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Practical Diesel Tuning: 5. Confirm Tune On The Road

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5. Confirm Tune On The Road

01.54

00:00 - With our calibration now complete on the dyno, I'm a big advocate where possible of confirming the tune on the road.
00:05 While the dyno is a great place to perform your tuning, it's incredibly difficult to accurately replicate the airflow and conditions we're likely to see with the truck out on the road at speed.
00:14 Since this is where the truck is going to spend most of its time, I always like to test and confirm that EGT is safe and the engine is smooth and responsive to drive.
00:22 It's not uncommon that we may need to make minor adjustments to the boost or fuel delivery when we test out on the road.
00:28 Or that we may find that the engine seems to create more or less exhaust gas temperature than we saw on the dyno.
00:33 This is where the datalogger really becomes valuable and we can scan the ECU while driving to see what is happening.
00:39 In particular, I like to datalog the engine performance in three different areas.
00:43 First I will scan the engine under normal cruising conditions at both highway speed and around town.
00:50 Here I'm looking specifically how much fuel is being delivered in respect to our fuel economy aims, this also needs to be considered alongside the exhaust gas temperature.
00:58 Next I'll look at the wide open throttle performance.
01:00 And specifically I want to look at how the engine responds under high load and sustained high RPM that we would expect under heavy abuse.
01:07 If we're dealing with a commercial truck or pickup that's expected to regularly tow heavy loads, then this is how we'd ideally like to test it.
01:14 This is essentially the worse case scenario for abuse for the engine and it's not going to encounter anything worse than this.
01:20 If everything checks out here, we can be confident in our tune.
01:23 Here we're looking at the exhaust gas temperature to make sure it's not getting out of control under sustained heavy load.
01:29 We should also be taking note of the air/fuel ratio if available and checking how well the boost pressure is tracking to target.
01:35 Lastly, I'll also check the engine performance under transient conditions such as fast throttle applications and gear changes for manual transmissions.
01:43 Here we're looking for smooth response to throttle input, no over boosting.