221 | Save Your Engine With Driver Warnings
- It's Andre from High Performance Academy, welcome along to another webinar. Today we're going to be talking about using an aftermarket dash display unit for driver warnings. Now when we see some of these aftermarket dash logger units fitted to high end racecars, it might seem a little bit superfluous. There's quite a large price tag for some of these dataloggers and ultimately when the driver is out on the racetrack, there's not a lot of chance they're going to be spending much time viewing the information on the dash logger. And that's absolutely true but I think a lot of people overlook where the true value lies with these aftermarket dashes.
So this is what we're going to focus on today. And really there's two areas that these dashes come into their own. The first functionality is the datalogging capabilities. So of course with any car, there's a huge amount of information going on, being transmitted between the ECU and the dash, also other sensors that may be fitted to the engine and to the chassis. And we want to be able to analyse all of that information at a later point when things are a little bit calmer when we're back in the pits so we can see exactly what was going on while the car was out on the racetrack.
So there's a variety of reasons why this is important. First of all we need to be able to confirm that our engine is operating correctly. Basically looking after our engine health, really doesn't matter what sort of modifications or adjustments we're making to the car, if we've got an engine that's desperately low on oil pressure or fuel pressure and it's not going to last for another five laps then we really need to deal with that first. So engine health, that's probably the main, or the first priority we're going to be using our datalogging for. Once we go past that though then we can use it for driver and car optimisation.
Basically making the car fast around the racetrack. So there's our first use is the datalogging but what we're going to be focusing on today is using the dash for driver warnings. And I know the argument that I hear quite often is when we're looking at some of these dashes that may be let's say in the region of USD$2500-$4000, it's hard initially to justify that kind of an outlay when we may have a car that's perhaps only USD$20,000 or thereabouts. So you're looking at a dash that's getting on towards quarter of the price of your car. However particularly as we start getting to more heavily modified engines where there's a lot of money tied up in the engine and the surrounding components, using some of these driver warnings to let the driver know that something is not right, this can give the driver then the opportunity to back out of the throttle, shut the engine down and potentially save the engine.
If you save an engine that's worth $10,000 or $20,000 all of a sudden that dash starts to look pretty cost effective. So this is really where I see some of the true value of these dashes. Now on display here in front of me I've got the Ecumaster ADU or advanced display unit. Obviously these dashes are available from a wide range of manufacturers, I just put this here because we happened to have one sitting on the shelf today. I am going to be focusing on some of the functionality in the MoTeC range of dashes.
But for all intents and purposes, there is a lot of crossover between most of the popular brands of aftermarket dash. So if you're using an AIM dash, maybe a ADU dash, MoTeC or maybe an AEM dash, then basically everything I'm going to be talking about today can still be done, just the software and the way that you might develop the different controls or functionality may be a little bit different. So the key really here is back if we look maybe a decade or so ago, it was probably pretty common to see racecars or street cars that were fitted with an array of analog or even digital gauges on the dash, monitoring everything from our oil pressure and fuel pressure through to boost, engine RPM, coolant temperature et cetera. Now that's all well and good but the problem is that particularly in a really fast car, there's a lot going on and it's impossible for the driver to monitor all of those gauges consistently and do a good job of driving the car. So what this means is that it's quite easy to end up having a problem with let's say our oil pressure and the driver not notice that.
Now it doesn't take very long in terms of an oil pressure problem to cause expensive damage. So with the analog or digital gauges, really not a lot of use. Yes you can start adding warning lights to them but there's some limitations there as well. So that's why I don't particularly like the analog and digital gauge array and the advantage of having everything coming into a dash logger gives us a lot more power with our controls. I just want to come back to that, what I just mentioned there, having a warning light on our gauges.
So a lot of the gauges that are popular in the aftermarket will have a warning light function built into them. So one of the examples that I've had a lot of customers have in their cars is the Defi range of gauges and let's talk about the oil pressure gauge for a moment. So the Defi oil pressure gauge is a good quality gauge and it will give you a good accurate read out. Of course again if you're watching it, you can catch a problem and then there is this warning light functionality to bring your attention to the fact something's not right. Now the problem with this is really very similar to the factory style oil pressure warning that every car has from stock.
