Practical Reflash Tuning: Step 3: Configure Base Tune File
Watch This Course
$229 USD $114.50 USD
-OR-
Or
8 easy payments of only $14.31
Instant access. Easy checkout. No fees.
Step 3: Configure Base Tune File
32.07
| 00:00 | - For the next step of our process, we're going to go through making some modifications to our calibration to get us to a point where the calibration is going to allow us to get the engine up and running so that we can actually begin tuning and optimising the calibration and there are some significant changes that are needed here as we've already discussed as we've gone through this worked example so far. |
| 00:21 | Now we've left off where we started with downloading our calibration so we've still got our stage 1 file open here as we can see and what we're going to do is begin by applying our speed density operating system patch, so we can come across to our operating systems tab and what we want to do here, we can see we've got our code modifications and we've got the ability to apply a speed density 2 bar patch. |
| 00:47 | So we want to apply that code modification. |
| 00:51 | Now this is going to open this little box here that's going to tell us exactly what we need to do and we can see it gives us a few steps here. |
| 01:00 | In particular we need to save the file with a new name, this is why it wasn't strictly essential that we save the file with a separate name once we've downloaded it. |
| 01:08 | We then need to close the file, open a new file and then we can use the write entire process to actually write this. |
| 01:15 | It's important we do this for the first time after the speed density operating system has been applied. |
| 01:20 | We don't need to use that write entire function because that is quite time consuming. |
| 01:24 | So we're going to go through that process here and we'll use the save as function and what we're going to do is remove our stage 1 tag here and we'll simply put HS108D cam as our reference. |
| 01:39 | So again as much or as little information as you want here. |
| 01:43 | So we're now going to close that particular file, we reopen our new HS108D speed density calibration, we can now see that the speed density air mode says applied and we also have our TCS patch which is saying applied so our speed density patch has been applied here. |
| 02:02 | We can close down our operating system tab and if we move across to our engine tab here, and we'll just quickly have a look, a little bit out of order here but if we come across to our airflow general we can now see that we have a set of VE tables which didn't exist in our original calibration, remembering the E38 engine control modules uses a virtual volumetric efficiency subsystem which is generated from coefficients so now we've actually got 3 VE tables labelled IMRC open, closed and displacement on demand. |
| 02:36 | Now if we open these up, the problem you see though of course is that they are filled with zeros. |
| 02:42 | We're going to address this in the next step but just understand that when you do first apply a speed density patch, you will have VE tables filled with zeros because these tables do not exist in the factory calibration so we are going to need to add numbers into this. |
| 02:58 | Another little idiosyncrasy here is that the VE tables that we will be generating here or adding numbers to, these use what is referred to as GM VE numbers and these are in the region of 2000 plus so not the typical 80 to 110% that we might be familiar with with a conventional volumetric efficiency system but that's OK, it's not a problem, the VE tables still respond in exactly the same way when we need to make modifications to them, even if the numbers themselves may not make much sense on face value. |
| 03:33 | So we're not going to deal with our VE tables right now, we'll come back and look at this but now let's start moving through our calibration and we'll see what changes we need to make. |
| 03:44 | One of the first areas to focus on is our MAP sensor calibration. |
| 03:48 | You'll remember that we have applied a 2 bar speed density operating system patch which infers that we can measure up to 1 bar of positive boost pressure. |
| 03:56 | However we're obviously not adding forced induction here and the stock MAP sensor is still in place which will only read to 1 bar. |
| 04:04 | So let's just have a look on the same tab we were already on here. |
| 04:06 | Under our MAP characteristics we can see we've got our MAP sensor linear and our MAP sensor offset. |
| 04:12 | And you'll see that the MAP sensor linear in particular has reverted to 200 kPa or 2 bar. |
| 04:17 | So if we don't pick this up and make an appropriate modification to this, we are going to end up having trouble so we need to enter essentially the values from our stock calibration here which will mean that the MAP sensor reading is still correct. |
