help to install an HHO device into a VW Golf 3

[IronHead]

You want to  connect the HHO line directly into the intake plenum  away from the break booster as much as possible .Use 1/2" or 5/8"  vacuum hose to do this .Other types of hose will collapse.

Yes I use  this electronic re-curve system (EFIE) and the DirectHit boosters on my 2000  4.0 Fuel Injected Cherokee . The power increase alone is well worth it. As far as the MPG  savings  that all depends on your Cell design and Alternator type. I use this type of alternator for very high full time loads  , I use up to 100 amps 24VDC in my Cells . These are PWM controlled  from 0 to 100 amps  at 24 volts and are connected to the throttle via 5k pot to the controller  but you dont need to go that far.

High end alternator link

http://www.electrodyne.com/index.html

[IronHead]

I suggest you build a dryer/bubble  with safe caps  something like this. This is a bit more than you need for a basic system  but you get the idea. For the wool you need pure  316L wool so it does not rust. you can find it here
AISI 316L Stainless Steel Wool
http://briwax-online.com/GMTStainless.html

[readyakira]

I use this type of alternator for very high full time loads  , I use up to 100 amps 24VDC in my Cells . These are PWM controlled  from 0 to 100 amps  at 24 volts and are connected to the throttle via 5k pot to the controller  but you dont need to go that far.

High end alternator link

http://www.electrodyne.com/index.html

That brings up another Idea I had that would prob be a ways down the road as I have yet to build the generator big enough and efficient enough.  But anyways I was thinking, for alternators,  what do you think about 2 alternators frame mounted in the drive shaft area and belt driven from the power of the drive shaft (my car is a truck) and some sort of switching unit that turns them on during decelleration.  If my thinking is correct, this would use the inertia of the vehicle to turn the alternators, thus reduceing the load applied to the engine.  It should also assist in reducing wear on the brake system as they should put a load on the driveshaft thus helping it to slow down? 

[readyakira]

My understanding is to inject the HHO into the air intake manifold, this would simplify the connection, typically the Mass airflow sensor (MAS) is located there and it is connected to the engine manifold and air filter by a plastic duct. you can drill a hole there (before the MAS and after the air filter), and put a connector in for the HHO gas inlet. put this close to the MAS unit.

The other thing is what IronHead has mentioned above. This is of course for HHO assist system.

As said above I think the line needs to be after your throttle plate.  If you place it between the MAS and throttle plate, you would have the chance of (pumping) excessive amounts of HHO into the intake which would probably mess up and adjustments you have made to the way the computer reacts to the added HHO.  There has been talk in places of using 2 lines one in the intake plenum, and one in the duct leading to the throttle plate, since under full accelleration the there is hardly any vaccum in the engine to draw with.  Best of course would (I think) be if you could route a line for each cylinder as close to the intake valves as possible.  This is the place where vacuum should be highest when the engine needs it most as it is the bottleneck of the cylinders.

[IronHead]

you will not produce enough HHO to pump into the engine it will never pressurize as long as the engine is running , you pull the HHO off via engine vacuum.When your engine is running your Cell is under constant vacuum. Even though the vacuum drops there is still enough to draw in the HHO. It has yet to be determand if more HHO is produced under high vacuum though it appears that way . Does not matter really if your just getting started in this and want to get some fuel millage enhancement. Just Build It , install it and go from there.

EDIT for my lack of proper reading.