neema
forum member
Does the standard GT still use 5w-20? This would explain a difference in oil pressure.
Motor oil weight for a tracked Coyote?
- Thread starter Ivan 5.0
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Does the standard GT still use 5w-20? This would explain a difference in oil pressure.
Yes, the only difference in the "track pack" is the addition of an oil cooler and spec'ing thicker weight oil.
There are no internal engine differences.
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Napoleon85
forum member
Yes, you are correct. 5w50 will result in much higher oil pressure than 5w20, and both the boss and gt tp calls for 5w50
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I talked to a fellow with a 2012 GT. He switched from 5W-20 to 5W-50.... and his idle + wot oil pressure went way up. Also got a note back from some rep at RP..and he sez if your are not intending to track your car, don't use 5W-50. 5W-50 is a lot thicker..and has a harder time flowing through the various orfices, crank shaft journals etc. Since it can't flow as well, it all backs up...and higher pressures result. Nascar uses 5W-20... but they are after max power..and use oil coolers.
Some drag racers use 0W-5... for the same reason, max power.
Using 5W-50 during winter months...or where temps hover between 30-40F, might not be a good idea. But no big deal to use 5W-20 during the winter, 5W-30 for summer use, and no track service. If you want to track it some weekend, ok, swap in some 5W-50..and go for it. Oil is "cheap", just use what's optimum for either the application ....or the WX.
Jimbo
Some drag racers use 0W-5... for the same reason, max power.
Using 5W-50 during winter months...or where temps hover between 30-40F, might not be a good idea. But no big deal to use 5W-20 during the winter, 5W-30 for summer use, and no track service. If you want to track it some weekend, ok, swap in some 5W-50..and go for it. Oil is "cheap", just use what's optimum for either the application ....or the WX.
Jimbo
JAJ
forum member
Having had a 2011 GT with a TVS2300 supercharger on it that I took to the track A LOT, I think you guys are overthinking this.
The Boss oil cooler with a stock radiator is just fine for most high power applications. Combined with a Boss radiator, you're incredibly safe. You can overheat it, but you have to do things that won't make you any faster, just hotter. Otherwise, you'll be fine.
As for oil viscosity, well the ECU programming estimates how fast the variable cam timing happens, which varies by oil viscosity. It has a table that says "at this oil temperature it will take this long" for the cams to move to a new position. If your engine is spec'd for 5w-50, then that table will be different from an engine spec'd for 5w-20. Mechanically the same, but they respond differently and the ECU is programmed accordingly.
The Boss oil cooler with a stock radiator is just fine for most high power applications. Combined with a Boss radiator, you're incredibly safe. You can overheat it, but you have to do things that won't make you any faster, just hotter. Otherwise, you'll be fine.
As for oil viscosity, well the ECU programming estimates how fast the variable cam timing happens, which varies by oil viscosity. It has a table that says "at this oil temperature it will take this long" for the cams to move to a new position. If your engine is spec'd for 5w-50, then that table will be different from an engine spec'd for 5w-20. Mechanically the same, but they respond differently and the ECU is programmed accordingly.
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Where are you getting this from? There is no oil viscosity programming in the ECU.
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^I'm with you, spill it JAJ
JAJ
forum member
FF Duty Cycle for Bank[1 or 2] [Intake or Exhaust] Cam
"FF" means "feed-forward", which means "estimate in advance" the named parameter.
The Ynorm is EOT (Engine Oil Temperature) and viscosity varies with EOT. If you change oil viscosity ranges, then you have to adjust the EOT values to compensate for the fact that thin oil at a low temperature is the same viscosity and develops the same duty cycle requirements as a thick oil at a high temperature.
"FF" means "feed-forward", which means "estimate in advance" the named parameter.
The Ynorm is EOT (Engine Oil Temperature) and viscosity varies with EOT. If you change oil viscosity ranges, then you have to adjust the EOT values to compensate for the fact that thin oil at a low temperature is the same viscosity and develops the same duty cycle requirements as a thick oil at a high temperature.
I don't see a source for where this information is coming from. I assume it is from some tune software or tool?
Having a pure closed loop system that does no learning seems an odd choice given that the mfg oil service interval is 7500 miles, and the viscosity characteristics of even synthetic oil will change pretty noticeably with that much use.
Having a pure closed loop system that does no learning seems an odd choice given that the mfg oil service interval is 7500 miles, and the viscosity characteristics of even synthetic oil will change pretty noticeably with that much use.
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JAJ
forum member
SCT Pro Racer package with calibrator-level access.
If you do enough research into VCT systems, you'll find a number of well framed scholarly papers on the topic. The whole purpose of VCT systems is to change the way the engine produces power and emissions. If you hold throttle and spark constant, changing valve timing causes changes in engine power output. That means that without compensation in the ECU, there will be a noticeable bump or jerk when the timing changes (and in a Coyote, it changes often and a lot). The ECU contains some very sophisticated logic that adjusts the throttle position and spark so that the driver doesn't notice VCT changes.
When the VCT controller receive a command to change cam position from the ECU, the cam phasers respond as quickly as they can, but it takes time for the physical rotation of the cam to finish. Thick oil slows cam position changes down while higher RPM's speed them up. The "Feed Forward" table I mentioned above has Engine Oil Temperatures on the vertical axis and RPM on the horizontal axis. For any combination of EOT and RPM the ECU can make an well-informed estimate of how long it will take the phasers to implement an upcoming VCT transition. It starts moving the throttle and adjusting spark when the change starts and if the hardware is working properly, it finishes when the change finishes. The driver and passengers never know that it happened.
