hi friends ive been running the base map from vishnu site for the v360 my afr's would vary between 10.8-11.4,but today they change to 11.8-12.5
whats going on??
a-could it be my walbro going out??
b-the rain has started and it has been cold could it be that the stock ecu leans out when driving in rain and colder wheather??
thanks.

 

I'm gonna jump in here JR as I happen to know that you were experimenting with a full tank of race gas over the weekend and running looney amounts of boost as well. LOL

All else being equal, given identical conditions...the change in AFR's might be cause for worry. However, if there has been a significant change(e.g. 20* F. drop in air temp) in ambient conditions in your location and at the same time you've gone from 91 octane pump gas to 109 octane VP, these factors combined might explain the change in WOT AFR's you are seeing.

Different fuels have different specific gravities. The volumetric efficiency of a fuel is dependent upon its specific gravity. The amount of air required for complete combustion of a fuel will vary with the density of the fuel.

The Combustion Air Requirement Index(CARI), is used to measure how much air is required for the Stoichiometric combustion of a given fuel. Different gasolines with different octane numbers require different amounts of air to achieve Stoichiometric combustion leaving differing amounts of residual oxygen after combustion.

Well, maybe this will help, or else, like me you're probably more confused. Race gas and 91 octane pump gas possess way different combustion qualities. So, dont be surprised if your AFR's are way different too. Maybe someone with some actual experience as to whether differing octane numbers do actually impact on AFR's might chime in.

 

i ask cause this is what happen:
i switch my map to a 100oct map and i used more then half a tank of vp109 so i instantly saw that my AFR where between 12.9 and 14.1 this is with a base map from the vishnu site,so i added 5%of fuel to the whole table and AFR went from 12.3-13.1,then i had 1quart of gas left and i fulled up with 91oct and used the 91oct map ive always been using,with the 91oct map my AFR's have been 10.8-11.4 always but now my car is also lean on 91oct with the exact same map that ive always used ,AFR's are now between 11.8-12.4 so whats going on??

thanks sparky i might as well go to at least half a tank of 91oct to see if the AFR's go back as they were?

 

Hey JR: I don't know but I think that the 91 oct map and the 100 oct map probably have different fuel and boost tables and different target AFR's as well. I dont know for a fact, but doesnt the 100 oct map pullout a lot of fuel compared to a pump gas map?

You're going from a low boost, 91 oct map, which adds fuel, and are running it on pump gas, to a race gas map which is pulling fuel and adding more boost, running on VP 109 and then you throw in a 20# F. difference in air temps between your two readings ...you're not gonna be able to compare AFR's directly, w/o taking into account all the variables.

 

update:
before all this happend when my car was normal i was using a map with launch control on it what i did with this map is that i copied and pasted the fuel and timing from the vishnu site map v360 2005,whats different from the site map compared to the map with launch control is the table for fuel threshold the ones from the site have a -100 and the map with launch control has 20. so with the map that has launch control i dont go lean as explained above,but if i install the map from the vishnu site i do go lean so i think that the fuel threshold table is making a diff in both maps.
so does the fuel threshold difference making the car react diff in both circumstances?
thanks!

 

are the 03/04 maps diff from 05 maps cause the cars had diff hotsides??
i ask cause my car is a 2005 jdm with a 9.8hotside with the TiAl turbo which map should i really use??
i tried the 05map but afr's are lean 11.8-12.5
i also tried the 03/04 map and the afrs are 10.8-11.2
so which map should i use?
thanks

 

Yes, the 2005 and 2004 map off Shiv's site are different. I looked at the 93 octane for 03-04 and the 93 octane for 05 Stage 0+ and found that the 03-04 has a more aggressive boost table than the 05, the fuel maps are the same, and there is more timing pulled on the 05 than the 03-04.

IIRC, the 05 had a more aggressive timing map from the factory than the 03-04 and boosted higher as well. I do not know about other maps. Check it out.

 

The 05 maps are different from the 02/03 maps because the ecus are mapped differently. The hotside is only one of the differences.

Shiv

 

thanks shiv and dustin!