and a fixed flow rate, one will get to know its effect on your engine very quickly. Due to its consistent repeatability, it is very easy to tune. This type of system is normally set to start spray in the peak torque region, where the engine is most likely to knock.

As the RPM climbs, the ratio of water to mass air tends to decrease. This may not be a bad thing because the tendency to knock is also lessen as the wastegate starts to open and prevent the boost pressure from increasing further. The volumetric efficiency of the engine also decreases as RPM climbs, breathing in less air. This also has the effect of reducing the engine's tendency to knock, demand of WAI flow is less. Unfortunately some engines do require continuous WAI flow at higher RPM due to heat build up through friction and turbo efficiency.

A 2-D pump speed system based on manifold pressure is a little bit tricky to tune compared to the single stage system. The user has to set the start and finish pressure points, those points are sometimes set at a considerable distance apart. Matching those operation points in a 3-D environment such as RPM/Boost
ramp (nonlinear) is quite difficult. We will be discussing it in more details later.

1) Low cost, simple and dependable.
2) Easy to tune
3) Very effective on a stock factory set up with a few pounds of boost extra.

1) Dynamic operating range is narrow, may not be as effective on a high RPM knock suppression.
2) For high power/ high % alcohol applications, considerable fuel has to be taken out (boost clamp) to make the afr tolerable. Some sort of failsafe mechanism is necessary to prevent engine destruction when the WAI fails to delivery the correct flow.


The 2-stage system
(2nd September 2007)

At present, adding a second manifold pressure switch to active an additional solenoid valve at a higher manifold pressure is the definition of a 2-stage system.
This arrangement gives the system greater flexibility as well as extending the flow range. It addresses the problem associated with the single stage system, too much flow at the start and not enough when RPM climbs beyond the wastegate setting.

As the system is based on boost trigger, it still won?t address the RPM related flow. For a turbo charge engine, the most significant active regions are the boost ramping stage and engine?s maximum torque range. A two-stage system fits these two regions nicely, allowing the some form of cooling demand during the
ramp-up stage. The second stage provides the in-cylinder cooling and knock suppression as the engine is under the most stress or highest BMEP (Brake Mean Effective Pressure).

1) Relatively low cost to give mark improvement to the single-stage system.
2) Provides well defined triggering points during the boost cycle.
3) Minimising the under/over flow problem.

1) Trigger points requires some time to set up.
2) Triggering points may differ on each gear if you have a fast spool up turbo
3) Require a bit more care during tuning

WI curve


Propressive Pump Speed system (PPS)
(2nd September 2007)

Does the pump speed controller perform better than a two-stage system, you are about to find out.

Changing pump speed merely put more pressure behind a nozzle, hence more flow. This type of system is commonly known as a progressive system (pump-speed).

Let us examine how much a M5 nozzle will flow between 40psi to 160psi. According the chart below (Published by Hago, a well know US oil heater nozzle manufacturer), the flow starts from 200cc/min and ends at 400cc/min., when pressure is increased from 40psi to 160 psi.


Almost all PWM pump controller on the market uses Shurflo pump, designed to operate between 0-150psi. The heart of the system is an electronic motor speed controller, vary the speed according to a sensor. It could be a MAP sensor, a MAF or any sensors that read engine load. It is normally a 2-dimensional system. A manifold-pressure type system does not take into account of any RPM change.

A swirling type atomising nozzle requires a head pressure of at least 30psi to produce a decent mist. Droplet size is very important to the inlet cooling ability and even cylinder distribution. Let say the system pressure starts at 40psi (as shown on the chart) and ends at 160psi. One can assume you will get a 4x flow range? In practice, not so, according to the chart, you will only get a flow change from 200cc/min to 400cc.min (see M5) instead of 200cc/min to 800cc/min. Flow/pressure obeys the square-root law.


Being "progressive" implies a reasonable dynamic range between start and finish. How progressive? Almost no one ever questions this. Most people just assumes it covers all the flow requirement between 10psi to 20 psi of boost once the range-dials are set on their pump speed controller. In practice, you cannot expect the same M5 nozzle will serve a wider operating range between 5-25psi by merely changing the dial, the range is governed by the law of physics and not a technically advanced motor speed controller.

If one would want to delve deeper into the subject, as the title demands. So the subject will continue?

Just to recap, good dynamic range (pressure/flow span) is the main factor one should expect from a "progressive" WIA system. Let see what a 150psi system can really offer. We shall take into account of the effect of manifold pressure, inline checkvalve as well as minimum pressure for a good atomised spray.