Whether you'd ever notice the difference if you change oil viscosity is a matter for debate. I don't think so, but I only ever ran oils that were close in viscosity to the OEM 5w-20 (I switched to a 5w-30 when I put the blower on).
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Alright that makes a lot more sense.
Your explanation of how the table is used makes even more sense in the case of the coyote which does not use use oil pump actuation. Since it uses torque exerted by the valve spring to adjust timing, it would make sense that with thicker oil the advances could be slower and retarding could be faster.
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Your explanation of how the table is used makes even more sense in the case of the coyote which does not use use oil pump actuation. Since it uses torque exerted by the valve spring to adjust timing, it would make sense that with thicker oil the advances could be slower and retarding could be faster.
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Feed Forward control is a well balanced equation of known parameters.
We have a few Process Loops where I work that implement this control strategy.
As for the Duty Cycle that usually pertains to a variable speed motor or drive.
I am trying to figure out if the VCT solenoids are on a pulse stategy to open and close them.
If this is true then the termoinology you use makes sense.
Can someone check and see if they can find these parameters in the 3V Programming?
If this is the case then there could definately be a difference in VCT control between Different viscosity oils as They are measured at 100* and the difference in Viscosity between say a 50w and a 20w would be massive.
But in the end it is still determined by the Controller how agressive the strategy would be to control the Pulse width.
We have a few Process Loops where I work that implement this control strategy.
As for the Duty Cycle that usually pertains to a variable speed motor or drive.
I am trying to figure out if the VCT solenoids are on a pulse stategy to open and close them.
If this is true then the termoinology you use makes sense.
Can someone check and see if they can find these parameters in the 3V Programming?
If this is the case then there could definately be a difference in VCT control between Different viscosity oils as They are measured at 100* and the difference in Viscosity between say a 50w and a 20w would be massive.
But in the end it is still determined by the Controller how agressive the strategy would be to control the Pulse width.
JAJ
forum member
5w-20 has a dynamic viscosity of about 8 cSt and 5w-50 has a dynamic viscosity of around 15 cSt at 100C.
If you want to adjust the calibration for a thicker oil, all you have to do is figure out the viscosity of the "baseline" oil at each temperature in the list (ranging from -20F to 240F, IIRC) and then figure out the set of higher temperatures that give the same viscosities for the new thicker oil. It's pretty easy.
Feedforward control just means you decide how to react to a change in advance and program accordingly. Simple as that. It is the opposite of feedback programming which decides how to operate based on errors resulting from the last sampling.
In the coyote motor VVT is not accomplished with solenoids. In the 3.7L V6 solenoids are used. And in the 3V it was oil pressure based as well. In the coyote motor they use torque modulations during contact between the lobe and the valve to change the phase angle.
So any change in oil viscosity in the coyote motor should not have a big impact on VVT comparable to oil pressure based methods of the 3V and the 3.7L.
The one sensitivity being how the viscosity will affect the time taken to accomplish the phasing. And I am not sure that this would really have MUCH of an effect since I'm sure the cam position sensors are used to determine if phasing is actually complete.
TL,DR; I'm pretty sure running 5w-50 in a Coyote motor will net no negative impacts.
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In the coyote motor VVT is not accomplished with solenoids. In the 3.7L V6 solenoids are used. And in the 3V it was oil pressure based as well. In the coyote motor they use torque modulations during contact between the lobe and the valve to change the phase angle.
So any change in oil viscosity in the coyote motor should not have a big impact on VVT comparable to oil pressure based methods of the 3V and the 3.7L.
The one sensitivity being how the viscosity will affect the time taken to accomplish the phasing. And I am not sure that this would really have MUCH of an effect since I'm sure the cam position sensors are used to determine if phasing is actually complete.
TL,DR; I'm pretty sure running 5w-50 in a Coyote motor will net no negative impacts.
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JAJ
forum member
The Copperhead ECU uses a lot of feed-forward strategies for various aspects of its operations, usually in conjunction with feedback. For most changes - pedal movement for instance - it figures out what the right value for everything should be a few revolutions in the future, and then it uses feedback to adjust for the final results (VCT, airflow, mixture, spark, etc). When you're calibrating it, it's remarkably tolerant of fairly gross errors because the feedback loop ultimately over-rules the feedforward algorithms. But, I can tell you from experience, when you get the FF values right, it's a really sweet sensation.
All of the FF Loops I have seen are not what I would call "simple".
They are usually pushing a signal into a cascade loop.
As JaJ pointed out earlier a table was made using X and Y axis most likely in a lab and the results get pushed into a Control Loop.
I do not know if there are any program changes between the gt and the track pack or boss.
But I am sure someone can open up the programming file on a boss or whatever is spec'd to use 5w-50 and see if the parameter in the tables have been changed.
steveespo
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This makes sense to me. I do run higher viscosity oils than stock during racing season and have not noticed any seat of the pants performance differences or idle/driveability changes during street driving.
Steve
That is my question, given all of this input. Particularly the GT and Track Pack as it would seem that the Boss would be different anyway.
Also, btw this is the first motor oil thread I've ever seen in the history of the Internet where people were insightful, informed, open to that insight, and discussed accordingly. Bravo.
JAJ
forum member
I agree - while I can identify where the programming would be dependent on viscosity, I've never seen complaints about shocks to the system when someone runs a thicker oil, so I have to believe that the whole system just isn't very sensitive to viscosity.
What you would feel if there's a VCT event is like a kick in the back or a dead spot, but just for a moment. I've had the programming out of whack through a different table set, and when you roll into the throttle, there's a kind of "punch" that hits, that "coming onto the cam" sensation. That's it. So just a brief flicker of that wouldn't really be that noticeable in the grand scheme of things.
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