🛠 Volumetric Efficiency - Live Tuning | TECHNICALLY SPEAKING

hi guys and welcome to the dyno room today we're talking volumetric efficiency now i know matt's already done a video on volumetric efficiency he's explained the ins and outs of how the software works and how we calculate everything in the background today i'm going to be using that theory putting into practice with this ra23 celica [Music] now before we lift the hood on this car i really would recommend you to jump over and have a look at matt's video on volumetric efficiency tuning that's kind of the part one to this practical video so maddie's done all of the theory of exactly how volumetric efficiency tuning works in the background in the engine management system even if you know everything there is to know about volumetric efficiency jump back over there for a recap there might be something you've missed or something that sort of clicks and you think ah that's why we need injector size or air temperature or engine size go over there have a look at that then we'll get straight into this and this is an ra23 toyota celica but because it's here it obviously doesn't have the factory engine in it let's crack it open take a look under the hood here she's absolutely beautifully presented they put a lot of time and effort into color coding everything making it all sort of flow and fitting this toyota um this is a this is a nissan sr20 turbo engine somebody's obviously got a sense of humor going with the all black theme it's got a powder coated plasma man intake manifold mated to a bosch 74 millimeter throttle body plasma clamps so it doesn't actually have silicon hose joiners attaching the intercooler piping to the throttle body or to the turbocharger instead it's got these clamps that click everything together for ultra high boost applications black intercooler pipes a black plasma man intercooler along the front and a really really nice black radiator just behind it that fits so beautifully well in the grill here on the hot side there we've got a garrett gt35 base turbo charger front cover is black the rear housing is black all of the air box part and the intake pipe is black the breather is black it looks really really nice the turbo smart fuel pressure regulator is even black it looks really really nice in here electronics-wise the part that i'm always interested in it's got the nissan r35 coil conversion which is getting super popular now for all nissan all pretty much every brand of engines they've been performing really really well allow huge cylinder pressures with no misfires readily available reasonably priced can't beat them really good thing we've got a haltech wideband controller on the car one of our wb1s it's got the oxygen sensor down here in the in the dump pipe we've got a set of bosch 2000 cc injectors air temp oil pressure fuel pressure sensors we've got a crank trigger kit on the front of the engine so it's actually got 12 teeth on the crankshaft and a single tooth on the camshaft meaning that we don't need to use the factory nissan crank angle sensor that's the one that sits up the top normally other than that it's a nissan sr20 it's going to make good power we better get inside and get on with what we're actually talking about today volumetric efficiency this car is running our elite 2500 series ecu meaning that the base fuel table can be tuned using the volumetric efficiency method the method that i absolutely love i recommend to everybody well over the old style injection time tuning method so let's talk about that just a little bit back before we had volumetric efficiency tuning we used to tune our base fuel table in what we used to call injection time and what that means is that in our base fuel table this one just here i'll click around in there a little bit what that means is that on the left hand side here we've got our engine rpm axes along the top we've got our load axes so in this particular car our load axes is manifold pressure along the top engine rpm down the side in the old days if we went to just here two pounds of boost four and a half thousand rpm instead of seeing a volumetric efficiency number there we used to see just an injection time it might have been three milliseconds four and a half milliseconds six milliseconds it all depended on the size of the injectors that you had and the engine combo you had so it wasn't really a uniform way of tuning an engine it was a lot more complicated there were a lot more numbers to enter things weren't as linear at all temperatures weren't taken into consideration so we needed to really focus on our fuel air temp compensation tables overall it was just a way more complicated way to do things fast forward into the future our ve tuning models have made everything so much easier they've made cars drive smoother better throttle response better fuel economy and faster tuning meaning that you get off the dyno faster you're not wearing the engine while you're sitting on the dyno tuning every single load cell you can linearize between load cells and still get a really really great result so let's take a look at how it works on the dyno remember before we get to any of this part you really should have