Variable Valve Timing and oil pressure

[Jeff.C]

Got thinking about something and thought cam timing is essential to this engine's peak performance since variable timing gives performance levels in the best of both worlds.
especially when tuning past stock parameters you can compensate to build a power level that is broad at all RPMs.

Thinking there are 24 degrees total to work with, and in the cruise throttle position ( The valve timing is ECU controlled by throttle postion ??) so at cruise, it is around 1-6 degrees.
Would think oil type, running-oil quality, and oil pressure play into it for peak performance by not reaching its full articulation, not starting a thread on what brand of oil you have been using ( don't care ) one other thing does exhaust type * (header) and muffler effect and play into cam timing for all-around performance.

 

[Murph]

You know...I kinda get the theory of how the VVT works on these things, but to be honest i have never really studied it out..how does it retain a certain position, somewhere between full advanced or fully retarded ...

does exhaust type * (header) and muffler effect and play into cam timing for all-around performance.

I'm not exactly sure what you are asking..

...but I'm slow...

 

[Murph]

.. if I remember correctly, once the rpm hits 5k the cvv unit is done, the cam remains in that position

"weak" ( wore down oil) allowing some bouncing around in that position...could be

as far as the rest it would be an arm pit guess for me...not sure how much choice you have on headers and such...I think yer experience in this stuff
is way beyond what I could offer in help..... and whats the goal? Sleeper street bike or gangster full on drag racer?...if your cam is bouncing timing 10 or 15 degrees ...Id say we have to fix that first.....

...what kinda cup holder you putting on it?
..

 

[Fred H.]

Oil pressure fluctuations could indeed impact VVT operation, but I don't see any direct coorelation to exhaust back pressure that would impact the VVT. However exhaust valve timing might(?) be optimized for a specific pipe/back pressure, though the VVT only impacts intake timing, but that might by default impact the exaust flow(?). Many years back Don Guhl and I contemplated playing with the VVT tables in the ECU but we never got past just talking about it. I think they are simply based on throttle angle and engine RPM, but there might be other parameters involved. I could probably find out if you need to know.

 

[Ivan_ipp]

Valve timing directly affects trapping efficiency as does exhaust design... (resonance)
The sooner the intake valve closes, the less chance there is of the charge getting pushed out the intake by strong resonance pulses reflected by the exhaust at lower rpms during valve overlap when time/area is highest. This increases trapping efficiency... as rpms increase and time/area decreases, it becomes beneficial to increase valve overlap to keep the power building as rpms climb.

When you look at the stock VVT table, it's pretty clear that Kawasaki used this (along with many other things) to detune this bike in most areas except very large throttle openings, but they did not allow it to make full power at high rpms either.
There are other VVT controls besides the main table shown here. (which I choose not to share here) The main table shows the most relevant part of the discussion anyway.

Here's a dyno comparison of 2 extremely similar designed exhausts... one with crossover tubes on the header tubes and one without. Both headers are nearly identical in every way besides the crossover tubes. One was designed for this bike, and the other for a ZX14.
AP header uses 44mm tapered headers and Arata uses 43mm tapered headers... collector lengths and diameters are also nearly identical.

Crossover tubes are a way to weaken strong resonance in an rpm range (depending on their location and diameter) in order to improve trapping efficiency. But, just as most things in life are a compromise, there are always tradeoffs, so as one area is improved, it will affect another area.
As is shown in the charts.

The point of a well designed exhaust is to trap the charge best in the rpm ranges that you use the most... and what the pipe designers had in mind when putting their offerings to market. Use a well designed exhaust for the rpm range that you use the most when riding your machine.

AP chose to keep the better efficiency below 4500 rpm as this is a more often used rpm range on the C14 than the 4500-6000 rpm range that is more commonly used on a ZX14 with it's shorter gearing.


Ivan

 

[Ivan_ipp]

Arata ZX14 pipe has no provision for the centerstand on this bike.
Construction is 100% titanium.

Ivan

 

[Murph]

I'm not up on this stuff at all so bear with me.....does the ECM "know" the position of the VVC, or is it looking at other data and deducing the valve timing? There is no sensor to tell the ecm the cam position?

Murph

 

[fastenova]

I'm not up on this stuff at all so bear with me.....does the ECM "know" the position of the VVC, or is it looking at other data and deducing the valve timing? There is no sensor to tell the ecm the cam position?

