Holley EFI How To: Traction Management and Traction Control

Holley EFI How To: Traction Management and Traction Control


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.

Only registered users can comment.

  1. Awesome Video. I would love a more in-depth video of the two sensor wheel speed setup. Like how you are calculating slip and so on. Thanks for the vids!

  2. How, where, and how much is it to activate this ? I’ll prob just build a front wheel speed sensor vs rear wheel speed based traction control if it’s too expensive. But I don’t see how to buy it if I wanted to.

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