Another bit of "info" on alky inj...Open for "discussion", I'm sure.
Rodney, from "Prometh.
There's a few simple formulas you can work with to get a "approximate" jetting target to begin with for different mixtures.
100% water target 10–15% of fuel flow
50/50 mix target 15–20% of fuel flow
100% methanol target 20–25% of fuel flow
If you don't know fuel flow you can do the following.
Horsepower x .75 = CC jetting (pure water)
Horsepower x 1.5 = CC jetting (50/50 mix)
63cc is equal to 1 GPH (630cc is the equivalent of a 10 GPH nozzle)
For example. 1000 horsepower. You would use 750cc pure water or 1500cc 50/50 mix.
I've been setting up water methanol injection systems for a little over 10 years now. Over that time I have set up thousands of new systems over the phone for customers and have helped hundreds of customers with competitors systems. Over the years of doing this I have found many other factors to play a role in how I jet a system. With every order we get for a system we have a spec sheet that we go over with the customer and fill out that we can refer to.
Engine Type and size
Type fuel (diesel, gasoline engine, pump gas racing fuel etc)
Compression
Aluminum or cast iron cylinder head
EFI or carburetor
Naturally aspirated, nitrous, supercharger, turbocharger
How much boost or nitrous
intercooled or non-intercooled
Horsepower/RPM
Type of application (street, strip, towing etc)
Tune Up
Have they hurt parts in the past?
Do they plan on turning it up?
Its during that phone call that I can not only determine their jetting but also how sever of a need they have for a water methanol injection system and what results we want to achieve by running a system. Some people just want to add an extra safety net and some insurance when they are perfectly safe as it is. So I set up the system pretty soft. Others will call and express over the phone they are hurting parts and on the edge with their tune up. MAybe its a grudge car or they race in a class where its very competitive. Its my job to open up the tuning window as much as possible so they can runner as big of a tune up as possible to win. There's a lot that I take into consideration with every system we set up.
Its important to note we also give the customer a range in jetting. Not just one combination or set of nozzles to save money. We send out additional jets so he can go up or down with his jetting. We also stand behind our systems and if the customer jetting isn't correct and not performing as it should.