Project X - Water/Meth Install!

[Richard L]

Originally Posted by tephra

and by tune - you mean fiddling with AFR/timing/boost/mivec?

Well I thought it was fairly obvious that you need to tune for water/meth to get the most out of it.

So I will be having a tune

ok so going back to my specific application - the chart shows I should use a 0.8 jet:

560 * 4 = 2240
20% replacement = 2240 * 0.20 = 448cc

160 - 25psi, and find closest to 448 = 0.8 jet.

Is that correct for single jet?

So If I want to run 2x jet's instead of 1, do I just get 2 smaller jets to still make up roughly 448cc/min for my boost level?

ie 2x 0.4 jet (@25psi) = 430cc/min

Yes, once you have the capability to tune AFR, timing etc. It will be a pity to run the minimum jet size without a tune.

I am assuming you are able to re-tune the car, with two maps. on the evo-X?

[tephra]

that will be the plan... same as evo7-9.

I gotta find a free ADC channel to input the failsafe signal then mapswitching is easy

ok so in the box I have a 0.8, 0.9 and a 1.0 jets.

I want to run 2x jet setup to maximum atomisation, etc

What sized jets do I need to run?

[scheides]

IMHO 20% is a bit high, I ran only ~11-12% when I had my IX turbo and made an easy 40whp/40wtq with tuning. If you wanna go balls-to-the-wall and not worry about tank usage, IMHO go with two .9 and 1.0. I went with 1.0 & .9 combo because that's what came in the pack Maybe start with .9 and .8, but if you want to try and conserve your tank a bit, you could go with 2x .7mm jets. A lot of the bi-turbo audi S4's I install run that setup, and I think for a stock turbo (or even upgrading to something just a bit bigger) it'd work just dandy, esp if the injection points were spaced out a bit.

[tephra]

Do the math with me :

560cc injectors

560 x 4 = 2240 cc/min

20% MAX replacement - means I need to be able to inject a MAX of 448cc/min Water/Meth

So if I want to run 2 jets, that means each jet needs to flow a MAX of 224cc/min...

Looking at the HFS6 doco I can see that a 0.5mm jet will flow 280cc/min.

So is it better to go a smaller jet for atomisation purposes?

I am thinking about 2x 0.6mm jets...

I might even try 1 pre turbo, 1 pre TB jet setup...

let me know if I am doing something wrong

[tephra]

everyone is quoting BIG jets so that's why I keep asking the same question

[scheides]

Your math works fantastic, you're in good shape! 2x .6mm jets would be awesome, the pre-turbo is up for plenty of debate, I would skip it personally.

[tephra]

ok good.

so will .6 mm jet give better atomisation that .8's?

why do people do more than 1 jet anyways?

[Richard L]

Originally Posted by tephra

ok good.

so will .6 mm jet give better atomisation that .8's?

why do people do more than 1 jet anyways?

There should not be a great deal of difference between the two jets.
1. The water pressure behind the inline valve is the same
2. Once the valve opens, the pressure behind the water jet is the same
3. The only variation is the amount of water flow pass the orifice of the jet.


The PWM- valve system is often confused with the PWM pump-speed system:
4. PWM valve system vary the flow by the pulsing of the inline valve (as in fuel injection system)
5. PWM pump system vary the flow by altering the pressure by change the pump speed.

The reason for two jet is to promote better distribution of water droplet in the inlet tract.


.

[tephra]

so I will use the included 0.8mm jet, but should I go for another 0.8mm or smaller jet?

is it ok to mix and match jet sizes? like if I use the 0.8mm as the jet CLOSEST to the TB and then a 0.5mm for CLOSEST the IC outlet... does that mean I would better charge cooling ?

[Richard L]

You can mix an match any jets to get the desire flow.

On the HFS-6, you have following adjustment:

- Idc trimmer: -20% --- 0 --- +20%
- Idc gain trimmer: -50% --- 0 --- +50%
- Boost Comp trimmer: 0 --- +20% (factory set to compensate from 2.5V of the MAP sensor signal. Ignore this if you are not connecting this to a map sensor)
(Factory default = 0)

With those adjustments, I would oversize the jet so that you can scale it at will. If you only install jet to cover you maximum flow, you can only thim the flow downwards.

Ideally Install jets with at least 50% extra head room to the flow recommend on the use manual.

As regarding postioning, my view (not all agree) is yo put ir as far away from the throttle as possible. This was done on 90% WRC cars, with the exception of the French team, not sure where they put theirs.

[FullBoostRacing]

I cant remember the nozzle sizes but I run the middle size nozzle from the snow kit during NASA/SCCA events. I am also using the stock windshield washer fluid bottle for storage.

With a 10 min session I have about a 1/4 tank of meth left, with the 15min session is almost empty.

When I do 1/4 mile I just switch back to the largest nozzle and switch my map out.

[Richard L]

what is the capacity of the stock washer tank?

[tephra]

Thanks Richard,

In addition to the 0.8mm jet pre-TB, do you think it's worthwhile going a smaller jet immediately after the IC? Or another 0.8mm?

[xPRimNT]

Lots of great information in here! Thanks everyone.

I'll be keeping an eye on this thread.

[Richard L]

Originally Posted by tephra

Thanks Richard,

In addition to the 0.8mm jet pre-TB, do you think it's worthwhile going a smaller jet immediately after the IC? Or another 0.8mm?

I often think pre-TB will cause pooling as soon as the water droplet hit the throttle plate, similar to a rain hitting your windscreen.

When the jet is far away from the any object directly inline, there is a better chance of the droplet retains its surface area.

As droplet evaporates, the size will also decrease in proportion. The more time you allow this process to take place, the better the inter-cooling effect and smaller droplets. Smaller droplet (lighter) also give you better cylinder distribution. Large droplets tend to fly towards the back end of the manifold/plenum.

There is also a myth about evaporated water displaces valuable space within the linlet tract. This is not very true. Water can only continue to evaporate if the RH (relatively humidity) is below 100%. RH dedictates how much water can evaporate in a given environment, subject to pressure, temperature. Water and methanol have a specific vapour pressure that allows prediction by methematical calculation.

Vapour pressure is closely related to "Van der waals" forces, which holds the individual molecules together. Apply enough energe to the molecule, it will
break loose and separate - basic principle of evaporation. Water on the surface of a container tends to evaporate first because it has only half the "VDW" forces. Water droplet is basically the same surface water suspected in air with all surface exposed to absorb heat energy.

I know most of the water manfacturers advise the opposite, put the jet at the TB. I have yet to hear a valid arguement for this, so far none makes sense.