Variable Camshaft - Optimum Power

[jddoxtator]

In the search for dragging every bit of power out of the gen2 coyote on natural aspiration I have come across the Optimum Power function of the variable camshaft tab.

This brings up a lot of questions.

First I have Enable Pedal Position and Enable % Load.

I noticed that Enable Pedal Position is set very similar to Fuel Enrichment Pedal in Power Enrichment. As in it is basically off until 6000RPM and very high throttle position.

First question is should I be changing this to mirror what I did in Fuel Enrichment Pedal, which was basically add a list of RPM ranges including rev ranges lower than 6000 RPM and range of throttle openings?

Next is Enable Load %

I assume this is a secondary condition for these tables to turn on. Intriguingly, this table only includes rev ranges BELOW 6000 RPM.

Is this an independent switch for below 6000 RPM or is it a secondary condition that also has to be met?

Lastly we have 2D maps for intake and exhaust valve closing angles.

Firstly we have a full range of RPMs from 1000 to 6000.
The numbers seem to represent additions or subtractions to the default intake opening and default exhaust closing degrees of camshaft rotation.

At low RPM this makes the intake valve open 10 degrees earlier and the exhaust valve close 5 degrees later.
Around 3000 RPM it really cranks things open at 20 degrees advance on the intake and 35 degrees of retard on the exhaust valve closing. Makes sense as this should be the area of the RPM range where we are expecting maximum VE on a full throttle pull.
By 6000 RPM we have really closed down the intake with 20 degree retard on intake opening and exhaust valve close time shortens a bit to 18 degrees retard. This also makes sense as VE has less time to reach capacity at high RPM.

This seems to closely follow the logic of maximum VE loading around mid range RPM so all checks out here.

So my only real question is how do I activate this cam timing and taker advantage of it properly?

Seems pedal position with a full rev range would be a good start. But i'm not 100% sure what Enable % load should be set to.

If I were to guess, i could use throttle position as my load and just match the number I use in Pedal Position as they are both in percentage form.

The goal is to turn this on Optimum Power when Power Enrichment turns on.

Edit:
cloned map from Power Enrichment Pedal to Enable Pedal Position and set Enable % load values to 69% at low RPM end and 35% at the high RPM end. Enable % Hyst. set at -5% values.

I choose 35% load as the max because most other economy and drive ability maps end around 29.9 kPa which would be about 30% load of a naturally aspirated setup. So to avoid table conflicts I am enabling at the high RPM at 35% and disabling at 30%.

Will test this for a while and see how it goes. Seems happy at idle so far.

[veeefour]

Ideally you should not use OP at all just like stock +21 calibrations do - entire VCT band is controlled with MP's, never entering OP.
Your MP angles should match OP angles - I see people modify OP VCT to gain something(wrong) N/A and MP's has to jump from
30 IVO to 10 IVO at high rpm...and it results in car not keeping up and jumping back and forth.

OP tables should have at least 20 increment to use it properly...10-11 is not enough.

Lowering OP entering point to 70% APP is what most people would do. This is what they teach you here...realized that is wrong some time ago.
You have almost perfect resolution STOCK...you can only make it worse and hide other problems by lowering it to 70% ish.
I did that too in the past. This is probably the biggest band ever sold here...second would be to spent days on calculating Torque Model...

[jddoxtator]

I get what you are saying. Basically, switching from Map point VCT to OP VCT can cause lurching in the overlap that it occurs in.

My thought on that would be, would it not make sense to then switch to these maps lower in the rev range and load range where the delta will be smaller and smoother? The valve maps do go all the way down to 1000 RPM.

I get that directly tuning the map points would be ideal, however this also changes every other aspect of the vehicles base point for other characteristics.

I'd much rather have a performance cam timing only come on when I am requesting it like in power enrichment mode. I figure by running Base Lambda a little richer than stock 0.95, we can mitigate some of the leanness in the transition.

Also would a sufficient hysteresis not take care of the lurching back and forth across the engage point?

Edit: Also, I am not entirely sure what angle VCT maps are pointing to as they use ft/lb and nm as table values. maybe that means something to experienced tuners, but I have no idea how to convert torque to VCT degree's.

[engineermike]

Jddoxtator, have you confirmed through logging that it?s not already entering VCT schedule OP? I believe you will find that it already is using OP. Disabling the mapped point OP, as gen2 and gen3 are from the OEM, simply means it wont use the spark, torque, and sd data in the Mapped Point OP table, but it still uses OP cam timing angles.