checked matt's video episode one of the ve tuning videos once you've seen that this will be a breeze before we even start the engine there's a couple of things that we need to fill in in order to give our ve model all the information it needs in order to determine how much air and how much fuel is going into the engine every time that camshaft spins around so if we go into the main setup the first thing we need to look at engine main engine capacity this is an sr20 it's a two liter engine so i've got here 2000 cc or 2 liters that means that every time that camshaft spins around that crankshaft will spin around two times because it's a four-stroke engine it'll move two liters of air from the intake out into the exhaust if it was 100 efficient so engine capacity that's pretty important we need to make sure we've got a manifold pressure sensor that's connected to the intake manifold that's between the throttle butterfly and the intake valve i've got one of them set up at the moment it's just reading no boost no vacuum we're just sitting here and a thousand and thirteen millibars of barometric pressure the next critical sensor is our inlet air temperature sensor so this sensor is normally mounted in the intake stream somewhere where it's not going to get heat soaked so you don't want it in the back of the inlet manifold typically somewhere a few inches just before the throttle body is ideal where you're going to get the most air speed now we need a working intake air temperature sensor because we need to measure how hot that incoming air is reason being the hotter the air is the less oxygenated that air is meaning that we're going to have to change our ve model depending on how hot or cold the intake temperature is the colder that air gets the more fuel we're going to need and lastly on our ve critical sensors the engine rpm sensors the trigger signal the one that tells us how many rpm how many revolutions per minute this sr-20 engine is doing i need to know how many revolutions it's doing in order to determine how much air should be pumping through that engine with the combination of these sensors all going into the ecu it can now calculate the mass of air that's going through this engine when it's at 100 efficiency so if i come down here to my base fuel table which i've already put some numbers in this and i've already sort of roughed a tune into it if we're at a hundred percent efficiency which up here somewhere at seven and eight thousand rpm that means that two liters is coming through two liters is leaving keep in mind and like matt was speaking about if we're adding 15 pounds of boost into this engine we don't call that 200 efficient we still bring that into our vehiculation with our manifold pressure sensor so we are talking about a rough v at idle of around 50 for a four-stroke engine and a rough ve flat out full power at around 90 to 100 for a super high performance engine but i keep talking about a hundred percent efficient yeah i know we talk about formula one cars being over 100 efficient i know that we talk about old v8 farm equipment being not very efficient look the idea of it is that most four strokes and i'm sort of speaking generally around 50 are at idle and around 100 flat out this is one of the great things about ve tuning is that if you know that you can rough a map in and with a bit more of the magic that we're about to talk about hit the key the thing will start run cruise drive and then we can rely on the o2 control to get us in the ballpark so that anyone can tune a fuel map but what is the fuel map well that's what i've got open right here in front of me so if we flick down to the screen this is what i was speaking about where i've got our load reference our fuel load reference for our manifold pressure across the top of the screen here and our engine rpm up and down the side if i come to a position here at let's say three and a half thousand rpm zero vacuum so that means we're not in vacuum and we're not in boost 76.3 is the number that's there what that's telling me is that i believe that this engine will fill the cylinder 76.3 percent of two liters of air that's how efficient it will be if i thought this thing was absolutely amazing and it's a formula one car and everything is perfect and it's the best engine ever made i'll put a hundred everywhere ideally if you could make a four-stroke engine that was a hundred percent efficient absolutely everywhere you'd be pretty rich that would be that would be ideal it's probably not going to happen at least in my lifetime i would imagine so you get the idea that all i need to do here is type in how efficiently we're filling this engine or how efficiently the engine is filling itself basically with its camshaft its engine design so what's happening here is at idle and down here we might be idling at about 20 inches of vacuum and about a thousand rpm i'm saying this thing's about 44 efficient it's got a fairly large set of cam shafts into it so typically with that at idle and light load you'll actually end up with a lower efficiency when you've got a big set of cams where it'll become more efficient as we start revving it likewise if it had a factory set of camshafts i'd