These are a basic oil pressure switch and they're designed so that that light, that oil pressure warning won't illuminate when the car is at idle and the oil is hot. So depending on your particular engine, the viscosity of the oil, the temperature and a bunch of other things, we may find that at 1000 or 800 RPM idle we may only have let's say 15 or 20 psi of oil pressure. So obviously to make sure that our warning light doesn't illuminate at idle, we need to make sure that our warning level is below that. So let's say it might be set at 12 or 10 psi. Now that'll be fine at idle if the oil pressure drops below 10 psi, that'll bring on our warning, letting us know something isn't right.
The problem however is that oil pressure does rise with our engine RPM and a good guide or rule of thumb here is that we should be seeing around about 10 psi of oil pressure per 1000 RPM of engine RPM. Now there are a few variables in there but that's generally a pretty good guide to where you should be expecting your oil pressure to be. So now if we have a problem with our oil pump, let's say we're running a dry sump oil system and the belt comes off the dry sump pump so we lose oil pressure and it drops down to nothing at 7000 RPM. Now we've got a very serious problem. But the issue here is that the warning isn't going to illuminate until the oil pressure drops down to 10 psi.
Now at this point we've already done almost certainly irreversible damage to our engine. So by using some smart controls for our warnings in our dash which we'll look at shortly, we can end up having that oil pressure warning be relative to our engine RPM. So let's say at 5000 RPM and above if our oil pressure drops below 40 or maybe 50 psi, then we'll bring on the warning. Whereas at idle we can revert to something a little bit mores sensible, maybe 10 psi. We can set up a table as we'll see.
Alright so I just want to go through and look at how we would do that in our MoTeC dash so let's actually for a start we'll have a look over at my laptop screen. This is the C125 that we've got set up in our Toyota 86 racecar. And this is probably a pretty typical page of information that the driver actually wants when they're out on a racetrack. So under normal circumstances the driver is really going to be ignoring almost everything except for this shift light module. So we're going to be watching that shift light module, we know when to select the next gear.
So basically all of the other information is almost irrelevant to us unless we're looking for something specific. Now we do have a couple of pieces of information that are relevant here. We've got gear, really with a sequential gearbox we're only looking at that when we're selecting a gear in pit lane. Once we're out of the pits really we don't need to know what gear we're in, we're going to already understand that. We've got our fuel remaining so that's pretty important for a race where fuel burn is critical and we need to be refuelling during a race.
So this is information that the driver can keep an eye on just to know when they're getting really low on fuel. Then really for racing the information that's relevant or important is we've got our lap time, so this will show us the last lap time that we just completed. Then we've got in real time it will show us what our predicted lap time is. This is quite useful during qualifying because if you're trying different lines or something of that nature, this is going to update in real time and show you what your predicted lap time will be and that works in conjunction here with our lap gain loss. So we can send a reference lap through to the dash and this gain loss function will show us whether we are doing better or worse than that reference lap.
So we can actually kind of judge our driving while we're going around the track. In particular if you don't want to waste your tyres while you're out there in a qualifying session you can straight away see if you're off the pace, you can basically abort the lap and have another go. So very little information there in real terms, you'll notice that we've got nothing about our engine coolant temperature, oil temperature, gearbox temperature, none of the actual vitals of the engine because we simply don't have time to watch those. And instead what we're going to be doing is relying on the driver warning to come up. So I'll just show you a quick video and see how those driver warnings work in real time.
So this is actually from a race that we just completed on the weekend. So we'll just reverse back a little bit. So this is avoiding a spinning car and we can see here that the driver warning ends up illuminating so that's the flashing red lights we've got here. So what actually happened there as we got hit in the rear, the fuel surge tank was slightly damaged so it resulted in an instant loss of fuel pressure. So that straight away brings, I was driving the car at the time, brings my attention to the fact that there's something wrong and as soon as that comes up, you can't read it here but along the bottom line you can see that that's gone red.
