nAst1: Progress and Concepts Thread

[robertisaar]

yeah, any XDFs made in TP V5 will only work in V5.... i haven't touched V4 in probably a year. i THINK the scalars and flags work, but none of the tables show up when using a V5 XDF in V4, but i could be wrong.

most of the outputs control the ground circuit. the only outputs on a 7730/7727/etc that give out a positive voltage are the fuel pump output, the non-present secondary injector/fuel pump controller as used in 90-92(IIRC) ZR1 corvettes(that PCM is actually largely a 7727 with some unique changes), the EST circuit, and the EST bypass circuit. if you wanted to, a solid-state relay or a good FET could have a ground switched from the PCM to control it and have that supply a 12V signal.

basically a 2-step rev limiter that cuts ignition signals, right? i'm working that(well, actually a 3-step) into the next release already without external hardware, 3-step fuel cut has been done for a while.

[Mars]

I know you were asking about what other people might want on this code. I know me and caffeine could really use a meth injection activation.

Straight boost pressure switch built into the ECM would be nice. (that way I can eliminate a mechanical switch)

If KPa > 140 THEN, : spray meth.


Of course you could get fancy and put in maybe a table for an RPM window switch activation, if TPS is greater then 90% and RPM is greater then XXXXXX : then spray meth.

just an idea. I'm sure people would love it.

[robertisaar]

true... and very easy to impliment, but what output could i use? currently running VERY short on them...

in my personal application, i actually removed CCP control from the PCM to allow that output to be used for TCC PWM control.... now i have CCP controlled by the TCC solenoid, so whenever the TCC is locked, the CCP solenoid is purging, that was the best compromise i could make.

it's actually why i looked into using an Arduino as an ECM.... LOTS of inputs/outputs(even external interrupts) available, however all of the internal timers are basically gone/used, so you can't do anything timer based that isn't based on some kind of external reference. injector sequencing and coil control are basically impossible.

for dead-simple stuff based on an analog signal, i would use a Schmitt trigger or comparitor to control an output. anything that can't be controlled that way would require some intelligent logic... Arduino is a simple/cheap path with a lot of support/documentation, can literally hook it up to existing sensors(well, most of them) and control it that way.

my personal path for more outputs will be via the 7730TCM project... since the transmissions that will be controlled are using between 4 and ~8 of the outputs that the 7730 can drive, that leaves up to 8 outputs left to do pretty much anything that can be imagined. it would actually be somewhat like a 93-95 3100 PCM in that it will have 2 processors working on different tasks with some communication between the two, but they can also work independantly.

[caffeine]

Meth control would be nice too, but I already have a meth controller that works on boost and fuel injector pulse width, so I'm not desperate on that front.

However, the ability to control a boost control solenoid could actually be cool as well; you could effectively use the ECM as a boost controller with a solenoid and have a table to even taper down the boost at high rpms.

As far as outputs, I doubt many boosted people will be running CCP or EGR, possibly A/C as well.

[Mars]

As far as outputs, I doubt many boosted people will be running CCP or EGR, possibly A/C as well.

or a shiftlight, or torque lockup in my case (non-lockup converter)

[robertisaar]

boost control is something i've had in the works for a while now too.... it was using one the of the EGR outputs, but i forget which. whatever pin it was with a TGP i think. it was somewhat convenient to work out like that, since the other one(that controls the EGR in TGP code) is earmarked for the gen4 VVT control. that leaves one EGR output left..... could use it for methanol control or a bunch of other functions. that will probably be a pretty broad use output.

[caffeine]

or a shiftlight, or torque lockup in my case (non-lockup converter)

X2 on shift light and torque converter.

[robertisaar]

well, when it comes to something like meth injection, if i used the TCC/shiftlight output, then that would pretty much limit it to manual trans applications not wanting to use a shiftlight and autos with no TCC...

these kinds of decisions slow down a lot of the development since i have to try and work out something that will work for the largest amount of people.

[Mars]

Could you not add a flag to pick between auto and stick ? I think the stock A1 code has this where, you select if you want a TCC output or a shiftlight output ? Use the same output for TCC, Meth activation, OR a shiftlamp.

