253 | Engine Protection Strategies - Haltech Elite
An important, yet often overlooked benefit of modern ECUs is their ability to provide built in engine protection strategies. In this webinar, we’ll look at some of the most common options and see how they can be implemented using the Haltech Elite ECU on our V11 Subaru STi.
00:45 - Why do we need it?
2:10 - What can we protect/what sensors do we need?
3:35 - RPM limiter
8:45 - Boost cut
12:50 - Engine protection mode
27:05 - Check engine light
28:05 - Questions
- It's Andre from High Performance Academy here, welcome along to another one of our webinars and this time we're going to be looking at some of the ins and outs of Haltech's engine protection strategies as applied in their Elite series of ECUs. And I think this is a set of options that are often overlooked by a lot of tuners and enthusiasts alike however this is a very easy way of protecting your engine and by simply setting these up and taking advantage of them, you can give yourself a little bit of peace of mind that if something goes wrong, you're going to either be alerted to that problem or your engine's going to simply be shut down to prevent any potential damage. So I'm going to go through and have a look at that and talk about how that works. So for a start I think it's worth talking about why we need engine protection in the first place and it's a case that there is a lot going on with a modern high performance engine and particularly when we're looking at aspects such as fuel pressure, oil pressure, or air/fuel ratio just for a couple of examples there, it doesn't take very long for an issue to cause some pretty expensive damage to our engine and even with a high quality dash logger or dash display fitted to the car, it's very difficult for the driver to keep their eye on every single aspect of the tune up while they're driving. Particularly if you are concentrating on driving your car on the absolute edge.
So it's very difficult for the driver to take notice of all of the aspects, all of the driver warnings and then actually take appropriate action in a suitable amount of time and particularly if we're talking about an oil pressure failure then you don't have very long to shut the engine down to prevent significant damage. On the other hand, if you are a tuner and you're tuning cars professionally for a living and you want to protect your reputation you can also incorporate these engine protection strategies as well, just to make sure that if you've got a heavy footed customer, that is maybe inclined to ignore warnings on a dash or gauges for that matter, that you can basically override the driver's right foot and actually protect their engine for them and usually they're probably going to thank you in the long run anyway. Alright so what can we protect? Well really that's down to what you want to install in the way of sensors. Obviously every engine is going to come equipped with some basic sensors such as engine coolant temperature, manifold absolute pressure would be pretty typical on almost every installation and of course we've got RPM so even with those basic sensors we can do some precautionary engine protection, even outside of the specific engine protection strategies that Haltech offer. But what we're looking at here is some of the more involved ones which will require some sensors to be fitted.
Oil pressure, fuel pressure, EGT and air/fuel ratio would probably be the key ones that I'd be looking at here, those are the usual ones that we'd want to look at to basically monitor and make sure that everything is under control. And once you've got those sensors installed this gives you the ability to first of all, of course log these, you can monitor what's going on while you are tuning, while you're on the dyno, while you're on the street but then it allows you to incorporate some of these engine protection strategies as well. So we'll jump into that just now, I'll just remind you as well, that as usual we will be having questions and answers at the end of the lesson so if there's anything that I talk about then please ask those questions in the chat and we'll get into those at the end. So let's start by jumping across to our Haltech Elite. So obviously I've got this set up and running at the moment on our Subaru version 11 STi.
This is set up as a bit of a plug and play system but really the specifics don't matter too much, what we're looking at here is the strategies that we're going to employ. So I've just got it sitting here at idle at the moment, we're not going to run this car on the dyno as part of this lesson, it doesn't really matter too much but what we're going to do is start by coming up to our settings here and we'll start by talking about some of the very basic settings. So outside of the engine protection strategies specifically. So if we start by going down, I've actually already done this, down to our little search function here, looking through the functions that are available, you can see I've started typing in RPM limiter. So that brings up our RPM limiter function which we can see here and we can see we've got some basic setups here.
We've got our cut method, in this case we've got injection selected, if we look at our drop down menu we can choose between injection and ignition. Now this is something that's often overlooked but is actually really important as a side effect to the reliability of our engine. Wherever possible I would recommend using an injection style limiter for rev limiting. The reason for this is there are a lot of engines with very sensitive valve trains and if you use an ignition cut this can be quite harsh. With an ignition cut, we're still sending a lung full, a cylinder full of unburned fuel and air out into the exhaust, where particularly on turbocharged cars that can end up burning or combusting in the exhaust.
