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carsey
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« Reply #30 on: July 21, 2014, 11:29:36 AM »
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But keep in mind the calc method can be pretty far off, and the relationship between spec load and spec boost isn't the same as the relationship between actual boost and calculated load.
Hope that makes sense...
Is that from looking at it as "spec load * 10 + 300 mbar" theory thats wrote into things like the wiki? I originally set my plot up to that, after working out roughly what PSI I thought I could run....however that soon turned out to be pretty far off the mark. Guess a small increase in displacement and a well flowing setup will mean less load needed by engine to make the boost desired. Even from looking at logs of other stage 2 cars with similar turbo/intercooler setups, mine seems to be making the same boost levels pretty effortlessly: - which I guess is always reassuring. Might have misread your comment with that above comment from myself though. |
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nyet
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« Reply #31 on: July 21, 2014, 12:12:25 PM »
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Guess a small increase in displacement and a well flowing setup will mean less load needed by engine to make the boost desired
It isn't that. It is because ME7's load->boost calc is very, very, very complex. |
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carsey
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« Reply #32 on: July 21, 2014, 12:35:47 PM »
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We wont get into that then lol.
As long as I know the tuned file is safe, and isnt going to cause any knock/lean or anything else bad, then that's my main priority. Now the boost profile is 99% done I can look into timing maps. Is there much that can be done in terms of leaning out the fuel mixture to get a touch more power..or is it best to remain where I am at.
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nyet
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« Reply #33 on: July 21, 2014, 12:38:13 PM »
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Post up some more logs with the refined req boost and i'll do my best to give suggestions.
You're doing great so far!
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carsey
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« Reply #34 on: July 21, 2014, 12:44:28 PM »
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 always reassuring to hear. Thanks! Ill get some logs tomorrow with the LDRXN I posted above. Tweaked LDRXNZK to suit the 15% reduced power as normally suggested. Hopefully that works out spot on, cant see why it shouldnt. Only other thing....is it normal for that much timing to run top end? 24* seems quite a bit, especially when you hear most people aiming for 21* up top. |
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« Last Edit: July 21, 2014, 12:49:56 PM by carsey »
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ddillenger
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« Reply #35 on: July 21, 2014, 04:15:19 PM »
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Is it normal for that much timing to run top end? 24* seems quite a bit, especially when you hear most people aiming for 21* up top.
With low loads, yes. |
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Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your experience!
Email/Google chat:
DDillenger84(at)gmail(dot)com
Email>PM
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carsey
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« Reply #36 on: July 21, 2014, 04:25:36 PM »
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Thanks. Ill aim to try get a about 2-3* added onto the load sites im seeing from the logs. (keeping it nicely smoothed into the other areas aswell either side) Lots of logging and adjustments I reckon.
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carsey
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« Reply #37 on: July 22, 2014, 09:41:31 AM »
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Well had chance to run the car out with the capped ldrxn above the actual engine load I was getting through logs and was less boost. I was seeing about 4-5psi less across the revs than with the ldrxn map flatlined. You can see it in the attached file with 131618.csv. Found that pretty strange as the max load map is above what the N75 should be controlling the actual engine load I got through the logs.
Also managed a run (not to redline) with the timing ive added on with the load map flatlined at 200. That log is 133536.csv if you want a look at it. Looks to be pulling 4.5-6CF from 5250rpm. Dont really want to be going over that I dont think.
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nyet
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« Reply #38 on: July 22, 2014, 03:12:06 PM »
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I'd pull some timing up top and bump i-max, or adjust ldrl..
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carsey
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« Reply #39 on: July 23, 2014, 09:42:23 AM »
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Raise IMX to meet the boost I want it to?
Will boost pressure still go above max engine load set through LDRXN though?
Looks like I might have to have another look at my boost maps then. Is there any serious downside to leaving it with the max load set well above what it is actually producing?
Hopefully with the addition of water meth it should control timing a bit more too, as should a nice colder day, been scorching over here recently. 25C+, not handy to tune cars, pleased the FMIC is doing a good job.
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« Last Edit: July 23, 2014, 09:44:20 AM by carsey »
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nyet
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« Reply #40 on: July 23, 2014, 10:04:50 AM »
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Raise IMX to meet the boost I want it to?
You want lde to be zero, as I said before. Will boost pressure still go above max engine load set through LDRXN though?
Again, you don't care about max load. You want lde to be zero so the PID doesn't have to trim. If it trims, the car's behavior will change over time, and you will not like the results. Looks like I might have to have another look at my boost maps then. Is there any serious downside to leaving it with the max load set well above what it is actually producing?
Stop. Worrying. About. Load.  Get lde to zero. |
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« Last Edit: July 23, 2014, 10:06:43 AM by nyet »
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carsey
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« Reply #41 on: July 23, 2014, 10:26:26 AM »
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Got you Why does the boost become lower, yet the max load is still above the actual engine load when the car is boosting fully at 20psi. Thats what im struggling to understand at the moment, Duty cycle should still follow the I and exit kfldrl in the same numbers as it enters, so in theory, it should still boost the same PSI, as what it does with max load flatlined. Guess it all gets calculated in a pretty complicated way. So now I just need to fiddle IMX until the car boosts where I want it to boost, a touch under ldrxn as I plotted out before. Just trying to get my head around it in a way I can see/understand fully myself and see whats going on. Thanks for all the help so far - learnt a fair bit  |
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nyet
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« Reply #42 on: July 23, 2014, 10:35:03 AM »
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The PID doesn't care about load. It cares about lde. STOP HYPERFOCUSING ON LOAD ALREADY.
You only care about setting LDRXN to get your req boost where you want it. That is ALL, nothing else. Once you have that done, and you like your req boost, you need to tune the LDR PID to have actual boost follow req boost.
In the steady state, wgdc (pre lin) will follow I max, but only if lde is zero. If you have a lot of underboost, in steady state, the P proportion of the PID will add to that.
In your case, the severe underboost was causing the PID to add a bunch of P to the wgdc.
I don't know how many ways I can say this. Get lde to zero, stop worrying about load.
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carsey
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« Reply #43 on: July 23, 2014, 10:40:45 AM »
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Cheers. Ill focus on getting the boost back up to where it was before via IMX.
Will the ldrxn I posted on a previous page still be ok or will it need a bit of tweaking? think it was about 5-10 above the data I got from logged from memory.
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nyet
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« Reply #44 on: July 23, 2014, 10:42:32 AM »
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Cheers. Ill focus on getting the boost back up to where it was before via IMX.
Will the ldrxn I posted on a previous page still be ok or will it need a bit of tweaking? think it was about 5-10 above the data I got from logged from memory.
You could always just ramp I-max or LDRL up to 100 at redline and see where boost ends up... At this point, though, i'd really look at a compressor map and see why you have to run your turbos at 100dc. Either your wg isn't holding or you are WAY out of the turbo's efficiency range. |
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« Last Edit: July 23, 2014, 10:44:10 AM by nyet »
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