expect it to pick up a little bit of efficiency at idle but again these are all just the numbers so what this is telling us here 50-ish percent at idle 100 flat out that's what we need to talk about but so far all we've talked about is the air going into the engine it's only one part of it right 14.1 or air two fuel ratio so air is the part that we've talked about now let's talk about the fueling if i wanna know about my air to fuel ratio right now i know how much air is going into the engine two liters if we know we go through all the mass and figure it all out then we get to the the mass or the weight of the air that went into the engine now i need to mix that air with fuel in order to put that that 14.7 to 1 or whatever air to fuel ratio you want i need to be able to put them together based on mass so i know the mass of air coming into the engine let's figure out now the mass of fuel that's coming into the engine so if i come down here to my injection system my injector flow rate this engine's got a set of the bosch 2000 cc injectors in it this here is what i've calculated out as the injector flow rate based on the differential injector fuel pressure so what that means is the pressure across the injector so if we've got say for example 58 pounds of fuel pressure up the back of the injector but then what if we've got 10 pounds of boost operating on the other side of the injector or forcing on the other side of the injector that would be 58 minus 10 48 that means that that injector has a differential fuel pressure of 48 psi and that 48 psi is the amount of flow or the amount of fluid that will be able to go through that injector so that's the reason why we need to map our injector flow rate versus our injected differential fuel pressure because our injectors are actually changing our flow depending on how much pressure is on the fuel pressure line itself and the manifold pressure ideally it's the job of the fuel pressure regulator in order to bump up our fuel line pressure when our boost pressure comes up in a perfect world that means that the flow across the injector would always be perfect but we know that's not always the case and we know that because there's diaphragms there's lines there's pumps there's all these things involved that are acting on that so it's always best to map against injector pressure differential in order to get the most accurate fueling so we know how much fuel is going to pass through our injector at all these different pressures there's one really important thing here as well it's all over the internet everyone loves to talk about it it's called injector dead time i'll click down on this table here all right to understand that we first have to realize that the injector is a little electronic solenoid when we apply power to that injector the little valve inside opens and runs a path for the fuel to get down through the valve out to the other side into the engine and fuel our dreams but it would be foolish for me to think that as soon as i apply power to that injector it's giving us a hundred percent of its available flow that's not the case when we energize that solenoid it takes a little bit of time for that pin tool to open and for fuel to start flowing that's what's known as our injector dead time so why is injected dead time so important well it's important because i need to know how long it takes for the injector to physically open and start spraying fuel at its advertised flow rate if i just assume that it operates at a hundred percent efficiency as soon as the injector driver opens well i'd be wrong and my air to fuel ratios would be all over the place now let me give you an example of that let's just say that our injected dead time is one millisecond so like a lot of injectors are all different they're somewhere between a half a millisecond to 1.5 milliseconds it's dependent on battery voltage and it's dependent on differential fuel pressure now let's just say for example at idle our injected dead time is one millisecond okay that's a millisecond there about that at idle this engine might be idling with our bosch 2000 cc injectors at let's say three milliseconds of total injection time let's say that's there now what that means is that one third of that injector pulse is dead gone to inject a dead time whereas two-thirds of it is spraying fuel into the engine now percentage-wise 33.3 percent of that injection pulse is gone what happens then later if if i'm trying to feed 10 milliseconds of injection time into this engine for example that percentage changes a whole lot and that's the reason why injected dead time while it's critical across the whole operating range of the engine you're going to notice more problems with injected dead type at light load idle and cruise conditions so now we know at 100 efficiency this engine is going to move two liters of air from one side to the other because of the temperature sensors we're going to know the mass of the air because of the dead time we know how long the injector takes to open when it starts flowing because of the flow table we know how much fuel is going through the injector now we just need to tell the engine management system what is flowing