This can cause pressure pulsations which can actually pop the exhaust valves back off their seat. Basically it's the same as an anti lag strategy. Now particularly if you've got a weak or sensitive valve train, let's say sensitive maybe more than weak, SR20DET is a really good example of that with a really heavy rocker, it's possible to end up with some pretty serious carnage on hand there, we may end up popping a rocker off so a ignition cut is quite harsh, injection or fuel cut generally a lot softer so where possible, I would recommend that you do use an injection cut. We've also got the option here to have a soft cut or a hard cut. Just as its name implies, basically the soft cut will employ the limiter smoothly and gradually over a certain period of RPM, hard cut, it's a full cut of your engine at the cut point so it depends again just what you're trying to achieve there.
Alright so once you've got that set up, we'll just go OK there and we'll come down to our RPM limit and we can see where we've got that set up so RPM limits here, we've got our main RPM limiter end limit and we can see that straight away we can employ a little bit of intelligence here in that we've got a 2D table relative to our coolant temperature. So a really subtle version of this engine protection here is to simply do what you can see I've done in this table, pulling the RPM limit down as the engine coolant temperature starts to creep up. So at 100°C, we've still got our normal rev limit there of 7600 RPM, at 120 you can see that I've pulled that number down to 5500 RPM. Now of course you can do whatever you want here, you can come to the table axis setup screen here, you are able to run in this particular table up to 16 sites, 16 break points and you can also enable a Y axis as well if you want to set up your RPM limit versus maybe throttle position and coolant temperature, basically the choice is up to you but that's a really easy way of doing this. What we do need to understand here is that the ECU will interpolate, so between 110 and 120°C it's actually going to gradually pull that RPM limit down so it's not just going to hit really quickly.
A good way of addressing that if you want is you can set this up a little bit more like this. So now if we apply that and we click on OK, so now as soon as we're over 110°C, whoops, we'll try and make that the same, Now our RPM limit will instantly drop to 5500 RPM as soon as we hit 111°C so again you can set that up however you want. So that's our first one. Now it's a really important aspect to mention here that is often overlooked, this as well as the next aspect we'll look at which is our boost limiter, our overboost cutout, is to make sure that these are configured before you start tuning the engine. It only takes something simple like a cable throttle that jams and you can end up finding yourself on the engine rev limiter so if you haven't set this up appropriately before you start tuning, it's very easy to end up with a simple mechanical issue such as a sticky throttle cable actually causing damage to your engine that would be really easy to avoid.
So that's our first one there, let's come back up to our settings now and we'll go to our overboost protection. So I'll just get rid of that and enter overboost. Let's try and get the right terminology, it's always interesting to just try and remember exactly how this is set up, how it's named I should say. So overboost cut. So again we've got the option to set this up as either a fuel or an ignition or in this case a fuel and ignition cut together.
Again, generally I would recommend a fuel cut primarily, if you really want to make sure that you're cutting everything I'd go fuel and ignition. That's going to make sure you've got a full cut, you're not going to continue with your boost climbing but it's also going to make sure that you don't end up with unburned fuel and air combusting in the exhaust system. You can set a delay so this needs to be understood pretty carefully. A delay can be helpful in so much as if you've got your cut set up very close to your target and you just end up slightly above your boost cut level you can get away with that using a delay but of course if you boost is rising very very quickly, even a small delay, a 10th of a second or so can end up with your boost rising quite dramatically above your safe level before the cut can come in. The other aspect here is the hysteresis.
So in this case before the cut will be deactivated, in other words fuel or ignition or both will be reintroduced, the boost will need to drop by, in this case, 10 kPa. So this just prevents us sitting right on that cut and it also is going to basically make the driver actually back off the throttle and allow the system to come back to normal. Obviously these are there for protection so we shouldn't be relying on hitting these all of the time anyway so once we've got that set up, we'll come down and we'll have a look at our boost cut, if I can find that. There we go, under our overboost cut here we've got our cut pressure. So again we can set this up as a 2D or a 3D table.
