Cobalt SS PCM swap -P12 research- - Tuning Forum

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Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 1:26 AM
I realize this applies mostly to LSJ swaps, but....

In thinking about what to do about HavBlue and tuning it while boosted, the simple solution would be megasquirt.
But, I've become obsessed with OEM+ kind of stuff so I started thinking about fully LEGAL boost solutions that still give you massive amounts of tunability while still letting me drive to the inspection station and breeze thru with no problems.


So I started researching the Cobalt PCM and the wiring schematics, and I discovered something a lot of Jbody people might not know.




The early model year Deltas (04-07) used the P12. The P12 was a nifty little gap jumper between the Jbody electronics and the modern can-bus the delta uses.
From what I have traced, the 04-07 deltas communicates via GM High speed LAN, GM Low speed LAN, and

-get this-


CLASS 2 SERIAL.
THE SAME CRAP THE JBODY USES.

GM high speed LAN originates from the C1 connector on the P12 PCM.
The Low speed LAN runs the gauges and is controlled by the delta BCM.
Class 2 is what communicates when a diagnostic tool is hooked up. the LAN networks do NOT communicate diagnostic data.

so the only thing to sweat is the GM high speed LAN.... so I dug for a while and found this schematic.

the green line is the GM high speed LAN connections.
I've blocked out the areas that are irrelevant to us.


as you can see, the GM high speed LAN runs components the Jbody will never have, nor would want to utilize.
this is a pretty big deal, because this means that the P12 can be wired in (with VATS disabled via HPT of course) to run a 60-2 (58x) ecotec engine and has the capability of handling boost.

you'd need a MAF sensor for the setup however, but a majority of the sensors are the same from the LSJ to the L61.

the only thing I'm a bit iffy about is if the class 2 originating from the P12 PCM will play nice with the Jbody BCM.
I fully intend on testing this out.









Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 3:21 AM
That is huge! PJ, you seize to amaze me man.

In theory, I think you are right on target.





Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 3:38 AM
also worth noting:

you also have to run throttle-by-wire when doing this.

I just picked an accelerator pedal off ebay. retrofit into the jbody looks pretty straight forward.

make a bracket that bolts to the brake/gas pedal assembly for the AP.
remove stock gas pedal (grinding will be involved)
wire up the AP
wire up the throttle body

I'm getting excited.

still looking into the capabilities of the P12 PCM to justify taking the plunge 100%


the AP was $55
I already have an LSJ engine wiring harness (only two PCM plugs are on it... the missing third plug is the same as the blue plug on the factory Jbody PCM -aka the P11 PCM-)
I already have an LSJ throttle body

I still need:
MAF sensor (I can run the P12 in speed density mode if I wanted)
P12 PCM




Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 4:03 AM
HUGE! Definitely subscribed as this is something I've pondered before. I didn't know the earlier delta computers were so different. Keep it up PJ!!



"In Oldskool we trust"
Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 4:22 AM
Very interesting.



FU Tuning



Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 4:54 AM
Pj if this works out i will love you forever. Opens up a hole new chapter for us LSJ guys and hopefully solve all my tuning issues. Definitely be watching this.






Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 5:03 AM
Do it!!

Ryan and I always mention the huge difference is the delta's tunability, and I've said numerous times that is love to throw in the whole harness from a cobalt. Big plus to ditch the trigger wheel and just have an OS that recognized the 60-2 wheel. Looking forward to updates!






Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 6:34 AM
This is absolutely amazing. Great work and keeps us updated on this discovery.
Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 10:07 AM
Question as I do not keep up on all the Ecotec stuff.

The 60-2 is that jbody Ecotec, or delta Ecotec?



FU Tuning



Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 10:21 AM
^delta

Ours is something like 7x

A nice plus if this works is getting to use the larger lsj tb as well.

It's a nice in between of ours and the ls1 tb.

I hope like hell this can be done. Tuning the lsj is worlds above our cars capabilities. Plus the motor can handle so much more stock.
Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 1:53 PM
Interesting.





Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 4:21 PM
Addicted to meth wrote:

Question as I do not keep up on all the Ecotec stuff.

