137 | How Does Ethanol Affect Ignition Requirements
When it comes to tuning on ethanol blended fuels there’s a lot of confusion around how the fuel will affect the optimal ignition advance. In this webinar we will be discussing the properties of ethanol and how they affect the engine operation and combustion process. Following this we will have a demonstration on the dyno of optimising the ignition timing on both pump gasoline and E85 to show the differences. This webinar will use our Toyota 86 running a MoTeC M150 ECU.
Hi guys it's Andre from High Performance Academy. Welcome to this live webinar. For those of you who are viewing on Facebook, this is something we're trying that's a little bit new. These webinars we air every week live to our HPA gold members. And it's an opportunity for us to demonstrate an aspect of EFI tuning.
We can demonstrate this on our Mainline dyno. And then everyone gets the opportunity to ask questions live. So we're just trying this out. We are broadcasting live to Facebook. You will also have the opportunity to ask questions.
So if you're watching this and there's anything that I talk about that you'd like me to explain in more detail please ask those questions in the comments and Colin will transfer those through to me. Colin's running the technical side of the webinar today. And I'll be answering all of the questions at the end of the lesson. Lessons should go for around about 30 to 40 minutes and we'll have the questions after that. I will mention that if you are watching on Facebook, you will only be able to watch this live.
You won't be able to review this after it's aired. OK thanks for joining us for today's webinar. And in this webinar we're going to be discussing the ignition requirements for an engine running flex fuel. And specifically what we're going to be looking at is what we need to do to optimize the ignition timing as our engine's tune moves from pump gasoline tune through to an E85 or for that matter, any blend of ethanol. And I think this is an area that there's a fair bit of confusion out there in the wider industry, even those professional tuners who are tuning flex fuel, or dedicated ethanol vehicles regularly, still don't really understand exactly what's going on and why those ignition requirements change as the ethanol content of the fuel changes.
So hopefully in today's webinar we're going to have a look at that in detail. I'm going to be doing a dyno demonstration on both pump gasoline as well as E85 using our Toyota 86 as a demonstration vehicle so you'll actually be able to see in real time how the ignition requirements change. One of the misconceptions I've often heard is if we have a calibration that's optimized correctly for pump gasoline, if we're swapping the fuel from gasoline to the likes of E85 then all we need to do is take our existing ignition table that's been correctly optimized for gasoline, add 10 degrees across the board and the job is done. As we're going to see in this webinar, nothing could be further from the truth. And of course there is some work that we as tuners need to do to get the most performance out of the engine as that ethanol content changes.
In order to understand what's going on there, to be able to do that job properly, as usual we need to really have an understanding of what's going on, why the ethanol content affects the optimal ignition timing. So I think what we're going to do is start by jumping back into my laptop screen here, and just having a look at what's going on inside the combustion chamber, inside the engine, during the combustion process. And what we've got here is a graph of the cylinder pressure inside the combustion chamber. We've got that on the vertical axis over here on the left hand side. And on the horizontal axis here we've got our ignition angle.
Now this is a common diagram I actually use for demonstrating and teaching about MBT timing. In this instance I really just want to demonstrate what we're trying to achieve when we're optimizing our ignition timing. And in this case the graph that's labeled B is what we want to achieve. What we're trying to do is start the ignition event, or start the spark so that our combustion pressure peaks somewhere around about this point here, which is somewhere around about 16 to 18 degrees after top dead center. Now if we can do this, what that's going to result in, is maximum cylinder pressure occurring at a point in the engine's cycle where we can take maximum mechanical advantage of that pressure.
Remember it's that pressure acting down on the top of the piston then being transferred down into the connecting rod, through the connecting rod, and finally into the journal of the crank shaft that creates torque which in turn creates our power. So this is what we're trying to do, and the key point here is that the combustion process takes a finite amount of time. Many people think that the combustion process is a little bit like a stick of dynamite exploding inside the cylinder and all of the energy of the fuel and air combusting is released instantaneously. That's not the case actually, it's a relatively smooth, slow, and controlled combustion event normally. Right we'll just head back to our notes.