For example:
1) Manifold pressure start: 10psi
2) Manifold pressure ends: 20psi
3) Inline checkvalve crack pressure: 30psi
4) Minimum pressure of the atomising nozzle: 30psi.

When the system starts: it will instantly see an initial back-pressure of 60psi and a final back-pressure of 70psi (extra manifold pressure). The actual dynamic pressure range is now from 60psi to 110psi. The system can now only manage a 35% change in flow, far from one would imagine a 150psi pump system should perform.


There are other factors that could also affect the performance of the 2-D progressive pump system. It may be a subject for a later discussion, depending on the interest of the readers. Chart below is a predicted performance of a progressive system compared to a single and two-stage system. I hope there will be people chiming in to add to this. At first glance, it doesn't appear there is a distinct advantage for adding a progressive controller. Adding a bigger nozzle doesn't alter the dynamic range, it just shifts the whole curve higher.


1) Easy to set the start and end point.
2) Some correlation between manifold pressure and flow
3) Cost effective.

1) Limited dynamic range, system becomes less effective after wastegate pressure. (see addendum)
2) Extra cost can easily be spent on a higher performance two-stage system with greater dynamic range .
3) If the 2-D system is used to replace high % fuel with alcohol, re-mapping the 3-D fuel map will be very difficult due to the wide dynamic flow range demanded by the engine.
4) Pulsing due to demand switch ~20psi ripple. (some system by-pass this switch, but risking system pressure beyond design limits).
May require further explaination
5) Response time due to inertia of a rotating - laggy (start) and over-run (stop).
May require further explaination


PWM valve water injection system:

These systems require a stable system pressure, normally held between 100-125psi. An inline solenoid valve and a PWM controller that modulates the opening and shutting time to meter flow. Before getting too deeply into the subject, note that there are two types of inline solenoid valves on offer.

Type #1

Pulse width modulation type:
(Optimum operating frequency range: 30-80Hz)


This type of system resembles the modern automotive fuel injection system. The system can also be controlled by a third party EMS with a spare PWM channel. Delivery rate can either be mapped or mirroring the fuel injector duty cycle. The latter makes tuning very simple.

The valve behaves similar to an on/off gated button on a garden hose. The longer the gate is opened, the more the flow (duration). Alternative, rapid opening/shutting the gate per second (frequency) also control the flow. The common EMS uses duration for load change and frequency for RPM change. The dynamic flow range is extremely wide, 100:1 is normal.

A WAI valve should closely match the closing and shutting characteristic of a fuel injector. This is important for fuel flow mirroring algorithm since the modern EMS has a correction stage to compensate the opening delay and shutting delay.



Type #2

Proportional lift type:
(Chopped DC (~400Hz) or DC current)


more information from, the maker.

This type of valve resembles the action of a rotary water tap. As more current is applied to the valve coil, the valve opens more. It is a very nice way to control flow.
There are a few minor problems associated with this type of valve: Atomisation at low flow and lift variations (hystersis of the magnetic circuit), approximate +/- 10-15% flow deviations.

All in all, it will deliver liquid well compared to the PPS system. There are some similarities between the two. The nozzle tip pressure is directly proportional to the flow. This is because the proportional valve acts like a variable restrictor upstream of the nozzle tip. Resulting in: restricted flow = low pressure. Low pressure = low atomisation.

NOTE: This type of valve has a typical open time of 4ms and closing time of 4ms at its designed voltage. It is too slow to be used as a true PWM valve. Open/close speed can be increased by over-voltage pulses. The design of spider valve is also vastly different from the PWM valve.



It is important to know some basic facts between the Proportional valve and PWM valve systems before choosing this type of system.

Here is an illustration of the difference in construction of the two valves, made by Clippard. Notice the proportional lift has a stiffer spring rate than the PWM valve, enabling the PWM valve to perofrm full on//full off a great deal easier.


Because the way the PWM system meters its flow based on a simple pulse width, it is very accurate. Further precision can be increased by introduce a suitable RRFPR to maintain Manifold pressure against water pressure. It is also possible to factor in a small duty cycle increase to the valve relative to boost increase.

Final consideration: If you are planning in future to create your own MAP via a third part system - only the "PWM-valve" can be driven directly by the ECU, matching the principle of a modern "fuel injection system" in every respect. Warning, before rushing off making your own system, Clippard valve is only rated up to 100psi, even with the smallest orifice version. The larger orifice type can only sustain 25psi. Multivalve is needed for flows over 500cc/min.