RSR Pro 1000 PSI Turbo Water Injection

It's the pumps. It's always the pumps. They can never be too small or too powerful, or, as they say, too rich or too thin. Usually they are fat and noisy or small and pitiful in their output. When they are fat and noisy and only come in one size they, most likely, are diaphragm pumps that crawled out of bilges on boats or escaped from agricultural spray systems.

Our high pressure pump pictured above to the left is small, is 1/3 the weight, and runs up to six times the pressure of the typical water injection kit pump pictured on the right. Higher pressures means far better atomization. It draws less that 3 amps @ 1000 psi.

Before we show you how we do this you need to know a bit about water injection's history and about RB Racing's history using water injection. Part numbers and pricing are listed below.

Part Numbers, Flow and Horsepower Ratings & Number of Nozzles

1000 PSI

Water Injection System
Description **
Nozzles 90 ** degree
1/4" NPT
Hardware: Note: Does not include any reservoir.
2500 PSI Hose
160cc's / minute
300 hp:
12% Water to Fuel Ratio
1000 psi operation
Dual Nozzles
3.5 Amp electrical load
Two (2) "B"
Nozzles with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; LED acivation light; Two B nozzles.
8 feet 2500 psi hose

180cc's / minute
350 hp:
12% Water to Fuel Ratio
1100 psi operation
One Nozzle
3 Amp electrical load
One (1) "D"
Nozzle with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; LED acivation light; One D nozzle
8 feet 2500 psi hose

180cc's / minute
350 hp:
12% Water to Fuel Ratio
1000 psi operation
Dual Nozzles
4.0 Amp electrical load
Two (2) "A"
Nozzles with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; LED acivation light; Two A nozzles.
8 feet 2500 psi hose

200cc's / minute
12% Water to Fuel Ratio
780 psi operation
Dual Nozzle
3.0 Amp electrical load
Two (2) "C"
Nozzles with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; Two C nozzles.
12 feet 2500 psi hose
210cc's / minute
400 hp:
12% Water to Fuel Ratio
720 psi operation
Triple Nozzle
3.0 Amp electrical load
Three (3) "A"
Nozzles with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; LED acivation light; Three A nozzles
8 feet 2500 psi hose $725.00
240cc's / minute
450 hp:
12% Water to Fuel Ratio
600 psi operation
Dual Nozzles
2.0 Amp electrical load
Two (2) "D"
Nozzles with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; LED acivation light; Two D nozzles.
8 feet 2500 psi hose $695.00
260cc's / minute
495 hp:
12% Water to Fuel Ratio
520 psi operation
One Nozzle
1.75 Amp electrical load
One (1) "E"
Nozzle with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; LED acivation light; One E nozzle.
8 feet 2500 psi hose $650.00
280cc's / minute
525 hp:
12% Water to Fuel Ratio
340 psi operation
One Nozzle
1.0 Amp electrical load
One (1) "G"
Nozzle with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; LED acivation light; One G nozzle.
8 feet 2500 psi hose $650.00
280cc's / minute
525 hp:
12% Water to Fuel Ratio
220 psi operation
Dual Nozzles
1.5 Amp electrical load
Two (2) "E"
Nozzles with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; LED acivation light; Two E nozzles.
8 feet 2500 psi hose $695.00
300cc's / minute
560 hp:
12% Water to Fuel Ratio
160 psi operation
Dual Nozzles
1.0 Amp electrical load
Two (2) "F"
Nozzles with anti-vacuum
valve and filter

90 degree 1/4" NPT
Pump; hose fittings; 30A Relay;
Hobbs Pressure Switch; On/Off Switch; Wiring; LED acivation light; Two F nozzles.
8 feet 2500 psi hose $695.00
Weld-On Aluminum Nozzle Boss; Counterbored for flush interior capture of nozzle.
For All Nozzles
Requires a .750" hole be machined on the mating surface
1" Overall Length
.875" Diameter w/ .750" diameter step .125" deep

** These are bench tested figures: Other nozzle combinations available.  Nozzles are $40.00 each purchased separately.

RB Racing: Art and Science 1998

The blue rail of this BMW K1200RS/GT/LT Turbo Plenum is a port water injection system with four nozzles. Water Injection is the best way to make power when you are dealing with forced induction systems. In this case we are running a turbo on a 11.5:1 high compression bike and doubling the horsepower with reliability. There is really nothing new about this...We've been doing it for nearly 30 years but people were doing it way, way, before we ever came on the scene.

The red rail is the secondary fuel injectors. You end up with eight fuel injectors and four water injection nozzles on a 1200cc motorcycle. More holes than Swiss cheese. Hard anodized inlet plenum. Later on, when we ran a series of tests, we decided that the port nozzle design wasn't a good idea as there was a slight variation in flow rates...little consistency.

12 O’Clock High: Six Decades Earlier

Sir Harry Ricardo and the High Speed Aero Engine. Incredibly complex, turbo-supercharged, radial and V-12 engines that had to take off with a full bomb load in conditions that were never ideal. You might think you put the pedal to the metal but, for the WWII fighter and bomber crews, death was always part of equation...It wasn’t a game and if you couldn’t squeeze out the last bit of horsepower you were dead. It was in this environment that water alcohol injection technology was refined. Wright Cyclone engine pictured above.

Nothing has changed except the passage of time. The pioneering research was done by people like Sir Harry Ricardo, the researchers at NACA in Langley Field and all the aero engine designers of the period entering the Second World War. Give credit where it’s due and don’t think the sun only started rising yesterday. Rolls Royce Merlin engine pictured above.

