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How do i know what arf ratio i need for boost or not boost

Practical Reflash Tuning

Discussion and questions related to the course Reflashing


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I don't know if I went true this and forgot but I want to know how to know where I need to run richer and what rpm.

Did you get the AFR course? the best way to understand the AFR ratio is to follow the course and understand how AFR ratio affect the engine.

You can find some infos in Engine tuning fundamentals or better afr dedicated course

I did the course, some engines have different target, I want to now how do I know the target.

I know how to get to the target, I just don't understand how the target is stipulated, I know afr are 1.00 lambda or 14.67 but in boost you need more fuel to cool down the engine.

Ok went over and look all the modules again and Andre does say boosted you don't want to run richer then .75 on boost and N/A .85 on top of rpm

The reason for choosing a target AFR is power and reliability. The dyno can tell you what AFR produces the most power, sometimes you have to use additional fuel for cooling, depending on the intended purpose of the engine (ie. a land-speed car or a power boat will be a full load for a long time, a lot different than a drag car that only sees full load for seconds).

I don't have a Dyno right now, I got a 2JZ with single turbo on AEM ecu and I know the target on full wot is 78 at the end rpm but I want to make sure I can find a safe table to start with.

start rich, 11.8 n/a and 11 at high boost and then use the dyno to decide if you want to run leaner

I know but like I say before I don’t have a dyno.

I would suggest you aim for around 0.78 lambda under full boost on pump gas. This might not be absolutely perfect but it will be a safe place to start.

Thank you Andre very helpful, I did tune and car is running good, this was my first tune and boosted car and it’s running good with no nock, I did not put any timing because I don’t have a dyno but will do next.