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Cols300

Cant reach boost target

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Hi All.

A quick intro, I'm Col, I have a Nissan 300zx that has very slowly been built over many years.

A few months back we finally got to tune it on a Dyno, and had some good results, but could not boost over 20PSI.

 

Now for myself, I know very little about tuning, very bare essentials, the guy tuning it had only ever used a LINK G4+  on 1 other occasion and was very straight up with me about this, and admitted that though he loved it as an ECU he has never had the opportunity to learn them inside and out.

Prior to it being on the dyno, a good mate of mine who helped me put the engine together, put a very basic tune in it, just so it was drivable, and we done a very small amount of road tuning to ensure it was not doing anything out of the ordinary.

So I guess the question is,

What have we missed, something in the background not letting it boost over 20PSI.

I'm sure the tuner could spend time on it and sort it out, but that's all $$ so I thought id ask the question on here.

What do you guys need to know to help push me in the right direction?

Can I upload some screenshots of the tune?

Like I said, I'm green to all this, so any input would be fantastic.

Thanks Heaps

 

Col

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The list of possible causes is extensive, from ecu related stuff to waste gate solenoid plumbing and wastegate spring etc.

Was ECU controlling boost?  If you unplug the boost solenoid does the boost then go higher?  

My suggested starting point is to post your map and a log file of it reaching whatever boost it can reach.  Here is a video to show you how to do the log:  https://www.youtube.com/watch?v=_P1LRANeO4A

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Hi Adam.

Thanks for your reply.

As far as I know, yes the ECU should have been controlling the boost.

When you say unplug the solenoid, do you mean take a hose off it, or disconnect it from the power source?

Col

 

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When you say unplug the solenoid, do you mean take a hose off it, or disconnect it from the power source?

Sorry, havent had my afternoon coffee yet and didnt make that clear at all.  What I should have said is pull the hose off (the hose that goes to the non-spring side of diaphragm). That will then eliminate all ECU influence and confirm plumbing/wastegate/mechanical system is all working properly.  Note be very careful and watch boost gauge closely as you slower increase throttle - if everything is right then boost should skyrocket like this so you only want to open throttle enough to prove that the system is capable of providing more than 20psi.

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Your "stutter" I suspect is just a rich misfire?  If we can believe your lambda readings it is running crazy rich, you have 0.54 on one bank and 0.58 on the other in the area where it misfires.

I think your boost problem is just the Wastegate DC% table has numbers too small and you have all PID's set to zero so it is effectively doing no correction at all.  Try adding about 15% to all numbers in your wastegate DC% table and do another log.

I would also suggest you do a firmware update as you are on quite an old version and there was some changes made to boost control since then.

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Your "stutter" I suspect is just a rich misfire?  If we can believe your lambda readings it is running crazy rich, you have 0.54 on one bank and 0.58 on the other in the area where it misfires.

I think your boost problem is just the Wastegate DC% table has numbers too small and you have all PID's set to zero so it is effectively doing no correction at all.  Try adding about 15% to all numbers in your wastegate DC% table and do another log.

I would also suggest you do a firmware update as you are on quite an old version and there was some changes made to boost control since then.

I just want to confirm, is this the wategate DC table I need to adjust?

So when adding the 15% its as simple as example 40 + 15% so change the number to 46?

Does this need to be done to all individual cells?

And sorry for all the questions, but PID's? what that? lol and do they need to be altered?

DC Table.PNG

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The table units is percent now, so what I meant by adding 15% is change the 40's to 55.  change the 25's to 40.  Obviously some of the bigger ones will top out at 100.

Dont worry about the PID's yet, just try the table.

 

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Just a quick question to simplify this:

What is the minimum boost pressure that you would see if you were to bypass the boost solenoid and only run wastegate boost pressure(ie vac line straight from compressor housing to wastegate actuator)?

Typical rule of thumb is that in most systems, max attainable boost is just a bit over double wastegate spring pressure.  But this can vary depending on wastegate type and plumbing.

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Not only is the afr`s crazy rich but its also TARGETING rather rich AFR`s. Your targeting 11.83 afr under load conditions i would still be inn the 14.7 area (during cruice conditions). You are also targeting 13.01 on idle. Although target is not really linked to the actual fuelmap as you can have whatever in teh taret table and still tune the main fuel map to whatever AFR you like it is good practice with this ecu to have reasonable targets and then tune to hit those... I have a feeling your milage have taken a big hit with this tune. And if you have driven it like this for some time i would probably change the oil just in case.

If this is now running as it did when leaving the tuner im going to put this in the nicest way possible.. Are there any other tuners around in your area?

Edited by Steve

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Not only is the afr`s crazy rich but its also TARGETING rather rich AFR`s. Your targeting 11.83 afr under load conditions i would still be inn the 14.7 area (during cruice conditions). You are also targeting 13.01 on idle. Although target is not really linked to the actual fuelmap as you can have whatever in teh taret table and still tune the main fuel map to whatever AFR you like it is good practice with this ecu to have reasonable targets and then tune to hit those... I have a feeling your milage have taken a big hit with this tune. And if you have driven it like this for some time i would probably change the oil just in case.