And what we need to know, so now we know what we're trying to achieve. We're trying to start the ignition event so that we achieve peak cylinder pressure at the optimal point in the engine cycle, remember somewhere around about 16 to 18 degrees after top dead center. Now there are a variety of aspects of our engine design that will affect what the optimal timing is. I'll also mention I'm gonna start using the term MBT here, which stands for maximum brake torque timing. It's also referred to as minimum timing for best torque.
That's the point that's the ignition advance angle where we achieve peak torque from our engine. So MBT timing is affected by a variety of the engine's design aspects. But really here what we're doing is keeping the engine itself completely the same, nothing's changing there, we're simply looking at the change of the fuel. So with respect to the fuel, one of the aspects that's important here and can affect our optimal timing or MBT timing is the burn speed of the fuel. So how quickly the combustion event occurs.
Remember we're trying to time the spark event so that the peak pressure in the cylinder is going to occur at 16 to 18 degrees after top dead center. So if the fuel that we're burning, the fuel that we're combusting, burns faster, so in other words if the combustion speed of the fuel is faster, this means that we don't need to start our ignition event quite as early. We can retard the timing slightly to that we still achieve peak cylinder pressure at the correct point. If we don't retard our timing as the combustion speed increases, what this is going to mean is that the peak cylinder pressure is going to occur too early in the engine cycle and this can have a detrimental affect on our power. Likewise if the burn speed is slower, we're going to need to start the spark event earlier in order to still get that peak cylinder pressure occurring at the correct point in the engine cycle.
So this is the key aspect we need to understand here. And the part that is often overlooked is that the burn speed, the combustion speed, on ethanol blended fuels is actually faster than what we end up with on gasoline. So if we understand that, what this straight away should suggest is all things being equal as we move from gasoline to an ethanol blended fuel, we may need to retard the ignition timing, start the ignition event later. Of course the other aspect with ethanol is that it has some properties that make the engine much less prone to suffering from knock or detonation. And obviously this is one of the reasons that we as performance engine tuners are drawn to E85.
We can often make substantially more power and torque on ethanol blended fuels that what we can on low octane, low grade pump fuels. So this is another consideration here. And generally I class an engine as being either knock limited or not knock limited. I just want to explain those two terms first before we move on. If an engine is not knock limited, in that case for us as tuners it's a dream to tune, we don't need to be worried about detonation occurring and we can simply optimize the ignition timing at every point in our ignition table to achieve MBT timing.
This means that for that fuel we're going to achieve maximum torque and hence maximum power at each point in the ignition table. On the other hand if our engine is knock limited, what this means is that as we're advancing the timing towards MBT the torque is still increasing as we're advancing the timing but we find that the engine begins to suffer from knock or detonation while we're advancing the timing and the torque's still going up. So this is a knock limited engine. This means that we can't advance the timing any further. And in fact what we have to do is leave a safety margin there between that knock threshold, the point where detonation first starts to occur, and the actual timing that the engine is going to end up running.
So on a knock limited engine this is where we can see some really significant gains in potential power when we move from gasoline to E85 or any ethanol blend for that matter. Ultimately if we're tuning an engine that is not knock limited on pump gasoline, what we should expect to find as we move from pump fuel through to ethanol blends, I'm gonna be using E85 for my example here today, we will often find, or should find, that the optimal ignition timing, MBT timing, is slightly retarded from what was optimal for gasoline. When the engine is knock limited though, this is when the properties of the ethanol fuel, will allow us to advance the timing further beyond what was possible on gasoline, and take advantage of that, the fuel's properties, to make more torque and power. So the properties of ethanol that allow us to do this is first of all ethanol has a higher octane rating than pump gasoline. Though there's no real clear exact value that is applied to the octane rating for ethanol.