For an interesting read you can download a PDF from NACA dated 15 August 1942. It still applies today. A second NACA PDF also validates the use of water injection.

Papa’s Got a Brand New Bag

Colorful 3D ribbon graphs, literature full of mumbo jumbo, and electronic controls full of potentiometers and blinking lights some 60 years later is nothing but a new box to hide a heritage born in the skies over Europe. People want you to believe that they invented water...well, people spend billions of dollars to buy brand name designer water in trendy plastic bottles that end up in the ocean and land fills, so anything is possible in today’s gadget-filled world. It’s a brave new world but to paraphrase a popular political phrase..."It’s the water Stupid!". If you want your high output turbo or supercharged motor to avoid engine destroying pre-ignition and detonation you are going to have to employ water injection and the way it has to be done was set in stone a long, long, time ago.

Pictured above is a schematic of a WWII aero engine water/methanol regulator...designed over 60 years ago!

Monster Marine Diesels

Engines bigger than your house and they use water injection to reduce emissions! Diesel engines obviously can derive some benefit from cooling the combustion process. This is really big industrial stuff so don't think about adapting anything. The company is Wartsila. If you're a diesel junkie these things are the pyramids.

Sex Boost Rock & Roll...The Formula 1 Era

It's 1987 and in your dreams you have your FOCA pass and a long-legged, high cheekboned bird of paradise has her tongue in your ear and her hand in your Nomex on the biggest yacht in Monaco's harbor. The shrimp cocktails and the fine wines flow and you've just qualified on the front row with your 800 hp turbocharged F1 missile. All abs and no flab, not a love handle or a stretch mark in sight, and your eyes focus like a Peregrine Falcon in a 200 mph dive. Wake up fool! You're wearing glasses, baggy shirts are covering your love handles and you're seeking status and approval from other idiots and you sure aren't in Monaco.

Time for us to reflect on the big boys, what was, learn a few things, and then slink back to our pitiful existence. Monday to Friday trying to pay the bills and seeking meaning through our toys.

Renault started it all in 1977. They always start it all. First with turbos, first with pneumatic valves, first to use water injection, first with a lot of things. Heavy thinkers, great engineers, Ecole Polytechnique. Think R5 Turbo. In 1983 the F1 Renault showed up with a 12 liter water tank, an electric pump and pressure regulator and about 600 hp from 90 cubic inches. By 1986 the power had been increased to 870hp but the water injection was gone as the fuels had improved.

In 1983 Ferrari also claimed to be the first to use water injection. With the cooperation of their fuel supplier Agip they managed to suspend water in the fuel in microscopic emulsified drops in a ratio of 90% gasoline and 10% water. They won the constructors championship. Like Renault they dropped water injection when heavier fuel elements (toluene) came into use.

Porsche and, later on, Honda showed up and cleaned house to the point where turbos were banned. Honda relied on a mixture of 84% toluene and 16% heptane and ran up to 58 psi of boost to achieve up to 1000 hp. Honda did not use water injection.

Don’t Drink the Purple Cool-Aid

Turbo gurus, blindly following false prophets, preach the doctrine of "You Can’t Run Them Too Rich" and demand that you slay the infidel detonation by richening things ad infinitum. They should have read Sir Harry’s Book, The High Speed Internal Combustion Engine, but as they say, those who do not know history are destined to repeat the same mistakes. Sir Harry Ricardo proved once and for all that you can richen things up to a point but, beyond this, detonation is going to rear it’s head no matter how much fuel you throw at it and, in fact, the extra fuel may increase the tendency to detonate! Going rich beyond the well-defined 12.5:1 boost maximum power air fuel ratio is going to cost you power.

Studies in the early part of the Second World War proved conclusively that as you add water you can lean out your overly rich mixtures as you raise your boost pressures. As Sir Harry Ricardo stated..."By the introduction of water...the fuel/air ratio could be reduced once again; in fact, with water injection, no appreciable advantage was found from the use of an over-rich fuel/air mixture". So much for those whose perspective begins with their birth date.

I Don’t Want To Learn...Just Give Me The Answers!