I wouldn't spend much time on the oil pressure fuel cut, as I think the majority of us here use an oil pressure sending unit that's wired to the dash and to the fuel pump relay. So low oil pressure already kills the fuel pump via the OPSU.

Also I really wonder if the 3900's variable intake manifold is worth the effort to get working... ? Like I just swapped a 3.5 LZ upper intake onto my 3900 and by the looks of it it would easily out-flow the 3.9 variable setup.

Awsome work soo far ! If you figure out the spark cut stuff, I'm definetly going to look for a 9396.

[robertisaar]

Could you not add a flag to pick between auto and stick ? I think the stock A1 code has this where, you select if you want a TCC output or a shiftlight output ? Use the same output for TCC, Meth activation, OR a shiftlamp.

I wouldn't spend much time on the oil pressure fuel cut, as I think the majority of us here use an oil pressure sending unit that's wired to the dash and to the fuel pump relay. So low oil pressure already kills the fuel pump via the OPSU.

Also I really wonder if the 3900's variable intake manifold is worth the effort to get working... ? Like I just swapped a 3.5 LZ upper intake onto my 3900 and by the looks of it it would easily out-flow the 3.9 variable setup.

Awsome work soo far ! If you figure out the spark cut stuff, I'm definetly going to look for a 9396.

care to explain the first part? the auto/manual switch(6BF, bit 7) is used for a little bit more than shiftlight and TCC control IIRC, i'll have to generate a full list of values that are effected by it... there's also a "manual trans" scalar that is read as 0 or non-0 for some IAC control. when the flag is selected as "manual", that could PROBABLY be used for a decent meth injection control... just have to setup the basic shiftlight controls so that the light will never come on unless above a certain RPM/TPS. that's a basic method that already exists anyways.

the oil pressure switches aren't used to cut fuel in any factory application... they're actually a secondary 12 volt supply to the fuel pump in the event of fuel pump relay failure. they COULD be used as a fuel pump-cut if pressure drops too low.

the LZ9 variable intake.... probably not that important, but the same controls that would operate it could operate a lot of other misc stuff... from what i can tell, that variable plenum volume scheme was essentially controlled based on load/RPM, so you could have it operate almost anything that would benefit from RPM alone, MAP alone or RPM/MAP.

i'm working on the spark-cut code... just need to get it 100% before it gets thrown out there. bad code here could cause some REALLY undesired effects, like instead of spark being cut, you get 50* of advance and multiple spark discharge or something. SA/dwell calculations aren't something to be taken lightly.

[Mars]

Oh, I was under the impression that the auto-manual bit just controlled the TCC or shiftlight. Had no idea it did more than that. As you can tell my knowledge is limited (non-existent) when it comes to this stuff. haha.

the oil pressure switches aren't used to cut fuel in any factory application... they're actually a secondary 12 volt supply to the fuel pump in the event of fuel pump relay failure. they COULD be used as a fuel pump-cut if pressure drops too low.

Wow, I thought for the longest time that it was a fuel cut. it's kind of stupid that it isn't.

Keep up the good work !

[robertisaar]

like i said, it COULD be used as a cut.... instead of the fuel pump relay directly powering the pump, sending it's load through the switch(which closes above ~4PSI and opens below it), it will only allow the pump to run when the ECM commands it on AND when there is more than 4PSI of oil pressure.

i'll have to look to see what all it does control.

[SappySE107]

Also I really wonder if the 3900's variable intake manifold is worth the effort to get working... ?

Don't use the variable upper, unless you like torque only perhaps. Close it flows small port 3100 top end. Open it flows stock 3400. Thats basically it. Non variable upper is significant flow over that.

[robertisaar]

hard to argue with the SAE dyno results GM has posted... torque drops after 4800, but HP still doesn't peak until 6000.



was there a specific RPO for 3900s without the variable upper, or were they all LZ9? wikipedia shows LZ8 as a 3900 with DoD, LGD as a E85 capable 3900 and LZG as E85 capable AND DoD 3900.

[SappySE107]

Post them from 06-09 for the LZ9. 08 wasn't variable upper that I remember.