View Full Version : Water / Meth Injection with Roots Superchargers

01-23-2011, 06:03 PM
ALL credit for this thread goes to stwatson from ClubRSX, just thought you guys would like

For those of us looking for that extra power from our motors with roots style superchargers without sacrificing safety or reliability, the application of water / methanol injection has been proven to work exceptionally well with this style of supercharger. The testing that I have performed was on a 2004 Acura RSX-S (2.0L IVTEC motor) with a Jackson Racing Eaton M62 Roots style supercharger and has led to the conclusion that you CAN USE as high as 18gph while spinning the blower at nearly 17000rpm! It should be noted that the Jackson Racing supercharging system does NOT come with an aftercooler or intercooler of any kind, so once the blower is spun past 14500rpm (this equals around 9psi for the RSX) heat and detonation becomes a very dangerous issue. With more pressure comes more heat, and more heat will require you to lower ignition or timing leading to a dramatic loss in power.

Enter methanol injection. To battle this increase in heat, I first went to several mainstream methanol injection suppliers and ordered a kit. The kit that I originally purchased was a trunk mount kit that supplied all the necessary parts for your basic water / methanol injection project.

*NOTE* - when ordering these kits they offer a “nozzle size calculator” that will usually ask for your range in horsepower to determine what size nozzle you need. These calculators are EXTREMELY general and do not take into consideration the different delivery methods of boost on the market. Turbo’s and Centrifugal superchargers deliver their boost in a MUCH different manner than a roots style supercharger, thus changing the water / methanol requirements, rendering this calculator useless if you are looking for optimal power on your roots style setup. We are spraying methanol through the compressor itself which brings the methanol into contact with the extremely hot blower casing, opening the door to dramatically increase the amount of jetting, which is the entire point of this experiment!

So my first kit consisted of a 1 gallon tank, a 150psi pump, a checkvalve, and a 4gph nozzle (250cc/min) which the calculator said was good for 200-300whp. For my mixture I mixed a 50/50 by mass solution of steam distilled water (available from any grocery store) and pure methanol.

At 9psi I noticed no problems yet very little gain from the methanol injection, so as we all seem to do eventually; I started looking for more power. From a blower speed of 14500rpm at 9psi I increased the blower speed to 15500rpm leading to 11psi. At this level of boost, the added heat became too much for the 4gph nozzle. I found after several full throttle pulls or a single pull on a hot summer day, I was beginning to see more and more detonation. Also, I noticed at the drag strip that neither my times nor my trap speeds were improving along with a dyno that showed negligible improvement from 9psi to 11psi. Needless to say I was upset.

Enter Alcohol Injection Systems (AIS)

At this point in time I began to speak with Rodney at Alcohol Injection Systems (www.alcoholinjectionsystems.com) and was introduced to the idea of increasing the amount of water / methanol I am spraying into the motor (THIS IS WHERE WE TESTED THE ACCURACY OF THE NOZZLE CALCULATORS YOU FIND ONLINE). Now I was extremely new to the idea of methanol injection so I was afraid to start spraying TOO much into the motor. Rodney explained to me how even if you spray too much, the only thing that will happen is the motor will bog. This does NOT hurt the motor! It’s simply a point in tuning where you have up to 3 different options to get this amount of jetting to work!

#1 – Increase the RPM at which the meth sprays (engagement point)
#2 – Increase the amount of methanol in your concentration
#3 – Decrease the nozzle size

If the motor bogs it means that you are spraying too much mixture for too little air. By increasing the engagement point you will allow the motor to move more air, thus allowing for more methanol injection. You may also have too much water in your mixture which does not burn like fuel. If this is the case you can increase the concentration of methanol in your mixture since methanol burns like gas and you can tune around this. If none of these work then you will have to lower the nozzle size…mainly because if you increase the engagement point too much then you will still experience detonation midrange before your methanol injection activates.

So now that I understood how to correct possible bogging issues, I then tested out three different sized nozzles from AIS (7gph, 10gph, and their largest 14gph). Since we were hesitant to bog the motor I started with the 7gph nozzle, and WOW! With little to no tuning the power increase from the 4gph to the 7gph was significant! Further tuning went on to show that even with the power gain from the 4gph to the 7gph nozzle, my intake air temperatures (IAT’s) were still increasing during the pulls…which meant more jetting could be used.

I easily swapped nozzles (with the push and release connectors it takes seconds to swap nozzles) to the 10gph and yet again another significant increase that could be felt. IAT’s were VERY close to leveling out, but out of curiosity to see how much this 2.0L motor could handle without bogging, I tested out the 14gph nozzle with engagement at 4400rpm…NO BOGGING! The motor took the 14gph nozzle like a champ and decided it was time for the dyno.

At 11psi with the original 4gph nozzle my car saw 298whp.


At 11psi with AIS #14gph nozzle the dyno showed 317whp…A 20WHP INCREASE WITH LESS IGNITION!


Ignore the torque curve in the last dyno...the RPM reader went haywire thus throwing off the torque calculation

As I did before I was still curious to see how far this eaton blower could go. After several months of research I decided that 17000rpm on the blower was the max to ensure the blower wouldn’t be overspun (there were several sources showing miata’s and other vehicles spinning the blower at 20,000rpm…however that seemed a little over the line with the blower requiring exponentially more power from the motor to spin it that fast…thus lowering the results). I swapped the necessary pulleys and pushed 16920rpm leading to nearly 14psi on the blower.