So that shows you a warning message. So you know straight away the flashing lights bring your attention to the fact somethings' wrong, you can look down at the dash at a glance, you can see what the warning message is and then you can decide what sort of course of action to take. Now obviously some of these warnings require slightly more drastic action. So if you've got a low oil pressure warning you're going to want to do something about that very quickly. Low fuel pressure though, slightly less critical.
We're going to start feeling the engine surge if the fuel pressure does get very low. Now we also obviously don't want to end up driving around the track with two red flashing lights in our eyes for the next hour so what we've got here, it's a little hard to see but on the steering wheel on the left hand side there is a red button and that is the alarm reset so I'll just replay this now and you'll see I actually go and I hit that button, you can see that that resets the warning, pull another gear, happy days, continue with the race. And we actually get, I think a little bit further into this, another driver warning comes up as well. I'll just check that, yep we've got another warning comes up there. So definitely not the best way to start a race but that's what the dash is there to help us with.
Alright so now that we've kind of got a bit of an idea of what's going on, I want to take you through some of the controls inside of our C125 dash. So this is following on from that picture that I just showed you of how the dash is set up, let's just quickly have a look at that again. So that's our race page, so this is the main one that we're on during a race. And we've got that page set up here. So we can choose all of the information that's going to be displayed.
So we've got our fuel remaining over here, which I've already talked about. We've got our running lap time that we'll update on the right hand side. We've got our GPS speed on the left hand side and then at the bottom we've got all of the information that we can scroll through using another button on the steering wheel. So while in most instances the driver doesn't need a lot of information, there may be times when they want some specific information. So for example on the top line of that information we've got two pieces of information being display, this is our driver rotary switch one and driver rotary switch two which just happen to be our launch control and our traction control set points.
So at a glance the driver can see what setting they've got for launch and traction. Then we've got for our qualifying as I mentioned, our lap gain loss and our lap time predicted. Then if we do have a problem and we want to start monitoring something in a little bit more detail, we've got our engine temperature, oil temperature and diff temperature so some of the engine vitals. Below this we've got our fuel pressure and our oil pressure so we can keep an eye on those. Now that's not the only page we have access to, while that is the one that we predominantly use out on the racetrack, we do also have this other page here which is labelled diagnostics.
So this gives us a lot more information so we've got all of those channels being displayed up there which include oil temperature, engine coolant temperature, oil pressure, fuel pressure. So also lambda for both banks of cylinders. So this is a good way, particularly when the car is in the pits, being warmed up, we can keep an eye on all of those parameters. It's also something I tend to do on a cool down lap, I'll just cycle through to that diagnostics page so I can actually have a look at what all of our temperatures got up to at the end of the session. So that's the way we can control the displays but really obviously we're focusing here on our driver warnings.
So we can come over and have a look at our driver warning setup here. And this is the range of warnings that I've got set up in our C125. So what I want to do is start with oil pressure since we've talked about that. So we'll double click on our oil pressure warning. And first of all we can set some conditions for this warning to come up.
So this is our conditions here and in this instance the conditions I've got set up are actually relatively straightforward, I've only really got two set points for this. So the first one of these says if our engine oil pressure is below half a bar for two seconds and our engine RPM is above 500 RPM for three seconds, then bring on the warning. So basically the time delays there just allow a little bit of time for the engine oil pressure to build after immediate startup. But basically if the engine is running above 500 RPM and we end up with our oil pressure dropping below half a bar then we're going to bring on that driver warning. So that's our low RPM area that we're going to be monitoring and bringing on that warning.
However the more important one is the second one and in this case if our oil pressure drops below 2.5 bar for half a second and our engine RPM is above 4000 RPM then we're going to bring on the driver warning. Now of course you can get a little bit more granular with this as well, this is a pretty coarse setup and I'll show you another option with this as well in a moment. Important to note that you can control which of the display modes you want these warnings to come up on and obviously with oil pressure we really want that warning regardless so that's what we've got here during race diagnostics or road, we're going to get that warning. Now what's going to happen when that warning is active? So what we want to do is come over to our message tab here and obviously pretty self explanatory, it's going to come up with a text message that says oil pressure, so that happens on the bottom of the dash and that'll be displayed in red to bring our attention to it. Now another thing we can do is display alongside that what the oil pressure is.
