Water Injection and IC water spray system for Legnum

[eddyvr4]

Paul, No - the temp probe is after both the Intercooler and the water injection.

The haltech does have a dedicated IC spray output with a boost level trigger and configurable hold time. but this was no good for me, i dont want the WI running after i lift off, which is why i ran both off the 5th injector output. But a good controller is the "autospeed intelligent intercooler spray" controller much better than my setup- google it....

 

[unclepaulie]

ah ok then, well yeah, i eagerly await results of further testing

 

[eddyvr4]

After all that, I guess I should have made a mention of whether the car actually seems to drive any differently. Well - yes and no.

Logic would say that unless the intake temps are high, (or its pinging) the system isnt going to benefit the peformance. The seat-of-the pants-o-meter confirms this, although if pushing hard for an extended period in the cold there may be some heatsoak issues it would eliminate, but its hard to verify either way, because my temp probe is not backlit, so I cant see it at night! But the acceleration does not dull off after a rapid succession of WOT applications. But i dont notice a vast difference in cold conditions to before, and theres just to many variables to conclude much other than none to a small improvement in my driving/roads, although ill reserve the right to upgrade my assessment over time and more kays.

So the peak peformance of the car in ideal (cold) conditions has not altered a huge amount

However in heavy city traffic and warm to hot conditions the peformance does not suffer like it used to, the car feels equally eager even under high temp conditions. So this modification has not improved peformance so much but allowed the car to peform at its peak under an extended range of temp conditions.

This is dissapointing to an extent, as my primary goal was to lift output power by pushing out my detonation threshold and retuning, this I did not achieve. No hiding from that. But if you look purely from a results vs parts cost, (under $A300) it’s a excellent result on the intercooling side and probably worthy of consideration, for those prepared to build and maintain something a bit more complex.

To summarise what was achieved:

Conditions - 3rd gear dyno runs 16 psi, ambient temp low 30s. Initial Intake temp around 43 degrees - )

1)
Temp rise on dyno run No WI/IC spray - 31 degrees
Temp rise on dyno run with WI/IC spray - 5 degrees
26 degree or 83% reduction in the temperature increase

2)
Intake temp recovery time after dyno run No WI/IC spray - approx 1 - 2 mins
Intake temp recovery time after dyno run with WI/IC spray - approx 10 seconds
6 times + faster stabilization of intake temp

Above achieved on a completely stock intake pipework and stock intercooler.


Again i stress the hotter the conditions the more the benefit, the colder, the less the benefit. i would consider the test conditions on the day as hot, but not extreme.



If I was to do it again I would spend the extra and get an off the shelf engineered kit…. Like an aquamist or similar etc.. It depends what your time and patience is worth...

 

[chrisssss]

wow that is awsome anything to reduce head in any means of cooling is a good idea well done

 

[eddyvr4]

thanks for the feedback.. Josh, if i can get my hands on a cheap 2nd hand evo cooler id go for that, altough it would be nice to measure the pressure drop on the factory unit at high boost just to quantify what its doing. My problem now isnt intake temps, detonation, or fuelling. I simply need to push more air through the engine with the stock turbos.. a less restrictive intercooler should help there, and your experience seems to suggest the stock unit might be restrictive..

 

[frozen]

i'd have also thought colder temps would result in power gains, seeing as there is a MASSIVE difference in how the car feels summer vs winter, due to colder air being more dense? Did you dyno run numbers with and without? or just temperatures. Very interesting read an intercooler spray kit is something ive wanted to do since ive had the car...

 

[eddyvr4]

Josh, when we did the dyno runs without the water injection/IC spray, once everything was stinking hot, (say after 3 or 4 full throttle pulls) if we did not give the car (and particularly the intercooler) a minute or two to cool down, the power would drop off markedly (say 10 to 15 kw) and youre likely to get detonation as the intake temps are too high as everything is heatsoaked.

We could have 'rigged' the runs to make it look like we picked up power with the WI/IC spray, by starting under a heavily heatsoaked condition, but I thought that would be somewhat misleading, especially if people skim the article and make uneducated conclusions.

So when things get hot, one could argue we do 'pick up' power, but is more accurate to say we minimise power losses when we activate the water injection/sprayers. On the road this should mean the car runs nice and crisp like it’s a cold day every day, and peformance should not taper off during an extended heavy footed run.

