questions on 2d system on a wrx stage 4?

[gualicho]

questions on aquamist ,i have an 2d system how do i need to tune my car is a wrx stage 4 what parameters etc. i been told to use 2 jets instead of one ,how do i do it? why ? and wich jetting do i need for my set up?

[Brad]

We will assume you are using the Turboxs Stage four at this point. The reason for two Aqumaist jets it the power you can make will require a good amount of wate to provide the performance you are after if you lean the fuel mixture to get the full benifit of water injection. One of the forum members si2wrx has a great personal web site if you have not seen it.
The other issue is one Aquamist pump does not supply the volume to run two jets, you will need a large accumulator or two. You could use two pumps. One pump without an accumulator will work but you will still be running rich fuel mixtures to control detonation.
I would place the nozzle in the dicharge end tank of the intercooler if it is a top mount.
For max on power you will most likely use two 0.7mm nozzles when you are at a 12.5 to 13.0 air fuel ratio
To date I have little experence with the Subaru. We are currently tuning a WRX for a customer with the UTEC. It has every thing except the large intercooler. This car does not have water injection yet. We just finished the 91 octane map and have just filled the tank with 100 octane for the next map. When the customer is ready we will add water and tune.

[Forum Admin]

The reason for the 2 jet recommendation on stage 4 with the 2d is because of the upgraded fuel injectors and the rich levels that stage 4 starts at before water injection. By the time you lean out the fuel for water injection the IDCs are too low for the 1.0 jet to flow enough water to suppress knock.

So the recommendation for those with upgraded injectors has been to use 2 0.7 or 0.8 jets. With the 2d since the IDCs are relatively low after tuning for WI the pump should be able to keep up with the flow of the two jets. Of course one accumulator always adds an extra buffer to make sure the system has the capacity to flow more than needed.