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Author Topic: med9.1 n00B HERE  (Read 21438 times)
bbowers
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« Reply #30 on: April 08, 2018, 08:32:36 PM »

I will post up another log this week continuing to follow my safe road tuning strategy of basing my advance in boost and fuel completely on my EGT temps.   
« Last Edit: April 08, 2018, 08:44:22 PM by bbowers » Logged
prj
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« Reply #31 on: April 08, 2018, 11:35:36 PM »

I will post up another log this week continuing to follow my safe road tuning strategy of basing my advance in boost and fuel completely on my EGT temps.  
You don't have an EGT sensor on the car, and the calculated value is only valid with the stock calibration, not with added boost. Basically the EGT value you are logging is utterly pointless and adjusting things based on that can melt your engine in some cases and certainly destroy your cats. But have fun Wink
« Last Edit: April 08, 2018, 11:37:22 PM by prj » Logged

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bbowers
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« Reply #32 on: April 09, 2018, 01:46:24 AM »

I don't see a safe way to add boost and fuel without having a good EGT reading.  I see the approach you mentioned, but starting lean and working rich until power loss seems like a recipe for disaster.  While I could blow black smoke, which I'm not doing yet; there are very few safety issues with starting rich and going lean.  Besides Carbon build up.  While I am starting at a bad power point, it will also be a low egt, so I can slowly increase from a rich point until meeting full power. Basically this is the same strategy you mentioned except I am starting at the rich side of the power band, where you start at the lean.  Which from my understanding can potentially cause detonation and ruin the engine.  I understand that these engines don't have an EGT, but I can't imagine that they don't use realtime information for their BTS calculations.  I've read a bit about the LSU4 which is suppose to give these multiple outputs, which may have replaced the EGTs in these engines.  I am attempting to read more on that.  Or, I potentially could revert to stock and measure the difference inbetween the two EGT's from stock boost and +5.  Seeing if the "projected" EGT's are different.  I would assume that the algorithm would include this information.  It wouldn't make sense for the engine to not take into account real time information and base information based on pre set information, as you suggest. 

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prj
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« Reply #33 on: April 09, 2018, 02:54:43 AM »

I'll give you a tip - with lambda 0.8 to 0.79, 98/93 octane (depending on your location in the world) and timing set correctly you will never encounter EGT issues with the stock turbo.
Obviously BTS still needs to be able to enrich further if you get massive knock due to a bad batch of fuel.
Also, if you do a fast pull (<8 seconds) you can even run lambda 1 to redline with this engine without any temperature issues (not that there is any point to ever start leaner than 0.85 on any turbocharged engine at WOT). And at 0.75 lambda you are most definitely blowing black smoke.

Disregard the calculated EGT readings, if you look at actual EGT with a gauge they can be more than 100 degrees apart.
If you actually look at how the EGT model is calculated instead of assumptions, you will see that after 170 load the stock model doesn't do squat, and that WOT EGT is basically more or less a single map in the cal.
LSU4 does not give you any information about EGT, it's only to keep the sensor heated to a fixed value.

If you want to measure EGT you need k-type thermocouple in the exhaust and a gauge/controller that reads it, but you don't really need to worry about EGT with such low boost, as long as you don't do something stupid like run lambda 1 to redline.
« Last Edit: April 09, 2018, 02:59:41 AM by prj » Logged

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bbowers
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« Reply #34 on: April 09, 2018, 07:23:04 AM »

Ok. Here is my most recent log I just did.  It seems from what I see that at 127 load request my numbers are following my KFLBTS exactly to the number, but when I requested 150 load is when the numbers took a nose dive again. 

This is because my LAMFA was set at .75 at 100 percent on my map which was lower than requested BTS.
« Last Edit: April 10, 2018, 04:00:46 AM by bbowers » Logged
prj
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« Reply #35 on: April 09, 2018, 07:32:42 AM »

You should be requesting over 170 load. And BTS - look at the FR and understand how it works and what the maps does.
You are making blind changes without realizing what the formula does, and this way you won't get your fueling under control.
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bbowers
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« Reply #36 on: April 10, 2018, 03:04:16 AM »

You should be requesting over 170 load. And BTS - look at the FR and understand how it works and what the maps does.
You are making blind changes without realizing what the formula does, and this way you won't get your fueling under control.

It seems the further enrichment from reading the FR as instructed is the offset when the maximum values of KFDLBTS are being reached and the engine starts to retard ignition angle to further reduce and as it does this it is trying to further enrich on a scale that is linear as well.  I am unsure of the best way to approach this. Is the engine further enriching becuase it is needing to adjust the ignition angle, and by fixing my timing it would reduce the overall fueling enrichment that is occurring through KFDLBTS, or should I make DLBTS enrich less, since we tuning to a higher power point, instead of exhaust and economy...

It seems the first run only triggered EGT so it was using KFLBTS with no adjustments, while the second run with the increased load triggered a second adjustment to KFLBTS.  This is why the second run used an adjustment factor further triggered from degradation efficiency.  Still looking further to understand this concept. 

