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- When it comes to using the Dyno to get the most out of an engine, there are a couple of ways we can use it.
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| 00:06 |
Remember that the Dyno is there to replicate the way the engine runs on the road and we want to keep that in mind when we are deciding how to use the Dyno.
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| 00:16 |
In general, when we're driving our car, we'll be using it in one of two separate ways.
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| 00:22 |
We'll either be cruising at a relatively constant RPM and load, or throttle position or we'll be accelerating through the rev range at full throttle.
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| 00:32 |
We can replicate these two situations using the Dyno to allow us to do the best job possible of optimising the fuel and ignition timing to suit the way the engine is being used at a particular time.
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| 00:46 |
The first technique we can use on the Dyno is called steady state operation.
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| 00:51 |
And this is where we set the Dyno to hold a constant engine RPM, or road speed in the case of a Chassis Dyno.
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| 00:59 |
We can then run the engine on the Dyno and the Dyno will apply more or less load as required to maintain the same engine speed.
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| 01:08 |
This means that we can run the engine and adjust the throttle opening to accurately access all of the zones in the fuel and ignition tables.
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| 01:18 |
If we're driving a car on the road and we go to full throttle, we'll expect the engines will begin accelerating rapidly and the steady state tuning technique doesn't do a great job of replicating the situation.
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| 01:32 |
To effectively tune the engine at full throttle, then we use the Dyno to perform ramp runs.
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| 01:39 |
When we perform a ramp run we can specify a start RPM, or road speed and a finish RPM, or road speed as well as how long the Dyno will take to perform the acceleration test.
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| 01:51 |
These tests replicate the way the engine accelerates on the road or race track and allow the tuner to ensure the fuel and ignition are correct under the same operating conditions the engine will see in the real world.
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| 02:06 |
These ramp tests are also where the Dyno is able to plot a power and torque graph and we finally get to see how much power the engine makes, which is one of the more exciting parts of any performance build.
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| 02:19 |
If you want the best results from any tuning job it is important to spend the time to thoroughly tune the engine in all of the areas it is likely to run in.
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| 02:30 |
This means using the Dyno in both steady state and ramp modes.
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| 02:35 |
The steady state tuning can however be quite time consuming and this, one aspect, a lot of tuners tend to overlook, focusing, instead on the much more exciting part of full powered tuning.
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| 02:48 |
I can assure you though that you are unlikely to notice the difference of four or five horsepower wide open throttle and seven thousand RPM but you're definately going to notice if the air fuel ratio is too lean causing a misfire or stumble in the cruise area of the map, where you spend a large portion of your time.
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| 03:07 |
This is why it's important to spend the time to correctly tune the fuel and ignition in steady state.
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| 03:15 |
One exception that is worth mentioning is that if you're refreshing a factory ECU then often you'll be able to completely disregard the cruise and mid-range areas of operation because the factory ECU can take care of this area.
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| 03:30 |
Instead we can concentrate solely on the full power tuning.
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