Gami jectors are great.  I don't know of anyone having any creep on the ratios.  I don't know of any other way to do it. 

Colyn,

 

There is another method. 

 

0. Check that you have a piston engine where each cylinder equipped with an EGT read out and the fuel system is fitted with an accurate fuel flow indication.  If not, skip the rest of the discussion or upgrade the engine monitor.

 

1. Do the GAMI lean test at WOT, 75% power or slightly less (go to http://www.gami.com/, enter the site and click on "GAMI Lean Test").  If the fuel flow spread of EGT peaks is .3 gph or less, do nothing if you wish to do nothing.  Skip the rest of this discussion since you are currently operating an engine with each cylinder probably producing similar power.  Running LOP should not be rough.

 

2. If the engine is turbo charged (or supercharged) and the spread is greater than .3 gph, follow the GAMI recommendations and skip the rest of this discussion since, theoretically, your non-electronic injectors are already receiving upper deck air equally.  If you think not, check the integrity of the injector shrouds and lines.

 

3. If the engine is carbureted, and the peak spread occurs at greater than .3 gph, definitely consider the GAMI recommendations (whatever those might be).  There may be an imbalance of A/F ratios at cruise that may be cured or bettered by adjusting cruise fuel flow to each cylinder by using GAMI injectors.  Carbureted engines are notorious for induction air imbalances, especially at different throttle settings.

4. If you are reading this line, you are operating a naturally aspirated, injected engine with a peak spread of greater than .3 gph.   Think about the effect that different cowl location air flows and pressures have on the injector bleed hole (hiding behind a fine mesh screen) and the associated air flow that helps with the atomization of fuel leaving the injector for that cylinder.  If those thoughts hurt your head, consider GAMI - otherwise, read on. 

 

5. It is possible to influence each cylinder's A/F ratio by using shrouded injectors and supplying a commonly sourced, equalized air flow/pressure to each injector shroud.  There may be additional benefits (other than low cost) since such a configuration may solve the A/F imbalances before changes to injector sizes.  Such a modification is independent of any changes that are made to alter engine cooling by messing with cooling plenum air flows/pressures.  If ram air is being utilized, feeding the injectors with such a ram air source ensures that the atomization air is equal to or higher than the MAP similar to a turbo/super charged engine (this certainly eliminates the possibility of forcing fuel back out of the injector bleed hole because the MAP is significantly higher than the cooling cowl air pressure).

 

How such a system is implemented is left to the builder/experimenter after considering such things as the consequences of blocking the air flow, water, ice, filtering, etc.

 

The following is

 and should be considered as such.

 

Below are pix of an implementation that uses a separate pitot-like tube for ram air pickup and a small plenum to equally distribute the pressurized air.  The first picture is of the pitot-like pickup.  These pictures were taken before the Lightspeed electronic ignition replaced the LASAR system.  Double click on the pix to expand them to 600x480 for more detail.