injector cranking primer enrichment evom

INJECTOR CRANKING PRIMER ENRICHMENT EVOM HOW TO
INJECTOR CRANKING PRIMER ENRICHMENT EVOM DRIVER

In the below figure, you can see our VE table which is also displayed graphically on the right-hand side. If you haven’t already gathered, this means that if we don’t have our main VE table tune nailed down, we haven’t got a hope of being able to correctly tune our cold start corrections. In most cases, all of the warm-up and cranking enrichment parameters work as adders or multipliers over and above our main volumetric efficiency (VE) table. If you don’t know the correct process to go through, it’s easy to insert errors into the fuel and correction tables that will end up producing poor results.Ĭonsideration One: The Main Volumetric Efficiency Table There are some considerations to keep in mind when tuning cold start.

Transient enrichment – This article won’t really touch on this however this is for aspects such as acceleration enrichment that may also need to be adjusted relative to coolant temperature.

Idle requirements – This is where the additional air bypass comes in, however we may also need to increase our idle target from our normal hot idle rpm.

Warm up enrichment – This is usually a 2 dimensional table relative to coolant temperature, however there can be an advantage in turning this into a 3 dimensional tables relative to coolant temperature and engine load.

Post start enrichment – This is the additional fuel that is injected for a period of time after the engine starts.

This will generally be less than 300 to 400 RPM so we require a bit of extra fuel to get the engine to turn over, catch and start.

Cranking enrichment – This is the additional fuel being delivered by the injectors when the engine is at cranking speed.

What Parameters Are Affected By Cold Temperature Operation? Even something as simple as replacing the factory injectors with a larger set can make a difference to the cold start settings required.

In the same way that you can’t take a non-flex fuel capable car running on gasoline and fill it up with E85, you can’t take the settings that have been used to perfectly tune one car, transfer them over to another and expect to get the same perfect results. When we’re tuning for cold start we need to keep in mind that every engine is different. To complicate things even further, we will also need some additional air bypass in terms of our idle speed control settings to maintain a sensible idle speed as the engine is warming up. We may also find that during the cranking phase of engine startup, we require even more fuel, over and above what we require once the engine has started. To make up for this, we need to provide additional fuel when the engine is cold. This means that some of the fuel is going to pool and be introduced in liquid form which makes for much more difficult combustion. Conversely, when the engine is cold, a portion of this fuel is going to wet out against the port walls. When the port walls and the back of the intake valve are hot, the fuel will vaporise off them and be drawn into the combustion chamber in vapour form, making for easy combustion.

Why Do We Need Additional Fuel When Cold Starting?īefore we get to the how, let’s discuss the why. Having said that, if we can turn up to an event and start the car while it’s still on the trailer in order to back it off, why not award ourselves this luxury? If it’s a drag car then you might not be quite so concerned.

INJECTOR CRANKING PRIMER ENRICHMENT EVOM DRIVER

If it’s a daily driver then obviously we want great cold start performance. While we’re tuning, we need to keep in mind what the car will be used for. In this article: Why Do We Need Additional Fuel When Cold Starting? | Cold Starts: Every engine is different | What Parameters Are Affected By Cold Temperature Operation? | Cold Start Considerations: One, Two, Three | Parameters Available In The Haltech Elite | The Cold Start Tuning Process Simply put, we want a car where, regardless of whether you’re in Outback Australia on a hot summer’s day, or you’re in Queenstown, New Zealand for ski season, you can turn the key with no throttle, have the car idle crisply and smoothly, all while maintaining good control of the air-fuel ratio as it warms up. Our aim when tuning cold start, is to get as close as possible to the sort of performance we get from a factory car.

INJECTOR CRANKING PRIMER ENRICHMENT EVOM HOW TO

This really comes down to not having a full understanding of the fundamentals behind it and not knowing how to make the necessary adjustments in order to get the cold start working perfectly. Cold start tuning is an area that a lot of tuners and enthusiasts really struggle with.

Injector cranking primer enrichment evom