Tuning Dual VVT? Watch This! | Cam Timing [FREE LESSON]
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- เผยแพร่เมื่อ 31 พ.ค. 2024
- VVT, AVCS, VVL, VTEC, S-VT, MIVEC or whatever your flavour of variable valve timing is, if you're tuning dual variable valve timing then this lesson is for you!
This is just ONE module from the detailed Variable Cam Control Tuning course, link below.
Starting with the basics, including where and how to get started, Andre runs us through an example on how to optimise dual variable cam timing. He uses a turbocharged FA20 in a Toyota GT86 for the example which is fitted with a MoTeC M150 ECU, however, the knowledge is not specific to just this setup, what is taught here will be the same process you follow too when tuning your own VVT system.
0:00 - Our Dual Cam Control Setup
1:00 - Table Familiarisation
1:50 - Load Axis Confusion Clear Up
3:13 - Closed Loop Fuel Control
3:46 - Getting Started - Exhaust or Inlet?
5:50 - The Variable Cam Tuning Process
42:28 - 1 of 5 Steps, Learn More
What to learn more about Variable Cam Tuning? Enroll now: bit.ly/2Tc5Gw5
#highperformanceacademy #vvt #camtiming #camtuning #learntotune #camcontrol #variablecamcontrol #dualvvt - ยานยนต์และพาหนะ
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Very informative. Always wondered what process to follow adjusting both cams. Changing cams in 10 degree increments per run gives a quick overview of where it works best.
Fascinating and extremely well presented.
These videos are great. One of the things I struggle most is transient throttle tuning. Will there be a video for that coming out?
Absolute quality video
Excellent video.
Interesting stuff!
Awesome
If I am using a stock tune that has existing intake and exhaust cam timing but I want to tune it myself. Should I zero out the exhaust and go thru the steps the same way you have? Also why did you start with the exhaust for wide open Throttle runs? Should you not zero out the intake side to find the timing the same way you did with the exhaust side? Basically starting with intake and exhaust zero out or would that be dangerous for the motor?
How did you manage to increase the cam timing 1 deg/s over the selcted range?
Can this be done within the MoTeC M1 software itself or is it controlled from your dyno?
Great video.
Howdy, what does intake cam error mean in a datalog for example? Cheers
gold👌
What's the relation between cam timing vs ignition timing if any? Will it have knock off effect Just like between intake and exhaust?
I think so, cam timing changes effective CR.
What to learn more about Variable Cam Tuning? Enroll now: bit.ly/2Tc5Gw5
Did the turbo surge at the 34:00 dyno run? That would be the first I have ever heard a turbo go off the left side of the map.
No, the EFR6758 turbo won't surge on the FA20. I think what you've heard is a rattle that was present from the exhaust system possibly - Andre
I don’t have a dyno available, is it possible to tune this way using a virtual dyno or is it too inaccurate?
You can road/track tune, and it's worth doing. We have had mixed success with virtual dynos while doing that, but like any tool if you understand their limitations (in this case the margins of error in accuracy) and work within those there is usually some advantage to be gained - Taz.
@@hpa101 Applied this lesson, and a few others, using the virtual dyno software. Managed to gain 49 awhp and 61 lbft torque on a e30 fuel blend using Cobb Accesstuner. The AVCS timing presentation here was what had by far the largest effect on the way the car feels. Pulls much smoother, and harder. Thank you for these lessons and keep them coming. Hope to see some more Subaru/ Cobb software on the channel.
How would you do this without closed loop fuel control? The issue is a bit of a chicken and egg as before you can do a torque optimisation you need to dial in your speed density/VE table to get the fueling right to get the camshaft peak power and ignition correct. With a flash based OEM platform this is very difficult/time consuming, there are thousands of tuners battling with this problem and I'm still not sure how to tackle it in a reasonable time frame after watching this video.