through the injector if i come to the main setup here into fuel the fuel type we need to tell the engine management system is this thing running petrol is it running ethanol is it running methanol because all of those fuels have a different volume by weight likewise we also need to tell the engine management system the density of that fuel now that density is how many kilograms for a cubic meter of that fuel the e83 fuel we're using has an advertised fuel density of 737.2 kilograms per meter cubed so meter by a meter by a meter fill it up with fuel all the way to the top it's going to weigh 737 kilograms if we were filling that same cube with water it would weigh 1 000 kilograms or one tonne this means that fuel is lighter than water and that's it that's everything we're going to need that means that we know exactly how much fuel is flowing through that injector we know all about the mass of the air the air to fuel ratio we're ready to rock and roll so the last thing is we need to set our target air to fuel ratio map we come up to here lambda target all right if we have a look in this table i've got this table set up as petrol afr i find that the easiest to tune it i personally like that some people can tune in lambda or in their ethanol numbers personally these are the numbers that i use if we come across here what this map is telling me is that right here i would like to mix in 14.4 parts of air to one part fuel so this engine at zero atmosphere so no boost no vacuum if this was an aspirated engine that would be wide open throttle at two and a half thousand rpm on our e83 fuel i'm going to run 14.4 parts of air to one part fuel likewise up here at 20 pounds of boost pressure and 8 000 rpm i'm going to run 11.4 parts of air to one part fuel our air to fuel ratio table now there is a lot of confusion about this table because it actually has two functions our first function is for it to command the air to fuel ratio for our ve modeling its second function is used with our o2 sensor it just so happens that it's exactly the same table so what's going on here is when we turn our o2 control on our air fuel ratio sensor that's mounted in the exhaust system will measure said air to fuel ratio if i've messed up my base ve numbers if i've messed up my dead times if i've messed up my injector flow my air temperature is in the wrong spot my engine size is wrong we're not going to get the air to fuel ratio that i've desired here the oxygen sensor is going to pick that up it's going to show me an air fuel ratio error then it's going to make a percentage change in order to try and meet this target afr table so for our practical example today i'm going to disable our o2 controller in the engine management system the sensor will still be there so we'll still be measuring the air-to-fuel ratio but there'll be no reactive feedback so what that means is there's going to be no percentage corrections in order to achieve these target tables we're going to be relying on the ve model only in order to achieve these targets all right so we're on our main line dyno here and what i'm going to be doing i'm going to cruise the car up she's up to operating temperature i'm gonna cruise into fourth gear and i'm gonna hold it at about 40 kilometers now so a fairly low sort of and it's about sort of 1500 rpm so what we can see here we look at the screen our target lambda is 14.3 our actual lambda is 14.3 14.4 now remembering this thing's got 2000 cc injectors in it so that's pretty good the smaller the injector the closer to the target you're going to be able to get all the time when we're talking about a 2000 cc injector on a two liter engine on a two liter engine we really do start to see little control issues there with really really low injector pulse widths so just keep that in mind but look here we've got a target of 14 3 an actual of 14.3 that means that my ve number there is probably about right our o2 correction is disabled so i'm just going to show you here in the software disabled if i go up to my target afr table now watch what's going to happen here instead of me wanting to go to say 14 3 there i'm just going to type in 12. one two three enter look at that no o2 correction 1 and 12 i've got 12 13 enter target's 13 actual 13. i'll go control z undo control z undo back to my target of 14 4 and it's 14 4. there we go so what that's telling me is that my volumetric efficiency at this particular position in the map is tuned correctly so what if we go and try and stuff some stuff up here let's come down to our injector flow rate what if i tell the ecu something that's wrong here i'm going to highlight that and i'm going to go it's out by 10 10 make the injector 10 bigger than it actually is enter oh it started to go a little bit lean here so now the engine's running at 15.7 to 1 instead of my target of 14.3 that's because the ecu just reduced the injector pulse width because it thinks more fuel is going through that fuel injector than it actually is control z to undo that change now let's say that it's got a really small injector in it i might go minus 20 for example so instead of the injector operating at 1851 cc's at the moment it's now operating assuming it's