| 04:31 | Now the easiest way to do this is if we come up to our compare tab here and we open a compare file, what we're going to use is our stage 1 file here as a comparison and we can see that now these 2 parameters in particular have turned green. |
| 04:47 | Green means that there has been a change and we can use the little options here to display either our current calibration, our compare or the difference between the 2 so at the moment we're on our current calibration, I'll click on show compare file and we can see we've got the correct values here so we need to enter these into our file so let's go ahead and do that now. |
| 05:07 | Alright we've changed those to suit, it's a good idea just to make sure, again just go back to your compare file and make sure that those have been changed. |
| 05:16 | Now in that case they have so what we can do now is close down our compare file. |
| 05:21 | We're now going to go back to our engine diagnostics and there's a few modifications we need to make here. |
| 05:28 | For a start, let's head across to our airflow tab and we can see here we've got some parameters here for our mass airflow sensor fail frequency high and low. |
| 05:39 | So this really defines when we are running the mass airflow sensor, where abouts the ECU will define that the mass airflow sensor has failed and then revert to the speed density subsystem. |
| 05:50 | And it is important here when we've removed the mass airflow sensor and we're doing a speed density patch to make sure that the MAF is detected as failed. |
| 05:57 | So simply put here, what we can do is enter both of these values at 0 Hz and this will make sure, even though there is no mass airflow sensor fitted, that the mass airflow sensor definitely will be picked up as faulty and will run on the speed density operating system. |
| 06:12 | We also need to, while we're on our diagnostics, head across to our DTC or diagnostic trouble codes tab and what we want to do is make sure that the mass airflow sensor will actually be detected as failed, so we can come down here to our parameters for our mass airflow sensor and what we're looking for here is P0101, 102 and 103. |
| 06:35 | So what we can see here is that at the moment it is set for MIL on second light. |
| 06:40 | So what we want to do here is we want to select no MIL light. |
| 06:45 | If we look at our options, we can also select no error reported and this is an area that is an easy mistake to make. |
| 06:51 | We don't want to select no error reported, the error needs to be reported, again for the speed density subsystem to operate but we don't want our MIL light to be active so we'll just disable that for our remaining options there. |
| 07:12 | While we are on our DTCs tab here, there are a couple of other options that you may want to adjust so we'll scroll down here, we get down to our P0420 and onwards we can see our catalyst system efficiency error. |
| 07:28 | So we'll have one of these for each bank 420 and 430. |
| 07:32 | Now this is going to depend on where abouts in the world you are and whether or not you're required to meet the current emissions standards or what the emissions standards are for your part of the world. |
| 07:44 | In this case we do have catalytic converters fitted but for a competition car we may well remove those, in which case we'd want to disable these 2 errors, otherwise we're going to end up with a check engine light for catalyst system inefficiency. |
| 07:56 | In this case we don't need to make any changes though so we can close that down. |
| 08:00 | We'll open up our engine tab again and we can carry on with our modifications. |
| 08:04 | The next area that's going to need some attention is our idle parameters. |
| 08:07 | So we can come across to our idle tab. |
| 08:09 | We've already discussed a couple of times now the fact that the idle speed will need to be increased and we want to do this but we don't want our idle speed any higher than we absolutely need so you can see in our normal operating area here from about 80°C and above, we've got our idle speed set at 550 RPM so what I'm going to do in both neutral and park is increase this and this is going to depend on your cam. |
| 08:34 | In this case I am going to set these values to 850, I know for this particular cam that will work well. |
| 08:41 | What we're going to do here is down at the lower engine coolant temperature we've got currently our target already set to 850, we're going to need to increase this but I don't want to go much higher than we need so we're going to enter values of 1000 there and see how that works out. |
| 08:58 | And this is a case here that we can always come back and address this so we're not always going to know exactly what the best idle speed is and we really want to test and find what the minimum idle speed we can use for our cam is, it's going to give acceptable response because otherwise if we set it higher than necessary we are going to have the system pushing or the car pushing which I've already discussed here so we'll just highlight here between the two adjustments we've made and we'll just use our interpolate function there, that'll give us a nice linear interpolation, we can close that down. |
