good afrs

[Fusion Ed]

The colours should not be taken as safe/dangerous. Its simply a visualisation to help quickly read the map. for example if you had a single green cell in the red area you know it would be wrong. The values in the load cells are approx AFR. They may not match exactly with reality, however by changing the injector constants and lag times you can usually get them very close.

If I am asked to remap a pulsar ECU I tailor the load cells to the response of the cars turbo. The map above is a stock fuel map.
Typically larger turbos change extremely rapidly around their boost threshold RPM, and the maps will also need rescaling. Again this would need to be done if changing injectors or airflow meters. The aim is to get as much of the map used as possible. This will give you the greatest resolution for achieving an accurate map. Some times I will also change the knock feedback and closed loop operation areas. Its also possible to remap the knock maps, so that if the typical knock sensor failure occurs the car will still drive normally. Obviously its nicer to have the knock sensor working like it should do, but in reality it does little to the ignition map, and offers the car very little protection, especially in the event of top end knock (above 4000 rpm)

 

[neil240z]

cheers for that Ed, it increases my mapping knowledge from 1%-10%, where you based Ed?

 

[campbellju]

As Edd says, the standard map is for interest only. In simple terms it is designed for economy (blue) and safety (red).

As a broad AFR guide:

Idle 14.3 to 15.1​

Low speed 12.5 to 13

Light throttle 14 to 15​

Cruise 14 to 15
Torque 12.5 to 13.5

Power 12 to 12.5

Hi Boost 11.8 to 12.1​

When you do the Maths on the response of your lambda guage vs the number of explosions per second at high rev vs the fact that every cylinder has a different compression, VE, air/load injector flow rate and ultimately AFR we are not talking an accurate science here. Its more like firing a shotgun than a rifle.


​

 

[Fusion Ed]

Agree with the above, but I do think its an accurate science just one with many variables.

 

[mattytappy]

good info guys.....its a real black ,dark art ,for some people...including me to understand...but from what i do the standard ecu in the closed loop areas is incredibly rich.....i take it the only way to get around adjusting those closed loop areas is to have a stand alone ecu and start from scratch and that the thats were the safc2 falls down on an emanage or simalar? it would be good to se a fuel ratio graph like that for the mines as i have noticed a world of differnce against the standard ecu so it would be nice to see how the are or were mapping the afrs.....then we could get close to copying it and doing it cheap for members to upgrade with

 

[Fusion Ed]

The ECU in closed loop is as above 14.7:1 which is ideal. Its not rich at all. Infact its the ideal afr for emissions mot etc..

The mines map would be easy to transfer to another ECU. The trouble is the hardware is the expensive part, like I said I am sure at some point i'll see a pulsar with a mines ecu. When I do I'll down load the map to see what has been done to it, its possible I already have it under another name, but I wont be sure until I see one.

 

[mattytappy]

tell you what my safc2 needs setting up and it all needs checking out properly....hows about you having a pop at it at the same time...when you free

 

[campbellju]

The map is an open loop control system, not closed loop ;-)

Cruise and idle are closed loop with the narrow band lambda. The narrow band is also used as a modifier for the open loop control.

A car control system is not very sophisticated. I know Edd was being cheeky when he said its an accurate science with many variables but the reality is its not. Many moons ago I used to work on Glass furnaces that burn around £8M in fuel pa. 1% improvement in ecomony is a lot of money. In simple terms they're a 14V engine, controlled to stoich, use 7 MAF's, 7 W/B lambdas, around 50 tempreature sensors and 4 water cooled cameras to monitor combustion. There is no black art, every variable has a precise number that you control to as rapidly as possible. Incidentally the furnace is "turbo charged" with 10MW electric fans and our Amercian colleagues like adding the industiral equivalent of nitrous that is as bad for a glass furnaces as it is for cars :lol: :lol:

Whether its an industrial furnace or a car the same things stands, make small changes, write things down, double check what you've done then see what affect it has.... Repeat.

 

[mattytappy]

cheers campbellju...dont hold your breath though...wink

 

[campbellju]

Alternatively, get someone else to do it then but it isn't rocket science... just a lot of variables :lol: ;-)
Jim

 

[stumo]

It's a good job i have a hammer!

 

[Fusion Ed]

One should point out to those who are not aware that when you put the e-manage ultimate into launch control mode it cuts and retards the ignition but NOT the fuel, thus chucking out loads of it out (that's the whole point). Often carbon is also disturbed in the exhaust and silencers adding to the 'effect'.