This one I've got set up versus coolant temperature and it's not a bad idea to do this. Obviously we don't really want to be thrashing a stone cold engine, that's where the most amount of wear happens in the engine so as you can see here, down at 20°C we've got the cut set to 120 kPa. Once we're above 40 kPa we're at 200 kPa. So you can do as you want there. One thing you do need to understand if you aren't also targeting lower boost when the engine coolant temperature is lower, again if you're doing this for a customer you may want to explain that if they do drive the car very hard and use full throttle when it's cold, you're going to hit boost cut.
So just understanding how that's going to influence the way the engine operates. So there's our very basic setup, we've got our engine rev limiter and our boost limiter. No trickery here, this isn't really engine protection but it's worth covering because again so many people overlook this. I'll also mention here with the boost cut, particularly when you're just getting started tuning an engine that's freshly put together, a combination maybe you're not particularly familiar with, the number one failure I see on the dyno with turbocharged engines is a boost control system that has been incorrectly plumbed. I do not know why this happens but time and time again, I see this.
I would say probably greater than 80% of the cars that come to me to be tuned that are turbocharged, we'll put them on the dyno, start running them and we'll end up with an overboost situation because someone simply hasn't read the instruction manual and set up the boost control strategy properly. This is the vacuum plumbing for the wastegate is really what I'm talking about here. So it's always a good idea to start with conservative boost cut limits, just to protect yourself in case that is going to be the situation you're facing. Alright let's get into our slightly more sophisticated options here, we'll come back up to our options and what we're going to do is in this case we will search for engine protection. With the engine protection you do need to enable it initially.
So you can see I've got a little green box here saying that it is enabled. We'll click on this and we've got three different levels of protection. So this is done in a reasonably interesting way. Rather than directly setting up all of your protection strategy within this, basically you're setting up levels of severity of your protection and then you can assign a specific sensor to achieve that level of protection if it goes into fault, depending on how worried you are about that particular input. So for example here we've got severity level one at the moment is enabled and we've got a variety of different options here for example we can choose to enrich our air/fuel ratio target a little bit.
In this case 0.1 air/fuel ratio units so not a big enrichment. We've got a boost correction as well here so we can reduce our boost pressure. So obviously if we've got a potential issue, it would be beneficial to reduce the amount of load being placed on the engine so you can choose to reduce that as much as you want depending on what you're actually trying to achieve here. We can at the same time also retard our ignition timing. So we're adding a little bit of fuel, we're reducing some boost, we're retarding the timing so we're basically just safeing up that tune a little bit here.
Then we can start to get a little bit more sophisticated here, we can bring in a rev limit, so I've just drawn through that but you'll get the idea. As usual we've got the option of selecting our rev limiter type so ignition or fuel, and we already know, I'm a big fan of fuel cuts here, and your rev limiter ends. So here we're going to pull that rev limit down to 5500 RPM. At the same time if you've got drive by wire throttle, you can also define a maximum throttle opening. So no matter what the driver is doing on the throttle pedal, you can limit what's actually happening at the throttle.
And this is one of those aspects that again is just often overlooked with drive by wire throttle. When we talk about drive by wire a lot of people complain that drive by wire's slow, it's laggy and really what's the point. I would argue that modern drive by wire is definitely not laggy, a lot of that came from OE setups that were designed to be slushy by nature. With a modern drive by wire throttle system, it's just as crisp as drive by wire and then it gives us the benefits to being able to do things like this, closing the throttle body. Alright then we've got our active condition here, so we'll just have a quick look at our options here.
At the moment you can see the current DTCs only so basically diagnostic trouble codes that come up while we are on the current drive cycle. However you can choose to also activate this with past diagnostic trouble codes, so something that has been logged in the past. Up to you there what you do, generally I think that during the current drive cycle should be enough there. So if we go to level two, basically we've got exactly the same options here under level two and level three but what we can do is just incrementally make these cuts more and more severe. For an oil pressure cut which we'll have a look at in a moment, we may want to bring our end RPM limit down to zero, essentially completely stalling the engine so really just dependent on what you're trying to achieve and what you're trying to protect.