So that's pretty handy because if I get an oil pressure warning, I want to know if the oil pressure has continued to drop to zero or it was a momentary surge. So here we've got the option to include the value. So obviously the channel that we're going to display there is our oil pressure. We can choose to display in PSI or kPa and then we can choose to display the current value or display the value when the alarm was triggered. So the reason that I want to show the current value is I kind of already know what the value should have been when that alarm was triggered because I've got those conditions that I've just set up.
And again just as I've mentioned I basically want to know what the current oil pressure is so I know how to react to that problem. Has the belt come off our dry sump pump and I've literally got no oil pressure? In which case we're keying that engine off straight away, we do not want it running for another tenth of a second. Or alternatively was it momentary surge, have I now got oil pressure back? Well that may be OK to get us back to the pits so we can then kind of dive in a little bit deeper and diagnose what's going on. So as I've said, that's a pretty straightforward option for setting that up but we can get a little bit more advanced if you want. So in this case what we can do is we can go into our calculations menu here and if we come down to the tables function or tables option, we'll click on that.
And we can set up a three dimensional table. In this case I've already got one that I set up previously. So three dimensional table, what we've got here on our x axis, we're going to have engine RPM, on our y axis we've got oil pressure. We can of course set all of our break points out here on the right hand side and then we're going to select a channel that's going to be output so in this case I've just chosen a general purpose channel with zero decimal places because we just want a channel that's going to either be zero or one. So that's going to basically be our alarm channel.
And then we can click on our table and now what we've got is a table of values. Zero, that warning is off. So basically we've kind of got this coarse line through here. Let's say for example at 3000 RPM if we're above two bar, we're going to be happy with that oil pressure, if we drop below two bar, then we're going to be bringing on that driver warning. However if we're up at 7000 RPM we're going to have that driver warning off if we're three bar or above.
Below that we're going to bring it on. So then you can just select the output of that channel, in that case GP41, general purpose output 41 and use that to drive our alarm. Alright so that's just one aspect there, we've just looked at our oil pressure warnings. Let's just jump back in though, we're going to have a look at some of the other warnings that we would normally operate in one of these dashes. So let's have a look at our temperature warnings.
So we've got a few here, probably one of the key ones that most people would use would be our engine hot, so monitoring our engine coolant temperature. So let's have a quick look at this, and this was one of the areas we were struggling with with our Toyota 86 for a long time until we basically revised the entire cooling system. So if we look at the setup for our warning here, the channel that we're looking at is our engine temperature. We've selected that if it is greater than or equal to 102 degrees C then it's going to bring on that warning. It's got to be at that point for one second.
Now if you've got a cooling system that's maybe a little bit marginal, 102 for a racecar it's probably actually not too bad, I'm not that worried about it but I want to know that our temperature is creeping up a little bit. However if we've got this set up like this, we're going to basically be in a situation where our temperature warnings are going to just constantly be cycling up on the dash. We can control how frequently it'll come back but basically it can be quite distracting to the driver. So we've got a few controls around that as well so we can use here, we've got use trigger value modifier. So basically what this does, it's exactly as it says here.
After the alarm is activated, the trigger value is modified by two degrees. So basically after it's initially been triggered at 102 degrees C, if we reset that, the next time the alarm's going to come up is when the coolant temperature gets up to 104 and we can also set that this will only increment two times. So otherwise of course we can just keep it incrementing up to the point where we've got a melted lump of metal sitting in the engine bay, that's not going to be too useful for anyone. So in this case it'll go 102 then 104 and then 106 and then it's going to constantly stay there. And again if you've just got one of these situations where odly for some reason we're just a little bit marginal and our coolant temperature then starts to drop back down, maybe you get stuck behind a car with limited air flow, coolant temperature starts to rise but once you're back into clean air, it drops back down.