If this is now running as it did when leaving the tuner im going to put this in the nicest way possible.. Are there any other tuners around in your area?

Hi Steve.

Thanks for the reply.

I know when he began tuning it, he was very skeptical that the lambda's were reading correctly, as one was reading a huge difference to the other, so tuned with probes in the exhaust.

Fuel economy has actually never been better, haha, I had an old Wolf 3D in before the link, and now that was a glitchy ECU and couldn't keep a tune in it, and was extremely rich, but in saying that, I really do not do a lot of road K's in it, and fuel consumption is not a huge concern.

I changed the oil before it was on the dyno and have done a few drag runs since, it will most definitely be getting changed once this issue is sorted and back on the dyno.

I understand what your saying in regard to "are there any other tuners in my area" This guy has a great reputation, if it makes any difference, he only tuned high end, no cold start or idle or cruise etc. as we were pretty tight for time.

Cheers.

Col

 

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Just a quick question to simplify this:

What is the minimum boost pressure that you would see if you were to bypass the boost solenoid and only run wastegate boost pressure(ie vac line straight from compressor housing to wastegate actuator)?

Typical rule of thumb is that in most systems, max attainable boost is just a bit over double wastegate spring pressure.  But this can vary depending on wastegate type and plumbing.

Hi Brad.

I am not sure, as I haven't done that test, If I were to disconnect both hoses from the solenoid and join them together, is this going to give me this information?

When you say minimum boost pressure, Minimum when? as in certain RPM or cruising?

Cheers.

Col

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Differences between banks is common. Especialy if you skimmed the tops and block and didnt degree your cams after.

Good tuner or not. It needs a new tune bad if the lambda readings are sound. 

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The table units is percent now, so what I meant by adding 15% is change the 40's to 55.  change the 25's to 40.  Obviously some of the bigger ones will top out at 100.

Dont worry about the PID's yet, just try the table.

 

HI Adam.

So I added the 15% into the to the wastage DC table across the board, and going by the boost gauge it most definitely went well above 20psi, maybe around 25-26 by the gauge, which I logged.

Strange thing is, I didn't save the table when I closed the software, and it still boosted well over 20psi, again around 25-26.

I didn't have time to open it up and do another log run though.

Does the log run reflect this?

Thanks Again.

Col

 

300ZX base 24-8.pclr

Log 2017-08-24 5;45;07 pm.llg

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The log shows a max of about 24psi with it settling at 21-22.  You were only at 50% throttle though so I expect that will climb with more throttle.

So if you are sure that boost has definitely increased just by increasing DC in the wastegate table then I think we can conclude that the mechanical systems, wiring and ecu is all working and capable, it is just the tune preventing you getting there.

I wouldnt be keen to go pushing things much more than that until the map is fixed up.

 

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The log shows a max of about 24psi with it settling at 21-22.  You were only at 50% throttle though so I expect that will climb with more throttle.

So if you are sure that boost has definitely increased just by increasing DC in the wastegate table then I think we can conclude that the mechanical systems, wiring and ecu is all working and capable, it is just the tune preventing you getting there.

I wouldnt be keen to go pushing things much more than that until the map is fixed up.

 

Thanks Mate.

Any ideas as to why is seemed to still hit higher boost after I closed the software without saving?

You mentioned in an earlier post that I originally had an old version of the firmware, and there were boost control changes in the newest version, by updating to the newest version, would that have changed how the original tune controlled boost?

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The map that you attached above has got the bigger numbers in the wastegate dc table so it you must have saved them permanently somehow - done a store or something? You can either manually change those numbers back or just load in your old map

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Sorry, I could have explained myself a bit better.

The map I attached was the altered one, + 15% across the board.

Once I done that log run, I closed the software without saving it to the ECU, and it seemed to still be boosting well over the 20psi

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Sorry, I could have explained myself a bit better.

The map I attached was the altered one, + 15% across the board.

Once I done that log run, I closed the software without saving it to the ECU, and it seemed to still be boosting well over the 20psi

So if you open up the wastegate table in the currently loaded map, does it still have the original values in it or has it got the increased numbers?

 

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Yeah it still has the original values, the lower ones.

thats why I thought I'd ask if by updating the firmware, the ECU controlled the original settings differently.

cheers.

Col

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No you are basically running open loop so the ecu will just command whatever the wG DC table has in it.  The firmware wouldnt effect that.  I suspect something else is at play.  

So would you say now that changing the numbers in the wastegate table probably didnt make much difference?  i.e the boost now is about the same as you had when you tried bigger numbers?

Can you also give more info on your setup - turbos, wastegates, 3port or 4 port valve etc

 

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Sorry to be a PITA, But I have re done both logs, the first one with no adjustments to the wastegate table and the second with + 15% across the board.

And going by the gauge, it made approx. + 5PSI difference, can you confirm that with the logs? What does the before and after PSI calculate to?

I have attached both logs and both base maps before and after changing the wastegate table

Turbos are GT675RS with standard wastegates, using a 3 port valve.

I hope im on the right track?

 

Cheers.

Col

3 port.JPG

Base 1.pclr

Base 2.pclr

Log 1 2017-08-26 12;38;42 pm.llg

Log 2 2017-08-26 12;51;49 pm.llg

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