a 1480 cc injector and look what's just happened now the air fuel ratio is 11.3 or 11.4 instead of my target of 14.3 i'll undo that change it'll come back to my target things are good what if i move my dead time around so instead of me having a dead time right now of 1.17 milliseconds if i highlight the whole lot p for percentage i'm going to go a bit crazy and go 100 bigger 2.2 oh you could hear the engine note change you went to nine to one i'm going to undo that change pretty quickly and bring it straight back up what i might do instead of making such a large change which you can see how much that affected the engine and even started pulling it down now i'll go page up page up page up we're not meeting our target anymore control z to undo that change page down page down page down so now i'm telling it that the injector is actually flowing fuel faster than it really is all of a sudden it's showing that i'm running lean undo back to our target of 14.4 give it some rev to make sure she's happy beautiful i'll turn this off so we can hear a little bit better so now with that practical example you can see that making changes to these critical inputs directly changes the air to fuel ratio that the engine is going to be running and we no longer meet our targets this creates a really big problem when we start to tune the engine because when i want a specific target air to fuel ratio i don't want to be mucking around trying to manipulate the maps because i've put the flow rate in wrong or i've put the dead time in wrong or i've put the engine size in wrong so we need to make sure that the things we've spoken about today are entered correctly in order to make sure the tuning process goes as smoothly as possible now the one thing that we didn't just do then is start it up and adjust our ve numbers in the base fuel map so i'll do that now and show you what happens when i change adjust the base ve numbers just like everything else still we we affect the fueling in exactly the same way we're no longer going to meet our target so the whole purpose of that base ve table is to go through and tune as many of those cells as possible in order to make your target lambda table meet your actual lambda okay we're straight back up to that rpm and after our post start correction start so post start being after the engine just initially starts we add a little bit of extra fuel to help it to get running so we're right on our target here i'm just going to highlight all those fuel cells and i'm going to go up up up up up up up up we're putting more fuel into the engine so this is one way that you could tune the engine you could ignore the target afr table you could put random numbers in here in order to achieve the air to fuel air to fuel ratio you want on the dyno but you're going to paint yourself into a corner if you try and do it this way sort of it's a misunderstanding of how the volumetric efficiency system works and where you're running the problems here is if all of a sudden you want to choose a different air to fuel ratio or if you want to change your injectors you don't have to retune the whole map all you have to do is dial in your new set of injectors so it's best to do it right the first time now the last thing that i want to do is turn on our o2 control function and show you that that's working separate to the ve model i'm going to pop up here to the main setup i'm going to flick our o2 control on press apply control f12 to reset the ecu okay you'll notice this page came back just then short term fuel trim so this is telling me how far out the base ve table is okay i'm going to get back to exactly the same load side on the dyno and here we go so right now the short term fuel trim minus one point minus one percent say give or take so that means that my base ve table is out by one percent in order to achieve my target now there's no shame in relying on the o2 controller to do a little bit of the tuning work for you and the reason why is you simply can't tune the engine across all of the engine operating conditions all the different temperatures all of the different cranking and post start tables so letting the o2 controller do some of the work around idle and cruising and realistically personally i use the o2 controller on over wide open throttle conditions because i always want that o2 controller doing as much work as possible in order to get the best driving engine to get the most efficient tune basically to get the best fuel economy i use the o2 sensor in order to set up my engine protection so if anything does go pear-shaped and the thing does lean out for whatever reason it's going to shut down before we can do real engine damage now the reason why i wanted to turn the o2 controller on was to have a bit of a look here and show you what happens here now if i mess up this ve map by let's say p for percentage i'm going to add five percent fuel to it meaning that it should go five percent richer than it is enter watch what happens yeah it went it did go rich for a second but then have a look at that the short-term trim immediately pulled that fuel out we're back to our target and all that's just happened is now our short-term fuel trim is working