Secondly, at least on some strategies (maybe all), it has to achieve BOTH the load AND the pedal position thresholds for it to enter VCT OP. So, if your goal is for PE and OP to enable at the same time, you could set the load threshold to all 0s and set the pedal threshold to match the PE pedal threshold. Not sure if you are aware, but you can change the axis to match as well.

And finally, the OP cam timing tables are not additions and subtractions to a default. These are the actual cam positions commanded. -20 means 20 deg advance from the 0/lock/neutral angle.

As far as the rationale behind the intake cam angle goes, in the mid-range you don?t have a lot of help from ram tuning so you close the intake valve early (max negative ivc) to trap compression and prevent reversion. At high rpm, Ram tuning gets going so you want to delay ivc because the cylinder is still filling as the piston rises on the compression stroke. The goal is to maximize ve at all rpm. Evc isn?t very influential most of the time and can be locked in to around 15, maybe advancing a few deg up top.

[jddoxtator]

Far as i am aware, there is no spark, torque or SD data that is a part of the VCT Optimum Power conditions. Every option in the table seems to reflect that it only affects Valve timing variables side of the equation. Obviously the change in VE speed density calculation changes the other maps, but it doesn't set specific number for those maps according to what I am seeing in the options for VCT Optimum Power. Maybe something unique to early 2015 models? This is an F150 by the way not a mustang.

Good to know that both conditions have to be met. Yes I basically match the load axis and pedal positions, with Power Enrichment maybe happening just a little before Optimum Power by about 5-10%. Not sure that throttle position directly translates to load, but should be close.

Are you sure the cam timing tables in Optimum Power are not additions and subtraction to the default cam opening positions? Its the only way the numbers in the table make any sense. Otherwise in Optimum Power we are actually opening the intake valve 10 degrees after TDC in low rev ranges and 20 degrees after TDC mid rev range. That seems like a recipe for absolutely zero power not optimum power. Stock Intake OP table looks like this:

RPM
1000 -10.00
2000 -10.00
2250 -10.00
2500 -5.00
2750 -5.00
3000 -20.00
3500 -20.00
4000 -8.00
4500 -6.00
5500 10.00
6000 20.00

As you can see, these values would not make any power if they are referencing TDC. That's not how you want valves to work. As a negative number would retard timing and a positive would advance if referencing TDC. However, if we take the stock Intake Camshaft - Intake Valve Opening 340.00 that is on the same tab page and apply those number to this. The table numbers actually make sense. In Intake Valve Opening i am assuming 360.00 would be TDC of the intake stroke.

Reversion won't be a problem here as there is no MAF sensor, just a MAP. Also, no Ram scoop on this vehicle. Just a cold air intake. I thought the goal was to open the intake valve earlier at low RPM to allow the vacuum created by the exhaust speed to start pulling in intake port gases earlier in the intake stroke, maximizing this at mid RPM where the Volumetric Efficiency of the engine is at it's max and then closing it down near high RPM to, as you suggested, trap the compression better and deal with shorter windows of operation due to high RPM?

[engineermike]

jddoxtator, if the OP mapped point is enabled and it switches to VCT Schedule OP, it most certainly will use the spark, torque, and SD tables associated with Mapped Point OP. Look under Mapped Point Configuration at the very bottom one. Does Mapped Point OP not exist in your strategy? I'm looking at a 2016 mustang cal and it's there.

The OP cam timing tables are definitely not additions and subtractions. Log VCT schedule and your cam timing numbers and you'll see they match the raw value when in OP. Your signs are switched, though. -20 means advance and +15 means retard from the neutral/lock position. 340 means IVO at cam angle 0 is 340 ATDC (combustion) or 20 deg BTDC (overlap). So -20 means IVO is 40 deg BTDC.

When I say reversion, I mean air reversing in the intake port due to late IVC at low rpm. When I say ram tuning, I'm talking about the manifold runner dynamics not ram-air.

[Plimmer]

You need to log "VCT Schedule Mode" to see if it says Optimum Power, then you know it will use the OP cam timing tables. For timing it will always use the mapped point you are in.
FYI it will only enter Optimum Power cam timing mode when the "Calculated Engine Load" (don't look at air load or absolute load) is above the set point in the table

[jddoxtator]

Oh, ok I see what you are saying now.

