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HOWTO: Ghost Cam and VCT simplification

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We are developing a guide to set up a ghost cam on a BF/FG. This involves understanding how the VCT system in the falcon works.

NOTE. This is NOT emissions compliant. This cannot be done on a road car, it must be for vehicles that are used on a racetrack or a powercruise event etc. This is the same as using aftermarket cam shafts. The unburnt fuel will not be cleaned up by the catalytic converter and you will be releasing high levels of carbon monoxide (NOx should be quite low as it is running rich, not lean). Do not leave your car idling in a shed with poor ventilation. E85 is much safer than Petrol however it is still not recommended to breath in the gasses.

Firstly the VCT works by the PCM calculating an intake camshaft position, it then adds the calculated overlap angle to this position to calculate the position of the exhaust cam.

Eg:

VCT_Intake_Cam = Calculated Intake position

VCT_Exhaust_Cam = VCT_Intake_Cam + Overlap_Angle.

Finally to confuse things the PCM then adds/subtracts from the intake and exhaust cam based on boost error. Note this in only in the FGs. This will not affect idle however it will affect your vehicles performance depending on how you have set up the boost control.

image.png.c26dc6288ce83187755edaac02d5f5ad.png

To achieve a ghost cam we need to understand how the overlap angle is calculated. 

There are 3 modes of VCT operation

cam source == 4 is Idle mode

cam source == 99 is VCT  Fault/Not Installed mode

Cam source == 3 is power/full throttle mode

cam source == 2 is part throttle mode.

Now in idle mode the camshaft overlap is capped by the same table that determines the intake camshaft position, so you cannot achieve any overlap, the best you can do is set both the intake and exhaust camshaft to 50 degrees which will give you some lump.

An easy solution to this problem is to force the PCM into cam source == 3 at all times. This means the main VCT tables are used at all times making tuning the vehicle much easier.

To force the camshaft to use the main maps at all times simply set these scalars out of range to -1000 rpm.

auF1079 (VCT Closed throttle disable RPM) set to -1000

auF1035 VCT Closed throttle enable RPM) set to -1000

Now to get a ghost cam the following tables need to be modified

auF0115 (BF/FG)

Maximum allowed overlap angle based on RPM and Oil Temp. Set the lower half of this table to 80 degrees

image.png.4450023c1d582419687b06db8f04e904.png

Now we can change the commanded overlap at idle via auF16492 (BF) auF0116 (FG)

image.png.2e6f724cccbfd45032bddc9f5b0f3cd5.png

Here you can see I have commanded 35 degrees of overlap at a TPS reading of 5, this means as soon as you touch the throttle the cam timing goes back to stock making car parks and low load no problem.

You also need to modify auF16503 and auF0115 to have similar timing values in the low load/low tps cells. In this example I set 600 rpm to -30 deg to stop the vehicle from stalling, this will also increase the lope when the rpm drops low as the decreased overlap will kick the rpm back up again.

image.png.7c6192d72e3f06c36c303d5e8ba3b69f.png

image.png.2faddbaea004e56e099f7ab6dc22fafa.png

I changed auF0494 (BF) auF16487 (FG) (TPS) axis to 5 in the lowest cell, this means you keep the commanded overlap when hot/cold.

Finally I suggest increasing your idle rpm to 1000 rpm to avoid stalling. 

In the FG there is an overlap adder for speed density auF2260. You will need to put smaller values in the 30 and 60 degree overlap cells. This will clean up the idle fuel trims

image.png.e92bb854d7951f449840620f678efb7e.png

Beware that if you command too much overlap you will foul your plugs and the car will misfire until they clean up. 35 degrees is quite a lot and I would only recommend this as gimmick not in a daily driven car.

Here is a video of what the above settings will sound like.

As you can see low speed reversing etc is not a problem.

Edit: This is possible to do on a BA if you use HAAT3VC or possibly HAAT2xx as these are the late model FPV BAs that had independent cam control.

