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  #51  
Old 26-03-2006, 02:28 PM
JohnA JohnA is offline
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Quote:
Originally Posted by mrex180
So John whats best to look at then EGT rather than IAT with WI?
Neither :wink:
Knock would be my main consideration

EGTs are affected precious little by W.I. (strange but true!)
IATs are affected only a tiny bit - depends mainly on the location of the nozzle, post-ic temps and methanol content

Emergence of knock's ugly head is what WI is meant to fight best.
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  #52  
Old 15-04-2006, 11:42 AM
mrex180 mrex180 is offline
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How critical is the jet placement and distance from the combustion chambers for atomisation?? My jets werent placed where i wanted them so is it worth tapping the turbo comp cover and putting jet in the outlet?? this would move the 1st jet back another 200-250mm from it's current location, then i would move the 2nd jet to where the first was??? Any thoughts?

2nd jet is the one closest to the BOV outlet in this pic.



Andy
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  #53  
Old 15-04-2006, 12:01 PM
JohnA JohnA is offline
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Can anyone say for certain without special photography of the airstream/mist moving under realistic conditions?

My view is that the finer the mist, the easier it is for the water to follow the air during sharp turns.
In my car I'll soon have the WI nozzles facing straight at the compressor eyes. I don't think it gets better than that.

But even for post-intercooler injection I'd expect sharp 90 or 180 degree turns to be an invitation to de-atomisation.
Maybe not pooling - heck, at 1 bar boost the airflow will be quite violent- but certainly not uniform distribution among the cylinders.

Maybe a relevant analogy is the positioning of 'extra' fuel injectors in older turbo conversions of n/a engines. No matter how well the extra injector was positioned, some cylinders would consistently run richer than others. Can't be that different with water mist.
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  #54  
Old 16-04-2006, 12:32 AM
mrex180 mrex180 is offline
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Thanks John, i agree how do you if you can't see it, one can only assume whats happening, even in that video of the cosworth motor with clear end on the intake manifold you can a fair % of water actually pooling on the glass and not going down the runners.. Whats your thoughts on a individual jet for each intake runner? besides the chance of one becoming blocked..And i like the idea of injecting straight into the compressor eye, are you going to put some info on your web site about the set up?

Andy
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  #55  
Old 16-04-2006, 01:01 AM
Richard L Richard L is offline
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When the engine in on boost, you can almost guarantee all injected liquid will end up in the engine. If you are injecting a large volume of waterdue to lack of intercooler, I think you should consider port injection.

In-cylinder cooling is more important. Wi has great effect on the intake stroke, cooling down the inlet valve and hot cylinder wall after the exhaust stroke. Port injection will greatly improve volumetric efficiency of your engine. If you are concern with block jet, use a bigger jet but control your water flow with a PWM valve.

It is not essential to have atomised water with port injection. The latest Subaru WRC car (during development) uses straight jets. It uses a 0.3mm straight jet without atomisation, pointing directly at the inlet valves, result was good better than manifold injection.
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  #56  
Old 16-04-2006, 09:53 AM
mrex180 mrex180 is offline
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Thanks Richard , thats interesting stuff alot of what i've read about port injection has been not so supportive, like what if a jet blocks or it more a track or strip thing not for street use, not enough time for water to atomise.

Andy
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  #57  
Old 16-04-2006, 11:12 AM
Richard L Richard L is offline
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I wouldn't pay too much attention on what other people said, not many have actually tried it in practice.

I suggest using port injection with manifold injection at the same time, until you get comfortable with it, you can decide. The effectiveness of temperature reduction by manifold injection is subject to how much water vapour the air can absorb at a given temperture and pressure. The humidity of the uncooled air has also effect of the degree of cooling.

Inlet tract cooling is only a small part of overall cooling process by water, journey after the intake valve is equally important but topic is rarely discussed - there were some discussion on this section earlier. Due to difficulties in measuring the temperature after the inlet valve, the discussion was not very detailed due of lack of evidence.

I don't have proof either but I have witnessed the effectiveness during many mapping sessions on rally cars, the onset knock event is more even amongst the cylinders compared to manifold injection. Knock events seemed to be more evident on one or two individual cylinders, I think this is due to uneven water distribution rather than hot spots or poor cyliderhead water jacket design.

You can acutally detect blocked port jet by using two flow sensors, just compare the signals between two branches. We can supply an internal filter for all jet sizes but only put them on the 0.3mm jets. The internal filter surface area is very small so it will defeat the object of preventing clogging when large flow nozzles tends to collect more debris in comparison.

I can supply you with sintered filters to be put into bigger jets but ensure the flow is PWM controlled so flow is limited.







Richard
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  #58  
Old 16-04-2006, 12:02 PM
mrex180 mrex180 is offline
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Thanks Richard great info How many jets can the race pump supply? as there would be 4 x 0.3's jets (1 for each cylinder naturally) then what could you use for manifold injection? And just for curiosity with port injection do the jets still face 90' to the oncoming flow or aimed straight down the port?

Andy
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  #59  
Old 16-04-2006, 01:51 PM
Richard L Richard L is offline
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In order to make your set up simplier, just injection atomised water for the time being.

You can increase the flow of the aquamist by adding a samll priming pump. Do you have the 1s or the 2d?

Here is a link how to add the priming pump:
http://www.aquamist.co.uk/phpBB2/viewtopic.php?t=127
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  #60  
Old 16-04-2006, 10:17 PM
mrex180 mrex180 is offline
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My system was originally a 2C then i added the FIA2 so i think it's virtually a 2D correct?? I have a spare washer pump left over which was my intercooler waterspray so i would just have to re-config the wiring..

Andy
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