deeman101

iTrader: (34)

So at startup it takes a baro reading of current conditions and uses that value? Or does it use current baro on startup and then revert back to a value set in the flash?

My main concern is what if hypothetically I were to tune my car to the very edge at 450ft, and then for a weekend go up to like 4000ft when I go snow boarding or something. Then I might start knocking on that tune at high altitudes because of the lower oxygen content. Of course I would want my tune to be a bit conservative but it still takes away from the margin of safety theoretically. Not sure if this is a concern practically but its something I was bothered by.

RoadSpike

iTrader: (5)

Typically at altitude at least with my tests you would need to run more timing and boost to get the same power. Less o2 content means richer and then safer so the point of safety really shouldn't be a concern going up but tuning from up back to sea level.

I could make the baro routine hold onto the setting but thats not really good for the car either. We would need a separate sensor and I could get a patch going for that later. The rom is already setup putting the baro into its own sub routine it would be trivial to change the code to use some other sensor.

l2r99gst

iTrader: (2)

In terms of your SD tune, that shouldn't matter. SD is using the absolute pressure, so altitude (oxygen content) is already taken into account. Your fueling should remain the same.

There is the possibility of VE and turbine efficiencies being lower, but you shouldn't have any issue at various altitudes using the SD patch.

The only issue that was the biggest potential problem was the fueling at startup, since the initial SD patch used a locked baro, that was incorrect for startup. Roadspike fixed that, where is uses the actual baro for startup, so now, that should be taken care of as well.

l2r99gst

iTrader: (2)

Thinking about it more and how the SD patch operates, under boost, your loads will be different. But, as Roadspike mentioned, it will be more conservative at altitude.

A quick example. At sea level, let's say you need 20 psi for 250 load (compensated). At altitude, you might need, say, 23 psi, for that same 250 load (compensated). But since we have the kpa to load table, it will give you a higher load for that 23 psi. But, that will push you further to the right in the ignition and fueling maps, being more conservative.

I guess a question for Roadspike is what load is used for the axes? Is it compensated load?

deeman101

iTrader: (34)

So in effect you could be loosing power unnecessarily as you go higher in altitude, or potentially running dangerously aggressive as you go lower if the table uses raw load instead of compensated. I guess we should wait on roadspike's response.

RoadSpike

iTrader: (5)

The current patch uses kPA as the x axis and rpm as the y axis. The kpa is a table in the rom so you can set that as a function to the volts of the map sensor. Check page 1

03whitegsr

iTrader: (8)

Somebody running 9653XXX6 want to try out a couple values to see if it helps or hurts this stuttering issue? I have an idea of where the issue might be coming from but my car is not together to test on.

PM me and we can work on this out of this thread.

And

PM'd

l2r99gst

iTrader: (2)

I wasn't talking about the VE table or the map sensor scaling table. I know what those axes are. Maybe you were confused by my use of the word axes. I was thinking about axes for the fueling and ignition load, which comes from your kpa to load table. I was asking what load is that table giving?

I think I have to stop thinking, because now that I just said that, I have more questions. In stock form, different loads are used for the fueling and ignition table, sometimes baro compensated, sometimes baro+temp compensated. I'm assuming with the SD patch that is changed to one particular load, unless there is something that I am forgetting with the whole operation of the SD patch? That's what I'm asking...which load is that?

I think part of my problem is that I routinely forget about the whole operation that John originally setup. Then, there are new creations like this and I have a million questions again because I simply forget everything again. : ) Maybe I just need to shut up and just keep reading every day.

95630706

I have experienced it between 3-4k. I need to rule out poor tuning though. Basically as revs climb I will get a couple mis fire type hiccips. Trying to capture it in a log.

RoadSpike

iTrader: (5)

haha no thats cool

Honestly I never really paid attention to what load it was I would probably end up reading banks original thread again to find out myself.

03whitegsr

iTrader: (8)

I think Tephra changed to a fixed load under all conditions with the "big maps" and that mixed with the SD patch makes things a little confusing.

I think now that a bunch of people have used it and the short comings have been identified, it may be good to completely reevaluate some of the changes made. I could be wrong, but I think some of the stutter issues could be due to how the MAF replacement was implemented in the IPW loop.

I see some potential points where the load could be calculated in a funny fashion simply because of how the main loop is vs. the CAS interrupt loop. Also, I think the MAF reset and MAF Filters could both be causing some issues.

RoadSpike

iTrader: (5)

That would make sense to me as well.

I'm glad i'm not the only one thinking about it haha!

VGergo

iTrader: (3)

Write in the Ecu the 9653 version looks like working cool I play a lot with the tables.. exspecialy the under load 100, the vacum part.
Only problem : In open loop my idle map afr is 17.2 instead of what is in the high octane fuel table 14.7, why ?

Can someone post his kpa to load table with Omni 4bar map sensor and 2.0 liter engine ? I'm so excite how others tables looks like.

RoadSpike

iTrader: (5)

Well you got a couple of choices fixing your idle's AFR I'm guessing you mean that the wideband is showing you 17.2 instead of 14.7. If thats the case you can incrase VE or increase load at the kPA you idle at. I can't recommend an idle kPa pressure since cams effect this area quite a bit.

The idle VE map should be extremely easy to play with however if thats the way you want to tackle it.