The mapped point labeled OP in the Mapped points configuration table.

That makes sense now. So if this isn't on, entering OP through conditions essentially does nothing or is ignored then.

Work to be done....

[engineermike]

No, entering OP doesn't "do nothing". When in OP it is using the OP cam timing schedule you referred to earlier. It just doesn't use any of the calibration data associated with Mapped Point OP. You can command any mapped point or OP cam timing you want to and the cams will go there, whether the Mapped Point is disabled or enabled. Enabling a Mapped Point just turns on the torque, spark, and SD data associated with that Mapped Point. When yours goes into VCT schedule OP, it follows the cam angles specified in the OP table, but uses calibration data (torque, spark, and SD) from a weighted average of the surrounding enabled Mapped Points (unless it hits a snap line or point).

[jddoxtator]

So enabling the OP maps will associate with OP or will it still just use the weighted average of the points?

Edit: just tried with OP maps enabled and she peeled 33" beadlock mudders for a good 10 feet. This is all very good information. I thank you by the way. i know i can be a bit abrasive some times.

[engineermike]

If you log mapped point weight, you should see 100% op if you enable the op mapped point, and it will use sd, spark, and torque data exclusively from the op mapped point. Just be careful because I don’t know how much effort ford put into calibrating the op mapped point they aren’t using. Most people just calibrate the various other surrounding points and leave op disabled. Personally I like to set mine up to use only 2 mapped points and a snap line in op mode, like Roush does and gt500 to a lesser extent.

[jddoxtator]

Alright, i have a course to watch with a worked example of mapped points. Sounds like I should spend some time studying that and take notes.

Also running 93 octane and it's winter, so i should have some relative safety especially considering power enrichment is turning on first.

[K44]

Mike, can you post a roush tune that only uses 2 points. All the tunes I have use 7.

Thanks.

[engineermike]

The gen3 phase 2 has 6 points enabled but only uses mp4 and 5 in OP. The gt500 is very similar and only uses 3 mapped points in op, but only 2 at a time using snap lines.

[veeefour]

Far as i am aware, there is no spark, torque or SD data that is a part of the VCT Optimum Power conditions. Every option in the table seems to reflect that it only affects Valve timing variables side of the equation. Obviously the change in VE speed density calculation changes the other maps, but it doesn't set specific number for those maps according to what I am seeing in the options for VCT Optimum Power. Maybe something unique to early 2015 models? This is an F150 by the way not a mustang.

Good to know that both conditions have to be met. Yes I basically match the load axis and pedal positions, with Power Enrichment maybe happening just a little before Optimum Power by about 5-10%. Not sure that throttle position directly translates to load, but should be close.

Are you sure the cam timing tables in Optimum Power are not additions and subtraction to the default cam opening positions? Its the only way the numbers in the table make any sense. Otherwise in Optimum Power we are actually opening the intake valve 10 degrees after TDC in low rev ranges and 20 degrees after TDC mid rev range. That seems like a recipe for absolutely zero power not optimum power. Stock Intake OP table looks like this:

RPM
1000 -10.00
2000 -10.00
2250 -10.00
2500 -5.00
2750 -5.00
3000 -20.00
3500 -20.00
4000 -8.00
4500 -6.00
5500 10.00
6000 20.00

As you can see, these values would not make any power if they are referencing TDC. That's not how you want valves to work. As a negative number would retard timing and a positive would advance if referencing TDC. However, if we take the stock Intake Camshaft - Intake Valve Opening 340.00 that is on the same tab page and apply those number to this. The table numbers actually make sense. In Intake Valve Opening i am assuming 360.00 would be TDC of the intake stroke.

Reversion won't be a problem here as there is no MAF sensor, just a MAP. Also, no Ram scoop on this vehicle. Just a cold air intake. I thought the goal was to open the intake valve earlier at low RPM to allow the vacuum created by the exhaust speed to start pulling in intake port gases earlier in the intake stroke, maximizing this at mid RPM where the Volumetric Efficiency of the engine is at it's max and then closing it down near high RPM to, as you suggested, trap the compression better and deal with shorter windows of operation due to high RPM?

OP mapped point was used in S197 and they stopped using it form S550 - not sure why. They took a different approach I presume.

[Plimmer]

If he has an 2015 up S550 it won't go into Mapped Point OP, only the cam will show VCT Schedule OP.