pid for cam overlap

[paulsmithsr]

any one have a pid for cam overlap on 2018 gt -- i log exhaust and intake cam angles
and want o know how much overlap or no overlap i have
any help would be apprecatited

[veeefour]

do a math?

[murfie]

Math that shows overlap for 15-17(should be the same as 18+), but not how much on each side of TDC, not sure if that matters to you. Not exact cam value overlap but a representation to see how it can be moved around.

Overlap.MathParameter.xml

[paulsmithsr]

i want to log overlap of cam while tuning car - i can do math just wanted it done for my while tuning

[K44]

What opens .xml files?

[murfie]

What opens .xml files?

Open scanner and press ctrl + m. This will open maths. Select a user math. Click folder(with Fx) in upper left corner and open the XML file. Then when you go to choose PID in charts/ graphs scrolling to the bottom you will see user defined and it can be selected to use. the PIDs the math uses need to be in the channel list. In this case 19053 and 19054 intake and exhaust cam angles.

(this should work for 11-14 cars as well, just keep in mind you are not looking at actual overlap but just a reference to cam movement. change 369/340 to 360's in the math if it makes you feel better about the numbers it shows)

Maths.PNG

PID user defined.PNG

[paulsmithsr]

Thanks. For info I will try

[paulsmithsr]

Ok work perfect. - changed to 360. Thanks a lot

[K44]

So how does this read. Are positive numbers overlap?

[murfie]

It's not representation of actual overlap. So 0 may not be 0 overlap. It's more about when the number moves in the positive direction overlap is increasing and vise versa. What ever the over lap is at 0 , 1 is more overlap, -1 is less.
It also doesn't represent where this over lap is offset to, more in the intake stroke or more on the exhaust stroke, just that there is a certain amount of overlap.

If you have been doing math manually, at least you should now see how you can be doing it in the scanner, and I would always be interested in what you can do with it.

[K44]

Haven't looked at it anymore than that. At least yet.

Here is a screen shot of what I see since the maths don't transfer.

[murfie]

Seeing as the base positions of the phasers are 340 and 369, the intake cam has to be above 29*, and the exhaust has to be 0 just to get to 0 "overlap". So seeing very little negative numbers other than very low load low RPM situations is going to be normal. I think MP 2 and 15 only represent no overlap. The rest of them mostly pushover lap over the intake stroke, with a few high load ones pulling it back over the exhaust stroke. You would have to know and use the base positions of the actual valve events, not the phasers to see true overlap. This is just good enough to get a picture, and like I said if using 360 makes you feel better, go for it. If you want negative number representing overlap instead of positive, reverse the intake and exhaust phaser variables in the expression.

[Grim5.0]

im finding it helps to map both IVO/EVC and then the overlap numbers calculated out. interesting the overlap similarity from several different 5.0's but using more or less evc vs ivo to achieve it at least at OP

overlap.png
ivc=evc.png

[murfie]

I pay way more attention to the compression and power stroke effective lengths, than overlap.

[veeefour]

im finding it helps to map both IVO/EVC and then the overlap numbers calculated out. interesting the overlap similarity from several different 5.0's but using more or less evc vs ivo to achieve it at least at OP

overlap.png
ivc=evc.png

I was struggling on what to do on 5.2 cross plane engine with GT350 heads that we build - quite a challenge it was.

[Grim5.0]

@veeefour that sounds like an exhausting task with out live read/write. I'd wager OEM probably uses a standalone style OS to bracket for best tq across the rpm and part throttle then puts those in as the mapped point cams.

Murfie I'm going to have to educate more on the cams. Have you settled on a formula for actual compression? Or are you just calculating the change from stock, at which point 360 or 369 or 340 wouldn't really matter for the base numbers.

[paulsmithsr]

I’m using as a reference doesn’t have to be exact just to gauge if I need more or less ivo/evc while tuning