1. Maximum Torque occurs at a 13.2:1 Air Fuel Ratio.
2. Transitional Fueling and Maximum Boost Air Fuel Ratios are about 12.5:1.
3. Water Injection is most efficient with a 50/50 water alcohol (or methanol) mixture.
4. Methanol, as an additive, is not a practical choice as it is prone to pre-ignition in higher than 50/50 percentages, is not safe to handle, and is not readily available. It's a good choice, but not necessarily the most practical one when you need some in a hurry. Methanol is usually found where racing fuels are sold.
5. Denatured (ethanol) alcohol, typically 95% pure, is available in paint, hardware, and Home Depot type stores in gallon containers for about $10.00. Expensive but available everywhere. Isopropyl alcohol can be used but it is often 30% or more water by content.
6. Water Injection allows ignition timing to be more aggressive or closer to stock. In other words boost does not automatically mean retard your timing.
7. Excessive amounts of ignition retard will cause a loss of power and overheating.
8. Water to Fuel ratios should be based on weight and not volume.
9 . Water weighs 8.33 lb per gallon.
10. Alcohol weighs 6.63 lb per gallon.
11. Air weighs .080645 lb per cubic foot. It takes about 150 cubic feet of air per 100 horsepower. It takes about 12 lb of air per 100 horsepower.
12. Water or Water / Alcohol to Fuel Ratios are between 12.5% to 25%. This means Air to Fluid Ratios are between 11.1:1 and 10.0:1 with water injection.
13. Maximum water delivery should be in higher load low to mid rpm ranges tapering somewhat at peak rpms where load is less.
14. Atomization of the water mixture is directly related to it effectiveness. Finer droplets cool the inlet charge better and with less mass they navigate the inlet plenum easier for more equal water distribution.
15. Don’t flow water through an intercooler.
16. Atomized water, just like fuel, does not like to make turns thus making accurate distribution something to think about. This is why port fuel injection is the norm. Water is a fluid just like your fuel. Using high pressures
up to 1000psi for the best atomization and even distribution. Using individual port nozzles is a bit complicated for a large # of cylinders and makes control difficult as nozzles vary in their output.
17. The introduction of water will allow higher boost pressures to be run without detonation. Higher pressures will increase torque. It’s always about torque.
18. Racing high octane gasoline should be used for all forms of competition and for higher than normal boost levels. Water injection as well as charge cooling should be used with racing gas. 91/92 Octane pump gas simply will not cut it. Water spray cooling of the intercooler is a good idea.
19. Fuel Injectors operate in the 1 Millisecond range (.001 second) and are not capable of long term usage for H20 as they will corrode or rust shut in a very short period of time. Unless a solenoid can open as fast as a fuel injector it should not be used to "pulse" water injection events as flow is not directly related to "duty cycle".
20. Varying voltage to water injection pumps or using similar schemes is a recipe for disaster. You have to eliminate the variables, not increase them.
21. Fuel Injection pumps cannot be used for water injection. Water is conductive. Gasoline is not. Water will corrode an efi pump shut in a very short period of time.
22. Water injection has a cooling effect on the engine head, valves, and cylinder. Exhaust temperatures (EGT) are largely unaffected at recommended water / fuel ratios.
23. The cooling of potential hot spots in the combustion chamber defeats pre-ignition, the most destructive form of uncontrolled or unplanned combustion.
24. Higher static compression ratios will require a higher percentage of water or water / alcohol.
25. No, water does not burn. We are not combusting the hydrogen in the H2O.
26. At around 13.2:1 or fuel air ratios of .75, EGT’s will peak.

27. People will try to selectively edit their way to get you to use water injection by stating "One can basically double the power output of an engine using water/methanol" and "It was used effectively in Formula 1 before being banned for adding too much power". This is pure bunk. Water or water/alcohol/methanol does not make power...superchargers and turbochargers make power. The cooling effect of the water injection only allows you to run higher boost pressures and leaner mixtures without engine damage. The increased density or higher pressure ratio is what makes the power, not the water. The last time we checked water wasn't a very good fuel. Water Injection definitely does not give "a 5-15% increase in fuel economy" as some marketers clain.

28. Ferrari suspended water in their fuel during their 1980’s Formula1 period. We don’t recommend that you try this...although Acetone will mix with water.

Running Water Injection since 1980

Harley-Davidson, Suzuki, BMW, Hondas, Kawasakis, Triumphs etc....all our race bikes have run water injection since the early 1980's. The thermal loads, even with intercooling and racing gasoline are too high and without water injection you simply can't run mile after mile on the long course at Bonneville without some additional form of charge cooling. Running 22 psi of boost between the two mile and four mile markers day after day and no engine failures. Mike Geokan's famous #226 Blue Bike and his new Bonneville Bullet use RSR Water Injection.

Nearly 30 years of water injection and turbos. We have been in the high performance business since the late 1970's.

Water Injection History at RB Racing

Early Systems: Way back around 1980 and a few times later on we did not even use pumps. We simply used boost pressure to push water into the engine through a small nozzle. What we would do was hard anodize an aluminum water container designed to be bolted to a specific location or in some cases to be collocated with the license plate at the rear of the bike (see above photo). We machined up o-ring sealed screw-on caps. The hard anodization was to prevent corrosion from water, methanol, or alcohol mixtures. We would employ a viton sealed check valve with a specific cracking pressure, typically around 5 psi, and flow the water through a small jet, usually .6mm, into the turbo inlet. You could not flow the water after the turbo as there would be no pressure differential. Flowing water through the turbo could cause problems with throttle shafts, mass flow sensors (LE Jetronic) and had a tendency to corrode any pot metal structures. We made hundreds of such systems on carbureted turbo kits for many different kinds of bikes.

Early K1200 turbo with water reservoir under license plate.

Next Step In Our Efforts: In the late 1980's and through the mid 90's we went to intercooled systems both with blow-through carburetors and from 1989 on with our RSR Fuel Injection systems. You cannot flow water though an intercooler and based on our earlier efforts we wanted to inject water after the turbo and not into the turbo. We sort of went a radical direction that meant that things were no longer practical but, what the hell, you have to win races and set records. If you are running for six wide open miles at Bonneville you must know exactly how much water is going into your engine. We did, and we never lost an engine.

What we did was use hard-anodized water reservoirs, fuel injection pumps, fuel injection pressure regulators and actual fuel injectors to deliver water, all under RSR EFi control. The problem with this is water will kill fuel injectors, rusting them shut, even if left overnight. Water is conductive, gasoline is not. Gasoline has lubricity, water does not. Fuel injection pumps will rust shut and die if water is run over an extended period. We would race at Bonneville during the day. At the end of each day we would drain the tank, pull the water injectors, and flush the system with WD40 and gasoline. The next day we would put in new water, get the water inspected, and have the container sealed by tech officials so we could stay in the gasoline class. It was a big hassle. Safety wire pokes holes in your fingers. Blood is slippery.

People used to ask us to duplicate these systems for them and we refused because it was too costly, too labor intensive, and when we let other people run the bikes they did zero maintenance and the systems rusted shut and failed. Usually they would detonate and blow the porcelain off of a spark plug when the water injectors would not open. We got tired of baby-sitting our systems for non-appreciative glory seekers.

