I was hoping someone either already had setup a VQ35HR trigger sync in EMUPro or understood it well enough that it would be trivial for them to help me figure it out…
There are lots of examples out there for a VQ35DE engine (2003-2006 350Z among others) but less so for the VQ35HR (2007-2008 350Z, and precursor to the 370Z VQ37VHR) and I’m not confident I understand this well enough to figure out how to adapt the differences…
This is the timing chart for the VQ35DE:
and this is for the VQ35HR:
The HR crank position sensor seems to use the same 3x(10+2) pattern as the DE, but with a rising edge instead of a falling edge; so I am guessing that I can just select the built in 350Z Primary pattern but set Edge to rising and this will work.
However I have no confidence I understand which secondary sensor pattern/setup to use with this (or even what it should be for the DE) beyond the fact that again it seems to use the opposite edge, with the DE using rising and the HR using falling.
The only example I’ve found is for a G4+ but the setup for the secondary sync doesn’t seem to be based on the same methodology, using TDC offsets and cam tooth counts:
For the 350Z, we recommend using a secondary trigger with the Pattern set to “Longer than factor” 3.0.
If you have a problem running this car, please record a scope file from cranking and post it here.
Ok, that would work for both the DE and the HR even though TDC is on a completely different tooth of the flywheel and alignment of the camshaft?
I guess I need to find an explanation of how the “factor” algorithm works. What little experience I have with this has always used the G4 method of specifying offsets and tooth spacing.
Let me explain the basics of our trigger and VVT systems.
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The trigger system is generic, which allows for a lot of flexibility. However, there are no full presets for a specific engine, so the primary and secondary triggers have to be configured separately.
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The primary trigger, secondary trigger (home, sync), and VVT positions can be considered separate systems configured independently (some exceptions exist).
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The primary trigger is from the crankshaft sensor and is used to calculate the crankshaft position. You have to select the pattern you are decoding and the first cylinder TDC offset.
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The secondary trigger is from the camshaft sensor and is only used to recognize the first crankshaft rotation in the cycle. You must select the pattern you are decoding and might need to swap phases to be on the power stroke.
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The VVT wizard automatically calibrates the VVT position settings, so you don’t have to do much. It can use the same sensor as a secondary trigger but has separate settings for pattern recognition.
Ok, that makes sense and is sort of what I thought; I think what threw me was the TDC Offset was buried under “Setup” and not with either the primary or secondary trigger configurations. Now that I found that I believe I just need to set it to a 40* rather than a 30* offset for the HR vs the DE to account for the extra tooth.
Or would THIS be the gap the ECU syncs off of, making the TDC offset 70*?
Upon further study of your OffSet help page, I drew the following…
Your example has a 36 tooth wheel but I’ve used yellow to highlight where the gaps in the 10+2 spacing would be. If the sync occurs on the gap I highlighted in red above, then it seems like a DE would use an offset of 80* but the HR sensor would land on the previous tooth and use an offset of 70*. Does that look correct? Do you normally recommend an 80* offset for the DE 350z ?
Also, should the secondary trigger be assigned to the Bank 1 (Pass) cam or the Bank 2 (Driver) cam sensor? I’m still trying to wrap my head around the Longer than Factor setting and which impulses it is calculating off of to line everything up.
If I use the bank 1 (pass) cam for the secondary sync, am I labeling everything correctly according to the description for “Longer than factor” ?
and then, if so, since the space between DT and PrevDT aren’t aligned should I instead configure it with a factor of 3 so it is like this with a 310* offset?
Here is an example of how the factors are calculated:
This is for bank one camshaft as a secondary trigger, with a falling edge and pattern as “Longer than factor = 3”.
A setup like that has an issue. The synchronizing edge is almost in the same spot as the first edge after the gap on the crankshaft. If the camshaft moves to the left or the right, the tooth number 0 on the crankshaft might jump around.
To solve this, we could select a rising edge to move the synchronizing edge to the right, but there is another issue.
If this is the neutral position of the camshafts and VVT can advance them compared to the crankshaft, it has to be considered for the synchronization process.
Assuming the intake can be advanced by at least 40 degrees, the synchronizing edge can move so much that it will switch the tooth zero on the crankshaft. To avoid this, you should sync on the second tooth out of the two that are close together.
This could be done with a different pattern called “Factor sequence,” where you can specify a sequence of factor values representing the sync point.
But analyzing all of this in theory is very inefficient. You should connect everything, crank the engine, and record the scope with EMU. After that you can measure distances, display factors, test patterns, and see where the ECU synchronizes in practice. If you know where the TDC is in relation to the crankshaft, you can also measure the TDC offset from tooth zero after setting up the correct sync pattern.
Thank you for the detailed explanation; this really helped fill in the gaps of my understanding. I really hate when I’m just guessing at the meaning of things.
One followup…
Is tooth zero determined to be:
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first tooth (rising or falling edge) after cam sync
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first tooth after a gap in the crank where it also aligns with cam sync
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first tooth after gap in crank when the gap is the first gap after cam sync?
I think your comment about using the second of the two close together means 3 is the correct answer (and then VVT could shift it around and as long as it didn’t push it into one of the crank gaps everything is still fine) but I want to be sure. I had been previously hung up on the idea that the cam sync and tooth zero had to be aligned but that doesn’t make sense in the context of vvt.
Also, is there any advantage in having the TDC offset be closer to tooth zero or is it all the same so long as it is accurate? And can the TDC offset be negative (-40* offset instead of 680* )
Number 3.
The first tooth, in the first gap, after the sync edge.
Correct.
There are no advantages.
The offset has to be positive.
P.S.
You can check what values are valid in the software.
If you input a value out of range, it will be clamped to the valid range.
Inputting -50 as TDC offset clamps the value to 0.
Brilliant. Thank you again, I really appreciate your patience and support.