So that's where we set up what's actually going to happen when a cut is enabled. We'll have a quick look at some of the options that you may want to choose here. So let's start by having a look here at our fuel pressure sensor so if we want to do this obviously we do need a fuel pressure sensor fitted so we've done that on our Subaru STi here, we'll click on our fuel pressure and we'll just go through the options here so for a start the simple aspect here is just the wiring of that sensor. So this defines the analog voltage input that the sensor is connected up to. We've also got our calibration here so we're just running the typical Honeywell 0-150 psi fuel pressure sensor.
We've got our display here so we can bring up a warning for minimum and maximum and then we move to our diagnostics which is the important part here. So for a start we can set up a raw minimum and maximum value for our voltage. So this is essentially going to protect us if the sensor is faulty or perhaps the sensor becomes unplugged, so it'll revert to zero volts or maybe it shorts to five volts or something like that. So we can set that up. These Honeywell style pressure sensors, they're pretty common and they work between 0.5 and 4.5 volts so generally I would set up a low limit there at maybe 0.05 volts or 0.1 volts and a high limiter maybe 4.95 volts so basically if we're outside of those realms, we know that something's gone wrong there.
So that's generally going to be a sensor fault there so you need to be a little bit mindful of that, doesn't necessarily mean that we've got an oil pressure problem but it does mean that we've either got a faulty sensor or faulty wiring. So we can then assign a severity to our DTC in relation to that. Now I'm not going to worry too much about that because as I say, this is more a faulty sensor or faulty wiring. What we're looking at is what's actually happening when our engine's running. So we can come over to our operating, tick that and then we've got our fuel pressure deadband.
So let's have a look at our options here. Fuel pressure deadband, essentially how much are we comfortable with the fuel pressure moving relative to what we'd expect so this is going to be dependent on your fuel system. So in this case we're running a manifold pressure referenced fuel system. So if we've got three bar of differential fuel pressure, what we should find is that as our boost pressure increases by one bar, so should our fuel pressure, our fuel pressure therefore should be four bar. So what this means is that if we set this deadband up to let's say 20 kPa, if our fuel pressure falls by 20 kPa over what's expected, it's going to go into a fault code there, a fault condition.
And we've got our pre condition here, so what do we need in order for this to be referenced? So on a turbocharged car we're probably more interested in what's happening when we are in boost. So we're probably not going to do any damage if our fuel pressure starts to drop away when we're in vacuum just cruising. So we can set that up as manifold absolute pressure which we've got there. And then we can define that. So maybe I want to set this up if I'm above let's say 80 kPa of positive pressure.
And that will then ignore the problem unless we are above 80 kPa. So we'll just set that up. And then of course we can select our DTC severity and of course that goes back to what we just looked at before. So relatively straightforward there. Now you do need to be mindful of the deadband value in particular here.
Everything is going to move around, your fuel pressure will move around, it's never going to be absolutely rock solid so it's a good idea to at least have a look at some logging and see what your fuel system is doing in terms of your fuel pressure under normal conditions. Once you know what's normal, then you can set a sensible deadband that's going to mean that the fuel pressure can wander around a little bit, it's not going to be annoyingly bringing in this diagnostic trouble code needlessly but if there is a genuine problem, is going to actually bring your attention to it or bring in the engine protection strategy. So again really up to the individual as to how exactly you set that up. Next one we'll have a look at, and this is one of the most important ones I find, I've seen so many engines lost from this which is oil pressure. So I haven't actually got an oil pressure sensor installed on our STi but I've just gone through the process so you can see how that works.
So again same deal, we've got our wiring, I've just chosen a spare input here, obviously it's not going to be doing anything for us. We've got our calibration, exactly the same Honeywell pressure calibration there. We've got our display warnings that we can set up and then our diagnostic so again just like our fuel pressure we've got our raw minimum and maximum voltages indicating a wiring problem or a sensor fault and then we've got our operating condition. So in this case we've got a little bit more flexibility in how we set this up. We'd do this from the menu substructure.