| 09:29 | Now we've also got the startup idle speed here for park and neutral so what we can do here is just highlight that entire table here and we can add let's say 300, 300 RPM to that entire table, again we may need to come back and make some changes to these tables at a later point. |
| 09:51 | We can also do the same to our park and our drive tables, making similar changes there. |
| 09:57 | We'll close those down there. |
| 09:59 | We've also got our minimum set point. |
| 10:00 | So let's open that up, again we can see 550 RPM here, what I'm going to do here is set that just a little bit below our minimum target and I'll set that to 800 RPM. |
| 10:11 | So that's going to give us a reasonably sensible starting point for our idle speed control. |
| 10:17 | However as I've said, we may need to come back and tweak this but this should be enough to get us up and running. |
| 10:23 | Next we're going to move across to our airflow tab and we're going to need to make some changes here. |
| 10:28 | Now making those changes to our idle target on their own actually aren't going to work particularly well. |
| 10:34 | This works in conjunction with this oddly named table which is our base running airflow. |
| 10:38 | And the particular table we want here is our airflow final minimum. |
| 10:43 | You could liken this to a feed forward or base value for our electronic throttle opening to achieve our target idle speed. |
| 10:52 | And what we're going to be doing predominantly is idling down in this area of the table and because we're going to need more airflow in order to achieve our target, what I'm going to do for the moment is just highlight the area that we're likely to be in, I'll come up to in this case 1200 RPM and we're going to start by adding 2 g per second to this table. |
| 11:14 | We do want to also be a little bit mindful of keeping a bit of a smooth trend here so what I'm going to do is just go between 1200 and 1600 RPM here and we can use our linear interpolate there. |
| 11:25 | Now again this won't necessarily be the correct values but it should be enough to get us up and running and as part of our tuning process, we're going to actually come back and revisit this table and we may well need to make further modifications to it to get our idle speed really dialled in. |
| 11:40 | Now one of the common areas that I see people going wrong when tuning the drive by wire engines that are fitted with cams is drilling holes through the throttle butterfly and this is very very common actually out there in the tuning industry for the LS engines. |
| 11:55 | And the reason for this is if we don't know what parameters to change wer'e going to be in a situation where particularly when the engine's cold, we simply can't get enough throttle opening when we're not touching the throttle pedal to achieve our target idle speed. |
| 12:09 | You'll find that the throttle opening percentage will max out at something like about 27% in our scanner or thereabouts. |
| 12:17 | And that may be not enough to actually get our idle speed where we want it to be. |
| 12:20 | So this is why a lot of tuners revert to drilling holes through the throttle plate. |
| 12:25 | Good news is, that's not necessary, it's actually this parameter here that we do need to change our percentage max which defines essentially the maximum opening of our throttle butterfly when we're in idle speed control mode. |
| 12:35 | So what we're going to do here, I just know from my own experience that a value of 5 here for this large cam is going to give us the desired result but bit of experimentation here, basically you want to use a smaller number here as you can to give the idle speed control good resolution and if you get to a situation where under cold start conditions you're seeing in the scanner the throttle position basically flatline and our idle speed is still below our target, that indicates that you're going to need to make an adjustment to this percent maximum value. |
| 13:09 | So we've got our idle speed essentially to a point where we should be able to get the engine up and running, let's move on. |
| 13:16 | What we'll actually do here is move a little bit out of order and we're going to come across to our torque management tab and we're going to have a look at our options here. |
| 13:25 | So the torque management aspect here, the engine control module is always calculating the expected about of torque that the engine is producing. |
| 13:33 | And if it exceeds any of the limits in this particular tab then it can end up closing the throttle body and this can be frustrating because obviously when we are modifying the engine, we're trying to improve engine torque so this can actually artificially clip our torque. |