Edit 2: You can increase the lope quite dramatically by modifying this table. This is the proportional gain of the idle spark feedback algorithm. By increasing it to 5000 it will toggle between min spark (-7) and max spark (MBT ~25 deg) causing even more lope.

image.png.285ca8aae93967acba3f81251a284226.png

If you are using the multi tune to do ghost cam you can add the following table to the ghost cam tune to increase your idle rpm, this means the non ghost cam tunes can retain a completely stock idle rpm.

image.png.a69e36d71b636e64799743651dcd1b40.png

Here is an example of the required tables in a BF to add ghost cam to to tune 4 only if utilising the multi tune functionality.

image.png.1b85fea0115ea891d2026ed6185d4af8.png

 

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If you have stock cams providing you don't you don't touch the tables such as "Expected position of cam hardstop" you will be fine. If you change these tables you run the risk of hitting the physical interlocks to stop the cams from causing valve piston interference.

If you run aftermarket cams and extend the overlap even further again (no one would do this) via the VCT system there is a possibility of valves making love to the pistons depending on the cam design.

The only other risk is fouling your plugs if you leave it idling lumpy for a long time without your air fuel/spark being correct. However that is no different to running actual cams

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ok, i understand.

i drive in traffic quite a lot to and from work, do you think that fouling the plugs would be an issue with the ghost cam tune?

i have the FG mkii XR6 na.

cheers, Steve

 

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Depends how much overlap you command and how much idling you do. Just tweak it until it drives how you want. Take your laptop with you, you can always adjust it.

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hi i must be missing something, probably knowledge lol

i can't locate any auf**** scalars.

i have searched for them but it doesn't find any of the ones mentioned

what should i be doing?

thx, steve

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1 hour ago, Roland@pcmtec said:

Send us an email with your file and the specific scalars you can't find, or if you are happy to share publicly you can post it here as an attachment.

actually it's the tables mentioned above that i can't find. Does it matter that the tune is a Herrod/Sct tune?

cheers

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19 minutes ago, fordsrule said:

actually it's the tables mentioned above that i can't find. Does it matter that the tune is a Herrod/Sct tune?

cheers

Are you using the Pro version of the software?

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1 hour ago, Roland@pcmtec said:

Is it a BF/FG XR6 Turbo? Do you have all the view levels enabled via View -> PCM -> Workshop etc?

it's an FG na

i'll look into the Views

thanks for your help

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23 minutes ago, Roland@pcmtec said:

What strategy? it may have different parameter numbers in the NA.

this is a shot of the screen, the strategy name isn't right?

 

WP_20180806_17_10_02_Pro.jpg

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3 minutes ago, fordsrule said:

this is a shot of the screen, the strategy name isn't right?

 

WP_20180806_17_10_02_Pro.jpg

ok, it looks like there might have been a setting in the Views list that was stopping it, i can find the tables now

thankyou so much

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Was mucking around with these settings, seems to give some lump but then it smoothes out, then comes back, then smoothes out etc. Is there other tables that should be fine tuned also?

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On ‎8‎/‎6‎/‎2018 at 5:19 PM, fordsrule said:

ok, it looks like there might have been a setting in the Views list that was stopping it, i can find the tables now

thankyou so much

Hi, the image below is from my tune, as you can see it differs from the example you posted in your guide. My query is which line do I change to match your example as I have more lines?

Thanks, Steve

my auf16487.PNG

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On 8/6/2018 at 4:49 PM, fordsrule said:

this is a shot of the screen, the strategy name isn't right?

That is because your car has been previously tuned with SCT. 

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6 minutes ago, Roland@pcmtec said:

That is because your car has been previously tuned with SCT. 

That would be right, but can you help me with which lines do I change?

Your example says the last two, but mine are different

thanks

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9 minutes ago, Roland@pcmtec said:

You can do whatever you want there. Experiment and see what works best. 

Oh, ok lol.

