Hi, I'm Ryan with Holley EFI, here with another Holley EFI how-to video.
Today we are going to talk about Holley EFI's integrated traction control and then if we
have some time after we'll actually talk about how to set up a wheel speed comparison traction
control using the IO in the advanced tables.
To start off we'll start talking about how our time-based traction control works, to
start with you add a traction control ICF to your tune if you don't already have it,
once you do, select your system type as active speed management, from there this screen will
pop up and you'll have to add a few things.
The first thing you'll have to add is a speed input so that it knows what to build your
traction control curve off of.
In this case, there is one set up as driveshaft speed.
You can use either an RPM input or an MPH input, it will use either and it will automatically
adjust your units depending on which is chosen.
From there you have an option to set up a minimum and a maximum driveshaft speed for
activation.
These will just set up the bounds for where traction control will actually activate, so
regardless of what you have put in the tables, it will ignore it, below this number or above
this number.
From there you have your X-axis max time and your timer ignores time.
The X-axis just sets up the X-axis of the table, I'll show you that in just a second.
And the timer ignores time is just a time-based way to ignore what the traction control would
do otherwise, similar to the minimum RPM.
So if you know for the first two-tenths of a second in your run that the traction control
isn't going to work anyway because of whatever reason that your drive shaft curve doesn't
look right, you can just put in .2 here and no matter what was in the table for the first
two-tenths of the run it wouldn't use the data.
From there we'll jump into the drive shaft curve, this is where you set everything up,
you can see since we had 4.4 in the max time that becomes the far right of our X-axis.
From there you'll have four lines on the table, you'll have what's called the base, retard
A, retard B, and rev limit.
The base is basically not used for anything, it's actually just to set up a predetermined
line based on your logs, so in this case, I've opened up a log of a run in the background
and you can see the driveshaft speed here.
You can see it actually has some spin.
So I'll just take since that log is open I can come back here and click import log file
and it will plot the curve for me and you can see that it exceeded the retard A and
retard B lines but it did not hit the rev limit line.
So we will discuss how these work using the log now and then we'll go back to how to set
them up.
So you can see in this run that we have a red line as RPM, this lighter red line is
the driveshaft RPM and the green line is TPS so you can see that he was full throttle nearly
the entire time.
So what you will see is driveshaft comes up, spun through here, traction control was able
to bring it back in line and allow them to continue without ever having to pedal the
car.
So what you will see is that you have your driveshaft, rev limit curve, your driveshaft
retard A and retard B curves.
As logged parameters, you can set these up in your inputs and outputs, which I will show
you in a little bit, but as you can see, it came up and right here it crossed to retard
A and the retard B line and got into the rev limit, so what that looks like is you look
at your driveshaft timing offset, you'll see that it came and pulled 8 degrees out, which
was the max.
It then proceeded past retard B, started to drop cylinders, you can see this in the driveshaft
rev limit, you can see that it dropped two cylinders so the way that our system works
is that when you exceed the retard B line, it will start dropping up to four cylinders
when you hit the rev limit line so the first quarter here, it will drop one cylinder, the
second quarter it'll drop two cylinders, then three and then finally four.
So it's a little hard to see in this one so I'm going to change the background color,
there we go.
See this blue line is how many cylinders it dropped so you can see as soon as it crosses
the threshold it went immediately to two cylinders and then it dropped down to one cylinder as
it started to come in line, it got back under control and started to put a little timing
in as you can see here and then it lost the tire again and went straight to dropping,
did one cylinder, then two, then back to one, and it got back onto the line and under control.
So the way that that looks in here, you can see that we have the baseline, which is what
he wanted the run to be and that is the driveshaft RPM here, then he had his retard A which was
set slightly above it, you can see here and to tell how far above you can click the view
delta and it will tell you the RPM difference from the base to whichever curve you have
selected, in this case, retard A. So you can see he had it set at 150 RPM above his baseline
through here and down to 100 right here.