I believe you are suggesting your power may have gone up under like for like conditions with your new inercooler, and your wondering why I maybe havent had the same result, even though my system now cools a lot better than yours. There is a simple explanation to this - your greddy cooler FLOWS better than my stock one.

If my stock intercooler is physically choking the flow of air, improving the cooling efficiency cant fix that (not much anyway) What would be ideal for me now would be a high flowing intercooler. Its cooling efficiency/size doesn’t matter much, because ive got the WI/IC sprays to enhance cooling, but it must flow well (ie have less restriction than the factory one). I felt the stock IC would Flow ok on the stock turbos, but hopefully im wrong, your experience certainly suggests so.

Equally, if you were to add a copy of my system to your car, with your Greddy cooler, you probably wont pick up any more peak power in cold conditions, you already picked up gains here with the higher flowing intercooler. What will change is the car will run equally hard even under hot conditions, or on the dyno, or on an extended hard blast through the hills on a warm night, so youll pick up power, but only when temps are high enough to otherwise drop power...

How often are your temps high enough to hurt peformance? I cant say... But Installing a cheap intake temp probe/display would give you a good feel for what your temps are doing, and how the car feels at different intake temps.

 

[Hotwire]

Eddy,

you have your temp intake probe post cooler, but have you been able to compare this to temp intakes at the airbox? Reason I ask is I notice on my Lib that IAT (which is taken at the MAF, prior to the TMIC) can be anywhere from 5* above ambient when moving, to up to 15*+ above ambient when in traffic. Then taking into account heat soak of the TMIC and I notice that after driving through traffic then boosting, my knock figures are far higher than when cool day or clear road driving.

SO my question is I guess, have you measured the physical temp difference over the intercooler? as i'm considering a water spray for my TMIC working off inlet temps...

 

[eddyvr4]

Hi Lee!…..I have.. As you would remember the mitsubishi climate control cluster has an outside air temp pickup which I treat as an ambient temp sensor. So comparing this to my IAT sensor (or Temp probe display as I refer to it) post intercooler/WI, I notice that under light cruising conditions, IAT is about 5 to 10 degrees higer than ambient - say 7 degrees on average if its not a real hot day.

I imagine most of this heat is picked up as the air passes through the turbo which obviously is being heated by the exhaust.

So I havent measured the temp diff across just the intercooler, but between ambient and post intercooler I see similar temp rise to you, maybe a bit less because we have front mount intercooler

The thing you may need to consider is when i shut the car off, my iat shoots to 50 - 60 degrees with latent engine heat. If your triggering spray off IAT only, you are gonna find the thing turning on for 10 - 30 secs or so whenever you hot start the car, even on a cold day, and you will chew water unnecccesarily. Im sure you can solve this with an additional input of some sort - IAT and some engine load maybe?

 

[eddyvr4]

I did end up replacing the factory intercooler in the end as well, with interesting results... to read more see thread

http://ozvr4.com/forums/showthread.php?3253-Ed-s-car&p=199150#post199150

 

[wil]

Wow nice write up.... Would have been more easy with the auqa mist kit... Im running 50 meth n 50 water!

 

[eddyvr4]

Thanks for the feedback Wil. Yeah, go a kit... I added about 20% metho somtimes, no doubt it helps, although i cant measure or notice a difference so dont generally bother.

I still get i kick out of driving my intake temps below ambient on a hot day!

System still working with no problems... oh, except, ive had the el-cheapo boost bleed valve bind shut if the car sits for a couple of weeks, resulting in overboost. im quite sure its caused by tiny residual moisture (from the water injection) in the wastegate lines 'rusting' the ball bearing up, just enough to make it stick... bit of wire to loosen it up then its fine. with a oscillating solenoid like the stock solenoid or an aftermarket EBC this would not occur. Maybe i should not be such a cheapskate and get one....

 

[wil]

no problems.... try running 50/50 hahaha...

this is the kit - http://howertonengineering.com/products/aquamist-systems/aquamist-hfs-3-injection-system/

 

[eddyvr4]

Yeah, although my idle stabiliser controller also died recently.. trawling the net there are a couple of comments (only a couple) i found where evo people were suspecting a pattern emerging where metho injection sometimes causing the ISCs to fail prematurely...so it did put me off just a bit.

i dont reckon it caused mine though, as it was playing up before i ran any metho or WI, however...

