Supercharger for Subaru?

Gannon · Post by **Gannon** » Wed Aug 29, 2012 5:15 am

Ideally the best point for the jet is straight above the intake valve, so you would have 2 jets, one over each head, tapped into the top of the intake manifold just on the bend on the head

steptoe · Post by **steptoe** » Wed Aug 29, 2012 8:27 am

Looks the pump for the job - if water injection does not work it'll make great screen squirters

Tweety · Post by **Tweety** » Wed Aug 29, 2012 11:17 am

Gannon, I see your logic but with the supercharger it will aid cooling it, make it quieter running and maybe other reasons.
In the bend in the manifold the SC and manifolds would need to come off to tap the hole. Not attractive to my schedule and lack of drive with my knees crumbling lately. Do you know what the greatest advantage would be to ahve them there?

Yeh Steptoe best to get the pump that's amde for the purpose- plenty of high pressure low quantity. I've been told that the nozzle will only allow a certain maximum amount of spray. so I assume I dont need a regulator to slow the flow down??? I think the fridge filter along with the jets filter will suffice for filtration. I wont buy a cartridge fuel filter as well. The fridge filter is good for 3500 gallons 8000 litres.

And I really would like the amount of water used per washer bottle fill to not pass 50 litres of fuel tank capacity. Apparently 10-20% is the common aim. 10% of 50 litres is 5 litres but I'd be, say seeking 1.5-2 litres. Now I'm aware of the fuel speweing out the exhaust I'm less concerned with the prime aim of economy. reckon might get back up to 25-28 mpg with another tune with those airleak fully fixed now. Efficiency is the aim.

Tweety · Post by **Tweety** » Wed Aug 29, 2012 1:43 pm

Quoting Snow performance

Pre- or Post- Supercharger/Turbocharger?

• Centrifugal/Turbo: (Procharger, Vortech, Paxton, Powerdyne, Rotrex, etc.) Never mount an injector nozzle before a centrifugal supercharger or turbocharger compressor. Sending fluid through the compressor wheel that spins anywhere from 50,000rpm to 250,000rpm can erode the leading edges of the fine aluminum. Studies performed by SAAB, concluded that pre-turbo injection will over time cause cavitation on the turbo wheel leading edges.
• Positive Displacement Supercharger: Roots style (B&M, Eaton, Magnuson, etc.) or twin screw (Lysholm, Kenne Bell, Whipple, etc.) Mounting the nozzle before this style of blower is perfectly safe and actually provides some additional benefits. The small amount of water-methanol fluid isn’t harmful to any rotor seals or surfaces or coatings, and it helps to seal the clearances and condense the air some more, resulting in a more efficient output. Additionally, it keeps the rotors and housing MUCH cooler, which reduces heat transfer to the rest of the intake and air charge.

I received the pump in the mail. pity its the wrong one. 220psi instead of 150psi. am waiitng for a reply from the supplier but 220psi is for high hp applications. 100psi + is ideal.

Tweety · Post by **Tweety** » Wed Aug 29, 2012 3:35 pm

Oh boy, what a steep learning curve.

Spraying Systems Company P/L are not car specialists. So they are limited a little on ifo to help me. This is the reason a kit purchase for water injention is preferable. Anyway received two spray nozzle assemblies in the mail They both have the filters and are 1mm diameter. But these arent the smallest nozzles available.

With these two nozzles implanted at 150psi I would need to tow a seperate water cart to feed the injection. Engine masters at Albury who sent me the 220psi pump do not stock the 150psi pump advertised. They pointed out that the ebay site has been discontinued and it states that on the side of the page on ebay but I have to speak to the original guy tomorrow when he returns.

See this chart. The highlights line is the nozzle I purchased.

Now the nozzle is a TX-4. the bar is at the top 1.5 up to 25 bar is the pump pressure. 150psi is about 10 bar so when operating it will go through about 29 litres/hour.

So I assume I return both nozzles and get them to replace them with one nozzle, the smallest which is 0.36 oriface the one at the top. But like the others the more psi you pump through it the greater the quantity of the water you use rather than have a finite amount that the nozzle can handle.

So a single 0.36 nozzle needs say 4 bar or 50 psi to pump 2.7 litres of water per hour. Again if I was to run this at cruising speed, my original idea was to have a throttle switch so it didnt run at idle, I would run out of water in around 50 minutes with 2.5 litres capacity. Thats why they have 9 litres water bottles in the boot with these systems. However it is common knowledge that 100 psi is required for full atomisation. If I use this 220psi pump which is 16 bar then it will use 5.3 litres per hour if on all the time.

Certainly cant run two nozzles for this application.