Two Suzuki GSXR RB Racing Turbos. RSR Fuel Injected, intercooled and water injected. E-Ticket to El Mirage and Bonneville 200 mph clubs.

Clunky Period: To get away from the labor intensive efi pump systems we tested some commercial Shurflo and Flojet water pumps. They were heavy, had large 3/8 NPT and 1/2 NPT fittings, and non-waterproof spade electrical connectors. They were, however, designed to pump water, could be operated "dry" without damage, and did not rust shut. Some alcohol or methanol variations would eat the plastic components.

Pictured above is a Shurflo pump we tested on a BMW K1200RS. It wasn't really elegant but it did work and we had to invent a regulator to keep the flow constant as it did not have an internal bypass circuit. Its large size makes it serious packaging problem on a motorcycle. After some testing we got rid of the clunky pump.

These are the billet regulators we machined up with Titanium seats and double nitrile diaphragms for testing. The Shurflo RV pump would bypass water from the regulator back to the anodized reservoir and the boost pressure was referenced to the upper part of the diaphragm to keep the water pressure constant. More complication. They were pretty things. The lure of billet parts, the siren call. Don't ask us for one. We don't make them anymore.

Hose Tech

Since we have about 35 years experience with carburetors, fuel injection and water injection, we have used about every type of hose and fitting you can think of. In fact, way back in 1980, we used some of the first "push to connect" fittings (Alkon) on air shifters that we used to make. Virtually all water injection sellers use these type of O-ring fittings as they are easy to work with. Measure, cut, push, done. The problem we have with these is they aren't rated for our 1000 psi pumps.

We use high pressure compression fittings and 2500 psi hose. We cover the hose with 1200 Deg F fiberglass sleeving for flame and abraision protection.

Water Reservoirs and Calculations

You're on you own here. There are all sorts of windshield washer bottles, radiator overflow tanks and fabricated assemblies that you can figure out on your own. Poke around and you can find about anything in an autoparts store. Too complicated for us. We tried dealing with a few companies like Flambeau but it was a complete waste of time as we won't compromise and we positively hate clunky generic crap.You mess with your own.

For your calculation purposes: 3785cc/gallon. If you use the 03-1001 330 hp System (180cc/min) you have about 20 minutes of operation per gallon i.e. 3785/180=21.02 minutes...or a quart every 5 minutes of operation. At 330 hp the water to fuel ratio is 12%...more at lower boost activation points. On the safe side call it 15 minutes.

This is a reservoir we fabricate for our BMW and Harley Davidson Turbocharger systems. It bolts to the license plate mounting points and blind holes hold the license plate. A clear hose provides a liquid level site gauge. Hardcoat Anodization is used to protect against water/alcohol corrosion. Motorcycles do not have "engine compartments" and space is at a premium. Expensive to do, but we do whatever it takes.


Here, mounted on a BMW R1100RT Turbo, the water injection was used on a 2000 mile test riding to the Bonneville Salt Flats where we were racing the Bonneville Bullett. Running pump gas the bike did not detonate up to 15 psi with a 10.7:1 compression ratio. Above this race gas is called for. We ran two small nozzles to cover the 240 hp. Don't try to pass semis in the midle of nowhere at 150 mph...we did and don't recommend it.

RSR Water Injection Pump Tech

Basic Calculations: We have to plan our pump design, quite logically, on the required delivery of water or water-alcohol mixtures to our target. Take a simple hypothetical situation of 300 horsepower which, at a B.S.F.C. of .5 lb per horsepower per hour (150 lbs of fuel)...which equates to about 22.62 gallons of gasoline per hour (150lbs / 6.63 lbs per gallon = 22.62). If we are trying for 15% of the mass using 100% water the 15% is .15 x 150 = 22.5 lbs of water per hour.

22.5 lbs water / 8.33 lb per gallon = 2.7 gallons per hour water consumption. To calculate cc's we multiply 2.7 x 3785cc per gallon = 10,219 cc's. To calculate the cc's/minute of water needed we to divide by 60 which gives us 170cc's per minute.

We used the same planning when we were using actual fuel injectors to deliver water at Bonneville.

Design Quandary: This brings us to an interesting conclusion concerning the water pumps people use for water injection systems. Companies like Snow Performance and others use Shurflo diaphragm water pumps that were designed for agricultural, recreational vehicle (RV), marine, or industrial fluid transfer situations. These pumps are rated in the range of 1.4 to 3 gallons per minute which is way, way, beyond the 2.7 gallons per hour of water we need for the hypothetical 15% contribution to 300hp. If you remember we only need 170cc per minute of water for 300 horsepower. The Shurflo pumps push out around 8000 to 19,000 cc's per minute. Actually there is no penalty for wretched excess but do you really need a 5 or 6 pound bilge pump to deliver 170cc's per minute?

It's pretty easy to see that these diaphragm pumps are not really the best pump design for water injection. They are big, clunky, heavy and are designed with 3/8 NPT and 1/2 NPT fittings. Just the thing for an RV sink but hardly the best pump for a water injection system. They are cheap and they do pump water reliably.

Another thing they do not tell you is that the rated presures, say 150 psi,  are not consistent. Don't even think about pulse width modulating slow solenoids to control water flow. At 150 psi with fluctuating pressures the atomization is incosistent.

Considerations of Pump Design

1. Diaphragm Pump Motor Design: The solution to this problem is defined by the problem: Water is corrosive, has poor lubricity, and must be isolated from the pump motor. The best way to do this, with some caveats, is to separate the pumping mechanism and the pump motor. Diaphragms, pistons, gears, swash plates, magnetic drives are all on the table.