So after 150 RPM above the base, it would pull timing out, it would step it out, so
when you come down here to your retard above limit table, you can see that he has it set
to pull two degrees and then after 2.35 seconds it pulls only one.
So, in this case, it exceeded the retard A and went straight to retard B which was set
roughly 200 RPM above.
So what happens when between retard A and retard B is it will continue to ramp timing
out and so once you exceed retard A it steps two degrees out immediately and then it proceeds
to retard B so as the driveshaft continues to go between the two lines, retard A and
B, as it gets closer to retard B it will continue to pull the timing out up to 8 degrees.
So if your driveshaft curve ends up halfway between retard A and B, in this case, you
would end up with about five degrees out.
From there, if it keeps going as we discussed, the rev limit curve, which was set 1000 RPM
above will start to pull cylinders out of it so in this case, it pulled two as you can
see, it was about halfway up.
To add up the curves you've got a few options.
You can drag dots, you can group edit so you can highlight, now you are able to drag multiple
dots, you can edit the deltas, you can go back to the actual view and add up the actual
RPM.
If you want to import a curve and set it to match, you'll take this yellow line that you
clicked from import log file, you can right-click on it and you can copy it to any of these
or you can offset to any of these which allows you to do math on it before you apply it.
So, in this case, we're just going to build a fake curve off of this so we'll copy this
line to base and pretend it's what we want.
From there I'd click it again and I would offset to retard A and I'd add 100 RPM to
it so now it is 100 RPM above.
Same with retard B, we'll go 200 above, then we will also offset the rev limit, we'll go
plus 500.
So now that we have rescaled everything, the table is automatically brought us into focus
so you can see very quickly now how the lines work and how they've both stacked and scaled
appropriately.
One thing that I've known is that it will use the time axis you already have up here,
so you can see that this one is kind of evenly scaled, you may want to do something like
this where you make the majority of the graph very early in the run where you want some
resolution and then we will re-offset that to rev limit to get it back.
There we go, so now we have a lot nicer curve that follows the imported driveshaft.
For the nitrous guys, something important here, nitrous guys don't want the rev limiter
coming on, so what we do is turn off the rev limit feature because you set the curve to
zero.
So, in this case, there is no rev limit, if you exceed retard B nothing else happens,
that's all there is.
You can also set it up for part of the curve, set the deltas here, I'm going to go 500.
So what you will see here is up to this point right here, the rev limit is active and that
is .68 seconds into the run.
What will happen in this case is at .68 seconds the rev limit will shut off, it won't ramp
down, it won't do anything it just shuts off at that last point and then it's zero the
rest of the run, it doesn't do anything.
You can also zoom in and out on this graph too, so if you want to zoom in and drag the
dots closer around you can do that too.
There is also the crankshaft curve which most people do not use but it has certain scenarios
where it can be quite beneficial.
It functions exactly the same as the driveshaft except it uses engine RPM instead of the driveshaft
or other wheel speed for the activation.
This is another log of it working.
So you can see on this one, wheel speed gets away, traction control turns on right here
and drags it back.
He paddles it because he felt something wrong after but he was way too late, the traction
control had already caught it and then out here it starts to go away again and it actually
snaps the input shaft on the car and that was the end of that run.
But you can see the G meter sags and then comes back.
Again you can see it picked up, dropped four holes in this one so it shot half of the motor
off, it actually drug the RPM backward and the driveshaft RPM down back under control
and then allowed it to keep accelerating ater.
When he launches the car here, watch the tire make about one rotation and then plant, so
right there and the traction control caught it, brought it under control and off he goes
into the sunset until right about there where it snaps the angle shaft.
So here's another one I did kind of as a giant guess on a friend's pro mod that we were just
trying to get down the track and under control.
You can see the drive shaft comes up has a little check mark, bounces there and then
shoots up and we got a little more and this was one of those deals where we're going in
the first round we hadn't made a clean hit and we timed it, kind of took a guess at what
the driveshaft curve should be and the result was this pass.