The alternative is to run the pump on say half throttle. Means cruising (which with the blower you have little throttle "on". So when accelerating, and on boost it will have water injection. And rely on the rejetting of the carbie at the dyno for more economy. I dont mind making/adding a larger water reservoir to the long necked Holden One I purchased to ensure I dont need to refill the tank more than one petrol tank full. Say to 5 litres.

This is getting complicated. What I wanted was the smallest water injected into the engine via the blower and due to the pump size required for atomisation minimum 100psi and the smallest nozzle size of .36mm whatever application I use there seems no way of having a reservoir of only 2.5 litres to last 50 litres of petrol and have it going on immediately past idle say 1500 rpm.

I'm confused!!

edit. ok, I'll source a Hobbs pressure switch to come on at 1psi. then use the 220 psi pump to the single 0.36mm nozzle. all I have to do is read up to find if I need to lower that pressure level with a regulator. Is there such a regulator say down to 100psi? or do I return the 220psi pump and look for a smaller one?

Gannon · Post by **Gannon** » Wed Aug 29, 2012 4:35 pm

Tweety wrote:Do you know what the greatest advantage would be to ahve them there?

With an intake path that has sharp bends like yours, because water vapour is heavier than air, you cant guarantee that you will get an equal amount of water to each cylinder and you dont want the water to condensate before it reaches the cylinder and pooling in the intake, this is why pre port injection is preferred.

Its not an issue with V8's where the carby is above the supercharger and the supercharger is directly the intake ports, but on a flat engine, the intake runners are long and flat before they reach the head.

Tweety · Post by **Tweety** » Wed Aug 29, 2012 6:12 pm

I hear you Gannon. Regardless of your view one issue that stands out is that two nozzles, the smallest available is 0.36mm oriface. ok for large engines and a boot to contain the big water tank but not for this application even on boost only as when towing boost would come on fairly often.

I havent ran the Sc in the summer yet. Best to run any supercharger as cool as one can get it, air intake as cold as you can etc. So if I have the single smallest nozzle and a 100psi pump with hobbs switch (comes on at 1psi) it would be preferred at the airbox end of the carbie in my view. 100psi is say 7 bar on that chart = 3.6 litres/hour and thats one nozzle only. One can only presume boost even when towing will only be used say 10% of the time. This would mean over 4 hours and 330 kms of touring say 30 minutes of boost time and pump time. Meaning 1.8 litres of water use. This is my projection and desire now, water injection on boost only, keep things cooler and reduce detomation to allow for normal timing advance.

Hope I make sense. I'm new to this stuff.

Happy to discuss it further and appreciate your ideas.

YouTube · Post by **El_Freddo** » Wed Aug 29, 2012 7:16 pm

Tweety, as Gannon said, that water droplet could be an issue. Hopefully the water will have evaporated by the time it gets to that T section of the intake, thus not being a problem.

I too don't know a lot about water injection but I believe it needs to evaporate before it gets to the cylinder.

Cheers

Bennie

Tweety · Post by **Tweety** » Wed Aug 29, 2012 9:57 pm

My understanding is that using sufficient water pressure (min 100psi) with an atomising nozzle/s (0.030mm min orifice) will produce a "fog". The fog will mix with the air/fuel mixture through the SC (under boost) and travel through the manifolds to the cylinders.

Yes the mixture has to negotiate the bends and thats the discussion here. Will the water liquify during its journey?

I am resitrcted to one nozzle due to the size of the engine, the fact that it isnt for racing and limited in water carrying capacity and finally the minimum size of nozzles that atomise.

If there were no advantages in pre SC location be it at the trumpet or at the custom lynx cut down manifold then one nozzle at the base of the other manifold just up from the ea81 manifold neck would suit. But many sites I read there are advantages in pre SC location for the nozzle if its a roots type blower. Like

Source http://performanceforums.com/forums/arc ... 93431.html

“The toyota blower is relatvely loose, and they are teflon coated rather than having rubbing strips in the ends of the lobes. The water helps cool and seal the blower blades to each other. The amount you would use is not an issue for the blower- different story if it is a screw blower however..

We used to use a windscreen washer pump to spray water/ meths into the throat of the su on the outside of a sc14- that sucker pumped a heap of liquid and we never had an issue.”

Centriphical turbos and SC's and twin screw type chargers are a different matter and serious damage can occur with pre water injection on those units.

steptoe · Post by **steptoe** » Thu Aug 30, 2012 8:53 am

note on the autospeed article one size jet only just atomised or nearly not spray - think it was the smallest one.

Now, if you had a Brumby you could have a big water reservoir ......

