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  #91  
Old 13-07-2011, 07:27 AM
Wayne in NZ Wayne in NZ is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

Wow Guys, I feel so much more smarterer.

What a read.
Way too much for me to absorb it all.
But my general gist of it all is:

50/50 water methanol mix is best "all round" ratio.

Tune car for max power at best air/fuel ratio without knock with no injection (12.5/1)

Add injection and then reduce fuel to bring air/fuel ratio back to optimum

Advance timing to gain more power to just before knock

For more power after that either add more fuel or injectant

Have I got that right?

I am off now to soak my head in a bucket of ice water for an hour or so. LOL
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  #92  
Old 06-12-2011, 09:09 AM
RICE RACING RICE RACING is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

First few pages in this thread are gold, roll back 2004. Where are these people now?

Anyway I can tell you in a practical testing environment allot of what is discussed as theory or quoted from 80 year old tests does hold true in a real modern high speed internal combustion engine.

WI does indeed take a fair bit (no scrap that ! allot of) knowledge and testing to extract the most from this quite complex science. From personal experience there is much to be said for testing testing then testing some more~! I know the years of work I have done has gained me so much knowledge in this subject and so much of it is hard earned, brain frying stuff, its a stressful job some days, as you are doing things no one else (or very little) can achieve, cause its hard, it takes time, money, analytical ability and a certain level of relevant education to have a hope to repeat what many great engineers found since way back to the 1880's (yes first tests on WI!)......

I love the topic and the science, its my most enjoyable area of research for the above listed reasons and many more once you get aligned with the great resources Richard has collated here and many other valuable members have linked or posted of their own testing you too can be on the very rare bandwagon of capable people who don't need "power in a can" to look great Lets face it, anyone can open their wallet or extend a bank loan to pay for race fuel or some other rubbish that eats injectors or fuel system parts, but very few men can actually say that they have fast and reliable and mega powered cars running just normal gasoline/petrol............... that is priceless, just like this forum and the science that is water injection
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  #93  
Old 07-11-2016, 03:21 PM
beetos beetos is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

Quote:
Originally Posted by Richard L View Post
I am trying to clarify between knock threshold and MBT.

Tuning these days, knock threshold arrives much early before reaching MBT, it appears that no one are too concerned about MBT. I wonder if it matters or not whether if MBT is the main aim anymore?

The general road car tuning strategy seemed to be accepted as follows:

Run as much boost until the flow linit of the turbo is reached, dumping as much fuel as possible until egt is below 900C. Wind on as much ignition retard as possible until knock disappears.

I was wondering if this common method can be improved? with or without water injection.
I was hoping for an answer to this question. I run J&S safeguard on two heavily modified engines, one a Cosworth YB and one a Porsche 930, 3.5L twin plug both with stand alone ECUs (Performance Electronics PE3's).

I can therefore say I know quite confidently when these motors are running close to or at the knock limit. Now, I have not dynoed these cars to see if I am beyond the MBT and might actually benefit from reducing timing, but in my experience, most heavily boosted cars I have had were knock limited in terms of power delivery. I have ordered water injection kits of both cars, and was going over my 'strategy' for tuning with it. Initial thoughts were just like Richard mentioned above....essentially run timing up higher, and maybe set AFRs at 12 to 12.5, watching EGTs and keep a few degrees away from knock on my water injection timing maps. Would you guys agree? Obviously, I should probably get them on a dyno, but I probably wont get round to it.
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  #94  
Old 07-11-2016, 10:01 PM
rotrex rotrex is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

It depends. Given a high octane base fuel, enough water meth, effectve nozzle location and a well designed combustion chamber/piston/squish etc. you might hit MBT before any knock occurs. If you plainly map to the knock limit, you might seriously overload your engine.
Most engines today run a rather high compression ratio and often hit knock before MBT.
My strategy (supercharger) was always to start with reasonable low timing, get the AFR you want and then increase timing step by step and feel if power increases. If either power does not increase anymore or knock occurs, you have hit the limit.
On a dyno, you can see rather small changes. The butt dyno works well enough for street use. If you do not feel any increase anymore, it is not relevant anyhow.
In terms of amount of spray, I found with my latest direct port nozzle location right before the fuel injectors on the top side that the more flow I dailed in the more extra power I was able to extract after adding timing. When I improved squish I found no more improvement past a certain amount of spray despite a increased compression ratio. I seems I am no longer knock limited. :-)
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  #95  
Old 08-11-2016, 03:26 AM
beetos beetos is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

