My problem is that I need to understand what every acronym means and how it does what it does. Then how all that works together. Lol i almost flunked electronics school because of transistor theory, talk about mind boggleing!! At the time. Lol
My problem is that I need to understand what every acronym means and how it does what it does. Then how all that works together. Lol i almost flunked electronics school because of transistor theory, talk about mind boggleing!! At the time. Lol
Those are air flow basics. Nothing super special in what I typed. Basic engine knowledge and intended use seem to be rarely thought about these days. It’s just moving air. If the air isn’t moving uniformly how can you rely on a air only reading....
The ideas are this:
1 give the MAF a chance to read the air flow properly (straight tube for 6").
2 set PE fueling to be safe.
3 make sure PE is enable-able.
4 correct VE table (with MAF disabled).
5 correct MAF table (with VE disabled).
6 enable MAF and VE, figure out blending point/rpm (as Team208 said).
Usually, steps 4 and 5 are done with CL/trims all disabled, using only a wideband;
Calc.VET takes a few shortcuts to quicken the process:
a. it uses trims/LTFT for CL and wideband for OL,
b. it corrects the MAF table using a.
c. it also calculates a portion of the VE table from b.
d. the rest of the VE table has to be smoothed to c.
e. this VE table now has to be logged to see if it needs correction (we've seen many cases where it was ok, just needed minor tweaks for cam/idle).
Originally Posted by joecar
I'm just listing what works for me in my apps. This is completely different app to app, build to build and tuner to tuner.
Man am I behind the curve on this stuff.
This isn’t recreational for me. I’d hope I’m up on it. Lol
I've seen a few cam's (I'm just a part-time tuner) have an upstream effect on MAF, so making MAF follow VE makes sense (rather than vice-versa);
I'm always comparing VE-calculated airmass (g/cyl) vs MAF-calculated airmass (g/cyl).
ok, good to know, thanks;
6 enable MAF and VE, figure out blending point/rpm (as Team208 said). This point could be hard to find at first but a good starting point is 500-1000 rpm over converter stall. After stall load if constant.
points out that converter behavior allows cam to do its job, and so has an indirect "upstream" influence on MAF; good one
I make the transient filter to be wide enough to hopefully avoid the influence of the last known trim;a. it uses trims/LTFT for CL and wideband for OL, This one is another one I do different. I've seen too much surging induced from not getting a clean fuel trim during transient. Thats when it locks to the last known trim and not steady fuel trim. This can make cells not get hit with the actual trim, just the last known. This can be filtered out but takes a better understanding of what to filter out and how to get the data needed.
but, I would like to come up with a better filter.
I'm also playing with filtering airflow g/s transients and airmass g transients.
Read the summary notes (you'll run into them), get your feet wet, sanity check everything, ask questions;
remember a basic few rules:
- make sure powertrain is sound (no leaks, no noises, no overheating, no worn-out parts);
- make sure injector tables match injectors (measure rail pressure);
- air source (i.e. MAF or VE) is separate from fueling;
- set the fueling (to be safe at high load), and correct the air source;
- eliminate all but one source of air, this is what you're trying to correct;
- eliminate each trim unless you're using it to do correction (watchout for OL STFT);
- make sure wideband works properly;
- use wideband for OL (don't use trims, in OL these are not updated and so are wrong);
- filter out transients (i.e. data where throttle and/or airmass are not sufficiently steady);
- load up the engine (i.e. dyno works much better than driving uphill);
- avoid going lean;
- avoid misfires;
- avoid knocking;
fueling can come from multiple sources (the richest of the active modes/tables wins), but this shows up in the fueling pids, so you don't have to worry too much about this.
It seems like you're up, you can tell by how your customer's cars run.
Thank you sir.
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