Before we do that though, we do need to have a look at our DTC severity. So for this one, this is going to be pretty catastrophic if we do have an oil pressure fault, we want to be pretty mindful of this. So I would probably be choosing a high level of severity here, probably level two or three depending on how many levels you're running and in worst case scenario you really want to cut the engine dead, let's say we've got a dry sump engine and the belt is just broken or fallen off. We've got zero oil pressure, we don't want that engine running around at 3000-4000 RPM until it finally falls to pieces, we want to cut that engine straight away to prevent any damage so once we've got that set up, then we come over to our ECU navigator structure here and we'll come through to our oil system which we can see down here at the bottom and we've got our DTC settings here, so our minimum RPM, the delay and a pre condition as well. So in this case I wouldn't really necessarily want a pre condition.
If I've got no oil pressure I don't really care what the throttle position or the manifold pressure is, I want the engine to be saved, so that's pretty important there. And then it works really in conjunction with this table here which is our oil pressure minimum, we'll bring that up here. Again we've got flexibility here, we can set this up as a 2D or a 3D table. Obviously our oil pressure is going to vary in relation to both our engine RPM as well as our oil temperature. So we could, if we had an oil temperature sensor, set this up relative to those two axes, that's going to give us the best way of plotting realistic oil pressure minimums that we're happy to see.
Often you're not going to have an oil temperature sensor, another good way of doing this or inferring oil temperature would be from engine coolant temperature. And again this table, once we've set it up, be it 2D or 3D, what we really want to do is get some good quality log data of what we actually can expect under normal conditions for oil pressure vs RPM and engine coolant temperature or oil temperature. And we want to fill the table in with sensible values, a little bit below, obviously our normal operating level. And the idea behind this is that we're protecting the engine against oil surge. So this is particularly common if we've got a circuit car which is pulling high lateral G forces, even braking G forces for example can be enough to slosh the oil away from the pickup and cause a momentary surge where the oil pickup is going to suck in air instead of oil.
So that's how we set that table up and really important and a really good reason to fit an oil pressure sensor, even though maybe in this case we haven't actually taken our own advice there. Do what we say, not necessarily what we do. Let's head back to our settings now and the next one we'll have a look at here is our wideband. So let's bring up our wideband O2 sensor one. So we've got this coming in via a CAN based wideband sensor.
So quite helpful there, means that we've got the integrity of the data is guaranteed. So then we've got the ability again with a conventional wideband to set a minimum and maximum value there. We've got our operating maximum so it's looking at maximum here, basically if the air/fuel ratio is lean then that's obviously the dangerous condition we want to avoid there. We can set that maximum air/fuel ratio that we're happy with, probably 5.9 is not where I'd want that to be but let's say we're targeting normally 11.5:1 so maybe I want to set my maximum there 12.5:1. This delay is really important here because our air/fuel ratio does always fluctuate around and particularly as well if you are using something like an ignition cut for flat shifting, you're going to definitely see a lean spike so setting this to zero is going to actually cause you more trouble than it fixes because you're constantly going to be bouncing off this diagnostic trouble code.
So while it might sound a little bit scary, you're probably going to need, realistically, to set this somewhere around about 100 to maybe 200 milliseconds to actually get sensible values. Again as well you can try and get yourself out of this triggering needlessly by setting this in an area where we're most worried. So let's say we're only going to be bringing this DTC in when we're above 4000 RPM. Then we've got this pre condition here again so in this case probably MAP is what I would want to be looking at and you can set this to whatever you want. Let's say again we want to bring this on if we go leaner than 12.5:1 for 200 milliseconds, when we're above 4000 RPM and 80 kPa.
Obviously we've also got the option here for a sensor failure which is kind of helpful but we want to be a little careful of how we deal with that. So for our operating maximum value, this might be something where we want to be pretty serious with our DTC severity so we might want to go maybe level two. Obviously we don't necessarily need to cut the engine completely, that's not necessary like with our oil pressure warning but we still want to bring the driver's attention to something not being right. Sensor failure, we want the driver to know something's not right so they can address it but yeah not necessarily that we're going to end up completely shutting down our engine. Alright we're going to move into questions pretty shortly so this is a good time to remind you that if you do have any questions you can ask those now, we'll jump into those in just a moment.