| 13:48 | There's a few aspects we're going to adjust here so we'll start with our maximum torque RPM vs gear and we'll open that up. |
| 13:54 | We can actually see that this particular calibration, we've already got the numbers here maxed out which is exactly what we'd want to do, making sure that they're at the maximum value which is 8192. |
| 14:05 | Likewise we've also got maximum values for each of our gears. |
| 14:09 | So what I'm going to do here is just set each of these to the same maximum value, just making sure that regardless essentially what gear we're in, we're not going to reach that maximum. |
| 14:18 | So let's go ahead and do that now. |
| 14:26 | Alright so that covers our 1st through to 6th gear. |
| 14:29 | I'm not going to make any changes to reverse 'cause frankly I don't really care if there is torque limitations occurring in reverse but we do have a little bit more work to do though, we're going to make those same changes here to our input, trans input maximum and our output maximum, although that's very close to the mark anyway. |
| 14:45 | Last aspect we'll look at here is our brake torque management. |
| 14:49 | So this is something that is easy to overlook and basically it limits the engine torque when your foot is on the brake. |
| 14:57 | I'll open that table up here and we can see that that's relative to throttle position as well as our manifold vacuum. |
| 15:04 | How you deal with this table is completely up to you, particularly if you're drag racing the vehicle and you want to be able to do a static burnout with your foot on the brake, you're going to need to modify this table which will require you to go through and max out those values. |
| 15:17 | Otherwise there will be no way of you doing a static burnout. |
| 15:21 | So again really up to what you're trying to achieve there as to how you deal with that. |
| 15:26 | Alright so this takes care of the key aspects with our torque management and should ensure that as we go through the process we're not going to end up with any torque clipping. |
| 15:36 | What we can do now is head back across to our fuel tab. |
| 15:41 | There's a lot of options here and what you're going to need to adjust will depend on the changes you've made. |
| 15:48 | At the moment we're on our general tab and we can see in particular here we've got the options for our injector control. |
| 15:54 | You will need to adjust these tables if you have fitted injectors that are different to stock. |
| 15:59 | In our case we know that we can cope with the required fuel volume or fuel mass with the stock injectors so we don't need to adjust and of that. |
| 16:07 | However what we are going to do is make a few other changes. |
| 16:11 | We can come through to our oxygen sensors for a start. |
| 16:14 | And what we want to do here is going to depend again on our personal preferences. |
| 16:19 | For the tuning aspect I'm going to basically disable the closed loop control. |
| 16:25 | This only works under the 14.7:1 air/fuel ratio target anyway, when we're in power enrichment. |
| 16:32 | There is no closed loop operation. |
| 16:34 | But the reason I'm doing this is that I'm going to be using the input from a wideband air/fuel ratio meter to dial in the volumetric efficiency table in both closed loop and power enrichment modes. |
| 16:45 | And this can get a little bit tricky because if we've got the engine running in closed loop mode we're going to have our short term and long term fuel trims operating under closed loop which will essentially remove any error. |
| 16:57 | Two schools of thought on this, there are tuners out there who prefer to use the short term or short term plus long term fuel trims as a metric to help them dial in their VE table under closed loop conditions. |
| 17:12 | That's fine, it will get you pretty good results, I personally prefer to do everything using the wideband. |
| 17:17 | One it's a little bit faster to act and a little bit more accurate but 2, we're going to need the wideband when we're under power enrichment anyway because the narrowband sensors simply don't give us the information we need so why not just do everything using the wideband? So what we're going to need to do here is first of all disable our long term fuel trim. |
| 17:36 | So we can do this by basically setting our minimum engine coolant temperature to the maximum value, so basically 256 here. |
| 17:43 | And the maximum temperature here, we'll set to the minimum, little bit confusing but basically we're setting those parameters so that irrespective of the engine coolant temperature our long term fuel trims will not be active. |
| 17:55 | We can also come up here to our O2 readiness, engine coolant temperature, we'll click on that table here and what we can do is basically set this so that the O2 sensors, their O2 readiness test won't run so again we want to max that particular table out there. |