Shurflo diaphragm pumps (usually model 8000, 8030 or similar) are used by firms and private individuals like Alcohol Injection Sytems, AEMSnow Performance, Devils Own, CoolingMist, Joe's, Kennedy's, Aquastealth, and probably about 50 others . These pumps are all about 5 to 7 pounds in weight and about 8.5" to 10" in length. These are not magnetic drive units. A number of DIY water injections use these type of pumps. Even Aquamist offers a Shurflo unit for about $900.00. They all claim or aim for the highest pressure rating...None are anywhere near commercial misting pressure ratings.

These guys all say they are better than the other guy and they seem to like to try to sue each other out of business. It's just a packaging buisness. We have an electronics acquaintence who was asked to design a control module for one of these firms...The target was a cost not more than $25.00 to$30.00, they would not pay for the design time, and it would have a retail of $200.00. Like we's a packaging buisness.

People make businesses out of packaging these parts. It's nothing new and just an easy way to put some parts in a box without having to engineer out a custom product like the older magnetic drive solenoid Aquamist solution. Greed is good. If you are running a ton of boost in a Diesel they are a good choice as some models will put out 150 to 250 psi as diesels can run 40 psi or more manifiold pressure.. No one uses regulators like we did at Bonneville. Some use internal bypass ...These are just on/off and deadhead at the nozzles and solenoids. They are also very loud in operation. Clack Clack Clack.

Flojet is the other main water pump manufacturer. They are similar to the Shurflo units. They are still big and clunky.

2. Magnetic Piston Pump Design: Diaphragm pumps are large, have huge NPT ports, and can be a bit problematic, and are next to impossible to fit into vehicles like motorcycles. It's a design fact that you need a certain amperage, torque, and pump capacity to fill a sink or empty a bilge.

Magnetic drive designs isolate the pump motor from the water medium and are exponentially more reliable than other designs. There is no mechanical coupling of the pump and pump motor. Companies like Aquamist used to make magnetic drive pumps. The problem with most magnetic drive pumps, which typically use impellers, is that they are very low pressure units, for the most part less than 3 psi. That certainly won't work for forced induction applications.

Aquamist pumps early on, on the other hand, were quite elegant and were magnetically driven. Aquamist had been the gold standard for purpose-built water injection systems for a long time. They used a small piston actuated by a solenoid coil and were high pressure, low volume designs due to the limited bore and stroke of the reciprocating piston, which was surprisingly small. They were regulated by pulsing the solenoid. If you wanted to flow more than a certain amount of water, about 300 ccs, you were out of luck. The volume, beyond this point, was simply not there, the pump was at its limit. Say you wanted to run four separate nozzles in your manifold and two nozzles to spray your intercooler. You run out of pump capacity. D'Oh! They wanted you to run two of the pumps beyond this point. The fins do look neat however. They also had nifty ribbon charts and trim pot electronics.

Aquamist finally gave in and went to clunky conventional Shurflo pumps...Less than $50.00 for a big pump is too much a temptation.

3. Gear Pumps: We researched out small 12V Gear pumps but there were limitations in pump flow and pressure.

This cute little unit was rated at 500cc/minute with a pressure of 80 psi. The problem as that it was a custom unit and the cost was $650.00 each. 80 psi wasn't enough pressure. There is always a catch. Physical limits get in the way when you go small, and custom design always costs money. It required custom PEEK gear material to pump water. 80 psi was too low for proper atomization, so this was a dead end.

Shurflo Pumps....Everyone's Solution

We almost signed a contract for a large number of these units that everyone in the water injection packaging business uses. You buy enough of them and they are less than $50.00 apiece. The economics seem compelling, but we came to our senses, luckily, and decided otherwise. We used them before and we never were happy about the situation. They are clunky, noisy, and heavy. Three strikes and you're out. The Chinese even make copies of these if you are feeling adventurous or want to go into business selling water injection systems.

Research...Bermuda Triangle and the Holy Grail

Step 1: Round Up The Usual Suspects: Commercial diaphragm pumps like Shuflo and Flojet are pressure limited to 60 to 70 psi (controlled by internal bypass) or 150 + psi uncontrolled. The $900.00 Aquamist/Shurflo unit uses a 125 psi internal bypass.These pumps are big and, when rated in gallons per minute, are way out of bounds except for use in industrial settings as bilge pumps or crop sprayers. Specialized Aquamist magnetic pumps were sexy but volume impaired (300cc) by their small reciprocating piston. Aquamist wanted you to use two of their pumps if you need additional flow. They even gave up on their own pumps.

Step 2: Physics 101: We looked at all the possibilities to make the perfect pump i.e. swash plate, diaphragm, impeller, peristaltic, gear driven etc. and they all came up short. Either they were pressure limited, volume limited, or impossible to package in anything but a large multi-pound package. Fluid is not compressible so you need a lot of force to generate high pressures. You need large DC motors to actuate diaphragms, gears or pistons and the higher the pressure the more amperage is required. No free lunch.

Step 3: Just Do It:The solution was to engineer a more powerful pump that would be small enough enough fit in the palm of your hand, and one that would run four to six times more pressure than the other pumps. Rubber isolation mounts would be needed to dampen vibration. The solution had to be a positive displacement piston pump without diaphragms. It had to be elegant, durable and as they say "bulletproof". Bonneville proof.

The below was the solution we came up with...Maybe not the best...but good enough for our racing activities.

