Resumen

En este seminario web, veremos cómo configurar correctamente el tope del acelerador y los ajustes de control de ralentí en Holley Sniper 2.

00:00 Hey team, Andre from High Performance Academy here, welcome to another one of our webinars.
00:04 In this webinar we're going to be diving into some of the intricacies of setting the idle speed control on the Holley Sniper 2 EFI system and this is definitely not a very complicated task but there are a few nuances to this.
00:17 Because it is relatively straightforward, this is going to be a reasonably short webinar.
00:23 As always we will be having questions at the end of the webinar and on that basis, if there's anything that you'd like to know about what I'm doing or anything you don't understand, then please get those questions through to Jaden pretty quickly in the comments so that I don't end up missing them.
00:38 Alright, so let's start by just talking a little bit about what idle speed control is and why we actually need it and a lot of this probably goes without saying but just to make sure that everyone's on the same page, we'll just quickly cover it off.
00:50 So, this is an adjustable or ECU adjustable air bypass essentially around the throttle slice that aims to give us consistent and accurate control over our idle speed.
01:02 And the reason we need this is that the amount of air bypass the engine is going to need to maintain a fixed idle speed or a specific idle target.
01:11 That's going to vary from when the engine is cold, maybe there's snow on the ground that's the middle of winter compared to the middle of summer where it's scorching hot or the engine is heat soaked.
01:21 It's going to be a constantly moving target and the aim with our idle speed control tuning is really to replicate the sort of idle control that we'll get on a modern vehicle.
01:32 And my line in the sand for this is always that I should be able to reach in through the driver's door and turn the key regardless whether it's freezing cold, scorching hot, the car's been running, it's up to temperature, maybe it's completely stone cold or it's heat soaked or anything in between and the engine should start and idle smoothly and consistently.
01:51 I shouldn't need to be nursing the engine with the throttle holding it open to make sure it doesn't Likewise, when we're out driving, we don't want to be worried about whether or not the engine's going to stall when we come up to a stop sign or a set of traffic lights.
02:05 These are the things that really make a modified vehicle sort of horrible to drive if we don't get them right and when we do get them right, it's stuff that we just don't ever have to think about again because the car drives as we'd expect.
02:19 And idle air control along with cold start tuning which we're not covering in today's webinar, these are two of the things that I think a lot of tuners get wrong.
02:27 And a lot of people, a lot of customers just accept because they think they're driving a modified vehicle so hence it's not going to drive like a factory vehicle.
02:38 I will add a little caveat in here, the Holley Sniper 2 system essentially is throttle body injection, it is a compromised system because it is designed to make EFI conversion from a conventional four barrel carburettor as simple as it can be.
02:54 And with this does come some compromises so it is in a proper multipoint fuel injection system, we're not running drive by wire throttle control here and in its base form it will work with a conventional mechanical distributor.
03:09 In our case we have chosen to add the optional hyperspark electronic distributor which simply plugs into the Holley Sniper 2 harness and then that gives us full digital control over our ignition timing.
03:22 Now, why I mention that is because we can also use our idle ignition control to help with our idle control.
03:32 So, the premise behind this is that by advancing the timing towards MBT, the engine will make more torque and at idle what this results in is the idle speed increasing.
03:43 Conversely if we retard the timing from MBT, we end up making less torque and that will reduce our idle speed.
03:50 So, this is a very fast way of advancing and retarding the timing in order to achieve our target idle speed and this works in conjunction with our idle air bypass which is inside the Holley Sniper 2 system.
04:03 But you can still use a conventional mechanical distributor, we just won't be having the functionality that I'm going to talk about.
04:09 So, we've talked about what we're trying to achieve and we've talked about the different ways we can achieve it.
04:15 So, there is a bit of a process that goes along with this as well.
04:19 And this is something that is quite often overlooked.
04:21 So, what we'll do is we will jump into my laptop software here and have a look at what we've actually got available.
04:30 So, there's a couple of ways we can tune the Holley Sniper 2 and one would be the LCD touchscreen.