Onward to read more german in this FR....yay

I will do another pull with my adjusted lamfa, that should put it above my requested BTS or hopefully not.  This way I know that BTS is still intack and my computer is following LAMFA only.
« Last Edit: April 10, 2018, 04:03:34 AM by bbowers » Logged
prj
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« Reply #37 on: April 10, 2018, 04:00:55 AM »

It seems the further enrichment from reading the FR as instructed is the offset when the maximum values of KFDLBTS are being reached and the engine starts to retard ignition angle to further reduce and as it does this it is trying to further enrich on a scale that is linear as well.
BTS only controls fuel. It does not modify ignition in any way. Ignition retard increases EGT if you didn't know that.
If MED9 FR is difficult in german, read the Alfa ME7.3 FR that is in english, the concept is similar enough.

Try to read more and don't assume things. The ECU works exactly as the diagrams in the FR detail - no more no less.
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bbowers
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« Reply #38 on: April 10, 2018, 05:23:24 AM »

Right.  As I understand it I want zero timing pull from the engine which is optimal.  This means that the timing isn't to far advance where the engine is detecting that there is knock or that detonation is occurring where the high pressure is before TDC.  By getting this timing pull I can conclude that my timing is advanced enough to not be to retarded.  This ensures that I am getting the best torque for that rpm.  Although I believe a professional tuner can run on a dyno and change the timing at a certain rpm and kpa and measure output to find best torque angle without knock. I believe the method I described is sufficient for a road tune.

By increasing the typical AFR that the timing is designed to run on we are changing the burn speed and this is why we are adjusting the timing. So that our burn speed hits maximum pressure after TDC.  We can see from our logs that when we are running .8-.85 AFR the timing is being pulled; which would suggest we are hitting peak torque before TDC and the engine is compensating to prevent knock and detonation. 

You are saying Ignition Retard increases EGT, But this is only true if the burn speed hasn't changed from stock.  With the increased burn speed, the retarding of the timing prevents detonation and knock.

Hopefully I understand it correctly. As I will change my timing in those areas of requested higher AFR to show for the increase in burn velocity, meaning I need to reduce the timing advance.  This way I can prevent knock and detonation.
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bbowers
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« Reply #39 on: April 10, 2018, 07:06:23 AM »

Ok. Seems I'm right on track to raise my Load request to 170

Here are my logs after I fixed my mistake.  Both Logs following LAMFA.  Very little Angle Correction. Correct Load request.  Although I'm still seeing -.01/.02 for LAMBDA specified and actual.

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prj
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« Reply #40 on: April 10, 2018, 10:45:11 AM »

By increasing the typical AFR that the timing is designed to run on we are changing the burn speed and this is why we are adjusting the timing. So that our burn speed hits maximum pressure after TDC.  We can see from our logs that when we are running .8-.85 AFR the timing is being pulled; which would suggest we are hitting peak torque before TDC and the engine is compensating to prevent knock and detonation.
This is not what knock/detonation is at all. Laminar flame speed has almost nothing to do with it and flame speed has negligible effect on power on gasoline within the narrow lambda window you are operating in. Irrelevant.
Detonation is spontaneous ignition of the mixture at different spots after the spark has fired due to heat from compression/charge. Pre-ignition is the same thing without the spark being fired, but not much danger with that on gasoline. Nothing to do with flame speed whatsoever, because the flame front is not in the locations where you have the spontaneous ignition pockets...
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You are saying Ignition Retard increases EGT, But this is only true if the burn speed hasn't changed from stock.  With the increased burn speed, the retarding of the timing prevents detonation and knock.
100% wrong. Retarding effective timing ALWAYS increases EGT until you reach MBT. Advancing effective timing ALWAYS decreases EGT until you reach MBT. If you are knocking you are not advancing effective timing. You are not doing anything. And you are nowhere near MBT on boost nor will you ever be on normal gasoline.
Quote
Hopefully I understand it correctly. As I will change my timing in those areas of requested higher AFR to show for the increase in burn velocity, meaning I need to reduce the timing advance.  This way I can prevent knock and detonation.
No you do not understand. Read a book about combustion engine basics... I guess that's why you are having so much trouble.
You're trying to run (tune a digital management system) before you are able to walk (understand the combustion process in the engine).

On this engine the difference in timing between 0.85 lambda and 0.75 lambda is going to be barely there. A degree or two if that. Fuel is mostly used for temperature control, but it is a good idea at WOT to run the richest you can without losing power at all times for safety (rich best torque) and only enrich further when you really need to protect components - as this carries a power penalty.

Where are you getting all this misinformation from? Wherever you are just disregard it and try for example a book from greg banish.
« Last Edit: April 10, 2018, 10:57:04 AM by prj » Logged

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bbowers
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« Reply #41 on: April 11, 2018, 01:46:22 AM »

Ok.  I bough this book and will give it a read this week.  Thanks
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bbowers
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« Reply #42 on: April 13, 2018, 12:06:54 PM »

Ok.

So I changed my LDRXN to 169.99. From reviewing my logs it seems I am not being limited to my max load of 170 by KFLDHBN since I am not going above the boost requested for this map at 40 degrees Celsius.

I also changed my rail pressure to 120 successfully.  My max boost pressure right now is at 2.1 Bar (actually 1.1bar) Since you need to remove ambient pressure. 

Thanks Everyone for their help.  I'm going to leave the tune like this until I get up the motivation to buy a downpipe and move forward to a stage 2 tune.
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