Thank you Rotrex, that makes sense. I think the J&S safegaurd, if calibrated correctly will alert well before serious knock occurs and it can pull out up to 2degrees per engine cycle on a specific cylinder, up to 20degrees. I think this unit keeps me well away from serious knock, but always better to be safe than broke....those 930 engines are not cheap to do properly!
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  #96  
Old 08-11-2016, 10:12 AM
rotrex rotrex is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

I use a J&S, too. 20 deg is too harsh unless you have a very slow burning combustion chamber design, e.g 60ies to 70ies Hemi heads etc. 10 deg worked best.
With the J&S serious knock is well captured. You can still hear it and also feel it from the power loss of the pulled timing under boost. I usually use it to point me to the map spots that need some correction. I had a pump issue once with the priming pump controller of my Aquamist 2c not working properly anymore and the J&S had some serious work to do as WI essentially failed. The engine spit blue flames from the exhaust with serious misfires as the J&S pulled 10 deg on all cylinders. That was a nice light show on the gauge. But nothing else happend.
As I am converting to an other engine I have sold my current engine and J&S last week.
The J&S is not as smooth as a fully tuned factory knock control system, but it does its job to indicate knock and provide some monentary correction. For street tuning, it is very very nice to have.
I would not "run" on it as in dail in full timing and the J&S does the rest.
I still can recommend it. It is 1000% better than having no means of interventing on highly strung forced induction engines.
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  #97  
Old 08-11-2016, 01:37 PM
beetos beetos is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

Completely agree. I will only use the J&S in the 10degree total / 1 degree per knock event mode, and never really lean on it heavily to pull timing under normal conditions, but it's nice to know it will be very aggressive in pulling timing if it has to, and also seeing the gauge go nuts gives plenty of knock warning.
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  #98  
Old 24-11-2016, 11:15 AM
djfourmoney djfourmoney is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

Quote:
Originally Posted by hotrod View Post
I agree I think trying to run ideal ignition timing is not as popular as it was in the past. I still think you should try to stay as close to ideal timing as possible.

Food for thought, the aircraft folks probably have done more testing and development on high performance piston engine in high load environments than all the automotive folks combined.

Many of them have timing fixed near ideal timing for max power. The way they handle max power for take off is they richen the mixture until the engine runs rough and then crank up the boost to the maximum recommended manifold pressure ( just short of det).

I think we should look more at managing boost pressure curves and less with playing games with the ignition timing.

I think the issue is it is much easier from a control system point of view to solve problems by pushing the timing values all over the map. It is much more difficlult to get fast acting stable boost control with enough head room so you can reach knock limited performance at high rpm with boost rather than ignition timing.

Most street turbos simply can't deliver knock limited boost at high rpm.

So they fake it by jacking in a lot of ignition advance, and create an electronic variable compression ratio by lighting the fire a bit early. It works to a point, but in theory it should not produce as much power as maintaining ideal timing and running the boost necessary to reach the knock limit.


Larry
I just wanted to highlight what I believe happens with the Mark 5/6 VW Golf GTI and the Focus ST; both have the Borg-Warner K03 turbo charger.

With the stock wastage and stock inter-cooler (those would like to believe) is poor are cooling the stock turbo when average off the shelf tunes are employed that removes the timed over-boost and makes that max boost (21 psi in the Focus ST's case).

I am running the car right now when drag racing with 40% Ethanol mixed with 91 octane fuel (California). I've seen max of 26 degrees of timing. Once the car reaches 210 degrees coolant temp, it reduces timing by 9-10 degrees and I loose about 1.5 mph in trap speed.

With an aftermarket internal wastgate, it's no so much how much more boost you run, but how long you hold it. On the stock WG that's about to 4100 rpm at my tuned boost of 23 psi and bleed down to 15 psi, a product of the stock spring in the WG.

With a Turbo Smart IWG with the standard spring for this car, it will hold 20 psi. The problem is that the turbo creates much more heat doing that. To combat this I know of two tuners of the car that tried this -

One complained about having to use increasing amounts of ethanol mixed with the fuel in order to keep the timing they increased initially (tuned car), at that point 30% (E30) and still got some knock, so they kept turning the boost down via the wastgate solenoid until they reached about 16 psi.