So it'll actually reduce that trigger value back down if the alarm doesn't activate in this again for 60 seconds. So quite a lot of control that we've got there over how that particular warning will work. Then of course we've got our message, it's going to tell us the engine's hot. It's going to include the value and it will show again the current value just like our oil pressure. And we've got our options here.
So this will be removed, this alarm will be reset when we press the alarm reset button and it will not redisplay that message until 10 seconds have elapsed. Probably actually in hindsight a little bit too tight there. We're going to probably not need that warning popping up every 10 seconds. And then we've got the option to what we want to do here. We are going to activate our warning light which we'll have a look at in a moment.
So that's how we can set up a normal temperature warning and we've got those as well in this particular setup for our differential temperature in this case 135 degrees, we've got that same modifier, so we're going to increment in four degree increments. And we're going to do that twice and then we've got another one for our engine oil temperature and also our gearbox temperature. So basically just monitoring and keeping an eye on all of those factors that are really going to be critical to the reliability of our engine. Now it doesn't necessarily need to be just about our engine reliability as well. There are a range of other options that we can use these driver warnings for which I'm going to touch on.
Now I'll just mention here that we're going to be moving into questions and answers pretty shortly so if you do have anything that you'd like me to kind of cover off or get into any more detail on, this is a great time to ask those in the chat. So in our non critical warnings, the first one that I'll talk about here is our pit limit. So this just lets the driver know that the pit limiter is enabled. So if we double click on that, so we're using in this case a general purpose output. This particular channel is generated from a CAN message coming from the steering wheel when the pit limit button is active.
So any time that's active, it's going to bring up the warning for our pit limit. So we'll click on our message. So that's going to bring up the pit limit message at the bottom of the dash. If we click on options here though, in this case I've chosen not to activate the warning light and you'll see why that's the case in a moment. And it's going to automatically remove that warning as soon as the pit limiter's no longer active so we don't actually have to reset an alarm there.
As soon as we disable the pit limit, that warning message is going to automatically be disabled. So how that particular pit limit works is in conjunction with the shift light module. So in order to have a look at that, let's move to our shift light module. So this is our pit limit warning here. And we can see, if we double click on this, what's going on there.
So we're flashing the shift light module, we're changing between cyan and magenta, it's flashing, so it makes it really pretty much impossible for the driver to ignore that the pit limit is active. Now importantly we can see that the LEDs at each end of the dash are not being used while our pit limit is active and I'll just show you again a quick photo so you can see. The shift light module includes these little LEDs here and then we've got these two outer LEDs and these ones are being used for our driver warning. And the reason that I'm doing that, we can see there this is our warning light here only flashing the outer LEDs. The reason that I've done this is that it allows us to have a driver warning come up but the driver is still going to end up being able to see the shift light.
So some of the less important driver warnings, maybe a oil temperature for example, that's not going to mean that we're going to instantly stop driving the car and it's really easy to not think this through, have a warning that uses all of the shift lights across the top of the dash and then when that warning's active you can't actually tell where abouts you are in the rev range anymore because it's overriding your shift light. So that's why I've done it that way. Alright let's just head back to our warnings. So that's our pit limiter there. The other one that I wanted to show you, and this is quite useful because it can really save a lot of frustration at the track, this is the last one that I've got here which is our power on warning.
So the conditions here are device up time is greater than 30 seconds, in other words the dash has been powered on for greater than 30 seconds but our engine RPM is zero. So this is where someone's keyed the car on and it's running in the run position but the engine hasn't been started and it's going to give you a visual warning that the dash or the car has been powered up and hopefully it's going to prevent you ending up with your battery going flat. So yeah quite useful aside from just protecting your engine. Now another thing you do need to consider with these warnings is that there is a priority to the warnings. And the highest priority is given to our warning number one which in this case, probably pretty understandably is our oil pressure.