harder i'm going to undo that change controls in it goes lean for a split second the o2 controller sees it goes back to have what we had originally let me pull some fuel out of the tune i'm going to pull out let's say p for percentage minus 10. you'll notice i like using percentages a lot more than pressing page up and page down i use percentages because it keeps the shape of the map and that's what i like so let's pull out ten percent one two three enter oh i felt it felt that on the dyno and it just went to 15.6 for a split second then we're straight back to our target and look at our short-term fuel trim it's now adding 10 percent so knowing what you know from seeing this you'll see how i'm actually tuning this car what i typically do is go through cell by cell i leave the short term o2 trim turned on and i'll go through and look at how much the o2 controller is doing how much work it's doing that way i don't have to do any maths in my head what i'm going to do here is go peep a percentage at five percent to these particular cells if i was tuning it you know what five percent is probably not enough because the truth is if it was only five percent too rich i would probably leave it at four or five percent so let me go i'm going to undo that change okay let's go for something a bit bigger let's go for 10 so now my short term fuel trim is sitting there at 8 so imagine i had just started doing my sweeps through this run i'm at 1500 rpm i'm at uh 23 to 24 throttle and i'm at zero vacuum or one pound of boost pressure it's ten percent too rich i could look at the numbers and think okay it's ten percent too rich i'll divide this by this or if i was in lambda i'd say okay i'm at uh 0.98 i want to get the 0.96 that divided by that is a point or minus that i should say is 0.02 so that's a percentage change i'll make why not just use the o2 controller you'd look at this and say all right i'm 9.5 10 out p for percentage negative 10. watch the short-term trim look at that we've got no trims our target is meeting our actual the va is right there move to the next cell and she's away and that's how it's done and i know i've only sort of focused on one cell here i've done that so we can see how repeatable it is on exactly the same cell if we were tuning this car we'd be going through row by row we would lock the dyno at 1 500 rpm i'd use the throttle to manipulate the manifold pressure to run across every cell that i can possibly get on our main line dyno then i'd let out more road speed and i'd come up to a higher rpm so 2000 rpm and i'd do as many load cells as i can get to that's what's known as steady state dyno tuning as soon as i got up to a point high enough where i felt a bit uncomfortable with loading the engine the engine's making a bit of heat from there i would move away from doing steady state tuning and i'd start doing power runs the beauty of all of this stuff coming back to it is that if you put in the work early on if you set everything up right if you put the right data in down low if you set your desired target air to fuel ratios as soon as you start going in the power runs odds are you'll be able to guess the shape of that table the first power run it's going to hold a dead flat air to fuel ratio because your guess is going to be pretty close then your short term fuel trim on your o2 controller is going to take up for any little errors or just anything that you weren't quite sure about then after that first power run you can see your short term fuel trim you can see what the engine management system was doing in order for your desired and target air fuel ratios to match then you can apply that short term trim to your base ve table and you're a tuner and there you have it so that's a practical example of how the ve model works on our engine management system now if you really want to be a tuner getting the fuel map is absolutely critical in getting a car to cruise idle start nice as well as keeping the engine alive under full power so doing this and practicing this over and over again is the best way to get a better understanding of how your engine management system works i remember when i first started tuning ve based engines and engine management systems the hardest part for me to get my head around was that the air around us has a mass and i'm mixing that mass of air with the mass of fuel that we're putting into the engine against my target air-to-fuel ratio table so get your head around that the air around you has mass as always i know it's been a really long one but thanks so much for watching my name's scott catch you next time [Music] you

Channel: Haltech

Views: 146,389

Keywords: haltech, ecu, engine management, tuning, tuning fork, engine tuning, technically speaking, volumetric efficiency, tuning using ve, ve tuning, tuning tech tips, tuning basics, programmable engine management, tuning a car, ignition tuning basics, how to tune a car, how to tune, efi tuning, celica, ra23 celica, sr20det haltech ecu, sr20det haltech, sr20det, sr20 tuning guide, volumetric efficiency tuning, volumetric efficiency explained, injector dead time explained

Id: uPjIS9Tg83M

Length: 34min 32sec (2072 seconds)

Published: Sun Aug 01 2021