RSR Pro 1000 PSI Pump...David Slays Goliath

RSR Pro 1000 PSI Pump Advantages

Correct Flow:The RSR Pump has the power to flow 640ccm. At 170 cc's per minute per 300 hp you can flow enough water for most any application. The smallest "A" nozzle flows 150ccm @ 650 psi for about 265 hp worth of water protection. Two small "A" nozzles flow 225ccm @ 360 psi or about 400 hp worth of water protection. One large "B" nozzle flows 285ccm @ 250 psi or about 500 hp worth of water protection.

High Pressure: The RSR pump is rated at 650psi with the smallest "A" nozzle flowing 150cc's/minute. RSR Nozzles deliver a fine mist, like a fog, that will pull the maximum heat out of your inlet charge. Even smaller nozzles will push the pump to 1000 psi, but the flow will cover even lower horsepower applications.

Quiet: Diaphragm bilge pumps are noisy. The RSR Pump is very quiet, with only a faint hum.

Small and Elegant: It is an elegant solution that is compatible with water, alcohol, methanol and any fuel you can think of. Small enough for simple packaging and covering over 530 hp @ 250psi and 300ccm. Keep in mind we only need 170ccs for 300 hp.

Low Amperage Draw: The RSR "Pro 1000 PSI" only draws 3 amps of power @ 1000 psi. Supplied with Deutsch DTM sealed connectors and MIL-22759/16 wire.

Durable and Long Life: No diaphragms to fail.

No Nozzle Leakage: No dripping of nozzles for two reasons: (1) The pump itself acts and a check valve preventing any flow if the pump is not running; (2) Our nozzles have built-in check valves and filters which prevent any siphoning in vacuum or on shut down.


The new pumps are alcohol and methanol compatible . We recommend denatured (ethanol) alcohol available in hardware, paint and Home Depot type stores as it is not watered down like Isopropyl alcohol and is easier to obtain than methanol. A 50/50 mix is optimum. Nothing is wrong with methanol per se, aside from it's corrosive nature, but it's not always easy to find. You can always dump in some cheap isopropyl alcohol, but it's mostly water anyway. If you are determined to run methanol you'll find it where racing gasoline is sold and it can be ordered over the internet. You will pay shipping and a "Hazmat" surcharge though.

People ask us about running pure methanol or even mixtures like 40% water and 60% methanol. We advise against this. Volatility is the key. Any volatile mixture will detonate at some point...But a more important consideration is high pressure venting around a hot engine. At Bonneville we saw a severe fire situation in a streamliner that was using a supposedly better engine coolant that, when spewed out into the engine compartment, it ignited and torched the driver's hands, helmet and the liner's engine compartment. Keep your mixtures @ 50/50.

Methanol molecule CH3OH with it's water brethren H2O. They do have an affinity for one another.

Rocket Fuel

When Honda was spending 500 millions dollars a year on their V6 Formula 1 Turbo motors they ran a mixture containing 84% Toluene (114 Octane). It has excellent anti-detonation properties and increases your octane rating. If you are running 92 octane pump gasoline and you add this stuff, your octane rating will be changed by the formula:

[(Quarts Gas x 92) + (Quarts Toluene x 114)] / (Quarts Gasoline + Quarts Toluene).

For example, if you add one quart Toluene to four gallons of gasoline, your Octane will increase onr point from 92 to 93. Add two quarts to four gallons and you get an Octane rating of 100. For you high boost junkies this is something to ponder. You can buy the product in hardware stores. Xylene has a higher flashpoint (less volatile) and has and octane rating of 117.

Denatured alcohol or methanol can be added in a 50/50 mix in our water injection systems.

Methanol Mix and Economics

Figure out the economics. Buy a gallon of denatured alcohol at Home Depot for $15.00. The weight by volume is: Water 8.33 lb/gal and alcohol 6.63 lb/gal. Water weighs 1.25 times that of alcohol. If we mix by molecular weight and do the math it will be 44/56 water to alcohol if we measure volume. This is too complicated, so let's just do two quarts of alcohol or methanol and two quarts of water per gallon. The water is free (more or less) so each gallon of 50/50 water/denatured alcohol will cost you $7.50 ($15.00/2). If you buy a methanol mix mail order the brew will cost you about $13.00 per gallon with shipping.

Now if you have a race gas outlet near you 5 gallons of Methanol will cost you around $34.00. This brings your cost down to about $3.40 per gallon of 50/50 mix of water/methanol. If you have to pay shipping for the 5 gallons your cost is going to be around $5.40 per gallon for the 50/50 water methanol mix. Oops! there is a $20.00 UPS Hazmat fee so that brings the cost to $9.40 per gallon if you ship your methanol in.

In short, it's sort of silly to ship water around, even if it is mixed with methanol or denatured alcohol. Hey, you pay more money for your bottled designer water so go ahead and pop the $13.00 per gallon for the premix and shoot up your boost juice. If you can just drive over and buy some methanol of denatured alcohol you'll be way ahead of the cost curve. Some race tracks sell methanol fairly cheaply.

Hey, if you mix your own, cheat a little and go 60% water and 40% methanol. No one will know and you can skim the profits. It's the American way. Mobsters used to do it's corporations and the government. Halliburton and no-bid contracts. Hell, put in some red or blue dye and give it a catchy name.

Millisecond Tomfoolery

A technical point about the delivery of the water is that we do not attempt to modulate, pulse or otherwise try to modify the flow of the water through the nozzles. In the late 1980's and early 1990's labor intensive systems, where we used actual fuel injectors, the response time of the injectors was around 1.6 milliseconds (0.0016 seconds) before linear flow could be predicted. By using actual fuel injectors we could precisely pulse the water flow with controllability down to a fraction of a millisecond in this linear region. It was a very short term solution. It was absolute in its control, but it was far from practical.