This is the warning that I am going to be most interested in and I definitely don't want for example our gearbox hot warning coming up and overriding an oil pressure warning because the oil pressure warning is going to be the most critical, that's going to result in instant destruction of our engine so we really want to know about that. So it's really important that you do give some consideration to how you're going to prioritise those warnings so that you end up seeing the information that is important to you. Alright so the other aspect here that's important to keep in mind is that driver warnings tend to often be ignored. So it's important to make sure that you do apply a little bit of common sense here and I'll just jump across to some data here from our race meeting at Teretonga. So this is one lap here and the channel that we've got down the bottom here is alarm acknowledged.
Always a good idea to be logging the alarm acknowledged channel which is basically going to show you any time the driver has been pressing the alarm reset button. So you can see right here at the start of the lap the driver has reset the alarm and then a further two times at this point here. Now in this particular situation the two alarms that had come up were fairly non critical, we've got a differential temperature and a gearbox temperature warning that popped up simply because our pumps weren't running for the diff cooler and the gearbox cooler. But the alarm warnings were doing their job, brought the driver's attention to the fact that there was a problem there and then we could address that and look into it further when we were back in the pit. But yeah just being able to see what the driver is doing with those alarms is quite important.
And what you'll find as well, this happens quite often where you've got a driver who maybe isn't paying for the rebuilds of the engine or the components, doesn't really care too much and particularly if the car is still going, they'll tend to still stay at full throttle and just keep pressing that reset button. So this is really good ammunition to have, particularly if someone comes to you as a tuner and says well hey the engine's blown up, it had no oil pressure for the last two laps and the driver kept going, why didn't the driver know about it? So you can say well the driver knew about it, just happened that he was pressing the alarm reset button about 50 times per lap and kept his foot flat. So just a little bit of ammunition there that's worthwhile having. But the next aspect here is to consider using the driver warning alarms in conjunction with some safety strategies inside of your ECU programming. So those driver warnings are there to tell the driver that there's a problem but really it's then up to the driver as to how they're going to proceed.
So I would always back up an oil pressure warning on the dash with an actual hard cut program into the ECU. Generally, you want to keep a little bit of room between the driver warning and the point where that hard cut does come in. But this just means that if the driver does ignore those warnings then we've still got some protection in there to help keep that engine alive. Alright so hopefully that's given you a little bit of insight into where these dash loggers can be useful. And again as I mentioned at the start of the webinar, if you can use a $2500 or $3000 dash to save a $10,000 or $15,000 engine, all of a sudden that particular dash starts to look like a pretty good investment.
We'll jump in and have a look at some of our questions. Now remember if you do have any other questions, please feel free to keep asking and I'll see what we've got. Nathan has asked, on the BRZ would you recommend devices that tap into the factory oil pressure gauge that give you more than 1/8th inch ports for the likes of temp pressure and the OEM low pressure sensor. OK yeah good questions Nathan so this can be a little bit tricky sometimes actually getting this information, so adding sensors. What I can say is that the correct approach is really going to depend on what you're doing.
With our particular installation, because we've completely got rid of the factory dash, we don't need the factory oil pressure sensor, low pressure switch. So we can disregard that, get rid of that completely and we've used an adaptor. Now I can't quite remember off the top of my head whether it's factory 1/8th BSP and the sensors and MPT, I think that's the way it is. Because we've actually had the engine apart, I took the opportunity to retap the front cover of the engine so that the oil pressure sensor is going straight in. Otherwise, you can get T pieces that you can thread in both the factory oil pressure switch and an aftermarket oil pressure sensor.
What we want to do there is use an 1/8th BSP T piece and then you can retap one leg of that T for your MPT aftermarket oil pressure sensor. In terms of the BRZ, you do have factory oil temperature which is kind of nice. So you can get that data via the factory OBD2 data stream so you don't need to add an auxiliary temperature sensor. But again you could do that with another T piece. It's important with an oil temperature sensor, for the best results you really want to have that sensor in the flow.