04:38 I'm going to guess that anyone that's coming along to one of our webinars probably isn't using that, so, therefore I'm going to deal with the laptop software.
04:46 So, what we've got here is our idle ICF, we've got our fuel and spark up there as well, but we're not going to worry about those for the moment.
04:54 And it was started on our idle settings here which you can see.
04:59 So, for a start we've got our idle spark and you can see that I've got a little tip box there saying that this is enabled.
05:05 Now, we actually would want to start with this disabled because while we are dialling in our idle speed control, we don't want the ECU basically fighting us.
05:15 And using idle ignition timing control in order to basically correct an error that's baked in.
05:23 So, we'd start with this disabled.
05:25 I'm going to leave it enabled for the purposes of our discussion here but normally we would start with this disabled.
05:30 We've got, this uses a PID control algorithm which is pretty typical for any closed loop system in terms of how aggressively this is going to chase the ignition timing in order to achieve our idle speed target.
05:47 I said PID, it actually is only using proportional and derivative and we have those terms here.
05:52 I've left these at the default values but basically the purpose of the proportional gain is any time we have an error between our target idle speed and our actual measured idle speed, the proportional gain will drive a correction in proportion to that error.
06:11 So, the bigger the error and the bigger our proportional gain, the more the idle speed will change.
06:16 Now, we do have to be a little bit careful about this though because if we make this number too large, our proportional term too large, what we're going to end up with is an oscillation in our ignition timing which will result in an oscillation in our idle speed.
06:31 OK so then the derivative term acts essentially like a bit of a braking effect.
06:36 So, if we are coming up to, if we started with our proportional gain set to in this case 34 and our derivative term set to zero, we'd have no braking effect.
06:47 And that is where we'd definitely set up this oscillation because as we come up towards our target idle speed, we're very likely to go past it and then the proportional term will reverse the ignition timing direction and we're just going to sort of chase our tail.
07:03 So, the derivative term works on the rate of change of error and the greater that rate of change as we come up towards our target, it will have a clamping effect.
07:12 So, a clamping or damping effect to reduce the change in our idle ignition timing.
07:18 So, that's what those terms do.
07:19 As I've said, I've used the default values here and I've found them to be pretty good.
07:23 We've then got our idle control type now for our Sniper, it is throttle body injection system so we are going to stick with Sniper TBI.
07:33 We've got slow, medium and fast there which I'm not going to adjust.
07:37 Alright, we've got a couple of other parameters here.
07:39 We've got our IAC ramp down.
07:42 This one here is our hold position.
07:44 So, what we want to do is set this at a point where when we get off the throttle, we don't want the idle speed to drop too quickly and risk stalling.
07:53 At the same time we don't want to end up with rev hang either.
07:57 So, basically this is going to define, so the idle air control valve opening percentage when we come off the throttle.
08:04 30% again is the default value, I've actually found in our application that works reasonably well.
08:08 And then we've got the RPM above idle to start our ramp.
08:14 So, in this case 1000, again just default values.
08:16 So, basically when we get to 1000 RPM above our idle speed target, we'll begin ramping down.
08:22 And then we've got our ramp down decay time, so how long this will happen.
08:26 So, again if we try and ramp this down too quickly, we're very likely to end up with the potential for our RPM to drop low and potentially stall.
08:35 Too long, obviously we just sort of get this unnecessary rev hang.
08:39 It takes too long to get down to our target.
08:41 And then at 100 RPM above our target idle speed, this is where we will re-enable closed loop control of our idle air control system.
08:52 Right we also have our IAC start up position.
08:56 So, basically when we start the engine, we've got a different table we'll look at in a second.
09:02 Where there's going to be some additional air bypass that's active to help the engine start up crisply and cleanly.
09:08 It's going to hold that for 4 seconds and then it's going to decay.
09:11 Over an additional 4 seconds.
09:13 Again, I've actually found for our purposes, and I should have mentioned this is just a simple basic, unknown origins, probably million kilometre 350 chev small block.
09:25 So, nothing particularly flash here.