Trying to pulse non-efi solenoids is crazy as they have very slow response times, typically around 10-15 milliseconds, or about six times slower than a fuel injector, making the delivery of water a very "notchy" proposition. Figure it out yourself. At 6000 rpm there is 10 milliseconds per revolution and each four stroke cycle takes two revolutions or 20 milliseconds. If the solenoid takes 10 milliseconds to open and a good portion of that is non-linear then water delivery via duty cycle variation is a bit non-linear and problematic. No one tells you this. The knobs and trim pots they give you are very comforting however.

Another control strategy is frequency, or voltage modulation of the pump itself. This is not a wise move and brings an unpredictability to the situation. High end ecus typically employ FPGAs and very high speed 32 bit processors to control things. Not a good idea to think you are modulating things accurately by varying duty cycles of the pump...way too crude.

It is better to treat the water flow as a constant flow (CIS) to pull the maximum heat out of the inlet tract without "missing" inlet events. Treat the water injection like an analog carburetor.

The best strategy is to size the nozzles to provide the correct peak flow of water at the highest load and then to taper it back to a figure of 12 to 15% of the liquid mass entering the engine at peak rpm. This way you will know what is happening beforehand and not twiddling some potentiometer and not knowing what is happening downstream.

Large Industrial Check Valves in the Lines...+/- 20% Problems

Large Industrial Check Valves, placed in the lines, to be effective to prevent vacuum siphoning, need to have greater than 15 psi (1 Bar) cracking pressure. A 15 to 20 psi check valve will knock exactly that much off of your system pressure which is hurting the atomization which becomes finer at higher pressures. If your pump is only putting out 100 psi this can be a significant variable.

One thing people do not think about is, if you employ multiple Industrial Inline Check Valves and multiple nozzles you are going to be dealing with two unplanned for inconsistencies. First, some of the valves are going to leak. They always do. Secondly, they never crack at the same pressure and will easily "crack" at +/- 20% of the advertised value i.e., in some situations, some will open and some won't.

We don't use them. Too many problems. Our RSR Pumps are, in effect, check valves as will not flow when they are not in operation. In addition we use precise nozzles with tested cracking pressures. In that we use 450 to 1000 psi line pressures there is no variation in single nozzle applications and little if any variation in dual nozzle applications

Solenoids to Prevent Siphoning...No


In some low pressure systems a 12VDc bubble-tight, normally closed, solenoid with a filter can be placed between the water pump close to the water injection nozzle(s). When the pump is triggered the solenoid opens. This prevents water from being sucked from the nozzles in the higher manifold vacuum. Water dripping post shut down can cause internal corrosion.

The solenoid insures there is no possibility of water flowing to the nozzles unless boost is present. It also prevents either vacuum or boost from causing either water drainage from the lines, or boost backflow though the system. The solenoid is normally closed and activates under the user defined onset of water injection triggered by the pressure activated switch.

Our 450 to 1000 psi pump acts as a check valve itself and we use precise check valves in our nozzles so we do not need solenoids. Another issue with these is they are really not for water. We don't use them.

Upstream, Downstream, and Orientation

Nozzle placement is most often decided by the architecture of the application. They can be installed in a Boost Only area such as in the plenum or plenum runners before the throttle body, or in a Vacuum-Boost area in the inlet tract behind the throttle body or air metering throttle valve (butterfly). Flowing water before the butterfly is not a good idea due to corrosion issues.

If you have a mass sensing systems of some type, you can't inject water before the sensing element as this will drive the hot wire or sensing element crazy. In this case you will have to place your nozzle downstream of the butterfly in a vacuum-boost area.

All RSR pumps are essentially a check valve for the system and unless activated no water flow can take place. There is zero possibility of siphoning the water from the reservoir in a vacuum situation. Our nozzles also have built-in checkvalves and filters.

30 Amp Relays

There is a logic behind how the RSR Water Injection is hooked up and how it gets it's power, which requires a relay. You want to be sure the water is not activated when the engine is not running and only activated under pre-defined boost levels.

Hobbs Boost Pressure-Activated Switches

User adjustable to trigger specific water injection events. There is usually just one of these used to turn on the pump and open the solenoid.These are usually referenced to plenum or boost pressure and not below the throttle where both vacuum and boost is present. Adjustable from .5 to 150 psi. 1/8 NPT. Water injection is best turned on and off. Pulse width modulating agricultural pumps and slow acting solenoids is a recipe for inaccurate water delivery. Activate at highest load at lower rpms.

Simply set the pressure switch with a test light, pressure gauge and either a Mityvac hand pump or compressed air source. Use a 7/32" Allen wrench to set pressure activation point. We use genuine Hobbs switches and they have gotten more and more expensive as time has gone by. Simple.

All RSR Water Injection Systems have a manual disarm switch (on / off) that can deactivate the system.

ECU Activation

These days we use high end Cosworth SQ6M ecus with front end FPGA's to run the calculations on when to "turn on" the water...not some add on box with blinking lights. The SQ6M is programmed to trigger a relay to activate the water injection for a variety of parameters. This box is about $7,000.00. Figure $3,000.00 for custom wiring harness and sensors. We use them on our Bonneville and street high-end Harley turbos.

With the SQ6M and other engine management systems you do not need a Hobbs Switch. Some people want to use solenoids and PWM (Pulsewidth Modulation) to control water flow. We just use the SQ6M to turn it on with a relay as the pulse modulation with a slow acting solenoid is a bit problematic.

