incorporate AFR target?

[nismoautoxr]

Can someone explain this setting . Its not in any of the MSxtra manuals I could find and there are spuratic metions on this forum of it but no thread really fully explained the affects of including it or not including it . I need a description of what it does in the code and when to use it or not to use it .

I have seen what it does to my AFRs on my wideband but not the whys and hows of it . When I dont incorporate the AFR target then the car as it is tuned now will run leaner AFRs especially in the high load areas above 100KPA (13.5-14.7). When I do incorporate AFR then it runs as I have tuned it which is closely following the table . I would suggest that the MS2x manual be updated to explain this seting as well as a good description of when it is appropriate or not to multiply map as well. I just need an understanding of how this setting works and what the application of it is .

[jsmcortina]

I added an entry to the glossary. http://www.msextra.com/doc/general/glossary.html
Hope that helps.

James

[nismoautoxr]

Thanks James . What I get from that is that if my car is tuned good now , there is really no reason to go back and turn it on . Does turning it on ignore AFR table 1? Is that why the AFRs went to pretty much 14.7 no matter what?

[jsmcortina]

No. Turning it ON makes it use AFR table 1.
With it turned off, AFR table 1 is not a direct part of the fuel equation.

James

[nismoautoxr]

Oh I see. Thanks James. That clears it up then

[robd]

Sorry to hi-jack but I've got a question on this. If you used VE analyse Live to tune your VE table and the AFR table in VEL is the same as your AFR table in your map, would you still need to do a re-tune if you turned on incorporate AFR, or would it basically just be trying to get your VE as close to the AFR targets which it should already be doing becuase of the way its been tuned? Hope that makes sense!!
Also do you have to have IncorporateAFR on for EGO Control to work properly?

Thanks

[nismoautoxr]

Robd, I would have thought that same thing but I can tell you from my observations this morning on the drive in to work after I changed that to "incorporate AFR target" that this is not the case . My car follows very closely to the AFRs in my AFR table 1 when it is not incorporating AFR target and it is substantially leaner than the table when incorporating AFR target. There must be some calculations taking place there that we dont completely understand

[techsalvager]

yes you will need to retune to match the targetrs with incorpate afr on.

[nismoautoxr]

I dont know what I was smoking ....LOL. I had that whole thing bassackwards. I initially had incorporate AFR target enabled and thats how the car had been being tuned . It was when I turned off the AFR target that it got lean. I am very happy I dont have to start all over on my VE table . Still dont understand the math of it all though.

Dont understand multiply Map either . If I try to multiply Map my VE numbers definitely dont work. Im already having to use a required fuel of near double what I should just to get 8s in the 15 KPA range and by the time it gets to the 200KPA range im in the 160-170s on VE. Heres the current MSQ. The car has 1200 CC injectors on resistors and the required fuel should be in the 4.0-4.5 range and Im having to run them in the 6 range to get it to work out .

[jsmcortina]

The basic fuel equation (simplified) is:

PW = ReqFuel * VE(rpm,map) * MAP * GammaE

With incorporate AFR it becomes:

PW = ReqFuel * VE(rpm,map) * MAP * stoich / targetAFR(rpm,map) * GammaE

Without "multiply map" the "* MAP" is removed. This is not recommended.

James