anesthes

iTrader: (12)

Glenn, Tim, anyone else. I know this has come up a few times. I've read, searched, etc. I know Glenn your one of the people that has mentioned interest in it.

Some people are running the 749 code, which for what its for, does well. But I'd like to get some peoples attention, thoughts, etc here in this thread.

My goal is to get re-scale 7730's VE and Spark tables to read up
to 190kpa using the $8D Base code, and a 2-baro map sensor.

The way I see it, only 3 parts of the code need modifications
(initially):

1) Code that reads map voltage and translates it to map values
2) Table of ve vs map needs re-scalling, and some basic "ve data"
as starting points.
3) Spark tables need the same.

What are your thoughts?? I know here and there a post on a thread has brought this up, but I think for project, and historical reasons we should put all pertaining information in this thread. If it works, this thread can be a sticky.

Anyone??

-- Joe


Links:

http://www.diy-efi.org/gmecm/archive.../msg00616.html

anesthes

iTrader: (12)

Well anyway.. Been looking at some stuff for a couple hours.

First thing I'm going to do, is write a small code-commenter in C.
It will use the $8D hack as its template, and go through any
dissasembled version of $8D you may have, and add the appropriate comment for each line. This makes it easy to switch back and forth between hand and hex (tc,winbin,etc) editing.

This won't really be specific to $8D but thats what I will be testing it on.. Time permitting, should have something working by the weekend.

-- Joe

RBob

iTrader: (1)

Joe, you can take the ANHT hac and save (cut & paste) it as text. Then work on making it assemble. The hac is set up to do just that.

As for 2 bar, patch in the $58 MAP code to create two MAP values. One will be 1 bar based and used for everything that currently uses the MAP term.

The other will be 2 bar based and will be used for the boost tables. The code to do this is in the $58 mask.

Now add in the required correction tables for boosted operation. Maybe a BPW multiplier, spark retard or another spark table, stuff like that. By then you'll be good with code and addicted to it . So more will follow as a greater understanding is reached.

RBob.

anesthes

iTrader: (12)

From my research, I think ANHT hack doesn't work but I'll look again.

Maybe I'm being ignorant, but I don't see why rescalling the tables, and adding more fuel and less spark > 100kpa would be soo difficult.

All you'd really want to do is say "x volts is really xxxkpa", so all your part throttle non-boost stuff still works great. All those calculations for kpa <100kpa should still work - you'd WANT them
to. Boost only happens when you make it happen.

$6E has a table that maps gps to MAF voltage. I bet $8D has a similar table, its just not documented. Wouldn't that be sweet?

Under boost you really just want more fuel, less spark and then PE should take care of the rest. Am I being stupid?

I've been talking to a couple people about this offline. It makes sense that simply rescalling the code that interprets what kpa
a voltage is would fix it. The problem lies in how exactly GM wrote the code to anayze the value. Does it store current kpa in
a memory address, and calculate on that, or does it store the pointer of the current kpa to a static memory address, which would break all the calculations. Thats really where this would become complicated, but I don't think its done that way.

As far as "retarding timing under boost" you really just want to do that with your spark table "rpm vs map". The general rule as a starting point is take out a degree per psi of boost, so scale the table that way. That should be a starting point for anyone really...


The $58 has a ton of extra functionality which maybe useful with a factory turbo, but I don't think it matters for MY and a lot of other applications. I honestly think a slightly hacked $8D will work tons better than a stock $8D and a BTM and FMU, which is what I'm running now.

The "easy" solution would be run $68 like Bort, Saturn.. Those guys have been happy with it. But to me running a modded $8D makes more sense.. No more repinning, you can easily switch back if things arn't working out (swap map sensor, replug in fmu + btm), existing scantools _should_ work with it, and if I/we do the hack the way I think we can, you shouldn't really need a modified def file even to edit it. (just translations in your head!)

-- Joe

anesthes

iTrader: (12)

This kinda ruins the idea of changing resolution, but I'm still unsure why it matters. It should make assumptions based on kpa, not voltage. So whats the issue?

http://www.diy-efi.org/gmecm/archive.../msg00476.html


I'll still research this..

