Screenshot (11).png this is your wot adjustment table. there's other adjustments too, but with straight gasoline and everything stock you shouldn't have to mess with the others.Originally Posted by Holmes26977
Screenshot (11).png this is your wot adjustment table. there's other adjustments too, but with straight gasoline and everything stock you shouldn't have to mess with the others.
Awesome thanks for the help I appreciate it
Here's the thing, how much boost can it make/take and how much boost will it still make power are two different things. The stock turbo will make more boost than the engine can handle for power on 87 because it will just be creating more heat and be causing knock retard along with other issues Your best bet is to slowly turn up the boost until knock gets where you don't like it then back it off a hair.
What I have found, and research from other tuners than have been on the dyno, is that it's better to taper the boost down in the higher RPMs and add more timing. I fought this a long time thinking that I needed over 20lbs boost the entire rev range and I finally was able to do it but it wasn't faster. Even with full e85 I can feel that this engine (although I have the gen1 version with a lower compression ratio) is that it's better to run say 16-17lbs boost on the top end (21 or so peak in the middle) with 22+ degrees of timing. My first mod will be an intercooler as charge temps climb fast, even on the stock tune.
That's another thing I'm having. There's a lot of tables for timing in this car.. mapped points. Is there just one map I can change the timing on or do I have to change them all?
you can change the global timing. that adds or subtracts the total end timing in all tables. you really need to log kr to see where your at. unless you start running race gas or ethanol you really cant add any timing. i think the tune i gave you was already bordering the limits. here's how the timing regulation works i believe. first is preignition tables, then cylinder pressure tables, then mbt tables, then borderline tables. The pcm will pick the lowest value of all at any particular load and rpm.
if i want to raise timing only at say 5500 rpm at 2.0 load, i make the timing higher in all the other tables at that load and rpm. then make the adjustment to the borderline table.
You could also use the lambda table to only add or subtract fuel at a certain lambda. Tell me if I'm wrong but isn't the practice of lowering boost at high rom just another strategy to keep charge temps under control?
Or is the ecoboost the only engine in history to make more power with a downward sloping boost curve regardless if charge temps? The timing strategy, as I understand it, start with the borderline tables. Then it gets capped by either the mbt timing table or the cyl pressure limit timing table. If border line is below these two and if there is sufficient load, then we see the knock learning adaptive start adding timing until either knock is achieved or the two capped tables has again been reached. Also this is for each cylinder individually. I wonder if there is any benefit to changing it to global. Having one cylinder at -2 one at 4 and one at 0 seems awfully unbalanced to me but I literally know nothing. I can only think.
Global timing on a high power DI turbo 4 is asking for trouble, if you ask me.
Lots of variables contribute to needing different timing per cylinder, carbon build up, rings wearing out at different rates, cylinder position (in the firing order), worn valve stem seals leaking small amounts of oil, etc etc.
Power balance isn't such a big deal, compared to 3 cylinders chugging along and one that's ripping itself to pieces due to knock.
Edit:
Don't know if many on this site have read these articles, but it's good info... Even if terminology is a little different because it's for Cobb.
https://cobbtuning.atlassian.net/wik...d+Tuning+Guide
Last edited by Seishuku; 12-05-2022 at 12:16 PM.
[QUOTE=Seishuku;708862]Global timing on a high power DI turbo 4 is asking for trouble, if you ask me.
Lots of variables contribute to needing different timing per cylinder, carbon build up, rings wearing out at different rates, cylinder position (in the firing order), worn valve stem seals leaking small amounts of oil, etc etc.
Power balance isn't such a big deal, compared to 3 cylinders chugging along and one that's ripping itself to pieces due to knock.
I see what your saying but wouldn't all 4 cylinders reduce timing due to knock down to a level that doesn't knock for any? Isn't that how global knock control works? If any cylinder is knocking then timing is dropped for all cylinders equally is the way I understand it so your example of "3 cylinders chugging along and one that's ripping itself to pieces due to knock" doesn't make any sense to me. Unless knock control had been disabled which nobody here suggested. Help me understand what your saying. See I think you would run into this scenario with individual cylinder knock control. One cylinder knocking and timing dropped and the other three advancing. This would have to have an effect on bearing load and harmonic balance of the engine. Basically 3 running and one dead cylinder. Gonna read your posted article so maybe Ill understand it better. Thanks for your help
That was just an over exaggerated example, I would think (hope) that the ECU would pull all cylinder timing to the lowest common value when detecting knock.
Just past experiences with other factory controls from the port injection days.
I would probably worry more about power balance if the ECU were to put a lot of advance in at once, but it knows to slowly ramp in and out on events, so I'm not super concerned about it.
Gotcha ok, thanks.
Thank you everyone for the info. I didn't think there was much room to add timing with the tune Steve gave me. I added some to the time and I had to take it back out because it was starting to pull a fair bit. I'm not used to boosted applications.
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