cyl switchoff for v8s v6s and straight 6s

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cyl switchoff for v8s v6s and straight 6s

Postby barana » Fri Jan 19, 2018 10:44 am

Can this be done Ecu-wise? I realise there's some mods needed in the engine also, but my question is just the Ecu side now.

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Re: cyl switchoff for v8s v6s and straight 6s

Postby antus » Fri Jan 19, 2018 12:01 pm

Probably not if its not a factory feature, but you have not defined which specific ecu and operating system your talking about. If it can be hacked in would partly be defined by if the cylinder injection is sequential and if each injection event is driven by the software code. If it is sequential injection and under software control it would then need something with the skills to understand and modify the code to implement it, and a way to flash the code changes in.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: cyl switchoff for v8s v6s and straight 6s

Postby barana » Sat Jan 20, 2018 9:06 am

Oh! The link didnt appear in my first post.
Have a read of this https://mechanics.stackexchange.com/que ... ation-work
It shows you how gm does it from the factory, it is detailed enough and very informative! Good read.

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Re: cyl switchoff for v8s v6s and straight 6s

Postby antus » Sun Jan 21, 2018 9:03 am

Thats a good read. In general i'd say no, the complexity and timing requirements would make it too hard to retrofit to another operating system. Some (most?) computers wont have enough hardware to do it also. But do you have a computer in mind? Are you considering implementing it?
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: cyl switchoff for v8s v6s and straight 6s

Postby barana » Fri Jan 26, 2018 6:05 pm

It would have to be a vs+ sequential.
It would be nice, I have the hw tools, but I dont know hc11 assembly.
What rtos do delcos use?
Have some hxkers mapped out the functions in the rom and the variables in memory ?
Program loops?
Is there any room left in rom to implement anything in vs+ delcos?
If I chose a start project, it would be variable cam timing to start with and then id move onto a mahl cam-in-cam setup.
Did I ask too many qtns? :)

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Re: cyl switchoff for v8s v6s and straight 6s

Postby antus » Sat Jan 27, 2018 6:41 pm

Well there is no OS. The code is written in assembler and implemented on bare metal hardware. Some operating systems have been mapped out, and some routines are common between code bases. Look at the1's enhanced to see what he has implemented on those computers here. viewtopic.php?f=27&t=2518

Variable cam timing requires engine hardware so you wont be able to implement that, unless you put the computer on an engine which has something you can actuate to change the physical timing. The system on my subaru is a solenoid on the end of the cam which can push the cam across, and the lobes have a slope so the timing changes as it is pushed. The solenoid lets oil flow to push the cam. That description might be a bit rough, but thats my understanding of it.

To get an idea look at some of the files in the disassembly area, such as this one: viewtopic.php?f=26&t=437

The PCM code is split in to 2 halves. There is a low 32kb with calibration and common code, and then 2 sets of high 32kb in the other half of the address space which are bank swapped. One runs and does engine, then the other runs and does transmission. This architecture makes it harder to disassemble and vary hard reassemble. This means the best way we have found to modify is identify what to change, write new code and then patch the existing binary rather than re-assemble.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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Re: cyl switchoff for v8s v6s and straight 6s

Postby barana » Sun Jan 28, 2018 12:32 pm

antus wrote:Well there is no OS. The code is written in assembler and implemented on bare metal hardware. Some operating systems have been mapped out, and some routines are common between code bases. Look at the1's enhanced to see what he has implemented on those computers here. viewtopic.php?f=27&t=2518

I gotta admit I suspected this based upon various descriptions, Its great having it confirmed, and its really cool, i might say, just like the mainframes of the 60's
antus wrote: Variable cam timing requires engine hardware so you wont be able to implement that, unless you put the computer on an engine which has something you can actuate to change the physical timing. The system on my subaru is a solenoid on the end of the cam which can push the cam across, and the lobes have a slope so the timing changes as it is pushed. The solenoid lets oil flow to push the cam. That description might be a bit rough, but thats my understanding of it.

Yep aware of phasors, and solenoids that allow oil in and out to advance or retard the cam ..i think 5% deg is 'nomal'? barra,toyota 's' and dodge v10. in addition the cam in cam looks great ► 1:45 https://www.youtube.com/watch?v=0uiDmcPEekc
Also , Have you seen the FIat variable valve lift tech? called 'multiair' https://www.youtube.com/watch?v=ITOwtCiQtC4 looks easy to retrofit :D .
antus wrote:To get an idea look at some of the files in the disassembly area, such as this one: viewtopic.php?f=26&t=437

ok,thx mate I will,see you in a few weeks!
antus wrote: The PCM code is split in to 2 halves. There is a low 32kb with calibration and common code, and then 2 sets of high 32kb in the other half of the address space which are bank swapped. One runs and does engine, then the other runs and does transmission. This architecture makes it harder to disassemble and vary hard reassemble. This means the best way we have found to modify is identify what to change, write new code and then patch the existing binary rather than re-assemble.
Ok so youre patching. Is the automatic bank erased and used for map B for manual cars? I take it it doesnt do a full bankswap, there is as u mentioned the main program in the first 32k,then it swaps in half a 64k bank and works on it? then swaps in the next halfbank... interesting.

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Re: cyl switchoff for v8s v6s and straight 6s

Postby antus » Sun Jan 28, 2018 2:50 pm

yeah thats right. 2 'views' of CPU's address space. RAM mapped down the bottom, calibration and common code above that and below 32k Various registers and the eeprom mapped over the top of the ROM too. Top 32k swaps between 2 banks. I think the manual code still has all the auto code - there are other road speed calcs and so forth which still apply and get run there. The1 and charlay86 have looked at that code a lot closer than I.
Have you read the FAQ? For lots of information and links to significant threads see here: viewtopic.php?f=7&t=1396

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