Generally E100 is sort of suggested to be somewhere in the region of about 105 octane. Although it does respond much better than that would suggest. Often in line with some of the very expensive racing fuels with octanes of 116 to 120 plus. The other aspect that works in conjunction with the ethanol fuel's higher octane rating is that it has a high latent heat of evaporation when compared to gasoline. And what this means is that as the fuel is injected and it goes through a phase change from liquid to vapor, it absorbs a lot of energy in the form of heat from our intake charge.
So it actually has a cooling effect on the engine. And heat is one of the main aspects that promotes detonation occurring. So anything we can do to cool the combustion charge temperature is going to make our engine less prone to detonation. OK so with all of that out of the way, we hopefully now have a bit of an understanding on what we can expect to see. We're now going to go into a demonstration on exactly how that all works.
So we're going to be using here our Toyota 86, which is turbo charged. Now the Toyota 86 is fitted with a horizontally opposed FA20 engine. It runs both port and direct injection and in stock form runs a very high compression ratio of 12.5:1. So what this means is that in stock form it is very very knock prone when we've fitted a turbo charger to it, and in fact even naturally aspirated under moderate load, the engine is quite knock prone, so we need to be very careful when optimizing the ignition timing. So what we're going to do for this demonstration is we're going to run the engine at two points.
We're going to run it at 2500 RPM at 60 kPa which is in vacuum at light load, and we're also going to run it under boost at 120 kPa. On pump fuel this correlates with a point in vacuum where the engine is not knock limited. As soon as we go to 120 kPa though, positive boost pressure on gasoline, the engine is knock limited. Then we're going to change the fuel over to E85 and we're going to run the engine at those same two points. We're going to be using the torque optimization function on our Mainline dyno to find what the optimal ignition advance is in both of those scenarios.
Now obviously we can't change the fuel here live. You'd be hanging around for a fair while, while we did this, so the first test is actually pre recorded. This is a test that we did as part of our flex fuel tuning course. So we're going to play that first and then once we've gone through that, we'll come back and we'll repeat the test running on E85 and we'll see what the comparison of those results are. And then of course we can have a bit of an analysis of those and some questions and answers.
Alright so let's move in now and we'll have a look at that prerecorded gasoline test. Let's have a quick look at what we've done here in the laptop software first. At the moment you can see we're on our main ignition table. This ignition table is the ignition table used for gasoline. And what you can see I've done here is I've taken a large block of the ignition table and set it all currently to 10 degrees.
The two points that we're going to test here are 2500 RPM and 60 kPa. So this is in vacuum and at this point the engine is not knock limited on gasoline. Once we've tested at that point we're also going to increase the throttle position, bring the engine up onto boost, and we're going to test again at 120 kPa, a point where the engine is knock limited. What we're going to be using just to demonstrate knock is a little warning box down in the bottom left hand corner. This is going to to flash red when the built in knock control strategy on the Motec ECU detects that the engine is detonating.
Once we've done this test we're going to move forward and we're going to do exactly the same on our ethanol ignition timing map. And we're going to be using an E85 blend. If we drop across to our flex fuel worksheet, we can see at the moment we do have a very small amount of ethanol still in our tank, we've got about 3% there. That's not really going to affect this demonstration. Let's get our engine up and running and we'll perform our first torque optimization test.
OK we've got our engine up and running, you can see we're now sitting right in the center of our 60 kPa 2500 RPM cell. And what I'm going to do during this torque optimization test is I'm actually going to make changes to the block of cells surrounding that cell that we're interested in. And this is just going to mean that we're not going to be affected by any interpolation from the surrounding cells. Let's jump across to our dyno screen and we've got our torque optimization test set up. This is going to plot how the torque changes with ignition timing, and this is going to help us to find MBT or the maximum brake torque timing, also known as minimum timing for best torque.