The 60-2 is that jbody Ecotec, or delta Ecotec?


the LSJ (2.0 s/c) was around as the LK9 (2.0 turbo) in saabs before the delta bodies started using it, but they always had a 60-2 trigger pattern.

the 2002-2005 L61 is a 6+1 pattern, just like most of GM's early FWD efi stuff... most 60* V6s, the twin cam engines, etc

in 2006, when the other ecotecs started showing up, the L61 was upgraded to "high resolution ignition" aka 60-2 trigger pattern.

the P12, in theory, could run any of the 60-2 ecotec engines... but it does not have any controls for VVT. That is didn't show up until the E67 PCM.







Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 5:01 PM
could news but the ontario guy shave work to do we need to find out how we can get our PCMS to carry the VIN of our cars for e testing our new systme the vin on the car must match the PCM



JBO since July 30, 2001
Re: Cobalt SS PCM swap -P12 research-
Thursday, April 11, 2013 5:07 PM
NOTa2_4 wrote:

could news but the ontario guy shave work to do we need to find out how we can get our PCMS to carry the VIN of our cars for e testing our new systme the vin on the car must match the PCM


you can change the VIN in HPT tuners I'm pretty sure.






Re: Cobalt SS PCM swap -P12 research-
Friday, April 12, 2013 1:17 PM
PJ - you can't. HPT is a bunch of dinks and the VIN# MUST match the Operating System ID - which means the VIN# must fit a model year.

For instance I cannot put a 1998 Jbody VIN# into a 2000+ Jbody PCM as the OS ID to run that hardware won't match the requirements of the VIN# as per HPT.



For this reason I am piggybacking, unfortunately. But I will watch this thread closely as I love when you come up with new Ecotec ideas and tear down limits.

-Chris-


-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
Re: Cobalt SS PCM swap -P12 research-
Sunday, April 14, 2013 10:25 AM
I think the only reason to change the VIN in the computer would be for emissions correct? That being said, a lot of us don't have emissions, or can opt for a tail-pipe inspection instead of a scan-port. With the proper "emissions" tune and a cat installed, that shouldn't be a problem.

I know you're going for the whole breeze through emissions thing PJ, but I'm going for the whole "I absolutely hate alpha-n" thing. So....
This is very interesting, and if it proves to be a possibility I'll be the first to run the setup. Keep us posted, please!



I roll on steelies. Work-in-progress daily-sleeper potential.
http://www.j-body.org/classifieds/engine/60493/
Re: Cobalt SS PCM swap -P12 research-
Sunday, April 14, 2013 11:51 PM
SweetnessGT wrote:

PJ - you can't. HPT is a bunch of dinks and the VIN# MUST match the Operating System ID - which means the VIN# must fit a model year.

For instance I cannot put a 1998 Jbody VIN# into a 2000+ Jbody PCM as the OS ID to run that hardware won't match the requirements of the VIN# as per HPT.



For this reason I am piggybacking, unfortunately. But I will watch this thread closely as I love when you come up with new Ecotec ideas and tear down limits.

-Chris-


but I'm not mis-matching the VIN and OS ID numbers

I've never had issues swapping PCMs amongst 03-05 jbodies
and the P12 PCM is supposedly class 2, just like us, so as long as I have a P12 and NOT the E67, it SHOULD work.


I have researched this very thing however, and haven't found anything really conclusive. I think it's going to boil down to just trying it and seeing if it works.
All I'm really gonna need to do is re-wire the engine harness and tap in to the class 2 serial.





Re: Cobalt SS PCM swap -P12 research-
Monday, April 15, 2013 3:52 AM
Just wanted to add, I read on a couple of other forums that when using throttle by wire even at 100% pedal you only get 80%. I do not know how factually that is but it is something to look at. I have seen it on about 5 forums already.