So if you're modifying a car like that, you're probably going to be wanting to put an oil cooler on any BRZ that's going to see the racetrack. And you're obviously going to have flow through the oil cooler plumbing. So there's quite a lot of sandwich plates that will include a port there for both oil pressure and oil temperature. Spikey has asked, could you discuss using coolant pressure warnings for coolant loss and head gasket issues, also crank case pressure? Yeah all additional sensors that can be really worthwhile having. Coolant pressure, it's quite common for coolant pressure to be incorporated predominantly on high boost drag engines where head gasket integrity can be quite touch and go.
So what you're going to be doing is monitoring that coolant pressure. And generally, you're going to expect that coolant pressure to remain at or pretty close to the rated pressure of the radiator cap that you're running. Say that might be 1.5 bar or thereabouts. So if you start seeing that pressure spike up and it generally will spike up quite rapidly so you can't miss that, then you will know that something is wrong. So again, you can set up some strategies there with your coolant pressure versus engine RPM or maybe engine RPM at boost pressure to bring on a driver warning.
Probably that's definitely something that I would want to incorporate as a safety shut down strategy in the ECU. Crankcase pressure, this is a good way of monitoring your engine health actually, particularly if you've got data historically over the life of the engine. Basically as our ring seal tends to go away, you will start seeing your crankcase pressure increase. If you end up with a catastrophic failure, melt the side out of a piston, you're going to see a very sharp rise in your crankcase pressure. But generally, you're going to know about that for other reasons.
I don't know if you'd really need the crankcase pressure sensor to let you know that you've got a problem there. Mikael has asked, do all of the features on this require CAN or OBD2 and what would be a good alternative for club level guys that might not have as high of a budget? OK so there is a variety of ways of getting information into one of these dashes. Now obviously we have used today the MoTeC C125 dash and yes Mikael they are a pretty pricey unit. There are much cheaper options available to suit different budgets. Generally, as I kind of talked about during the webinar though the different dash models will all have much the same functionality anyway.
So ways of getting this data, CAN or OBD2 if you've got a car that can provide that information is going to be your cheapest and easiest way of getting that data into the ECU. You'll find a lot of late model cars now actually ave a lot of data on the CAN bus. Provided that you've got a template that will decode that, makes it really easy to get that information. The other option of course is just to add additional sensors for the information you want and then wire those directly into your dash. Most but not all dashes will allow you to add analogue voltage inputs for the likes of fuel and oil pressure sensors or analogue temperature sensors.
So you do need to check the specifications of the dash you're interested in purchasing just to make sure that it will be suitable. There are dashes now, the likes of the AEM dash range which they don't have inputs going directly into them. But you can buy an interface board or a CAN expansion board where you can wire your sensors into that and we'll send that information through to the dash. Lastly, if you do have an ECU running your car, provided that can produce a CAN datastream, again these dashes are going to be able to interface with just about any aftermarket ECU so a lot of flexibility there on getting that information. Usersony has asked will this give me a danger to manifold warning? Well absolutely if you want a danger to manifold warning then yes you could program that in but basically the flexibility there is just up to the imagination of the end user.
Spikey has asked, thoughts on setting up warnings for fuel pressure differential, i.e. multiple fuel pressure sensors for tank filter and rail? OK so again you can pretty much do whatever you want. I find it's easier to keep things simple and mainly what we're interested in is what is the fuel pressure that's getting to the injector. So monitoring the fuel pressure at the rail is probably the most sensible option. That's going to end up being affected if you've got a problem with the lift pump or something of that nature.
Maybe a fuel filter ends up getting blocked. Now the important thing and I didn't actually mention this with the warnings that we looked at but we can still jump back. So let's just have a quick look at our fuel pressure warning. And that's our one there, we'll double click on that. So this is really straightforward with this particular car because it runs a returnless or dead head fuel system.
So you can see basically I've just got it set up if our fuel pressure drops below 2.5 bar for half a second and our engine RPM is above 2000 RPM, it's going to bring on that warning. Now it gets a little bit trickier, sorry I'll start again, this is easy with a returnless fuel system because we are running a fixed fuel pressure. In this case, we're running four bar rail pressure. So if I get from four bar all the way down to 2.5 bar then yeah I've definitely got a problem and I want to know about that. However, if you're running a conventional fuel system with a manifold pressure referenced fuel pressure regulator.