So you can see the driveshaft curve looks a little ugly, we see some stuff in there,
but you can see that, driveshaft timing offset, you know to pull a little timing right there,
right there, and then a little out here where it probably didn't need to and then we had
the rev limit turnout early in the run here.
So you can see right here, that calmed it down, maybe it didn't need to but it worked
and then out here it started coming up and it actually did bring it under control and
allow us to make the rest of the run.
This is one of the ultra streetcar using just the timing offset, they do not use the rev
limit because they are a nitrous car and you can see right through here, you can see that
the driveshaft curve started to come unsettled and set it back in with the timing and you
can see that it was enough to really dip the motor down to make it happen.
Yeah, they were negative three points six degrees of total timing to make that happen,
they pulled 14 degrees out.
As a side note, when you are getting that extreme with the timing, if you are running
a distributor you need to make sure that your rotor phasing is on point and that you don't
pull so much that you jump to the next terminal.
With the coil near plug of any kind you have a lot more leeway to get extreme with your
timing retards for power management in general, whether it be wheelie control traction, traction
control, just timing retard for launch or any reason really.
Alright, so this is the wheel speed traction control and how Doug and I decided to set
it up on his car for a no-prep event.
A little different than a lot of people do, we think it works better by but I figured
that I would share it every one to give a try if they wanted.
The big thing that we did was that we created a PWM table for wheel slip, all it is is a
data table to be put in or to be fed into for an advanced table of some kind.
So what you can see is we just took front wheel speed and rear wheel speed and made
them axis on here and then we made this diagonal here zero so the scaling is equal on the X
and the Y for speed and then from there we kind of fudged in the numbers a little bit,
I believe there is a little inaccuracy in the match on this one but someone would have
to double-check me if they wanted to, but basically you're just building the wheel slip,
you can run the math on each cell and figure out what the exact slip number is if you wanted
ultimate accuracy.
The important thing is that there is interpolation on this table, so if you're flying through
these zeros as you get to this corner right here, you're going to have these four cells
being used, so it's very important that you not only put the slip percent in but the inverse
on the opposite side so that you don't get a false read as you are traveling through
cells.
So that is why there is this one row of negative numbers offsetting on this side.
You can see we just used the duty cycle, in this case, rear-wheel driveshaft RPM and basically
using RPM version of the rear wheel and then front wheel speed RPM and then type and frequency
don't matter too much, it's just the duty cycle that you care about.
From there we just feed it into an advanced table, in this case, we used front wheel speed
and the wheel slip percent to build a table of how we wanted to pull timing so this is
really nice because you just need the one table.
So you just take your wheel slip percent, whatever is output from the PWM table and
then by your undriven wheel speed and you can build a nice table, you can be more aggressive
or less aggressive based on speed and the slip percent.
So you can see at low speeds here he didn't rely on it as heavily as he did at higher
wheel speeds so basically as he got further down the track he wanted it to pull timing
sooner and how that looks in the log is like this.
So we've got rear-wheel speed here, we've got his slip percent, which gets kind of high
right there, probably because he is in wheelie which is why he had the time delay to start
at two and a half seconds from launch.
So it doesn't activate until out here.
Interestingly in this one, he actually used the time-based traction control for the first
part of the run so you can see where it was active through there trying to keep it on
a curve and he actually shuts it off at around that two and a half which is over to the wheel
speed.
So, in this case, you can see real speed is good it has a little slip here, here is the
slip percent so you can see the driveshaft based time-based curve was working through
here keeping him under control and out hereafter for two and a half seconds you can see that
it started to get out of control here we had about three to four percent slip and if you
look at his wheel speed table it actually was pulling ten - 12 degrees to try to keep
that under control because actually tickling it all the way back here trying to keep the
tire under control.
Now once it gets through this area it settles in and has no-slip, well negative slip so
it doesn't activate the traction control, but that is how I would do wheel speed based
traction control.