RBob

iTrader: (1)

Notice Ludis's last paragraph. It is the same as I suggested. And is really the best way to do it. And the code is already available to do just that.

The lookups are by KPa. The MAP input is converted to a KPa value that is held in RAM. This allows the lookups on nice even KPa boundries (20, 35, 30, 35. . .). So you want to keep that term available. Minimal code changes are the result.

Once into boost the > 1 bar term can be used to modify the fueling and SA. Can create a boost KPa by subb'ing 100 KPa from the 2 bar KPa term.

RBob.

anesthes

iTrader: (12)

Hey,

So.. Heres the logic your suggesting:

1) Read in MAP voltage, convert it to kpa and store it somewhere
2) Convert MAP voltage (while voltage <2.5, voltage *2, if voltage
> 2.5, voltage = 2.5) so everything in 730 is happy.
3) Find a part in the code to reduce timing by a divisor if map2
kpa >190
4) Find a part in the code to increase pw (bpw multiplier like $58
does it?) my a multiplier if map2 kpa > 190

Thats Kinda exactly what John Guynne (sp?) did.. I wonder how far he progressed.

Hrmm..

Tim made a statement on a post about a year ago about the "aftermarket stuff being better than $58", because $58 behaves exactly this way, with the exception of timing being
map based in a table. Though I see conflicting opinions of a $58 hack that allows scalling of ve from 30-190kpa. Which is true? Tunercat surely does not display any table like this with a 2bar map selected.


I think I stressed this in my previous posts, but my issues with $58 are:

1) Tons of stuff that doesnt matter for our applications in the code.
2) EGR and such doesn't work in V8
3) Repinning harness (again)
4) Scan software for 730 is widely support, not $58
5) Ability to go back to "aftermarket stuff" in 2 seconds by
switching prom, map, and plugging BTM + FMU back in.

-- Joe

anesthes

iTrader: (12)

What do you all think the possibilities of leaving the current MAP sensor inplace for all the tables, but adding a second MAP sensor to an unused input??

-- Joe

RBob

iTrader: (1)

Can do that, there is another MAP input to the ECM hardware.

RBob.

Grim Reaper

Joe & RBob. Some interesting "strategies" mentioned. I have a couple of possible "strategies" I would like to contribute to a possible 2-bar MAP 7730.

I'd like to keep this conceptual at this point, just listing as many possible software approaches as possible: starting with the obvious, install 2bar Map and halfing the injector PW. There are obvious flaws with just doing that. But once everyone has "brain-stormed" the possible software strategies, then consider the pros & cons of each - looking for the simplest method that works effectively.

I learnt a long time ago when I was in software development, that too many times programmers just dive into the code without analyzing all possible solutions. Then they'd get 3/4's the way through only to realize that it won't work and have to start all over.

I got "house pests" right now, but as soon as I feed them and send them on their way, I will a couple of other approaches I've thought of at one time and another.

anesthes

iTrader: (12)

Glenn, RBob, I appreciate your input..

I've thought of a couple of different ways of doing this, and I'd like to share them.. This has been the only thing on my mind all weekend. I might be facing a divorce


Method #1: 2-bar map (The one I wish worked)

Modify the code that translates voltage to map integer value,
and re-do math for 2 bar map.
Then rescale tables.. Most of the code should work, right?

I don't know. I don't think GM wrote the code to just store
the map value as a number, and then reference the number. I havn't dived that deep into it, but I'm guessing from what I do see, and have read that it's just not done that way..


Method #2: (John Gwynne and others method)

Modify the code that translates the voltage to a map integer
value, to see the 2 bar. Save it as a new variable. Then, convert
it to 1 bar math so the rest of the code up to 100kpa still works.

Then write a function to increase injector pulse during boost, and a function to decrease advance during boost.



Method #3: (My crazy idea)


The above to methods utilize a 2 bar map sensor in place of the 1 bar. After lots of research, and hearing peoples comparing of 730 vs 749, I've come to the conclusion that the loss of resolution on
running a 2 bar map <100kpa is kinda bad. So I thought of this
new idea, kinda scary..

You leave the map sensor alone, and run happily as a 1 bar.. You add a second, 2 bar map sensor to a new input (if one exists). Then you modify the code, so when the 2nd map sensor reads >
2.5 volts, you reduce your timing advance + give more fuel.