On the vertical axis here we have our engine torque and on the horizontal axis we have the ignition timing coming across from the Motec ECU. So I'm just going to click begin and now I'm just going to advance our timing at a degree every second and we'll see how the torque is affected by the ignition timing. OK so that's our first torque optimization test complete. And what we can see here is that the dyno has drawn in a cross hairs at 32.7 degrees of ignition but at this point we've achieved 111 newton meters of torque. So what this means is that for pump gasoline at 60 kPa and 2500 RPM we can achieve MBT without knock and MBT timing is 32.7 degrees.
We're now going to go ahead and repeat this test, only this time we're going to go up to 120 kPa. OK we're up and running now at our second point. You can see that we're in the center of our 120 kPa 2500 RPM cell and we're going to go through exactly the same process. But this time what we're going to do is advance the timing to where you either reach MBT or much more likely we're going to have our knock warning indicator in the bottom left hand corner of our screen come on. So let's go through the test now and see what our results are.
OK so we've just had to abort that test. We got up to just on 20 degrees of ignition timing, ignition advance and the knock warning came on. And that's the onset of detonation so we can't advance the timing beyond that point, and in fact what we'd actually need to do to provide some safety is retard the timing a little bit from the point where we first encountered knock. So it's likely we'd end up with our ignition timing limited to perhaps only 16 or 17 degrees. We can see on our dyno screen that we reached 378 newton meters of torque at 19.4 degrees of ignition advance.
But if we look at the trend of our graph we can see that the trend shows that the torque is still increasing. OK so hopefully that demonstration was pretty clear. In particular obviously you could see that on 120 kPa of boost or 20 kPa of positive boost pressure I should say, the engine was quite knock sensitive. Now obviously I've mentioned that this is running a 12.5:1 compression engine so that's to be expected when we start adding boost to an engine that was originally designed to be naturally aspirated. However we also see this in a factory turbo charged car.
In my own experience probably greater than 85% of the turbo charged factory cars that I've tuned over my career are knock limited on pump fuel so this is what we can expect to see with a factory turbo charged engine or even one that's been modified with larger turbos et cetera. We can find that as we start moving into positive boost pressure on gasoline the engine does become quite knock sensitive. This results in us requiring to retard the timing away from MBT in order to avoid knock. So we're going to perform our live test now on E85. After we have performed this test I will move into questions and answers so if you do have, anything that I've discussed that you'd like me to talk about more or anything through these tests that you'd like me to clarify or discuss, please ask those in the comments and I'll deal with those at the end of the test.
Alright let's just jump into my laptop software for a start. And we'll have a quick look at what we've got going on here. You can see at the moment I'm sitting on our flex fuel tuning worksheet. We're currently sitting with an ethanol content of around about 84% so we're just a touch below our 85% target but this is still going to demonstrate what we're talking about here. So in this particular instance we have two ignition tables and this is the ignition table right now that we're looking at for our ethanol content, our E85.
And this works in conjunction with this particular blend table which tells the ECU which table to use, whether it's using the gasoline or the ethanol ignition table. Well we can see it's sitting at 84% ethanol, the blend value is 100%. What this means is that the ECU is using all of the values from our second ignition table here. And we can also see before we get started that I've set the block of ignition table values in the areas that we're going to be testing to 10 degrees before we start our test. What I'll do right now is just highlight the section at 60 kPa which is where we will do our first test.
We'll just get into fourth gear here and we'll start our torque optimization test on our Mainline dyno and we'll see what our results are. Alright I'll just make sure that we're in the middle of the zone that we want to tune there, sitting at 2500 RPM and 60 kPa. Everything looks like it's OK here so what we'll do is we'll begin our test. So I'm just going to advance the timing through here until we go past MBT and we'll see how that compares to our ignition timing on pump fuel. Yeah so we're just coming through 34, 35 degrees now.