Murph

Since there are camshaft position sensors on both cams, and we can assume that the ECU thinks the timing between crank and cam is static (not skipped a tooth or stretched), it could definitely tell the position of the cams relative to the crank, so it should be a closed loop system on the VVT module...

Whether Kawi does anything with that besides throw a code if the intake cam timing does not match the "commanded" value based on the VVT solenoid, I do not know, but it definitely could tell whether the VVT system is working based on sensor readings.

 

[Murph]

Fast..

Thanks, I was running off memory and wasn't sure if there was two cam position sensors, it only makes sense

 

[Konehead34]

Interesting stuff boys, guess i should have taken auto shop back in high school instead of home ec. But the girls were better looking in home ec....wink, wink, nudge, nudge..

 

[Murph]

instead of home ec

Kone...its ok to be in touch with your feminine side.....really......




I took home ec too.......smoking hot teacher right out of college...
..so we were what....two years apart.


Now....back to the subject at hand,,,thesse boys are heavy hitters, I'm pulling up my chair and taking notes...

 

[laker9142]

Like Ivan said, once you decide which rpm range you want to tune for you can pick your pipe and tune to it. I believe you're wanting to get a mostly stock concours into the 9s so you'll be running wot and high rpm. With that said, vvt doesn't do much for you because vvt is aimed at lower rpm grunt. EXCEPT that you can use the vvt (off lable) to act as a slotted intake sprocket. Start at stock value above 7500 rpm do a pull. Adjust by 3 degrees both ways until you find the sweet spot.

But I believe you know all this already. Also if the oil pressure is so low as to cause vvt problems then you'll have other oiling problems too. Oil quality doesn't matter as long as there's no air in it.

 

[Fred H.]

Thanks. Ivan brings up some good points as well. You might be able to tweak the VVT tables in the ECU and squeeze a little more out of the engine, but not having messed with them myself I can't say if it would be worth the effort, because you'd probably also need to rework the spark and fuel tables to match your changes due to changes in VE.

 

[Jeff.C]

Valve timing directly affects trapping efficiency as does exhaust design... (resonance)
The sooner the intake valve closes, the less chance there is of the charge getting pushed out the intake by strong resonance pulses reflected by the exhaust at lower rpms during valve overlap when time/area is highest. This increases trapping efficiency... as rpms increase and time/area decreases, it becomes beneficial to increase valve overlap to keep the power building as rpms climb.

When you look at the stock VVT table, it's pretty clear that Kawasaki used this (along with many other things) to detune this bike in most areas except very large throttle openings, but they did not allow it to make full power at high rpms either.
There are other VVT controls besides the main table shown here. (which I choose not to share here) The main table shows the most relevant part of the discussion anyway.

Here's a dyno comparison of 2 extremely similar designed exhausts... one with crossover tubes on the header tubes and one without. Both headers are nearly identical in every way besides the crossover tubes. One was designed for this bike, and the other for a ZX14.
AP header uses 44mm tapered headers and Arata uses 43mm tapered headers... collector lengths and diameters are also nearly identical.

Crossover tubes are a way to weaken strong resonance in an rpm range (depending on their location and diameter) in order to improve trapping efficiency. But, just as most things in life are a compromise, there are always tradeoffs, so as one area is improved, it will affect another area.
As is shown in the charts.

The point of a well designed exhaust is to trap the charge best in the rpm ranges that you use the most... and what the pipe designers had in mind when putting their offerings to market. Use a well designed exhaust for the rpm range that you use the most when riding your machine.

AP chose to keep the better efficiency below 4500 rpm as this is a more often used rpm range on the C14 than the 4500-6000 rpm range that is more commonly used on a ZX14 with it's shorter gearing.


Ivan

Your post & charts are a great help thanks

 

[laker9142]

Got to say, Laker viscosity affects the operation of the VVT low end and the Midrange is smoother now with no lag transitioning back and forth.

Oil is oil is oil. No matter how used or thin it is, it retains its non compressable properties. In this case it's strictly acting as hydraulic fluid. You could use any non compressible liquid for a short time.

You may want to check the screen at the entrance to the solenoid valve.

Still on the quest for breaking the bike into the 9-second (9.99 or lower)
Every 1/4-mile run made up to the 1000-foot mark is top of third gear and forth a few feet before the last timer. Your first 60 feet time in drag racing sets the whole run the higher the number time to pull 60 feet to the first timing light ) impacts your ET.