The Low octane retard vs map code is a good example of a timing
reduction function. Prolly wanna duplicate that code with our
new map values, then write an additional function like the 749s fuel multiplier.


Comments please??

LBSZ28BLOWN

I was wondering if anymore has been done with the second
2bar map sensor for the 730 8D.

anesthes

iTrader: (12)

No. working on #3. #2 would run worse than $58, or 1 bar w/ additional boost electronics.

-- Joe

RednGold86Z

iTrader: (1)

I think you'd have to DOUBLE the pulse width (with 2 bar) if you left the MAP scale with 100 KPa limit (and installed a 2 bar). Ambient would now be 50 ish KPa, so BARO (uggh) would have to be changed. Spark would have to be rescaled so that the non-boost WOT spark advance occured at 50 kPa and tapered off as boost came on. PE would have to be enabled at 45 kPa. Delta MAP accel enrichment will have to be twice as sensitive and twice as much. Lot's of things could go wrong here if you get my drift.

Hope you don't overlook these,
Good Luck

anesthes

iTrader: (12)

Hence why I decided to use 2 map sensors like some the '87 carbed cars. Just, one of mine will be 2 baro.

-- Joe

anesthes

iTrader: (12)

Anyone remmber the guy who wrote the hack fro $8d, that would allow a second MAP to be used for ALDL recording ?

-- Joe

Grumpy

If your going to try 2 bar with the 8D, be sure to include an AE/TPS/RPM scaler. Then if you want the boost fuel correct you need more then just a multiplier, it takes a 3D table.
There is more then 1d of timing retard involved for boost if you want things correct. The 1d timing change goes back to the days of the Corvair, and alot has happened since then. When in boost you'll want an actual MAT timing correction, as well as a boost timing correction.
If your going to be stripping down the code, why not start with a economy version like the 58?. And the 58 has Source Code available.

anesthes

iTrader: (12)

I was gonna take some of the code direct from $58 for the BPW multiplier. So it would be multiplier vs kpa vs rpm.

$58 just isn't happy with my car. My car barely drives with it. Sure once I get into boost, i'm 100% certain it runs better there. But the part throttle is really night and day difference.

Looking at the logs, I think the fueling modes have much to do with it. If you look at my $8d log at the blm vs inj pw, then you look at the $58 log, it looks like $58 is switching between quassi and async for fueling. These transisions in itself maybe cauising the problem.

Another issue may simply be VE resolution.

Moreso, $8d has some options like maximum TPS for idle, which is set to 3.1% on my bin. If you remember all my bucking problems existed under 4% tps. Perhaps $8D is curing it by going into idle mode? (which I will test btw!) and max vehicle speed for idle
of 17mph. Dunno if this cancels out the other theory.

Maybe $8D is just better with a manual? Between shifts, $8d hangs my rpm for a few ms to give a clean shift. in $58, my rpm dropped to idle immediatley which caused a nasty shift unless you were drag racing for groceries.

-- Joe

anesthes

iTrader: (12)

..And did John Whatever his name is, ever get that 2-bar additional sensor hack to work with $8d for aldl recording?

I supose the wb-o2 hack might work eh?

-- Joe

Z69

As far as the repin & 58, I'd think you should be able to just change the I/O address in the code to the correct 8D address.

You might try using multipliers for for the retard.
One each for the map, rpm, mat.
It should work the same as the boost multiplier for bpw.
Might be able to do all the multipliers with one subroutine.
If more resolution is needed, You can break the multiplier up into sections. 2k-3k,4k-5k etc. Could take less room than a table.
The old software I deal with at work doesn't support tables so this is how you can approximate a curve with it.

Although a table will always work better.

Now that I think about it, a multiplier is a linear 1d table.
Starting to ramble...

anesthes

iTrader: (12)

Well here is what I was thinking.

wb-02 is 0-5v right?

Map is 0-5v, so the wb-02 hack would work for a second map. Then you change the ALDL output address, use something like the second MAT output or something to that effect.

Then change the math, by using a baseline of idle or something. That would be phase one, and would allow 2-baro readings for the aldl.

-- Joe