On the inside my car looks like a fighter jet.
Re: Cobalt SS PCM swap -P12 research-
Monday, April 15, 2013 3:33 PM
so today I received my electronic throttle



mounting it looks like it'll be pretty easy, just need to remove the old throttle in order to mount this one (the throttle and brake pedal are one assembly)



a cool side effect of swapping to electronic throttle is now I can finally fix the weird stagger between our brake pedal and throttle... heel-toe downshifting will now be easier to do.

I also bought a P12 PCM on ebay, and gave them a 2005 cobalt SS VIN to flash on to it.
this is irrelevent to me really, but I figure some higher-volume PCM distributors or recyclers may interchange more frequently, so I wanted to make absolutely 100% sure I would get a P12 with a cobalt SS calibration already on it.

the next step when I get the PCM is to wire it up on a bench, and get HPT to connect to it so I can license it and disable VATS.

I have a spare pedal assembly for a Jbody that I will be modifying for the electronic throttle so I can swap it into HavBlue and minimize my down time.

once I do that, I'll begin building the new wire harness for the P12.

I'm going to be incorperating a partial wire tuck during this project.





Re: Cobalt SS PCM swap -P12 research-
Tuesday, April 16, 2013 10:20 PM
modified electronic throttle is done.

all I need to do is modify this brake arm for the manual setup already on the car.

I ground off the pin that holes the throttle on the Jbody assembly, then removed the throttle pedal.
I made a flat piece of aluminum that bolts to the throttle stop on the Jbody assembly.
then, I made a support bracket for the back of the plate to keep it from flexing and welded it to the Jbody assembly.
the electronic throttle bolts to the plate, then you bolt the plate to the Jbody assembly.. that way it's removable.

the HVAC is very close to the Jbody assembly, so making the bolts accessibly was nearly impossible without the aluminum plate sub-assembly.







it's hard to tell, but I brought the throttle pedal forward so that when I'm pushing the brakes, I can blip the throttle easily with my heel.






Re: Cobalt SS PCM swap -P12 research-
Wednesday, April 17, 2013 4:09 AM
The capabilities of the P12 are >>> than jbody, even the LD9 speed density OS. With the P12 you can run straight MAF (maxing at ~67 lb/nin), 2-bar speed density/VE controlled by an rpm based crossover. The SD VE table has HUGE resolution, as do the spark tables. You get two IAT sensors so you can do ambient and post IC, you get the ability to control a Bosch IC pump if needed, injector scalability is pretty reasonable. I haven't done throttle body scaling, but it's there if needed. The P12 also gives up simple things like open loop EQ ratios and LTFT learn delays - things that newer platforms take for granted that we've never had.

Plus, I like being able to randomly make the CEL flash at Phil when we are out tuning...I don't think we can do that with a Jbody




Re: Cobalt SS PCM swap -P12 research-
Wednesday, April 17, 2013 4:30 AM
Quote:

Plus, I like being able to randomly make the CEL flash at Phil when we are out tuning...I don't think we can do that with a Jbody


Dont think you can make it flash, but you can turn it on.

I always like doing that to people to see how they are going to react.



FU Tuning



Re: Cobalt SS PCM swap -P12 research-
Wednesday, April 17, 2013 5:45 AM
oldskool wrote:

Plus, I like being able to randomly make the CEL flash at Phil when we are out tuning...I don't think we can do that with a Jbody

I dunno every light on the dash flashing and all the gauges dying on a jbody is pretty troubling, lol.



"In Oldskool we trust"
Re: Cobalt SS PCM swap -P12 research-
Wednesday, April 17, 2013 11:11 AM
Ah, yes, I meant I can turn the CEL on and off with the P12, but you can do it enough so it "flashes" lmao.



Re: Cobalt SS PCM swap -P12 research-
Wednesday, April 17, 2013 3:52 PM
oldskool wrote:

Ah, yes, I meant I can turn the CEL on and off with the P12, but you can do it enough so it "flashes" lmao.


I've done that before when I made the mistake of tuning people... it was pretty funny.

I also have forced the automatic transmission to shift into random gears while driving sometimes. that usually gets a pretty ineteresting reaction haha


but on topic, the capabilies of the P12 really has me excited to get the car wired up and running on it.






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