And woah we've actually got a fairly haphazard looking map there, a fairly haphazard looking torque optimization test. Unfortunately I must've just moved my foot on the throttle very slightly. I'm just gonna back off there because we can see, if we use a little bit of imagination here and we draw a little bit of a trend line through here, we can see that by the time we got up to 40 degrees here where I backed off the throttle, we can see that our torque is dropping away. Now the important point to take away from this, is despite our couple of little blips here, we can see that the dyno has shown us for this particular test point, MBT timing was 30.6 degrees and we've made 109 newton meters. Now you'll remember hopefully that our test on gasoline showed that MBT timing for gasoline was 32.7 degrees.
So it's not a huge difference there. We're around about two degrees retarded from the ignition timing that we found was optimal on gasoline. Interestingly there's only a two newton meter difference there between the torque registered, which is probably as simple as the difference between our two tests as well. OK so with our test now complete there at our 60 kPa zone, what we're going to do is just clear the values there on our table and what we're going to do is go through and set up our test for our higher point. We're going to be going through remember to 120 kPa.
So I'll just set up our torque optimization test with a correct scaling to suit that. We'll get our engine up and running again in fourth gear. And we'll see the effect of that ethanol at a point where the engine was severely, well quite heavily knock limited. So I'll just get our engine up to 120 kPa. Alright we're sitting at 120 kPa now.
So you'll remember that we saw the onset of detonation on gasoline at this point was around about 19 or 20 degrees of ignition advance. So again we'll be looking at our knock warning state here to guide us. I'll just get our test started. And we'll see what the results are. OK so we're just coming up to 16 to 17 degrees.
So remember this would be about the safe amount of ignition timing that we were going to be able to use on pump gasoline. Coming through now to 20 degrees, remember this is the point where the engine was suffering from knock on gasoline. We've got absolutely no indication from our knock warning at this moment. Coming up through 22 degrees of ignition advance. We can see that the torque is still climbing as we go past 24 degrees.
Our torque's starting to plateau now. We've still got no indication from our knock warning so I'm just going to keep advancing the timing. And we can see now that we've plateaued and actually starting, our torque is starting to fall away as we go through 29 degrees so I'm just going to back off now. So looking at our torque test on our dyno there, which thankfully this time is much clearer. We can see that the dyno's shown us that for this particular point in our table, 2500 RPM and 60 kPa, our optimal MBT timing was 24.2 degrees.
And this also coincided with a torque output of 423 newton meters. Now if you can remember back to our test on gasoline, we were limited to about 16 to 17 degrees before to give us a safety margin. We ended up with knock occurring at about 20 degrees and at that point in our torque optimization test, we were seeing around about 378. So we're at around about 55 newton meters of torque better off with the E85 tune there. So hopefully this has given you a bit of clarity around what we can expect with E85 tuning.
Basically for me the amount of ignition timing that I'm going to expect the engine will take as I move from gasoline to E85 is going to be very dependent on how heavily knock limited the engine was while I was tuning on gasoline. In the areas of the map where the engine was not knock limited on gasoline, so these will typically be at least in the light load areas, the cruise areas of the map, we'll often find that we need to retard the timing, albeit quite a small amount, only perhaps a few degrees. On the other hand if we move into an area of the map where on gasoline we were heavily knock limited and needed to purposefully retard the timing away from MBT in order to eliminate the chance of knock occurring and give our engine a safety threshold to make sure that it stays in one piece, this is the area where E85 really comes into its own, or ethanol really comes into its own. But the question I quite often get asked, is how much more ignition timing do I need to add? And hopefully this is demonstrated that it's dependent on the engine. You need to run the engine on the dyno and let the dyno show you what ignition timing is correct for the engine.
In some engines we may need to retard the timing, in others we may need to add a few degrees, in some we may need to add 10 or even more degrees of ignition timing over what worked for us on pump gasoline. Alright we'll move into some questions and answers. And if you do have any more questions, please make sure you ask those in the chat and I'll answer them there. Our first question comes from Janu who's asked is this Toyota 86 on the stock high pressure fuel pump or aftermarket? What can we do for cars like direct injection WRX that constantly have high pressure fuel pressure problems due to E85? So at the moment we are running the stock direct injection pump for our Toyota 86. The 86 is a slightly unique situation whereby it does use a combination of port injection and direct injection so we aren't limited solely to the direct injection system.