I'll give it a go then

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On 8/25/2018 at 5:49 PM, Roland@pcmtec said:

You can do whatever you want there. Experiment and see what works best. 

I have no idea what to do with that table as mine had been tuned with SCT. It has more rows than what you showed from your BF table. Can you give me a little more details please?

Just want a little "tiny" rattle from ghost cam ? Very tiny bit

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It is the TPS vs cam angle. So it depends what TPS angle you are seeing at idle as to what you need.

Eg if you set the low TPS cells to a high overlap but when you flick he AC on it the TPS increases it will drop you out of that cell. So you need to experiment and see.

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Just touching base on this, has anyone fine tuned their ghost cam settings and willing to show what they have found works best for drivability too? Mine tends to want to drop idle rpm too much coming back into the overlap cells, even with idle speed set higher

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I will double check in the morning.

 

Even with 35deg overlap, i barely get much lump, would running e85 have an effect on this? The effects were a lot more noticable on 98, on e85, same settings seems to just "stumble" rather than have a lump. Maybe the fuel trims are off

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With stock cam adder values, around -10. Lowering the numbers for 35 and 60 degree overlap brings it down to about 8, but cant lower it further, and thats lowering them from 1 to 0.5

Edited by richardpalinkas

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On 7/31/2018 at 2:23 PM, Roland@pcmtec said:

 

Now in idle mode the camshaft overlap is capped by the same table that determines the intake camshaft position, so you cannot achieve any overlap, the best you can do is set both the intake and exhaust camshaft to 50 degrees which will give you some lump.

 

What tables/ scalers need to be changed to achieve this method?

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Got all the fueling sorted. Sounds good in park/ neutral but driving still has the issue of overshooting below idle rpm, sometimes stalling. Ive tried gradually reducing the cam angle so its not as sudden, which doesnt make too much difference. Is there more parameters that nees to be adjusted such as idle airflow or spark timing at idle to help it not overshoot? 

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13 minutes ago, richardpalinkas said:

Got all the fueling sorted. Sounds good in park/ neutral but driving still has the issue of overshooting below idle rpm, sometimes stalling. Ive tried gradually reducing the cam angle so its not as sudden, which doesnt make too much difference. Is there more parameters that nees to be adjusted such as idle airflow or spark timing at idle to help it not overshoot? 

Definitely recommend setting the idle rpm higher and also more airflow at idle. If you raise the airflow to get the idle timing lower (eg 5 degrees ish) then you have more timing reserve to catch the fall. If you are already idling at 20 degrees the PCM can't respond quick enough to catch it. Timing cause the idle to jump almost immediately, more idle air has a small lag delay and can oscillate.

I also recommend leaving the oil temp table fairly standard, that way when the car is cold it won't have the lumpy idle.

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On 11/25/2018 at 7:44 AM, fordsrule said:

Well finally got around to flashing the ghost tune, didn't blow anything up so that"s good lol

Sounds like it is misfiring. How much overlap is that?

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1 hour ago, Roland@pcmtec said:

Sounds like it is misfiring. How much overlap is that?

As per auF2260, but i have read it again and you say to reduce the values there so there is no misfire, i will have to make that adjustment.

But the idle did change to more of a lump just after the end of that video

Cheers

 

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Hi Team,

New member to PCMTECH & tuning of such ECU's.

I took the time to read through the ghost cam scenrio, got to work, great..after the 1st run got over it, sounds good though..lol...one thing i didnt find as a scalar is auF2260 i dont seem to find this. Car is a 2013 FG XR6 MK2 turbo following strategy  HAEK4MF.HEX / BBMF

Is this missing on such stargey?

running PCMtech version 0.74.

regards

Abs

FG-MK2-XR6-TRBO-GhostCam&Overboost-16-12-18.tec

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You need professional or workshop to see the cam overlap adders (auF2260). You can upgrade to professional for the difference in price (there is a product you can purchase online for the upgrade).

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