If you don't have closed loop fuel control (which is pretty standard for just about any quality ECU these days) it simply creates one more step - After a change to cam timing that's sufficient to cause your fuelling to more rich or lean, you need to switch to the fuel/ve table and correct your fuelling. If you don't do this, any change in torque could be attributed to fuelling as opposed to cam timing. This is difficult, if not impossible to do accurately when reflashing a factory ECU unless you have the ability to live tune. In most instances though with a reflash we already have a well developed stock cam target map to work from and can focus on just the WOT cam targets as shown in this video. Yes it's time consuming, but you also can spend as much or as little time on it as suits your budget and objectives - Andre
@@hpa101 One more gotcha If you use a map sensor, then when changing the VE table to correct the lean/rich AFR, you will also change your load and hence timing as well. This means your torque change could be due to a AFR change OR spark change when all you did was change your cam timing. We see this ALL the time with reflashing any OEM Ford with the OEM computer. Most tuners struggle to do this let alone understand that the spark/afr could change when changing cam timing. We often see them go in circles trying to dial in an aftermarket camshaft with full exhaust+intake VCT as the OEM cam targets are not close, the speed density (and hence load) is not close hence they cannot easily determine the best cam timing for peak torque (or even dial in the speed density properly). They also do not have an option for aftermarket ECU as in say a Mustang or F150 for example, no ECU is available to run the 10 speed auto or all the auxiliary body control modules. This is a real problem we have, and currently there is no tuning course we can point them to. I'd love to have a chat with you guys about this if you are interested. roland at pcmtec dot com.
André you're the best. Some cam manufacturers actually give fly cut numbers depending on cam or for head milling/thinner gaskets. LT1 track attack cam recommended 0.080 thou cut for intake valve vvt in lieu of VVT delete.
Have you done any of this to get your VVT range? I was thinking with aftermarket pistons like JE/Wiseco I could make sure I have the room to fly cut? Example, instead of ordering 9.7:1 forced induction pistons, could order 10.25/10.5:1. Leaving room for valve cuts without losing target compression. Or running inverted dome and milling head? I don't like cuts in a piston if I can help it. Good for atomization bad for flame front propagation. It all depends on engine you're building I suppose.
I'm only coming from a building perspective. I wouldn't be opening a motor for that purpose alone for minimal gain.
Andre, I have to interject here. Advancing the camshaft "pushes" the torque peak LOWER. Retarding the camshaft timing "pushes" the torque peak HIGHER. The relationship has always been opposite, retarding an ohv fixed cam pushes the torque to the right on the dyno graph. VVT cars usually are set at max advance because all engines start at idle. As RPM increases, there's only one way to go, that's to retard cam timing as rpm increases. A fixed cam is a tradeoff and set somewhere around the middle of the degrees retarded on a VVT. I'm getting lost in your explanation. It would make more sense if it could only advance 10 degrees and could retard 50 degrees like the Motec is showing. That zero should be peak torque and trail off as you retard the cam.
HOWEVER, if you are not moving the intake and exhaust cams SIMULTANEOUSLY, you will introducing complexity with the lobe separation angle. It will give you a false sense of improvement as you move a single cam and the torque changes. First you need to find optimum lobe separation angle by rpm and move BOTH cams simultaneously maintaining the optimum lobe separation while advancing and retarding the cams together to find the peak torque.
That's the very beginning, then you can move out from there and use the cam timing for spooling turbskies and stuff.
Hey Kurt, I'm not too sure what specifically you're referencing in this video as from what your comment says I don't disagree and nor does this video? If we're dealing with the intake cam or a single cam engine then retarding the cam timing will favour high rpm cylinder filling while advancing the cam favours low rpm. I'm not sure if you missed the explanation that the intake cam timing numbers are inverted on the dyno screen, -50 is in fact 50 degrees advance and 10 degrees is in fact -10 from the natural base position? The numbers in the MoTeC ECU are correct (deg Advance for Intake, deg Retard for exhaust). You'll note however that the optimised intake map is advanced at low rpm before retarding back as the rpm increases which is typical. If I've missed your point then feel free to clarify.
With a dual VVT engine the natural or non-energised cam position for the intake is typically the maximum retarded position (not quite in the case of the FA20), not maximum advance, while for the exhaust it is the most advanced position. This results in minimal overlap which provides a good idle quality. As an aside, you'll normally find that these cam positions also usually offer pretty close to the maximum available power/torque at high rpm too.
It's worth noting that there's no set in stone method you MUST adopt to tuning dual VVT - The one I've shown is the one I've developed that has worked well for me. Bare in mind that while I'm choosing to deal with one cam at a time, and yes, this will of course affect the LSA, this is a moot point due to the iterative nature of the approach (we optimise the intake, followed by the exhaust before revisiting the intake etc). In my experience this is the fastest way to get optimal results. The approach you've suggested will get you to the same point by a different path and assumes that the optimal LSA will remain the same irrespective of the cam timing which also isn't necessarily a valid assumption - Andre
@@hpa101 ahh ok bud yes I wasn't paying attention to that part. I actually go about it your way lol. I've watched all the videos and the online stuff since the wayback machine left the building
@@curvs4me All good, glad we got to the bottom of it as you had me confused 😂- Andre