This is some info and experiences with using water injection (by
vacuum) with a Toyota 1.5 L carbed engine in good condition:
* with this carb, there is a R port that is situated right above the
throttle plate and can be used to control water flow so that there is
little flow at idle.
* had trouble regulating the flow and so had flows of anywhere from
25% (1 to 4) to 2% (1 to 50) water to gas ratios. Yes the car ran on
1/4 water using Bosch single electrode plugs with a slight miss under
hard acceleration for 50 miles.
* when testing the acceleration of the car in 5th gear from 25 to 60
MPH...I found that the time required to reach this speed with a 2%
injection rate was 13% greater with the water than without....meaning
around a 13% loss in "power".
* also have seen no increase in MPG and maybe a slight loss.
* have noticed a reduction in oil used over the last 4500 miles (3500
with water injection) and am assuming that the rings/valves have been
steam cleaned, thus improving oil use from 5K per quart to around 9K
** during this period of using water injection I also used Marvel
Mystery Oil as a top lube, putting it in the gas and also used a PCV
** my impressions of the water injection is that it does smooth out
the engine, but it does so by reducing burning temps and thus
power...so considering no MPG gains, the trouble of keeping it going
and possible damage to the carb...I probably won't use it.
** I am going to try using it on occasion for cleaning the engine
though....using a 1 to 8 mix of water to MMOil and with a few
drops of dish detergent to keep it emulsified...running it thru the
same port at around 5%...maybe a gallon at a time.
>> posted as information only....use at your own risk.