| 18:14 | Now that we've disabled our long term fuel trims we'll just come up as well to our closed loop enable which is our ECT vs startup and we're going to basically max out this table here. |
| 18:23 | Now this particular table we can see that our maximum value there is 152°C, if we highlight over the top of it, we'll be able to see down, it's changed but down the bottom right hand corner if I go over this again, we'll see the range that we can set this to. |
| 18:40 | So let's just set that to 152 and we'll close that down so that's going to disable our closed loop, making sure that irrespective we're not going to go into closed loop operation with our short term and long term fuel trims. |
| 18:54 | We'll move on now to our open loop base tab and we have a number of modifiers here for our open loop target so for example if we click on our open loop gas gear we can see the relationship here between our intake valve temperature, our engine coolant temperature and our actual air/fuel ratio target. |
| 19:15 | So personal preference comes in here as to what you want to do with this. |
| 19:19 | It can be simplest here just to set all of these tables for the moment to a value of 1 and this way it's going to just ensure that essentially you're always going to be chasing a static target while we are dialling in the VE tables. |
| 19:34 | It is important if you do that, it's always a good idea to come back and make sure that you've reset these tables back to their default values once you've completed your tuning but for our purposes, we're going to go through and set all of these to 1 so we'll carry on now. |
| 19:48 | Alright next we can move across to our power enrichment tab. |
| 19:52 | And there's a few changes we are going to be making here. |
| 19:55 | So first of all we can see we've got our power enrichment, equivalence ratio gas and our equivalence ratio alcohol. |
| 20:04 | As part of our 2 bar speed density operating system we also now have our boost enrichment. |
| 20:08 | So this can be useful for supercharged or turbocharged applications giving us a little bit more control of the air/fuel ratio targets as we move into boost so we can see at the moment, that's enabled at 110 kPa. |
| 20:22 | Of course we shouldn't be getting there. |
| 20:24 | Alright so we've also got our enable parameters. |
| 20:27 | Typically we're not going to need to make any changes to that at all. |
| 20:31 | We also have our throttle set point so we'll open that up and we can see this defines the throttle position above which we will actually move into power enrichment. |
| 20:41 | We can see that this starts a little bit higher at low RPM and then as we move through and the RPM increases, we can see that the throttle position required to go into power enrichment drops. |
| 20:53 | Now this again becomes a bit of a personal preference and it's a bit of a balancing act here. |
| 20:56 | Lowering those numbers, particularly at low RPM will give us a little bit more power at part throttle or higher throttle openings. |
| 21:05 | However if we are tipping into power enrichment, under light throttle and cruise conditions it's going to adversely affect our fuel economy. |
| 21:12 | So the numbers we've got in there are probably a pretty good place to get started, going to give us a good gain over stock but we're not going to be adversely affecting our fuel economy. |
| 21:22 | The main work we need to do here is in our EQ ratio gas table, we'll open that up and this is an area that warrants a little bit of discussion as well because for a lot of tuners dealing with equivalence raito is a term that they just haven't dealt with and basically this is just the inverse of lambda so if we look at this table here and we pick, let's say a number here of 4250 RPM. |
| 21:44 | 1.2, so let's see how we can turn that into something that makes a little bit more sense so we'll bring up our calculator here. |
| 21:51 | And we'll enter a value of 1.2 and what we're going to then do is use our inverse function which is this little one here. |
| 21:59 | Click on that, it gives us our lambda target for that equivalence ratio so this is the same as lambda 0.83. |
| 22:06 | Now personally, and if you've gone through any of our courses you'll know that I prefer to work in lambda so for me this is absolutely fine but if you want to go one step further and convert this into air/fuel ratio, what we can do is multiply this by the stoich air/fuel ratio, in this case 14.7:1 for pump gas so we can see that's 12.25 which is quite rich as well. |
| 22:25 | So we need to choose suitable equivalence ratio numbers here and I'm not going to get too involved. |
| 22:31 | What we're going to do is start with something that's nice and safe. |
| 22:33 | Let's start with a number of 12.5:1 and we want to flatline this for the moment because it's going to make it easier for our VE table calibration because we won't be chasing a moving target so what we want to do is 12.5:1, we'll divide this now, we're going the opposite way, by our stoich value, 14.7. |
