trying to decide between Aquamist 1s and 2s systems

[zsz2k]

I understand the difference between the two; my question is, without a dyno to tune the 2s system on, are there still obvious performance benefits?

The manual itself states that water injection doesnt' follow a fixed ratio like air/fuel. The 1s system is easier to install and cheaper - so are there real performance gains to be had from the high end system?

I should probably rephrase this: how well does the system need to be tuned before the 2s system shows notable improvements over the 1s system? And the second question is, how hard is it to fine-tune the system to give these results if you don't have a dynamometer?

[Brad]

The simple answer is the 2s will provide more improvement over a larger rpm scale. The 1s is only correct one time during a full load run. Since the 1s only delivers a set amount of water in can not increase as rpm and load increase.
The 2s can be programed to deliver a correct amout water at about any boost or rpm.
Tuning the 2s can be time consuming at first. It can be done with out a dyno if you are sensitive to your cars performance. One of the things you will notice when the water flow is correct is that the engine is quiter.
The other problem with tuning the 2s is you well get it correct and then fiddle with it and have to start over.
Depending on the application the 2d is a good compromise if the car has electronic fuel injection.

[zsz2k]

Brad,

Thank you for the quick response! I had a feeling that the 2D system would be most appropriate. If the unit can be controlled from an external ECU, I imagine that ECU could perhaps even meter detonation and adjust the parameters in real-time; am I right?

I have an Audi A4 with Bosch EFI. I have an aftermarket turbo kit that includes programming. I don't have access to the ECU software and I don't think the vendor has released a WI-specific program (nor are they likely to release one in the near future - although I just emailed them to find out).

What is my best option? Is there a way I can program a 2d system myself with some third party WI-related controller? I would rather go with a 2d setup in that case as it seems much more flexible than either 1s or 2s.

[janis]

1S is upgradeble to a system 2. I don't know if it's a "no-penalty upgrade"
But you could start with a 1S and upgrade,..

[Brad]

zsz2k, The high speed valve of the 2d will pulse at the same rate as the fuel injector. You then select a nozzle size that gives the best performance. The will be not need to tune it differently most of the time. If you wish to run the water injection on its own map the 2s is the kit to use with a MAP sensor.
If you want you can use a 2c with a third party ecu.
My best advise is a 2d.

[welding rod]

Don't get a 1S. That is what I have. While it is definitely worth having, it is nowhere near as good as a system would be if you could match water injection rate to rpm as well as the boost reference.