With the added boost, I was able to lower the methanol engagement point as low as 3600rpm and the motor STILL DIDN’T BOG with the 14gph nozzle THAT LOW! However IAT’s were beginning to increase during the pulls again which meant there was room for even MORE jetting!

From here I worked with Rodney and setup a dual nozzle system using the 14gph nozzle and my previous 4gph nozzle. A T-fitting from AIS and some more line and I was good to go for a total of 18gph.


I increased the engagement point to 4100rpm to ensure no bogging and BINGO…the IAT’s remained flat at 90 degrees for 4 consecutive full throttle pulls and no bogging. The power from the blower is substantially higher and I will have dyno results coming soon.

So again, for those of you looking to get more power out of your roots style superchargers, do not rely on the nozzle calculators for your choice of nozzle! I have nearly quadrupled the amount of jetting the calculator said I could use and the car has never run stronger. Also…at 18gph you run through a LOT of water / methanol so I also upgraded to AIS’s top notch 3gallon trunk mount tank (pics coming soon) which adds a sexy clean look to the entire setup!

My greatest thanks go out to Rodney for all your help and to AIS for the highest quality parts and unbeatable customer service!


Calculating what concentration you want to run: I recommend either a 50/50 mix or a 70/30 mix (methanol / water)

.5 gallon = 64 0z
lets split it 32/32
32 fl oz meth = 32 x 0.05159 = 1.65088 lbs
32 fl ox h20 =32 x 0.0652= 2.0864 lbs

now add 2.0864 and 1.65088 = 3.73728

divide meth lbs into total lbs 1.65088/3.73728 = 0.441733
giving you a 44% by mass mix ratio

meth is at room temp and h20 is at fridge temp (distilled)


By mass 50% meth 1 gallon mix = 56 fl oz distiled h20 & 72 fl oz meth
By mass 55% meth 1 gallon mix = 50 fl oz distiled h20 & 78 fl oz meth
By mass 60 % meth 1 gallon mix = 46 fl oz distiled h20 & 82 fl oz meth
By mass 65% meth 1 gallon mix = 38 fl oz distiled h20 & 90 fl oz meth
By mass 70% meth 1 gallon mix = 32 fl oz distiled h20 & 96 fl oz meth
By mass 75% meth 1 gallon mix = 26 fl oz distiled h20 & 102 fl oz meth
By mass 80% meth 1 gallon mix = 22 fl oz distiled h20 & 106 fl oz meth
By mass 85% meth 1 gallon mix = 16 fl oz distiled h20 & 112 fl oz meth
By mass 90% meth 1 gallon mix = 10 fl oz distiled h20 & 118 fl oz meth
By mass 95% meth 1 gallon mix = 6 fl oz distiled h20 & 122 fl oz meth
By mass 100 % meth 1 gallon mix = you got to be kidding me, you fail

K20A EP3
02-02-2011, 03:14 PM
wow its looking like i need to get started om my water/meth setup. Wheres the best place to find the kits?

02-02-2011, 04:58 PM
wow its looking like i need to get started om my water/meth setup. Wheres the best place to find the kits?

yes you do, now do it!

02-02-2011, 05:51 PM
wow its looking like i need to get started om my water/meth setup. Wheres the best place to find the kits?

so far the best im seeing is alcoholinjectionsystems.com

02-08-2011, 03:46 PM
so far the best im seeing is alcoholinjectionsystems.com

I have an AIS kit for sale is anyone is looking =P

02-09-2011, 05:53 AM
I have an AIS kit for sale is anyone is looking =P


also looking into this...

02-09-2011, 04:13 PM

also looking into this...

Nothing wrong with building your own kit but be sure to buy the right stuff for everything. Last thing you want is a pump failure, clogged nozzle, or leaky lines =X

02-10-2011, 04:47 AM
i heard the AIS kits had pumps that (occasionally) failed.

02-11-2011, 01:58 PM
i heard the AIS kits had pumps that (occasionally) failed.

From who? Call Rodney if you have any concerns. AIS has been using a custom pump made for them for the past few months with few failure. Plus no one can beat AISs customer service.

BTW I think your think of Snow Performance, now they have pump issues - ask me how I know =/

05 hatch
06-19-2011, 06:14 AM
What are you guys hooking your power wire to for the pump? Im installing mine soon and need a little help. I hate wiring.

Sent from my Droid using Tapatalk

07-01-2011, 07:18 PM
Fuse tap to an ign source under the dash. I used the 10amp labled "alternator". Run that to the power wire on the pump, then ground it.

K20A EP3
07-11-2011, 02:56 PM
Just an idea so dont bash me 2 hard....

Would it be possible to just use the oem washer fluid bottle and pump? lol

07-11-2011, 06:01 PM
Just an idea so dont bash me 2 hard....

Would it be possible to just use the oem washer fluid bottle and pump? lol

almost yes, the tank needs to be higher than the pump so there is a constant gravity feed. what i was going to do with my underhood tank was i was going to feed the tank to refill it using the rear washer line