| 22:49 | This gives us our lambda target, so that becomes 0.85 and what we want to do now is use the inverse function again and this gives us 1.176 so 1.176, same as our air/fuel ratio target of 12.5:1 so let's now enter that into our equivalence ratio target table. |
| 23:10 | So this is just a broad starting point, we wouldn't necessarily leave that as it is. |
| 23:15 | Once we go through our tuning, we can come back and make modifications as required. |
| 23:20 | Just as a little bit of good housekeeping here, I will also set our alcohol table which we're not using as well as our boost table here to the same values as well. |
| 23:30 | So we shouldn't be using any of these but just in case we do end up for some reason in one of those tables, we've dealt with those. |
| 23:39 | Now we also need to come across to our cut off or deceleration fuel cut off tab and this is another area that we will be making some changes so we can see at the moment, particularly with our rev limiter, our extreme cutoff here is is 6300 RPM. |
| 23:53 | We're going to be revving this a lot further than that so I'm going to set the value here to 7000 RPM. |
| 24:00 | And there are a few other changes that we will need to make here as well. |
| 24:03 | So we can see if we click on our in gear, we've got values here of 6200 so again of course we're going to set all of those to If you don't realise this, it can be a little bit frustrating because you're making changes and the rev limit doesn't seem to be changing. |
| 24:18 | We've also got our extreme resume so this normally we set a little bit below our maximum RPM so in this case let's set that at 6980 RPM. |
| 24:31 | We've also got some modifiers here for our cold engine. |
| 24:35 | We can see there that we've got that set up, 4600 to 5000 RPM at low coolant temperatures and then again we've got values of 6200 in this table so how you deal with this again up to you, can be beneficial to keep that lower RPM limit when the engine is cold, for simplicity here I'm just going to set that entire table again to 7000 RPM. |
| 24:58 | So that should deal with our main parameters however we've also got a lamp RPM setting here, 6200 again, I'm just going to set that to 7000. |
| 25:10 | Alright so that deals with our engine rev limit, we now will be able to rev this all the way through to 7000 RPM. |
| 25:16 | Obviously a little bit cautious here because as we increase the RPM we are risking damage to the engine, this needs to be chosen, suited to your particular cam, in particular your valve springs, in this case the HS108D and the valve springs will work quite nicely at 7000 RPM and even above. |
| 25:33 | Alright one other aspect, I'll actually just dive back to our power enrichment tab because I did just realise that there's a couple of other areas that I want to discuss here. |
| 25:41 | First of all we've got our enrichment rate here so this defines how quickly we'll ramp between the stoich air/fuel ratio target and whatever we've set in our power enrichment equivalence ratio tables. |
| 25:51 | What we find is that if we set this to a value of 1.0 we're going to ramp quicker which can give us crisper response. |
| 25:57 | Subtle but important, the other pararmeter that's just worth discussing here is our delay parameter and this is one that a lot of novices get confused about. |
| 26:06 | It seems on face value like it's going to delay our transition into power enrichment until we get to 5000 RPM. |
| 26:12 | This actually doesn't seem to do anything in GM's car lineup, it's for their trucks, however, again as a matter of course, we can just set this to a value of 0 RPM, just eliminating that possibility. |
| 26:22 | Alright we'll get back into order now. |
| 26:25 | There's nothing really left for us to do here with our air/fuel ratio targets but we'll just quickly talk about our temperature control. |
| 26:33 | We can see here we've got the option for our catalyst protection. |
| 26:37 | So this is important to understand, if you aren't running catalytic converters. |
| 26:43 | The engine control module is always calculating the expected exhaust gas temperature and with catalyst over temperature protection enabled, if the temperature that's calculated is deemed to be unsafe, it will richen the air/fuel ratio target. |
| 26:56 | Now if you've got catalytic converters and you want to keep them in one piece, really you've got no option but to keep this in place but if the cats have been removed for off road racing or an area where you don't need catalytic converters definitely you want to disable that. |
| 27:10 | We also see there's the maximum enrichment that is allowed there, so a factor of 1.3 which is quite significant. |
| 27:17 | Alright let's move on now and we'll go across to our spark tab. |
