Road Tuning: Step 10 - Confirming Tune
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Step 10 - Confirming Tune
04.39
| 00:00 | Now we've been through the entire process of tuning the engine. |
| 00:03 | That leaves one last part, is a final check-up on all of the parameters we've already tuned just to be sure that everything is exactly where we set it and we're happy with every aspect of the engine's performance. |
| 00:15 | So, we're gonna go through that procedure now. |
| 00:17 | We're gonna start by revisiting our idle and making sure that's where we wanted it to be. |
| 00:24 | So what we can see here is we're idling at around about 1000rpm and our lambda's sitting at around about 1.0. |
| 00:31 | So we're happy with that. |
| 00:33 | That's where we wanted it to be and over the course of tuning the car we've also had plenty of opportunity to make sure the idle speed is stable over a wide range of operating conditions. |
| 00:44 | So that lambda 1 and 1000rpm idle that's basically where we want that to be. |
| 00:50 | The next part that we're going to check is our cruise mixture at sort of a normal road going speed limit and that's where we're going to spend probably about 90% of our time if this is a road car. |
| 01:04 | So we want to check it in two areas. |
| 01:06 | We want to check it at around about 40-60 kilometers which is what we'd expect to see on an urban street and then we want to re-check that also at around about 90-110k which is what we'd expect to see at open road speed limits. |
| 01:25 | And you could see here we're sitting at around 3000rpm, which is a normal cruise rpm for a 4-cylinder engine and our lambda is sitting at lambda 1, so we're pretty much exactly where we want to be. |
| 01:37 | Remember here, don't chase your tail too much on the air fuel ratio. |
| 01:42 | It will move around a little bit. |
| 01:43 | And when I say I'm targeting lambda 1 I've got a margin of about .01+/- that I'm going to be happy with and I'll accept. |
| 01:53 | You're never going to get a rock solid 100% perfect number that just doesn't fluctuate. |
| 01:59 | So if our cruise mixtures are okay, the next step of the process is to confirm everything in another wide open throttle pull. |
| 02:08 | Though this time what we're going to do is an acceleration run through the gears so we can confirm how the car is responding to gear changes and that sort of lets us re-check our transient response as well. |
| 02:23 | So I'm going to do an acceleration run now from first gear to the top of third. |
| 02:55 | Okay, so we so we've data logged that run so we don't really need to look at the laptop while we're doing it although I will be watching the air fuel ratio meter on the windscreen while I'm doing it. |
| 03:05 | Normally, I'd also be listening for detonation. |
| 03:09 | So after we're stopped we can review the log file and make sure everything is okay and we want to zoom in on the area we're interested in which is our wide open throttle. |
| 03:18 | So first of all, we're wanting to check our lambda and we can see that the lambda is tracking where we want it. |
| 03:27 | Particularly, what we're interested in is looking at what the lambda is doing right at high rpm sustained load. |
| 03:34 | So the top of third gear here at 7000rpm we're seeing a lambda of .87 which is exactly what we're targeting, so we're happy with that. |
| 03:43 | The other thing that's interesting is we can look at our noise profile here for knock. |
| 03:47 | As I said, I'd normally be doing this audibly as well, but we can see if there's any areas where the knock threshold has been exceeded and make any changes based on that. |
| 03:59 | So if everything checks out in the data log file and we're happy with everything, we can say that our engine is 100% completely tuned Now what that means is we're going to have an engine that's going to drive perfectly, it's drivability is going to be great at all areas of throttle position and rpm. |
| 04:17 | It's going to deliver good torque, good fuel economy. |
| 04:21 | It's going to be reliable and it's going to deliver good power. |
| 04:24 | And realistically, if this is done properly on the road you're going to get a result that is as good, if not better, than what most professional tuners will be able to deliver from a dyno-tuned vehicle. |