I really like that kit, looks great, although i reckon the lower end Kits probably achieve the same outcome.

 

[wil]

my friend's been running the hfs-6 i think for over 2 years on 2 bars of boost.... had no issues... he opened up the head to have a look:

View attachment 9568

yeh prob lower end kits will be the same, but make ensure they have failsafe!

 

[bradc]

What an awesome thread, well done!

 

[eddyvr4]

Thanks Brad, positive comments like that makes the effort of writing it all up worthwhile!

 

[eddyvr4]

Having done further experimentation in recent months, I thought it was time for another chapter as i see some other interest on the forum in water sprayers and the like.

To recap on the story so far, i run a parallel water injection/ IC water sprayer system , which i established with a fair degree of certainty, holds down my intake temps consistently, and i think exceptionally well. What i also learnt along the way (despite my attempt to prove the opposite) was that throwing water at the stock intercooler (and dose of WI on top of that) was not a substitute for a bigger intercooler, as i picked up big gains after replacing the stock cooler as well. I could overcome the heatsoak with the stock cooler, but it was still a flow restriction.

Otherwise the car just has a full exhaust and more boost and ECU flash, all the intake pipework is stock. According to the dyno leaderboard, the car rates as (suprisingly) the most powerful Auto Legnum in Australia on stock turbos, so i think its a good honest vehicle from which to experiment further. (The fact it since ran less after some ECU finger poking is a closely guarded secret...a temporary setback!)


Anyway, what i never took the opportunity to play with, was how much knock suppression my system was really delivering. When i had the car dyno tuned (Haltech interceptor) , Steve knight wasnt too keen on playing with the timing much, and we saw no detonation on the tune, so it was left at that. dissapointing, yes, but dyno time is expensive...

The nett benefit i noticed at the time following the water injection and sprayers, was the car always felt like it was running strong. Prior, some days it felt flat, and others good, now it just always felt good. this makes sense as i had a much narrower range of intake air temps the car had to deal with, and also was probably never needing to pull timing as detonation was probably rare.. but i cant prove this, i wasnt doing much knock logging, it was tuned & that was that. Shameful i know, but i was just enjoying driving it.

However the months(yrs?) rolled on, and in the meantime the ECUs had been cracked and i had the opportunity to spend some time with Lee (Hotwire) having another go at retuning the car on the road, with lee on the laptop tuning my ECU, and terrifyingly for him, me at the wheel.


This time the goal was to reflash the factory ECU so i could remove the haltech piggyback, tune the 3 port boost solenoid, but also to see what we could do in terms of timing advance and power gain, given that i should have a engine with far better resistance to knock than a standard legnum. The aim was for more responsiveness in the midrange, where the car spent most of its time in my hands.

firstly we got in a base tune and mapped in the 3 port solenoid and fattened up the boost in the midrange if not across the board, however we were seeing knock in the top end. hmm thats unusual, so took some timing out there. that was as far as we got that night, The car felt good, and as luck had it a dyno day was up the next week. So I put the car on, it ran a lot stronger up to 4500 rpm, (thats why it felt good!) but then we had lost power up top due to the timing lee had pulled. bugger.. why was i seeing knock up there now? boost and timing was not extreme.

Confused, i inspected the system to find a series of water leaks in the water injection hoses.. ah-ha! that mustve accounted for it! fixed that and went back for another run. we got back what we lost, but again it seemed like the car, whilst strong on a relatively 'normal' tuned map, would just not take much more advance than where we started. We had a good try, but there just didnt seem to be much more gains to be had. This was dissapointing, as whilst the car is strong, why wasnt the WI giving me a more noticible envelope of timing to play with? Dont know. The frustrating part was you could feel the car was noticibly more responsive and willing with a couple more degrees advace.. it felt great.. but it would knock and, painfully, we had to remove it, (however, we picked up a degree here and there, although i do see more background and occasionally non trivial knock now. its borderline. (pending further logging). So gains, yes, but less than expected on timing
　
The big concern/reservation i always had, was the shape of the VR4 inlet manifold, with its side entry it is not a shape to allow even distribution of water into each cylinder, maybe the near end cylinders were missing out on enough water, and it was pinging on those cylinders.. That was my main thought...

