LHU (a20nft) cams timing

Hi everybody! :hi:
My name is Evgeny, and i am from Russia (sorry for my bad English).
So, i have a nice car Opel Astra J OPC with a20nft engine and we made some modifications with this car.
Spec list:
ZFR7163 turbo
ZZP Connecting rods
ZZP stage 2 cams
ZZP #82 valve springs
Wiseco 86.5 pistons
Deleted Balance Shafts
f40 transmission
Bryce_eng aluminium flywheel and clutch for 650nm+ of torque
Front mount evo9 intercooler, 2.5" piping
89mm custom Maf housing (84mm inside diametr)
3" exhaust.
Cortex ebc boost controller
LPFP DW300C with externaf fuel filter.
fuel ron100
Fully rebuild head and block
Opel injectors (stock), stock HPFP,
AEM X-Series OBDII Wideband UEGO

Here is some photos:

https://a.d-cd.net/FwAAAgFSjuA-960.jpg

https://a.d-cd.net/csAAAgNSjuA-960.jpg

Here is the result on stock cams and valve springs:

https://a.d-cd.net/wSAAAgIyjuA-1920.jpg

As you can see torque curve drops down at high RPM. To achieve more torque at high RPM ZZP stage 2 cams and #84 valve springs has been installed. We asked ZZP to send us calibrations for the camshafts, and they sent it to us (of course, not for free).
Finlay we made some dyno tests,made some calibrations and here is what we got:

https://a.d-cd.net/bEAAAgFKA-A-1920.jpg

After we got such a bad result, I decided to understand in more detail what the numbers on cam position map mean.
Astra J opc stock Intake Cam Position and exhaust cam position maps (e39a)

https://a.d-cd.net/hEAAAgFKA-A-1920.jpg

The map contains only positive values. The minimum value is 1 degree, the maximum is 25 degrees.
Based on the data in this article: https://pages.mtu.edu/~mahdish/Docs/..._MScThesis.pdf the maximum angle of rotation of the phaser is 50 degrees (angle of rotation of the crankshaft). As we know, the camshaft rotates 2 times slower than the crankshaft, therefore it can be assumed that the angles of rotation of the phaser at camshaft degrees are indicated in the map.

Cams phasing is all about overlap and back pressure (turbo engines). To find out the overlap values we need to know the valve opening and closing timings in crank angle degrees, and lobe profiles. Intake and exhaust valve profiles for park position and completely phased position and Valve timing diagram for the stock GM Ecotec LHU engine (https://pages.mtu.edu/~mahdish/Docs/...ScThesis.pdf):

https://a.d-cd.net/DBAAAgEqA-A-960.jpg

https://a.d-cd.net/cgAAAgMqA-A-1920.jpg

However, one important question remained. What value corresponds to the parking position of the phaser? 0 or 25? It is known that at high boost values and high revs it is necessary to reduce the overlap to reduce the back pressure. If this is true, then in the stock map, at high loads and revolutions, the overlap should decrease (the phaser tends to the parking position). If my assumption is correct, then 0 is the parking position of the phaser, and 25 is completely phased position. Am I right or not?
If i am right then look at the maps by ZZP:

https://a.d-cd.net/0EAAAgFKA-A-1920.jpg

ZZP increased overlap at high loads and revs for St2 cams. For a better understanding, I approximately drew stage 2 cam profiles for stock and for ZZP maps (High load and rpm):

https://a.d-cd.net/tkAAAgMqA-A-1920.jpg

large overlap...

So, before we start real testing i wold like to find out the correct direction. What value corresponds to the parking position of the phaser? 0 or 25? Or completely different?

i dont know what the park values are but the ignition map advances when numbers increase + and the exhaust cam retards when numbers increase +. Move positive will induce more overlap. If you already knew this then apologies.

When you assembled the motor did you verify piston to valve clearance at the min and max of phaser travel? if you know your setup is non-interference then you can just change the numbers on the cam table while watching the cam position and see where the cam sensor stops reporting a shift in position for a change in table value. thats how we figured the 2.0 lnf stuff on the e69 ecu.

Quote:

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i dont know what the park values are but the ignition map advances when numbers increase + and the exhaust cam retards when numbers increase +. Move positive will induce more overlap. If you already knew this then apologies.

When you assembled the motor did you verify piston to valve clearance at the min and max of phaser travel? if you know your setup is non-interference then you can just change the numbers on the cam table while watching the cam position and see where the cam sensor stops reporting a shift in position for a change in table value. thats how we figured the 2.0 lnf stuff on the e69 ecu.

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Ignition timing advance refers to the number of degrees bTDC. If exhaust cam retards when numbers increase, then completely phased position for exhaust mean max retard (Moved closer to TDC). If so, then I was right.
We didn't verify piston to valve clearance with stage 2 cams.
For stock cams:
https://a.d-cd.net/0AAAAgJuA-A-960.jpg

Cam phasing does not follow the same nomenclature as ignition timing advance.

I think most of the things you said are correct.
The cams parked are exhaust cam fully advanced, intake cam fully retarded (least overlap).
in VCM editor, the values are in cam degrees, 0 is parked 25 is fully actuated (think of it with respect to the cam phaser actuator if that helps any)

The one thing that that we differ on, is the statement that less overlap should help at high RPM high load, that is not necessarily true.
The physics of it are much more complicated than that, think of it in terms of "air inertia" if that helps. There are a few rules of thumb that may help, but for an engine as modified as yours, i think the best thing would be find the right answer on a dyno. Personally i would start with the stock tables and phase each cam a few degrees in each direction individually, and see what helps. The physics of it are so complicated don't make assumptions that you know which direction will be "better". Don't be afraid of overlap, you can make plenty of power with a lot of overlap in turbo applications (in the right turbo operating range).

The one rule of thumb that seems to hold true for me, is that advancing the intake cam (more overlap) tends to make better power. Of course if you go too far and get charge dilution and make less power.

So, we performed some road tests.
1) Intake 14 deg, exhaust 9 deg. (from 4800 rpm)
https://a.d-cd.net/9wAAAgJLQ-A-1920.jpg

2) Intake 7 deg, exhaust 7 deg. (from 4800 rpm)
https://a.d-cd.net/fwAAAgJLQ-A-1920.jpg

Speed in kph.
More info after dyno tests.

Wow thanks for taking the time to do this and post about it.
Very much appreciated !

Quote:

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Originally Posted by ZeroBoostBuick

Wow thanks for taking the time to do this and post about it.
Very much appreciated !

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I'll try to give much more complicated info about cams timing later.

some offtop
My car)
https://a.d-cd.net/SEAAAgM0XeA-960.jpg

https://a.d-cd.net/1JAAAgC2w-A-960.jpg

Hey buddy,
I know this is a 2 year old question, but you also need to change cam values in Airflow- variable camshaft- WOT desired angle . If not once your cylinder fill goes over about 80% you are reverting back to stock values.