Things are a little bit trickier there because really what you're more interested in there is the differential pressure across the injector. Now again using your dash you could make up a calculation there looking at the difference between fuel pressure and manifold pressure, essentially giving you the differential fuel pressure and then base your warning on differential fuel pressure. So that'll work well for the likes of a turbocharged car where the fuel pressure can be maybe 30 or 25 psi at idle but we may need to have 60 or 70 psi of rail pressure when we're at full boost. So that allows us to account for that. Alright I'll head back across to our questions.
Spikey's also asked, recommendations on what conditions to use for a lean condition air/fuel ratio warning? OK this one is a little bit tricky. I actually caught myself out with this years ago when we were racing our Mitsubishi Evo drag car, we took it over to Australia for a race meeting. And because we were racing in a very different condition I kind of decided to safeguard everything because obviously with a car that's running down the drag strip in eight seconds or thereabouts, you don't really have a lot of time to figure out what's going on. So I set up some driver warnings for the air/fuel ratio or lambda and it ended up catching me out because of course what we end up with is a lean condition on a gearshift if we're using an ignition cut. So if you are going to be looking for a lean condition, you'd want to be very careful that you're filtering out around gear changes, making sure that it's ignoring the data around gear changes.
Generally, I'd probably actually go about this a different way. With most of our racecar stuff now, we're running closed loop fuel control, even under wide open throttle. So I'd probably be tending to base my warnings more around the short term fuel trims. So if we're seeing our short term fuel trims exceed maybe plus or minus 5% for an extended period of time as well, so that'll again ignore our gear cuts, that's going to be something that I would probably want to bring to my attention. Kelvin has asked, are you able to trigger some engine protection strategies following any warnings? So let me think about this.
So generally, I've kind of touched on this, I would generally not try and interact between the driver warnings in the dash and what the ECU is doing. So I just basically have the ECU as a safety backstop with those strategies for something that I'm going to be really worried about. Oil pressure's another good example that I've already touched on there. So yeah I'll have a table in the ECU that's going to basically bring in a rev limiter that will kill the engine if our oil pressure drops to some level that I consider to be dangerous. So actually follows on, this next question from Mikael is basically exactly that.
Can something like zero oil pressure be programmed to cut the engine to save the internals so yeah absolutely. The way of doing that is just with a general purpose RPM limiter. The way different ECUs will employ that or enable that is kind of variable but basically that's what it does. You've got a three-dimensional table of RPM versus oil pressure and where we are happy with the oil pressure, we'll have our RPM limit set to our maximum and below that we can set our RPM limit to let's say zero or 1000 RPM, that will cut the engine. Nathan has asked if you could rate an engine/car error code from most important to least, what would it be? Nathan, I'm not too sure I can really answer that.
Really I've kind of covered in terms of the mission critical stuff, we're looking at the stuff that's going to instantly kill the engine and the oil pressure is right at the top of that list. But beyond that, the oil and coolant temperature, probably coolant temperature is a little bit more critical than oil temperature and moves a little bit faster. Those two, I'm going to be wanting to keep an eye on really closely. And then air/fuel ratio or fuel pressure which really influences our air/fuel ratio is probably a fairly good order of what I'm going to be keeping my eye on. And then there's obviously all of the rest of the stuff to do with the rest of our car, transmission and differential.
Alright plenty of questions there, hopefully everyone enjoyed that webinar, hopefully everyone's got a better idea of how they can use a dash in order to help protect and save their engine. And remember if you do have any questions that crop up after this webinar has aired, please ask them in the forum and I'll be happy to answer them there. Thanks for joining us and I look forward to seeing you again soon. Now for those who are watching today on our YouTube channel, this is just a little bit of a taste of what we put on every week for our HPA gold members. Now our gold members get to review or rewatch these webinars after they've aired live in our archive, we've currently got over 220 hours of existing webinar content covering a wide range of topics including engine tuning, engine building and wiring.
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