09:27 I've found all of these settings work really nicely.
09:30 Alright, so next we're going to come up to our idle speed target table.
09:36 Click on that.
09:36 This is an area that is really important to get this right.
09:41 We want to make sure that the numbers in this table are realistic and are at an RPM target that our engine can comfortably idle at.
09:50 And for a basic small block V8 like this, we probably with a stock cam could get it idling quite comfortably at around about 650 RPM.
10:01 Just because of the limitations of this system, I've gone and been a little bit more generous than this and once we're up to operating temperature, I've got this set to a 750 RPM target.
10:12 What we can see is that there's a bit of shape to this curve down here.
10:16 And we can see particularly at lower coolant temperatures here, we're starting to target around about 1000 RPM and then we'll drop down from there.
10:24 This is pretty typical with an OE factory tune as well.
10:29 At colder start up temperatures, we tend to target a slightly higher idle speed.
10:35 This will basically smooth out our idle and make it more consistent, less likely to stall during that warm up phase.
10:42 And then once we get up to, in this case it's about 140 degrees Fahrenheit, don't ask me what that converts to in degrees C, we can't actually display temperature in the Holley Sniper software here in metric units which is interesting.
10:57 I'm not quite sure why that's the case but that's where we're at.
10:59 But we see from 140F upwards we're basically at that 750 RPM idle speed target.
11:06 Now, why this is important is if we've got a stock engine that's been, let's say, quite happily idling at 600, 650 RPM, and then we go and put a really aggressive cam with a lot of duration, a lot of overlap in it, there's probably a better than average chance that there's no way in the world that particular engine will now idle at that same 600 or 650 RPM.
11:29 Depending on the size of the cam, it's quite likely that we may need to increase that idle speed target up to 850, even 950 or above.
11:37 So, it's really important to make sure that the idle target that we're choosing are sensible for the engine configuration.
11:46 If we were tuning a four cylinder engine, which with the Sniper 2 we're definitely not going to be, a small capacity four cylinder engine probably is more likely to want to idle with a stock set of cams at maybe 850 to 950 RPM, and then with aggressive cams, probably more in the region of 11 to 1250 RPM.
12:05 So, again, just make sure that you're choosing sensible idle targets because otherwise you're definitely going to end up chasing your tail trying to make the ECU do something that the engine is just simply incapable of doing.
12:18 All right, we've got one more table here that I want to show you.
12:22 And that is, of course, our IAC parked setting table.
12:27 Now, this one is a little bit maybe counter -intuitive if you've come from different ECU platforms.
12:33 Normally you would expect this table to sort of be our base position when we come back to our idle target.
12:41 But in the Holley, remember, we have the parked position of 30%.
12:45 Sorry, let's go back to settings, I'll get that right.
12:49 We have our IAC hold position, I should say, of 30%.
12:53 So, this one here is what is used during startup.
12:57 So, it will set our idle air control valve at whatever the duty cycle is in here while the engine started.
13:05 Then we have the hold and decay times that we just looked at previously under our IAC settings.
13:11 So, what we want to do is adjust these numbers here in order to basically get us an engine that's going to start nice and crisply and cleanly.
13:20 We don't want it to sort of obviously rev up excessively but we also don't want it to start an idle low.
13:25 So, we can go through and adjust these parameters until we get a good idle, a good startup, good crisp clean idle startup.
13:32 Sorry, good crisp clean engine startup.
13:35 And then good control over our idle speed initially before we start going into that decay.
13:39 So, we don't want to end up with it revving up and sort of holding at 12, 1300 RPM and then dropping back.
13:45 Generally, sort of 1 to 200 RPM above our target idle speed is what I'm going to be quite comfortable with.
13:52 Alright, now another aspect here that is important to understand is before we go ahead and start making changes to our idle control, we want to make sure that our fueling or volumetric efficiency is well tuned.
14:06 So, we can see here while I've been talking, we're sitting here at about, what are we, sort of 35, 38 kPa and about 800 RPM.
14:15 I'll talk to you why it's about 800 RPM in a second.
