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  #41  
Old 16-05-2016, 10:29 AM
rotrex rotrex is offline
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Default Re: Nozzle spray angle...

You might just pull timing some 20C past the IATs you usually get with a nozzle spraying before the sensor.
There is a IAT ignition correction table in your ECU that can be used as a kind of fail safety.
The same would work for the fuel IAT correction.
This would work on top of closed loop fueling maintaining your AFR if WI fails or injects less than intended.
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  #42  
Old 10-02-2017, 09:12 AM
jondee86 jondee86 is offline
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Smile Re: Nozzle spray angle...

Back again Finally got the supercharger installed and the car running but
without the W/I system (I have the HFS3 here waiting to install). I have two
nozzle holders already in the ducting; one close to the S/C discharge and one
in the last elbow before the intake manifold. Here are some pics...







At the moment I am driving the car in the <100kPa zone and working on
getting some sense in the fuel map.

Cheers... jondee86

Last edited by jondee86; 17-07-2017 at 09:03 AM. Reason: Fixed broken links...
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  #43  
Old 10-02-2017, 09:34 AM
jondee86 jondee86 is offline
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Question Re: Nozzle spray angle...

However, I have found a small matter that needs to be made clear before
the water injection system is installed. I noticed when looking at the log that
I made today, that the ECU was pulling fuel under steady running, so that
the AFR was made leaner than my target AFR



When I investigated the cause, I found that the ECU Manifold Air Temperature
correction table was the reason for the trim. It is the same table that I used
for my N.A. engine. The Aux Temp sensor is located in the S/C discharge
manifold and is only for logging. The MAT sensor is located in the intake
manifold, and is an ECU input. At the time of making this log the intake air to
the engine would have been about 20degC.

So what is the best way to avoid having the ECU pull fuel with a S/C engine ?
Simply set the correction table to zero at all temps and rely on the fuel map
alone to maintain correct AFR's ? Any advice appreciated.

Cheers... jondee86
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  #44  
Old 10-02-2017, 10:16 PM
rotrex rotrex is offline
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Default Re: Nozzle spray angle...

Could it be that you exceed the AFR correction range in closed loop operation?
I run my car with +-25% range.
The IAT correction for fuel is similar for NA and FI.
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  #45  
Old 11-02-2017, 06:49 AM
jondee86 jondee86 is offline
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Default Re: Nozzle spray angle...

This is the IAT compensation table I used with N.A. and now with F.I.



Ambient temps in NZ are typically between 10 and 20degC, maybe up to
25degC on a good day So the amount of compensation applied on an N.A.
engine is relatively minor and positive.

With the F.I. engine the IAT is measured after the S/C and under light cruise
running the temp measured at the inlet manifold was 57degC. It is to be
expected that the S/C discharge temp will increase as the manifold pressure
increases. Using the above table this will result in more negative trim being
applied at a time when the ECU will be commanding a richer mixture.

The target AFR table requests more fuel according to boost, and as temp
varies with boost, it could be said that the AFR table calls for more fuel with
increasing temperatures. At the same time, the IAT compensation table is
reducing fuel with increasing temp. Which leads to these two possibilities...

1. Set the IAT compensation to zero and adjust fuel with the target AFR.

2. Allow the IAT table to apply corrections and adjust the target AFR richer
to compensate.

3. Leave the target AFR alone and let the IAT compensation trim the mixture
leaner as the manifold temp rises.

Seems that we are balancing two variables here, and I am wondering if we
can safely reduce this to one variable

EDIT: Thinking about this while I was out walking this evening; obviously the
IAT compensation will be useful when misting to lower the charge temp. So
option 3 looks good. And with this option I am going to assume that the AFR
target numbers are nominally based on (say) 20degC ambient temp, so that
fuel can legitimately be trimmed as the charge temp rises. Right/wrong ???

Cheers... jondee86

Last edited by jondee86; 11-02-2017 at 10:06 AM. Reason: Walking in the fresh air clears the head :)
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  #46  
Old 11-02-2017, 01:35 PM
rotrex rotrex is offline
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Default Re: Nozzle spray angle...

AFR is a target the closed loop controller, if active, will try to hit that within it s limits.
IAT compensation compensates for a physical phenomenon. Air density drops about 3% every 10C. Your IAT table compensates for a part of that.

Your IAT is high because the supercharger is hot and heats the air even while cruising.

Fueling is not derived from the AFR table, but from a VE or a pulse duration table.
The AFR table is just there to tell a controller to correct the fueling table in closed loop operation.

with your SC now operative, you first map the fuel map. An indication of this is if your fuel trims are close to 0%, say +-2%. Means your closed loop controller has hardly anything to do.

The ECU also adds fuel proportionally to boost. This works out pretty well if the base feeling is mapped right. also leave this alone.


It seems to me you really need to look into your ECU's operating manual and see how it works. There are several different strategies. Therefore it is hard to give you advice without even knowing what ECU it is, what mode it runs in, if it has a wideband sensor signal fed into the ECU, what the trim value actually means..... (trim can be a correction based on the average % of fuel trim based on a AFR table but could also means corrections based on correction tables, e.g. IAT, barometric pressure, coolant enrichment etc. . So all stuff completely outside of closed loop operation.
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  #47  
Old 11-02-2017, 11:00 PM
jondee86 jondee86 is offline
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Default Re: Nozzle spray angle...