Normally Aspirated...Not Our Bag

Some people want to use water injection with non-boosted, normally aspirated engines. High desert heat, high compression etc. This is not an area we are going to do development in. If you choose to do so you can source vacuum operated switches yourself to control the activation. You are on your own in this regard. We remember the Spearco Injectronic units way back when and even got to baby-sit George and Pat Spears booth at a SEMA trade show once eons ago. George dropped out of the turbo and water injection business, ditched his previous connections with Carroll Shelby, and went into the intercooler business which he later sold, then retired. The engineering, nozzle, sizes and strategy is up to you.

Some vendors promise a 5 to 15% increase in fuel economy. They also have a big bridge for sale.

You can even rig something up to spray you if you so choose. We're turbocharger specialists. You get to be the other specialist whatever that is.

Digital Turbo Dashboard

Shown here running at 2.64 Bar (24 psi) in bright sunlight. You can read more about the ORCA Turbo Dash development. You can also watch a movie of the dash in operation on one of our turbocharged Harleys.

3 Bar display with 30 leds 30"Hg to 30 PSI (3 Bar). First ten l.e.d.s are green and represent the 1.0 Bar Pressure range. The second ten l.e.d.s are orange and represent the 2.0 Bar Pressure range. The last ten l.e.d.s are red and represent the 3.0 Bar Pressure range. A three digit "Bar" digital read out (0.00 to 3.00) is directly below the 30 l.e.d.s.

There are two four digit Type K Thermocouple displays which can be used to monitor two egts or any other temperatures like charge cooling etc. Celsius and Fahrenheit selectable by pushing blue and red buttons simultaneously. Last digit displays "C" or "F" in bright green.

Two l.e.d. display lights for water injection: Blue l.e.d. for water injection pump activation. Three button control for the display functions: Blue: high recall; White: display dimming function; Red: reset of high recall. Simple, logical. Bonneville race quality.

This is the most sophisticated microprocessor based dash for turbocharger and supercharger use. Display is only approximately 6" wide by 2.5" tall. A total of 45 leds and three buttons. Buttons are high force, easily activated, even wearing gloves. Hard anodized and machined from billet enclosure. Water resistant but not submersible.


Bench Testing Prior to Installation

Whatever nozzle and pump combination you choose you should bench test the system before you install it in your vehicle. Whenever we engineer a new water injection for one of our turbo kits we bench test the delivery using either digital flowmeters or simple burettes (100ml up to 2000ml). Water is not hazardous, so all you need is a 12VDc power source and something to measure the flow. If you don’t measure it you will never know. To simulate boost pressure we employ a pressure regulator and a gauge to accurately mimmick the delivery at different boost levels.

Just flow water, and not water/alcohol, in your testing for obvious reasons.

For you creative types you can use our nozzles both up and downstream as well as squirting water on your intercooler. It can get as complicated as you wish. Remember it’s all a heat equation. Heat equals power...but too much heat equals destruction.

Time to get cold and wet. Those nozzles make a mess.


With probably 100 individuals and half as many greedy capitalists pushing water into engines it's pretty easy to check around and put together a DIY Water Injection system for under well under $200.00. A water pump from Northern Tool and a bunch of parts from the hardware store and you can be a DIY Water Injection expert. Check around. All the information is easy to come by.

Power Up

RB Racing simply can't use the generic Shurflo systems as they just aren't suited for the applications and racing that we do. We tend to avoid compromise and push the envelope. It's really a pain in the ass to get all the details worked out, especially when you are working with 200 mph motorcycles that have little or no space to work with. Not everyone needs this level of sophistication and expense. We do. Whatever you decide to do, roll your own, or buy something, sooner or later you have to find out what she'll do. Power that thing up and stand on it.

RSR Water Injection Calculator

Mike Geokan's famous #226 Fuel Injected, Water Cooled, Intercooled, Turbo Harley Davidson with Water Injection. Bonneville record holder.

RSR Pro 1000 PSI Turbo Water Injection Systems

RSR Water InjectionPart Number
CC's Minute (CCM)
Two "B" Nozzles
One "D" Nozzle
Two "A" Nozzles
Two "C" Nozzles
Three "A" Nozzles
Two "D" Nozzles
One "E" Nozzle
One "G" Nozzle
Two "E" Nozzles
Two "F" Nozzles

Water Injection Calculator

Maximum water delivery should be in higher load low to mid rpm ranges tapering somewhat at peak rpms where load is less.Water or Water / Alcohol to Fuel Ratios are between 12.5% to 25%. This means Air to Fluid Ratios are between 11.1:1 and 10.0:1 with water injection. Enter several horsepower figures for mid range and peak rpms. Use our Boost and Airflow Calculator to see what your engine requires in boost to make a certain horsepower.

Enter Peak Boost
psi Maximum (Peak) Boost.
Peak Horsepower
hp Peak Horsepower at Maximum Boost @peak rpm. Set by wastegate.
Nozzle cc's per minute
Choose cc's minute from table above
% Water
percent Enter % Water. Enter 100% if you are to stay in the "Gas" class at Bonneville
% Alcohol / Methanol
percent Enter % Alcohol / Methanol. Maximum recommended is 50%. Enter 0 (Zero) if 100% water is entered

 Typically you are looking for  12.5% at peak rpm/boost and 25% at peak boost at highest load in mid to past mid rpms.

Percent Water at PSI


Bonneville and Street

Do we actually race this stuff? Well for the last 30 years the answer is yes. All of our turbocharger systems and projects use water injection. Works for us.