That's ironic because that's about where I am know. I maxed out the pre-load on my OE wastegate to about 3 mm. The car will hold 23 psi about 700 rpm longer.

The result is I picked up 1.7 mph with full timing restored (car about 200 degrees after my burnout). I know exactly that much because I did another pass about 30 mins later which is not enough time to let the car cool, and it went 100.44 mph when it previously went 101.96 mph.

I should mention the car is stock ATM, it only has a tune. A car with a 91 octane tune will barely crack the century mark at the drag strip, but most run 98-99 mph.

I did that with my base E30 tune (99.82 mph) and with a bit more timing advance on 40% ethanol it's run 100.25 mph. The truth is the car could have run 100+ mph at any time. I've only had five months and it has 30+ passes on it but I am just figuring out the proper shift points.

Anyway, the other tuner runs a Turbo Smart IWG and has achieved the elusive 300 whp mark with 35% Ethanol.

He won't divulge how much boost he's running or how much boost he's holding (I asked). He sent me a message that if I replaced my current tuner with his services he would spill the beans but to only paying customers. He didn't say the last bit like that but it was implied.

I purchased the same IWG and added W/I (AEM) to be able to push the stock turbo at least as far as he was able too. It's also the reason I went pre-turbo and post inter-cooler with my W/I system.
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  #99  
Old 09-06-2018, 06:13 AM
arthurtoo arthurtoo is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

I'm running an aquamist HSF-2 kit for my JDM 2006 Subaru STI. injecting only water at 42% IDC onwards. car runs great!

but i realized that there is a very very minor knock during initial injection and it's persistent throughout my logs. should this be of a concern or is there anyway to totally eliminate this?

thanks.
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  #100  
Old 09-06-2018, 06:37 AM
RICE RACING RICE RACING is offline
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Default Re: Tuning for water injection: fuel, ignition, and EGT

Quote:
Originally Posted by arthurtoo View Post
I'm running an aquamist HSF-2 kit for my JDM 2006 Subaru STI. injecting only water at 42% IDC onwards. car runs great!

but i realized that there is a very very minor knock during initial injection and it's persistent throughout my logs. should this be of a concern or is there anyway to totally eliminate this?

thanks.
Knock has to be one of the most mis understood terms in the after market performance world.
Typically when an engine is raised in power its vibration recorded through the acceleration sensors will go up (knock sensor), the shape and amplitude of these traces and the zero cross over point can be literally traced within a couple of CA to an in cylinder pressure transducer!, so its a very accurate representation of what is happening inside the combustion chamber.

As the BMEP goes up the 'knock' goes up, this all has to be defined in the ECU you chose to run, some do this better than others, some work, most don't! I would say so far that in all the ECU I have used (not owned or paid by anyone but out of my own pocket!) there is only ONE ECU that you can buy that does this properly and its made by Life Racing in the UK, all the others I would not piss on personally. Why does it work??? they build their own engines that race in LMP1, they are running on knock limit all the time, and they just work as intended, unlike the spec sheet racers with glossy web pages and blogs etc.

Now having got that out of the way and back onto your question.
You need to know what is normal what is not in your own engine, or otherwise the severity of the events, this is easy to define with nothing more than an acceleration sensor and some experience and the correct electronics that have a history of management in the real world at the peak of competition, if your own stuff you run does not meet these then its hard to honestly rely on the information you are being presented with. And note if someone tells you to use audible knock tools then put them in the *fuck head basket* never ever to be consulted with ever again!

Knock has to be quantified and acted upon within one engine cycle, you need to know what it is, if its normal, and where its heading (towards pre igntion) and countered at all costs, the importance of this varies with heat release or potential energy in the chamber IE: the more power it makes the more critical it becomes, some engine types when stressed will fail catastrophically and instantly when moderate levels of knock are exceeded.

Final note, some knock is good! generally the closer any engine runs to destruction the better its performance will be! so its not uncommon with Life Racing electronics to run the engine on the verge of this point all of the time to extract the most power and highest efficiency. Water Injected cars will allow you to run closer to this point without then quickly leading to pre igntion, this is no one really talks about, but is one of the key things that WI allows (not higher ratios of meth than 50% cause that will lead to far inferior performance FYI). So its a long reply but is normal to have light levels of 'knock' and its a healthy by product of an optimized engine. If you levels are right I cant say obviously as that information is not at hand and not validated.
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