The ECU is an Adaptronic e440d and it does have a lot of tables that adjust
for temperature, but once the engine is up to operating temp all the tables
are zeroed out except for the IAT table. So when manually adjusting the VE
values obtained by the autotune function to get the trim closer to zero, I only
look at the logs where the engine is at operating temp and under steady load.

There is a wideband connected directly to the ECU for monitoring the AFR.
The manual is quite comprehensive but it does not explain some of the finer
points. I am trying to discover if the VE set by the autotune is before the
IAT correction is applied, or after ?

Looking at the logs it seems it is before, as the correction applied by the IAT
table makes the reported AFR leaner than the target AFR. On a N.A. engine
this would be acceptable, but on a F.I. engine I am not so sure.

I'll ask Adaptronic about the actual strategy used.

Cheers... jondee86

PS: I spent some time today researching IAT compensation and have come
to the conclusion that the answer is to set the target AFR a bit richer and let
the compensation table take out fuel according to the manifold temperature.
So long as the adjusted AFR's are in line with the recommended AFR for the
level of boost, I think that this should be fine.

Last edited by jondee86; 12-02-2017 at 10:24 AM. Reason: After thoughts :)
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  #48  
Old 16-07-2017, 08:16 AM
jondee86 jondee86 is offline
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Smile Re: Nozzle spray angle...

Small update. Progress has been slow due to numerous small issues that had
to be resolved, and the onset of winter here in NZ. I am investigating why the
s/c is only making 5.16psi @ 7430rpm at the moment, when it should be
making closer to 8.4psi @ 7600rpm.

This engine was sold as N.A. with 10.3:1 compression, and as s/c with 8.9:1
compression. The same camshafts and cam timing were used in both versions.
So I am thinking that maybe there is a little too much overlap for s/c use and
I have retarded the intake cam by 4 deg. This will be tested later in the week
and logged to see if it has any affect on boost.

EDIT: Tested and no apparent change before hitting the limiter.
Bouncing off the limiter did produce another 7kPa and push the IDC up 8% to
80%, but I exclude those values as not representative of a steady pull to
redline.

The other possibility is that the N.A. factory intake/air filter setup has higher
pressure drop now that it is handling greater flow. I am waiting on a new filter
to construct a "free-flowing" intake. This will also be tested once on the car.

And last, when I lifted at 7430rpm the IAT with water only was 54 deg on a
day when the ambient temp would have been no more than 14-15 deg. So if
meth can drop the temp closer to ambient there should be some improvement.

I'd like to get the experimentation over before going to a smaller pulley.

Cheers... jondee86

Last edited by jondee86; 19-07-2017 at 07:28 AM. Reason: Added results of test...
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  #49  
Old 16-07-2017, 12:10 PM
rotrex rotrex is offline
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Default Re: Nozzle spray angle...

For intake restrictions it is best to measure pressure level before the SC intake.
From this value and boost pressure, you can calculate the pressure ratio.
Any cheap vacuum gauge or boost gauge will do. If you see more than 100 mbar of intake restriction, investigate. At a pressure ratio of 2, a 100 mbar intake restriction causes boost to drop by roughly 0.2 bar. 2 = 1.8 bar / 0.9 bar. At 200 mbar, you get 2 = 1.6 / 0.8 = 0.6 bar of boost or 0.4 bar less than without any intake restriction.

Intake restrictions usually show at high air flow, so near max rpm and WOT.


With this and SC rpm you can look up the corresponding air flow in the compressor map.

This number should fit reasonably to air flow you calculate from AFR, and fuel flow derived injector size, injector duty cycle and differential fuel pressure.
The calculated air flow should also fit to your power level. If you burn much more fuel than you'd expect from the power the engine generates, you indeed might blow fuel out of the exhaust during overlap. At 5 to 8 PSI and high rpm this is usually not too big of a problem.
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  #50  
Old 17-07-2017, 08:48 AM
jondee86 jondee86 is offline
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Smile Re: Nozzle spray angle...

Thanks for the comments. Due to space restrictions, I have two short
radius 90 deg bends after the throttle, so a little bit of resistance there
that I have to live with. However, I am aware that resistance will vary
as the square of velocity, and I always intended that the intake in front
of the throttle be as free-flowing as possible. I will be using an Apexi
500-A002 filter and 75 dia alloy tube with a single 90 deg bend.



All going well this will get at least partially enclosed in a "cold air box" to
try and avoid sucking in too much warm air. Even if this only brings a small
gain, every little bit helps

I have no idea of the fuel consumption yet, as the car has not been drive
very many kilometres yet. But I'm getting hold of some 440cc/min DENSO
injectors, as the injector duty cycle hit 70% @ 5.16psi with the 365cc/min
injectors I am using at the moment.

Cheers... jondee86

Last edited by jondee86; 17-07-2017 at 08:52 AM.
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