Personally with this engine I have not heard of any reports of damage to the direct injection pump as a result of using E85. Of course there are problems potentially with the corrosive nature of E85, and more particularly actually the hygroscopic nature of E85 so we'll talk a little bit more about that shortly. But yeah in my own experience and being involved in several of the 86, BRZ, and FRS forums around the world, I have not seen reports of the FA20 engine suffering from problems with the direct injection pump. Hackman has asked do you guys use ethanol conditioner like Lucas or straight E85? In this particular instance we are running straight E85 so it's a pure mix of 100% ethanol. The ethanol we're using is a denatured product that's designed for the perfume or aerosol market.
And this is just mixed with our local pump 98. There is definitely nothing wrong with using a corrosion inhibitor. There's a range of corrosion inhibitors on the market. Particularly if you are living in an area with high humidity, that would be a sensible approach there. M Work has asked does E98 work better than E85? That's a really good question there and again this is an area with quite a bit of misconception.
If we could plot the knock resistance that ethanol gives versus the ethanol content of the fuel, so in other words from E0 through to E100, we kind of plotted the effect of the knock resistance on the engine. What we find is that we actually get the largest improvement in knock resistance as we move from E0 or pure gasoline, through to around about 35% to 40% ethanol content, we see a really large increase in the fuel knock resistance. Once we go past E40 we do still see the knock resistance improve but it's much less dramatic than what we saw from E0 to E40. Once we get past around about E70, there's very very minimal effect, and personally I've seen no improvement in power and torque from going from E85 or E70 for that matter through to E100. So very dependent on your engine combination though, if you're running a very very high compression engine that's incredibly knock sensitive or knock prone on gasoline then there may be some advantage, albeit minor, in you running a higher ethanol contents than 85%.
Jessie Thomas has asked what about corrosivity, lack of lubrication, and water vapor from the fuel mixing with oil? OK yes there are some potential problems with the corrosive nature of ethanol blended fuels that you do need to be aware of. Definitely with later model cars, this is becoming less of an issue. We are seeing that even in our dedicated, what's classed as pump gasoline, there still can be minor content of ethanol in those pump fuels. What we're seeing is that OE manufacturers these days are providing fuel systems with their cars that are still compatible with ethanol to a degree. The biggest issue of course is the actual flex fuel capability in that if the ECU isn't designed to cope with the fuel requirements on ethanol blends then there's no way of the ECU adding the correct amount of fuel as the ethanol content varies.
The bigger problem there as well which you've touched on, is the hygroscopic nature of ethanol. What this means is that is tends to absorb moisture from the air. So this becomes a bigger problem in very humid parts of the world. Here we're in quite a dry area so this isn't a huge issue for us, but if you are in a humid area then the ethanol fuel can absorb reasonably large quantities of moisture out of the air over time. So there are some precautions that you need to take in there with the design and management of your ethanol fuel system.
But this really goes a little bit past the point of our webinar here, we're really just focusing on our ignition timing requirements. Hackman has asked what race gasoline would you say E85 is closest to as far as knock resistance? Probably in my own experience, we did some back to back testing with a high power drag car that we were tuning and we found that the results between E85 and VP racing Q16 were almost identical. In fact in that test I think we were running a Mitsubishi 4G63 engine at about 38 PSI of boost with a moderately sized turbo charger on it was making somewhere in the region of about 550 kilowatts at the wheels. And we actually saw a very minor increase in power as we went from VP racing Q16 to E85. It was only in the order of magnitude of a few kilowatts but still that was the comparison.
