Practical Reflash Tuning: Speed Density Conversion
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Speed Density Conversion
02.18
| 00:00 | - We've already covered in some detail the differences between a MAF based ECU, and one that utilises a MAP sensor to calculate load. |
| 00:09 | On some platforms we may have the ability to swap from a MAF based load measurement system, to one where load is calculated by the speed density principle instead. |
| 00:20 | This is achieved by modifying the way the factory ECU operates. |
| 00:26 | This isn't something we as tuners can reasonably achieve, and to do this we're going to be relying on a patch, or operating system being available for our particular car, to allow the engine to be run in speed density mode. |
| 00:43 | In some applications, we may have the option of running either a dedicated speed density system, or a hybrid system. |
| 00:51 | Where the MAF sensor is used under low load conditions, and then the ECU switches to using speed density at higher load levels. |
| 01:01 | A hybrid system like this, can provide the best of both world in many instances. |
| 01:06 | With good control over the air fuel ratio, thanks to the MAF sensor, along with the speed density system. |
| 01:13 | That means we don't need to worry about the MAF resolution, or airflow limits in a high powered engine. |
| 01:21 | The process of converting to speed density is very dependent on the particular ECU. |
| 01:28 | In some cases, the stock ECU might already include a VE table that's referenced of the MAF files. |
| 01:35 | Or during transient conditions. |
| 01:38 | And in this case, the job is quite straight forward. |
| 01:42 | In other ECU's that were never designed to run in speed density mode, we may need to develop a VE, or volumetric efficiency table from scratch, and this can be quite time consuming. |
| 01:55 | Given the dramatic differences in approach between different ECU's, it isn't possible to outline a generic approach to the task that can be applied to every situation. |
| 02:07 | For this reason, we'll deal with speed density conversion in our worked examples, and these will be added to over time. |