14:18 And if we come down here and we cycle through to our fuel tuning, what we want to do is make sure that we are on our target.
14:27 We can see here our closed loop compensation is sitting at 0 to 1% and if we come through another one, our lean tuning, we can see that our target AFR is 14 to 1 and while it's moving around a little bit, our measured Y band air fuel ratio is sitting exactly at that point.
14:44 So, we want to make sure that we don't have any crazy closed loop trims in here if we've got closed loop enabled, which most likely with the Sniper 2 we will.
14:51 We want to make sure that we're ideally plus or minus about 2 to 3% from our target in terms of this closed loop compensation number.
15:00 We're sitting at 0 to 1% so everything's looking pretty good there.
15:05 Important to mention that this is going to always be moving around depending on engine temperature, heat soak, etc, atmospheric conditions, that is what we have that closed loop fuel control enabled for in the first place.
15:18 But what I'm getting at with this is there's not much point as our first port of call trying to dial in our idle speed control when we have an engine where the volumetric efficiency isn't tuned and our closed loop trims maybe plus or minus 20% in picking up all the pieces.
15:34 So, make sure that our VE table is dialled in properly.
15:38 Now, the other aspect with this, is we really want to make sure that our engine is up to operating temperature.
15:44 It needs to be over, I believe it's 160°F before we really want to get into tuning our idle control.
15:51 So, it's a bit of a process that we need to go through for that.
15:55 Just make sure I'm following all my notes here.
15:57 So, once we're up to that warm up temperature, what we want to do is make some adjustments to our idle, our throttle stop on the Holley Sniper 2 itself.
16:08 So, I've got a photo of that.
16:09 I've got a photo of what this looks like on our engine here.
16:12 And the confusing thing for those fresh to this is we have two throttle stop screws here.
16:17 The one on the left is the one that we want to adjust.
16:21 The one on the right is for our secondary butterflies which are here.
16:24 And this is set by Holley in the factory when these units are assembled.
16:29 And we don't want to be going and adjusting that.
16:32 So, all of the changes we want to make that I'm about to talk about here are going to be made through this primary throttle stop.
16:40 We'll head back into our tuning software.
16:43 And there's a couple of parameters that we need to be aware of here.
16:46 So, first of all, our throttle position sensor reading.
16:51 We want to make sure that it is reading zero when the throttle is closed.
16:55 If it's reading above 2%, then the ECU will go into that idle air control valve hold, which is going to be 30%, and it's not going to try and chase our idle target.
17:06 And initially, we want to make sure that our throttle stop is reading zero.
17:07 And initially, as we're opening and closing the throttle stop, this will affect our TPS reading.
17:12 So, we want to make sure that it's reading zero while we're actually trying to achieve idle control.
17:18 If it's not, if we need to open that idle air bypass screw, sorry, the throttle stop screw, and we end up with a reading here of maybe 3% or 4%, it's OK.
17:27 All we need to do is turn the ECU or power the ECU down for five seconds, then power it back up and it will actually relearn that closed throttle setting.
17:36 So, at the moment, we are sitting at zero there.
17:38 What we want to do actually is come back across though to our idle tuning.
17:43 And what we want to look at here is two things.
17:45 First of all, we have our IAC position, which is reading at zero, and then secondly, we've got our RPM, which is sitting at about 800 to 820.
17:53 Now, remember, at warm operating temperatures, we really, we've targeted here 750 RPM.
18:01 So, what this means is that at the moment, the IAC is completely closed.
18:06 Yet we're actually still 50 RPM, 50, 60 RPM above our target.
18:10 So, what I'm going to do is I'm going to jump out of the car for a moment and I'm just going to go and wind that throttle screw out a little bit, which will have the effect of closing the throttle plate a little bit.
18:21 And we'll see how that works.
18:23 Give me a second, we can maybe just jump to technical difficulties here for a second while I'm making this adjustment.
18:28 We'll come back in about 20 or 30 seconds and I'll show you what I've done and what it's achieved.
19:16 OK we're back.
