ok.

Why wouldn't you use the smallest correction interval for both?

OR

Why would you have a higher correction intervals for a higher gear?

 

The correction interval is used to determine how often the ecu makes a wastegate duty cycle % change. It is similliar to the intergral in a PID tuning loop. Too much integral, or in other words too much interval (adjusts too fast) and an otherwise stable system becomes unstable. During a long 5th gear pull you really don't need much correction. The RPM's don't swing much and the ecu can lazially make WGDC% changes and its sufficient.

However during a first gear and second gear pull the engine speed is rapidaly accelerating. Our control system has changed drastically because the engine acceleration is so much faster than a high gear pull. To avoid extreme undershoots or extreme overshoots of boost the interval counter needs to be much quicker to account for the vastly faster engine acceleration rates and in general how much faster things happen in the lower gears.

So I hope that explains it. Too fast of a correction interval in a higher gear can cause overshoots and/or hunting of the boost around target boost. Too slow of a correction in the lower gears leaves the system unable to compensate for changes quick enough.

 

Yeh but correction isn't based on RPM, its based on over/under shoot.

So if you experience overshoot with a fast correction then you are correcting by too much, ie your TBEC has too greater values in it.

faster+smaller corrections = best
slower+larger corrections = ok, reacts slowly, can hunt
slower+smaller corrections = ok, reacts even more slowly
faster+larger corrections = worst, will cause hunting around target psi

Anyways - the inbuilt correction interval crossover should still work. You just need to use the stock crossover table (rather than my gear table)

 

I understand its not RPM based. The acceleration of the engine causes the issue however.

Does calculating the crossover for the stock system differ from calculating the gears for your system?

 

should be the same...

 

Like I said, its a real nit pick.

V6 is working really well. I've yet to test out or use the alternate startup IPW values. I guess I have to find a power source that keeps 12v when the car is cranking huh?

The features are really nice. Yesterday I felt the car nose over in the middle of a third gear pull then come back alive. Now I told you that I can't see the CEL flashing (I look at the road not the gauges). I looked at the log (felt like it went wayyyyy lean). Well that was the boost pull on high knock taking the wastegate out. This is really important stuff for people like me. Also I'm on the limits of the stock fuel pump with E85 so one of these days the AFR safety will do the same to warn me. Let me tell you, when the ECU pulls the wastegate out you know. Its not violent, its quite soft actually. However your left saying "where is all my power"? This is really great stuff I can't stress that enough.

I'm gong to play around more with the gear based boost control in the coming weeks. Anymore the car almost drives itself. Just mash the gas in first and second, no need to work the throttle peddle. This combined with the NLTS should make a drag passes a breeze. If drag racing wasn't already easy enough then this makes it brain dead proof. As long as you have an IQ equal to or greater to a dog then you can drag race an evo set up properly.

One of these days we are going to have to figure out how to use disconnected emissions devices like the EGR valve. It would be nice to have a tephra mod to enable/disable the EGR. Not checked it runs the stock EGR code. Check the box and you can use settings to configure it for, oh I don't know a nitrous window switch and/or water injection switch. We could even keep it PWM based and use the stock EGR duty cycle tables so that you can get more flow at higher RPM. Or if it is a nitrous window switch just plug in 100% duty cycle at higher RPM's for on/off control.

I think the evo has an EGR temp as well? If so thats a spare input.

Thats the future though, just thinking out loud again.

 

how does your log look in terms of load/timing/afr/IM boost when boost is cut?

my problem with boost cut was that load would drop (coz the MAF stops seeing new air) however IM boost would stay high for a little while.

This would cause the timing to jump high (because of the "low" load) and also less fuel to be injected (load goes into ipw calc).... not sure if its bad or not...

 

Mine is fine. When boost drops load drops but my fuel maps and timing maps are set up to run wastegate boost just fine. Its a slow transition and causes no issues, only helps get rid of the knock. My AFR's stay the same and I get only slightly more timing, maybe 1-2 deg more due to slightly less load.

 

your AFR is placid.

 

Tephra, but isn't that the point? Load goes down, and I mean actual load as in conditions inside the cylinder, such that the likelihood of anything bad happening goes WAY down with the reduced effective compression ratio. So going lean at that moment, when boost drops, should not be a problem. Much like when you slam the throttle closed, the MAF see not just less new air but literally NO new air. But this is even softer since air does still keep flowing through the MAF, just at a reduced rate. I can't imagine that for anything even approaching a microsecond does air flow through the MAF stop when the boost drops from 20psi down to 12 with a wide over throttle [shrug]. Alternatively, if you are really worried / you find it is causing problems, couldn't you add a momentary IPW/MAF reading adder to keep fuel flowing for just a few extra rotations. Not too much of course or you just risk flooding the cylinder and going super rich (though that certainly would cool things down). Anyway just thoughts from a lurker waiting for the 03 VIII version

 

How about some 94170015 love for all us O.G. 2003 guys?

 

i will do 96530006 first.

i reckon all evo8's will be able to run this rom.. ie 94170015 and 96940011 and 96420011

be good to get someone with the above's to test 96530006 so I dont have todo as many ROM's

 

WE skipped that question or not? Just interested

 

well do mrfreds mods like normal.

except when you change the scaling on the old tables you need to do it on the new 3d tables...

 

I think the problem is that you can still have alot of air flowing into the cylinder and almost no fuel... that is really bad if it happens in a certain way because having so little fuel it can auto-ignite VERY easily since there isn't enough to cool the charge and the cylinder is already torched from the uneven flame fronts. I think that is why alot of systems usually choose to cut spark instead of fuel.

I think what he meant to say was "you just have to change the scaling on the new tables instead of the old tables referenced in the mrfred thread. Everything still works as it should".

I was going to do a staged release of mods and accompanying XML like I did for 5.10, but I wanted to wait for a final version. Nothing like doing things twice! (or 6 times, as I've been spending all my time at work this week )