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How does pcm retard spark per psi of boost ?


Plumbs
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Hi all , just first time on the forum . Bit of back ground . I’m a plumber. I own a Gt Xy rep, a F6 310 600 rwhp e85 tuned by forced and I built from scratch a turbo b series for my wife’s 2005 Territory Ghia . Base tune also done by the Barra guru Jami at forced as well went 320 rwhp on 6 psi 98 . 

learning to tune my own cars via pcm is something I would love to crack . Just looking at the demo . It seems there are multiple layers in the Ford pcm and just don’t explain themselves too easy. 
 

And , no I don’t want you to tell me how to tune my car as that’s what Forced performance are for . But just point me in the right direction please?

I understand that the Ford pcm ( if I’m correct?) is all based on torque . So for me I think this is where the black magic starts .

ok specific question. In the demo , how does the pcm pull spark for psi of boost ? 
Will leave my first question at that for now . Regards Graham.

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41 minutes ago, Puffwagon said:

This involves telling you how to tune the pcm so I'm not sure you want the answer 😉

Here is some more info.  Long story short you change the numbers in the borderline knock table and it will change the spark values...most of the time.

Thanks Puffwagon, so am I in the right area of fo 218 spark blk adder to adjust for lambda ? 
is the crank angle on the left -5 is decreasing bdtc timing from borderline knock ? Eg if I lift the lambda number that would increase timing say 3000 rpm up on boost ? 
it looks like the pcm doesn’t use boost pressure to pull timing but throttle pos and torque load and lambda? .

this stuff is very interesting!! 

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They are spark correction tables, not the borderline knock table. I'm on mobile and don't know the table number off the top of my head.

You are right in assuming that the final timing will change if you change the lambda in the base fuel table, due to the spark lambda correction table.

Yeah it calculates a load value based off a whole bunch of stuff including pedal position which gives the correct spark and fuel requirements, providing it is tuned correctly to start with.

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Ok reading what Roland sent me auf16593 is where it’s at .

what is the load units measure ? Volumetric efficiency? so does anything above one mean boost ? 
Is the timing run of the camshaft degrees or bdtc of the crank ? Eg what’s the camshaft degree have to do with timing? Speed density and charge intake ? 
Am I asking the right question lol? Regards Graham.

 

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Edited by Plumbs
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11 hours ago, Roland@pcmtec said:

This tells you exactly how the spark is calculated

https://forum.pcmtec.com/topic/77-info-ford-spark/

That's the link I posted in my first reply 😉 

To the OP; Here is another link that should answer most of the questions in the previous post.

Have a read through the forum and you might find your questions answered before you ask them.

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  • 2 weeks later...
On 7/4/2021 at 10:03 AM, Puffwagon said:

That's the link I posted in my first reply 😉 

To the OP; Here is another link that should answer most of the questions in the previous post.

Have a read through the forum and you might find your questions answered before you ask them.

Hi , thanks heaps . Have successfully tuned car to 11 psi full duty cycle . Afr’s look good and light cruise at 80-100 km getting 17-18 to 1 . 11:1 under full throttle and boost . 
gone conservative on timing till I get my tuner nerd knock monitor, which is on its way . 
My wife’s shopping trolley is an absolute weapon ! Very happy and very quick ! Quick enough for what we use it for ! 
borderline knock advice was excellent!

No doubt, many more questions to come ! 
regards Graham. 

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