In terms of the ignition timing that the engine was comfortable with, both fuels we could tune to MBT timing at 38 PSI of boost. Bellotech's asked have you tested Ignite red 114? No I haven't. In all honesty since E85 became more prominent, probably here in New Zealand we were a little slow to adopt E85 just because it never really made it as a pump fuel. I think right now there's only a handful of fuel stations around New Zealand, and they're all based in the North Island, that actually have pump E85. So we were a little slow on the uptake of E85.
But since E85 has become more prominent I really haven't used many of the race fuels. It's a case of the cost of the fuel for these proper race fuels is often several times what we're paying for E85. That's not to say that E85 isn't without its own set of issues. If we go from gasoline to E85, we're going to need to inject somewhere in the region of about 35% to 40% more fuel by volume in order to make the same amount of power. So this obviously requires potentially a bit of a rethink of your fuel system.
Our next question, I use it for stuff asks, how does E85 affect exhaust gas temperatures? What we'll find is that on E85 the whole combustion temperature is much lower so this is indicated in our exhaust gas temperatures. We can expect our EGTs to be quite a lot lower than what we would see on pump gasoline. Marcus has asked how do you use a torque optimization test using a reflashing system that does now allow live changes to ignition timing? Good question there. Obviously if we can't make live changes to our ignition timing then that torque optimization test is not particularly useful to us. This is only one indication though of where our optimal MBT timing is.
Quite often when we're reflashing what we're going to do, unless we've made dramatic changes to the engine's mechanical specifications, we're going to focus most of our energy on tuning at wide open throttle. And there what we're doing is no different, whether we're reflashing or we're tuning a stand alone after market ECU where we can make changes live. What we tend to do is make a change to our ignition table, assuming of course we've already got our air fuel ratio dialed in where we want it, we'll do a ramp run on our dyno, we'll look at the results, come back to idle, make any changes we need to. In this case we may try advancing the timing by one or two degrees, and then we'll run the engine again. So in this instance it doesn't matter if we're reflashing or tuning live, we're not really making changes while the engine's running.
And we're looking for an increase in torque and power through those ramp runs. This would be indicative that we have moved towards MBT timing. Fortunately when we are reflashing a factory ECU often the base ignition table and the cruise idle part throttle areas is already quite well calibrated by the OE manufacturer and calibration engineers, that gives us a little bit less work to do. Nelson's asked if you're using a chassis dyno that doesn't have a torque optimization function, what would be a suitable way to find MBT timing? You definitely don't need a dyno that offers the torque optimization function. Our Mainline dyno is a great training tool because that makes it really really clear and obvious exactly how the ignition timing is affecting our engine torque.
However as long as you have a load bearing dyno, that's an essential part of this, as long as you have a load bearing dyno, what we can simply do is set the dyno to hold the current steady state and what we're going to be doing instead of watching the torque optimization test, is we're going to be watching the live output of torque that the dyno is showing us. And we'll simply advance the timing and watch the torque output. We're looking for the point where that torque output peaks. If we go too far we're obviously going to find that the torque drops away. Status quo asks if exhaust gas temperatures are lower does this affect turbo spool? I would assume it's later.
Yeah look in reality I don't tend to see a dramatic difference in spool between E85 and pump gasoline. The other aspect here is we are burning a lot more of the fuel than we are when we're burning gasoline so this increases the exhaust flow. So while the exhaust gas temperature may be a little bit lower, generally we don't see that as detrimental to the turbo spool. Turbo tunings asked is a dyno required for the torque optimization test? So regardless of whether you have a dyno like we do that does a torque optimization test, if you do want to correctly optimize your ignition timing to MBT you do require a dyno. This is impossible to do absolutely accurately if you are road tuning or tuning on a race track.
Alright guys it looks like that's taken us through to the end of our questions. So hopefully that's given you some more insight into why ethanol fuels require different amounts of ignition timing and why just taking an across the board approach of adding let's say 10 degrees to a gasoline ignition table is not going to give us optimal results when we're tuning on an ethanol blended fuel. Thanks everyone for joining us and I look forward to seeing everyone next week, thanks.