I retested the flow rate, 170cc. as expected. I even retested the injector inside a pressurised juice bottle, so i could look to see if it was atomising ok with 15psi of pressure working against it. again exactly 170cc of output. So that was fine. the boost pressure was obviously not pushing water back down the nozzle then.
Hmm. for about 2 months... a lot of <hmmm> going on .... why.. why.. <scratches head>
　
The conclusion that i started to draw based on the evidence, is that for my engine controlled low intake temps and the water injection was not enough to 'buy' me more timing advance. My intake temps due to the combination of water injection and water sprayers (they always fire together) were always very low (say less than 40C) , yet it would still detonate if we tried to push the timing advance just a couple degrees further than, say what Lees map looked like already. (lees car similar mods to mine, but no WI) So, Low temps as measured by the temp probe are good, but not enough in there own right to allow much more advance.

My temp probe in the intake could also be misleading as the water may evaporate as it hits it, resulting in an artificially low reading.. so many unknowns...

The other point of note we had was that after continual full throttle runs and extended idling with lee and myself in the car it did appear to become more prone to knock, even though the intake temp never rose much more than say in the low 40 degrees at full throttle. ie it seemed like the engine itself still became heatsoaked (I think this is just a fact of life with our cars) even though the intercooler never did. the logged (load)power didnt really drop off, but the tendency to knock would rise. So why wasnt my water injection taking care of that? That was preciscely its point!. In my real world spirited driving i never noticed it as an issue, (ie the engine seeming to become heat stressed) but it was less resiliant than i expected, given the supposed benefits the WI was meant to bring me.

The other dillema was also, how could others get more power out of there car than me, without knock, and without any water? it wasnt lower intake temps thats for sure! This could be explained in that others arent getting more power than me, just that they are running higher numbers on the dyno because they dont have the auto losses, and those running bigger turbos arent producing as much power as me either in the midrange instead they are producing more up the top end... .. Maybe, maybe not..maybe just me dreaming up excuses for failure....

After much internet surfing (firstly about what better car i could get, then checking my bank balance to see if i could afford a V8 Audi S4, (and all the mods it would need) then browsed promptly back to the water injection forums...

One day, going back over the numbers, i remembered that i had targetted injecting about 10% water compared to the fuel. the rule of thumb for WI is 10 - 20% water to fuel, i went to the lower end of that figuring it was the safe option. 20% sounded like a heck of a lot, that must be for dragsters and the like. My car currenly logs about 67% injector duty cycle at peak, which = 1567cc fuel/min so my water injector at 170cc was about 11%.. near enough.

(Footnote: At 67% duty cycle i have about 50% headroom to run E85 on my current injectors.. yes?.. Anyway, back to topic.. )

But thinking about this further, and looking at the little cup of water on the bench, it was hard to imagine how that tiny amount of water distributed over 6 cylinders for 1 minute could be taking out much heat. 170cc divided by 6 cylinders = 28cc per cylinder per min, or 0.47cc per cylinder per second. One half of a mililitre per cylinder per second, at FULL throttle! How on earth could that be removing any heat whatsoever! especially if it wasnt being distributed evenly, ie some cylinders could be seeing even less than that... suddenly 10% is not sounding like much at all!

So - with renewed enthusiasm, apart came the nozzle for a full recalibration (out with the micro drill set, out to 0.70, then 0.75mm) . Now i had it flowing 300cc/min, which is about 19% of the fuel volume. (and the intercooler sprayers are now flowing about 100cc x 2)

Now i had about twice the volume of water...Watch this space.......

 

[hozza]

Keen to see what happens.
So did you replace your cooler and still keep the water sprayer?

 

[TME_Steve]

Nice rightup Ed, lower intakes don't always mean more timing advance, quite often a car will only knock on a cold night when it flows that little bit more! Still more water should help, What I would also ask you is, can you get a gain from that extra flow that others cannot? IE can you run more boost at higher RPM than others?

As for this:
(Footnote: At 67% duty cycle i have about 50% headroom to run E85 on my current injectors.. yes?.. Anyway, back to topic.. )
Yes and no, yes you have more room to move, but no in that injectors get a bit unstable at high duty cycles so I would say don't go past 80% so you only have about 20% up your sleeve if you followed my rules....