There's one other aspect that I want to just talk about here. If we go back to our, actually our check engine light as well, we can also set the check engine light up if we've got this wired, in this case we've got this wired to digital pulse output four and that will bring on the check engine light if there is a diagnostic trouble code. So even if you've got the engine operating under the conditions of a level one severity cut, the check engine light's still going to come on and bring the driver's attention to the fact that something isn't right there. So again just even if it is your own car, you sometimes may find that some of these problems come up and you're not immediately aware of it so bringing on a fault code light to make yourself aware that you've got a problem there is a really smart option. Alright let's head into our question and answer session and we'll see what we've got here.
Alright so our first question there comes from Timothy Bradley who's asked how does this compare to the AEM Infinity 506 with a Haltech Elite? It compares very well to the Haltech Elite because this is a Haltech Elite. The AEM Infinity to be perfectly honest, it's been so long now since I've used our AEM Infinity, I can't actually remember off the top of my head the specifics of the engine protection strategies that they use. I know that they do have engine protection strategies and if I am correct I think we've actually done a webinar on the Infinity already so I would suggest having a look in the webinar archive, that would probably be a pretty good place to go. Cuso has asked, is this webinar sort of an extra lesson or are engine protection strategies more explained in the tuning courses? No Cuso the courses themselves, so for example where we've got the Practical Standalone Tuning course where we run a full worked example using the HPA 10 step process on the Haltech Elite ECU, what we're looking at there is the fundamentals so the setup of the ECU for inputs and outputs, configuring the fuel and ignition tables, setting our base fuel pressure, base ignition timing and then actually tuning the fuel and ignition. We've tried purposefully to keep these to a minimum so that we don't end up with lesson that's 10 hours long covering every single potential aspect of the Haltech Elite software that you may want to consider.
Then what we do is we add these more advanced topics that are only going to suit potentially a smaller crowd of our members in our webinars. So there's a lot of webinars, if you actually search in there in the archive, that will cover some of the specifics such as cold start tuning, such as transient enrichment, boost control etc, on the various platforms that we cover. Next question comes from Bey who's asked, swung onto tuning lambda, just for splashing in methanol, in Scotland we don't have many fuels, a good video would be teaching guys how to use PID values for closed loop fuelling and boost. Ah yep good point, closed loop tuning for boost in particular I think is one of the things that people struggle with the most. If you're not aware of it Bey we actually already have a complete Boost Control tuning course which goes into detail on how a PID control algorithm works.
More importantly though, once you actually understand how that PID algorithm works, it also gives you a step by step process you can apply to dial in the PID gains and get your boost control rock solid. Suhas has asked, with Turbosmart electronic wastegate, how do we set up boost protection strategy? At the moment I don't actually think pretty much anyone out there in the industry is running the Turbosmart electronic wastegate, we've actually wired one of our vehicles for it so we're hoping to do some content on that in the future. Essentially though, the boost protection strategy's going to be identical. You've got the ability to set up a boost cut. Once the Turbosmart electronic wastegate is configured and operating, essentially from the ECU's perspective it's no different from how it would manipulate a normal three port or four port solenoid to control boost.
It's just doing it in a different way so our boost control protection strategies are exactly the same. Alright looks like that's all we've got in the way of questions there, oh no one last one there. Ar Jar has asked, other than fuel pressure, oil pressure, oil temp, ECT and wideband, what other sensors would you consider worth getting that are critical? Actually oil temp is another one that I didn't touch on. Essentially while I've gone through a few things here, there are a variety of other different engine protection strategies you can incorporate. Let's say you've got oil temp there, you can do exactly the same with oil temp but the strategy, the way you go about setting it up, really exactly the same.
The other one that I would consider is a thermocouple for exhaust gas temperature. On a turbocharged car that can be really really powerful and can protect you from a lot of nasties if something goes wrong there so again you can set up a maximum exhaust gas temperature that you're comfortable with seeing. Above that you can bring in a protection level, severity level based on the DTC that you've created there. Alright that's all we've got in the way of questions so thanks to everyone for joining us. Remember if you are watching this in our archive at a later point, if you've got any further questions, please ask those in the forum and I'll be happy to answer them there.
Thanks for joining us and hopefully we'll see you all again next week.