Interesting. Pipe choice is critical then.

 

[Ivan_ipp]

Try an extra rear wheel with a smaller rear tire to make an attempt at the gearing.

Best pipe your going to have on this bike is the AP... it has the best peak #s that you're going to get with the stock cams.
Shorter headers than these will just kill the torque and it won't be fun to ride.

I can do some tests this week that will show how the VVT settings affect things with my latest work and the AP pipe.

Here's a chart from my website that I did back in 2018 just setting the cam at 0 and again at 24 degrees across the rpm range.
The test was done with stock exhaust, but included the first version of my programming so that the extended revs would be shown as well as other restrictions removed... this way the results of just the cam timing settings would be shown without other influence.

Also attached a test that I did in 2021 during BW header tuning that shows the effects of a 5 degree advance vs. "0" (full retard) only above 9500 rpm.

 

[Jeff.C]

Try an extra rear wheel with a smaller rear tire to make an attempt at the gearing.

Best pipe your going to have on this bike is the AP... it has the best peak #s that you're going to get with the stock cams.
Shorter headers than these will just kill the torque and it won't be fun to ride.

I can do some tests this week that will show how the VVT settings affect things with my latest work and the AP pipe.

Here's a chart from my website that I did back in 2018 just setting the cam at 0 and again at 24 degrees across the rpm range.
The test was done with stock exhaust, but included the first version of my programming so that the extended revs would be shown as well as other restrictions removed... this way the results of just the cam timing settings would be shown without other influence.

Also attached a test that I did in 2021 during BW header tuning that shows the effects of a 5 degree advance vs. "0" (full retard) only above 9500 rpm.

Oil is oil is oil. No matter how used or thin it is, it retains its non compressable properties. In this case it's strictly acting as hydraulic fluid. You could use any non compressible liquid for a short time.

You may want to check the screen at the entrance to the solenoid valve.

Interesting. Pipe choice is critical then.

I get that oi is oil when used in the sense of hydraulic, leaning toward the angle lost viscosity and Parasitic frictional losses. Thanks for the tips

Oil is oil is oil. No matter how used or thin it is, it retains its non compressable properties. In this case it's strictly acting as hydraulic fluid. You could use any non compressible liquid for a short time.

You may want to check the screen at the entrance to the solenoid valve.

Interesting. Pipe choice is critical then.

I get that oil is oil when used in the sense of hydraulic, leaning toward the angle lost viscosity and Parasitic frictional losses in the phaser but my writing style assumes people read like mind readers, my bad.
Thanks for the tip on the screen forgot there was one there!

 

[Ivan_ipp]

Try a 180/55... compare it to the 200 circumference ....look for the lowest sidewall. Try 20 -22psi at first

Did you get rid of those roto tiller handlebars?

 

[Murph]

Losing those bars should improve performance. ...
...well.at least make the ole gal look faster....

 

[Murph]

What's your top 1/4mile speed to date?

 

[Jeff.C]

128 - 131

 

[Murph]

One of Kawasaki s claims for the C14 early on was the ( when released in 08) aerodynamics of the styling.... Then in 2010
They swelled her up...

 

[Murph]

Cloak.. Is your plan to keep the C14 "streetable"? Drag and commute on it?....be hard to lengthen that swing arm!!!...

 

[Murph]

Have you thought about gluing Bags from a Connie to a ZX 14 , changing the badges.....and telling people its a Concours?...

...I mean this is dirt track racing small block country here, you aint cheatin' you aint tryin'...

..on a more serious note....that banjo that ties the engine to the rear wheel....that thing has to be a HP vampire??


Murph

 

[Murph]

A set up super sweet road bike and balls out drag bike are quite a distance apart for sure..

 

[connie_rider]

In the runs you're doing now, is the ZX Cam installed again?
Or, do you currently have the stock cams?

Ride safe, Ted

 

[Jeff.C]

Referring to post #21 the BW IPP tune, the numbers were run on October 19, and those 60-foot times, are quite an improvement over the ZX Cam and my tuning.

But the low-end and mid-range torque was to be expected with that flash, more testing coming soon once the Heli bars are replaced with OEM bars so that my weight is shifted more forward for better control of launch and more comfort.