19:17 So, just a little adjustment there.
19:18 Too difficult to really show you what I was doing under the engine bay.
19:22 But essentially what I did there was just took the throttle stop screw here and wound it out, I would have probably gone maybe about a half a turn.
19:30 Just another point there as well, if you're setting one of these up from scratch, generally what I'd do is start by winding that throttle stop screw out completely until the throttle blades are closed.
19:39 And then wind it in one full turn, that should get you at least pretty close to the ballpark.
19:44 But let's head back to our tuning software.
19:46 Now, what we can see is that our idle speed is right on our target, 750 RPM.
19:51 And we can see that our IAC position is sitting at about 9%.
19:55 Now, this IAC position is going to move around as conditions change.
20:00 So, it's never going to be rock solid here.
20:03 But the general recommendation here, and there is a bit of flexibility depending on what you read and who you listen to.
20:09 But this should be somewhere between about 5% and 12%.
20:14 So, the reason for this is what we want to do is make sure that when the engine is at operating temperature where it will need the least amount of air, we don't want to have the idle air control valve too far open.
20:27 I want to have that mostly closed.
20:30 And that's going to also give us a good range of control, particularly when the engine is cold and it's going to need more idle air bypass.
20:38 So, once we've got this.
20:39 Into that ballpark of sort of 5% to 12%, obviously at the upper end of that scale, we should get good idle air control, idle speed control, and we shouldn't end up with situations where we are stalling.
20:53 We're going to go into Q&A really shortly.
20:56 So, again, I did mention this is going to be a pretty short one.
20:58 If you've got questions, you can chuck those in the chat.
21:01 We'll jump into there in a second.
21:02 Now, I also mentioned that while I didn't do this for our demonstration, the idle spark control, we want to make sure that this is disabled while we are setting our IAC position.
21:15 As I mentioned, yep, I cheated a little bit.
21:16 I haven't done that, but do as I say, not as I do.
21:19 Once you've gone ahead and got the IAC position at a warm operating temperature into that 5% to 12% position, you can come back in here and enable the idle spark control.
21:34 And if we also come through to our timing control, we can see here, this is what our ignition timing is doing at the moment.
21:45 Even with the idle spark control enabled, what we're really looking for is the difference between these two values shows you what that idle spark control is doing.
21:55 Base timing is the ignition timing that's coming from the base timing map.
22:00 And you can see that at the moment, that's 20 degrees.
22:04 And we're actually at about 22 to 23 degrees.
22:06 And so the idle spark is adding about three degrees to advance the timing, to add, move towards MBT to increase our idle speed.
22:16 And you'll see that moving around.
22:17 If you're getting very extreme values at positive or negative, that's obviously indicative that there's some problems there with the IAC control.
22:25 In our situation prior, where we were sitting with our IAC control at zero, we were still idling too high.
22:33 I probably should have actually shown you this, but the idle spark would have been pulling a lot of timing out in order to try and fix that.
22:39 And we don't really want our engine sitting there idling with very, very low timing.
22:43 It's going to create a lot of heat in the exhaust system.
22:46 All right, we'll jump into our questions now and see what we've got.
22:49 If you've got any more, please keep them coming.
22:55 The Damon Rules has asked, could the same way of deco... OK, that's...
23:01 Looks like questions from a previous webinar.
23:04 My bad.
23:04 Yep, no, we've got no questions.
23:06 Jayden's just filled me in.
23:08 Relatively simple topic, but hopefully everyone's understood that.
23:12 And applying these basic steps to tune your idle speed control is going to give you a vehicle that drives much, much nicer.
23:20 It's not going to stall, which is also really frustrating I find when you're out on the open road, and particularly with an automatic transmission where you have to pull it into park or neutral in order to get the inhibitor switch to allow you to actually start the vehicle, you end up feeling like a bit of an idiot.
23:36 Alright, if anyone is watching this at a later point in our archive and has questions, please feel free to ask those questions in the forum and I'll be happy to answer them there.
23:44 Thanks for watching and we'll see you next time.