| 27:21 | Now there's a few things we need to discuss here, we're actually going to begin by talking about our spark advance and we'll talk about where we're going to make our changes. |
| 27:31 | We can see we've got this table here called MBT or max torque timing. |
| 27:35 | A lot of people think this is where we need to make our changes. |
| 27:37 | This is actually used as part of the torque calculation model that the engine control model uses so we're not going to be making changes here and instead the tables that we'll be using are our high octane and low octane spark base tables. |
| 27:51 | If we open one of those up we can see we've got a 3D table here, we've got RPM on the horizontal axis which is pretty self explanatory and we see we've got spark air mass in grams per cylinder on the vertical axis. |
| 28:04 | This part here does confuse a lot of people because obviously we've converted to a speed density operating system using manifold absolute pressure so most people would expect to see MAP as that load axis. |
| 28:15 | Despite the fact that we are using the speed density operating principle, the engine control module is still actually calculating mass airflow from the volumetric efficiency table so everything in the background is still operating on the cylinder air mass. |
| 28:30 | And don't worry, we'll see exactly how to tell where we're operating in this table as we move through. |
| 28:36 | We'll close that down for now, we're not going to make any changes to this table or these tables at the moment. |
| 28:42 | But what we will do is head over to our retard and what we want to do is make a couple of changes here. |
| 28:48 | First of all we've got our option for our maximum knock retard vs RPM vs MAP and we'll open this up. |
| 28:56 | And we can see in stock form this allows basically up to 10° of timing to be pulled which is pretty significant and you need to understand that GM here were basically making a calibration that would work across the world on various octane fuels so they've given a lot of control to the knock control strategy. |
| 29:16 | I don't think we need to be anywhere near that aggressive, particularly when we're dealing with the tune in first person and we're seeing exactly what the engine wants for our fuel and conditions so what I'm going to do is reduce the strength of that a little bit. |
| 29:30 | Personal preference here, really I'm just going to multiply that by 0.75. |
| 29:34 | 8° there, just open that back up, 8° there now our maximum amount of trim, still significant, you may even like to pull that down to a factor of 0.5, giving us only 5° of available trim. |
| 29:47 | We also need to consider our burst knock retard here. |
| 29:51 | And we'll find that in a modified calibration like this, that burst knock retard is going to become overly active and it's going to be pulling timing unecessarily. |
| 30:00 | Without diving too deep into the system. |
| 30:02 | Disabling this does not disable the knock retard strategy but this is kind of preemptive of knock occurring. |
| 30:10 | The actual knock retard parameter that we log in our scanner, that's a result of the knock actually occurring so it's in response so it's a reactive system, this is predictive and tries to pull timing in order to prevent knock, in my experience it does a terrible job so what we want to do here is come down to our base vs cylinder air delta and what we're going to do is simply zero out that table there. |
| 30:34 | We'll enter a value of 0, press the equals key, so that's going to stop our burst knock retard system from making any changes. |
| 30:42 | We're also going to just as a matter of course here, open our remaining tables around the burst knock control and we're going to 0 all of these out as well as our other parameters so let's just go ahead and get that done now. |
| 30:57 | The last change we're going to make here, if we come back a little bit out of order here, we come back to our airflow tab and we come across to our dynamic tab, and this is good housekeeping here, we've got our dynamic airflow which is the factory GM system where it reverts between the mass airflow sensor and the speed density subsystem. |
| 31:16 | So we've got our high RPM disabled here at 4000 RPM and what we want to do is essentially just make these up around 8000 RPM so that we're never disabling the dymanic airflow subsystem. |
| 31:29 | And at this point we've basically made the key changes that are going to be necessary to our base calibration. |
| 31:36 | We're ready to save that file now so let's go ahead and do that. |
| 31:40 | We can just use our little save tab here, save icon I should say in our tools tab and that's going to save, remember we can just check here the file name at the moment is our HS108D cam file so this is our modified calibration after our speed density operating system has been applied, so we'll press save there and at this point we're ready to move on with the next step of our process. |