Tweety · Post by **Tweety** » Thu Aug 30, 2012 10:52 am

Yes mate saw that. and have a 0.36mm nozzle on order.

also this email received from snow performance today that I had been sent the 220psi pump instead of 150psi:

Hi Tony,

That is the pump we are currently using in all of our kits. You should be able to bolt it up and go but if it is over injecting, you can turn down the pump pressure by turning the allen screw on the pump head counter clockwise.

Sincerely,

with 220 psi pushing through that small nozzle it should atomise ok. Will seek a hobbs switch for 1psi 'on'. any larger on nozzles and it would consume too much water.

Tweety · Post by **Tweety** » Fri Aug 31, 2012 2:24 pm

Update:

Emailed Howard Instruments of Heidelberg re: hobbs switch to come on at 0.5-1psi boost. There are some that have these for sale on the www. Answer:

Tony,
I don’t believe that you will get an accurate switch point this low

03 94574755 Regards Rodger

So where are we at now? I'll purchase a second kickdown switch to switch the pump on throttle.

The 220psi pump is more than sufficient and will stick with it. Got a 0.036 nozzle for spraying Systems Company P'L (note: their nozzles are not suitable to screw into a manifold but are suitable to mount outside a carbie trumpet on its own mount). Have the filter unit. Limit supply of tube and fittings though.

Plan is to hook up the system on a bench and measure its flow when constantly pumping and if needed adjust the pump down to reduce water output. Well thats the plan.

Tweety · Post by **Tweety** » Fri Aug 31, 2012 5:23 pm

Set up the pump and connected the nozzle assembly. This being the finest nozzle you can use for atomisation being 0.036 from Spraying Systems Australia. 220psi pump.

As you can see here the result is best described as "cold steam".

First run, pumped one litre in 8 minutes.

unscrewed the small screw at the pump and second run pumped one litre in 10 minutes.

Means if running the pump only on boost I could run boost say for 25 minutes a tank of fuel. Thats ok I think. If not I'll need to increase the water storage from 2.5 litres.

So am on the search for a system that will switch the pump on at low boost or at half throttle. I'm concerned that less than half throttle will hit boost say uphill and not turn the pump on. Gotta check this out.

Tweety · Post by **Tweety** » Fri Aug 31, 2012 9:14 pm

So following this testing today I've found that Snow industries (maker of my 220psi pump) has a 60ml/min nozzle, half the flow of the Spraying Systems Company nozzle tested today. Furthermore you can screw it into your pre sC intake manifold.

Available from Rocket Industries NSW. A solonoid also available for when your nozzle is mounted at vacuum location to stop sucking water.

Baccara P/l have pressure switches. have emailed them for info.

Tweety · Post by **Tweety** » Mon Sep 03, 2012 7:29 pm

Baccara sold me a pressure switch that turns on at 0.5 psi. $43.

I've had tweety in at the auto elecs, thought it was a starter issue. Turns out the regulator is putting out 18 volts!!!! The guy said I'm lucky I got away with two blown headlight globes and didnt fry my ignition. pick up tomorrow. then water injection install.

YouTube · Post by **El_Freddo** » Mon Sep 03, 2012 9:46 pm

Tweety wrote:Turns out the regulator is putting out 18 volts!!!!

Wow, that's crazy! Very lucky indeed. How's your battery?

Cheers

Bennie

Tweety · Post by **Tweety** » Mon Sep 03, 2012 10:13 pm

Wont know the details till tomorrow but think its ok as they didtn mention it today. they said they have it running though. Battery is new too. I'm very lucky eh bennie.

Tweety · Post by **Tweety** » Tue Sep 04, 2012 5:03 pm

Water injection.

It isnt easy finding a simple boost switch unless you want one to come on at 5 or 10 psi. I wanted one to come on at 0.5 psi.

Baccara sold me a pressure switch [email protected] for $43 plus postage. This switch is made by a Chinese firm called LEFOO. Item number LF42. Not much info on the web except that its used for remote operation etc.

Hooked it up to a test light and blew into it to find it only came on every second time I blew into it??? So pulled it apart.

This is the switch

Note the two white items on the right.

When I pulled the switch off the diaphram housing it exposed these peices. One is a small rachet shaped like a hole saw and the other shaped like a space station lol. Anyway they were replaced with a small length of tube. reassembly and it works just as I wanted each time I blew into it.

With the tube in place

The discarded internals.

This will be hooked up to the earth lead of the water injection pump and it will be mounted on the manifold with an extension peice. Rated at 80C temp. dont know the temp a manifold will get up to but play it safe ?

YouTube · Post by **El_Freddo** » Tue Sep 04, 2012 7:18 pm

Looks like someone decided to drop the top end of their pen into this switch

It's not really an accurate way to test a switch either!

Cheers

Bennie

steptoe · Post by **steptoe** » Tue Sep 04, 2012 7:35 pm

You beat me Bennie !!