General S-AFCII Tuning Q...

Paz

Paz

-NIGHTSPIRIT FAMILY- UK Drift Since 2001
Just a quick question about S-AFC (II) Tuning here.. Where do you set the "Lo" and "Hi" Throttle points?

Im thinking it would make most sense to have one at 10% and one at 100% or very close? That way, you can set close to the lowest fuel Map, and the absolute maximum fuel Map the car will ever need and then the SAFC will do its job and average between the 2 Maps depending on throttle?

Any input?

Thanks

Paz
 
normally they are set to 10% low and 50% high. so basically when you have TPS readin over 50% its on high throttle. SAFC II has two maps with two throttle maps per channel, so you can run a normal map and a nutty one.

if you set high throttle to 100% it will only ever hit high throttle map when your foots nailed on the floor...

try 10 and 60 for yours dude, it averages it out and make the crossover smooth for you (indicated in the fuel correction percentage in metering mode) anything higer than that just seems silly as you only ever going to be on low throttle, you can set it a bit higher (70 max maybe) in 86 as most of the work is done on full load. you can still knock out a load of fuel on high throttle. high/low throttle is more for economy/engine efficency. if you only set up one map your better off messing with the high throttle settings...

hope that helps dude :wave:
 
mittomatto said:
if you set high throttle to 100% it will only ever hit high throttle map when your foots nailed on the floor...
Click to expand...

It usually is :D

The only thing im thinking is, as you say it averages between the 2 settings.. So say 10% and 60% as suggested, when im in between those 2 values it'll use an average reading from the Lo and Hi which is cool.. But what happens when youre above 60% throttle? The engine is under more load than has been mapped so doesnt this cause problems with mixture etc., as it has no map to use when its above 60% load (for example)? It would just use the 60% map when really it needs more?

Im thinking if i set it at 90-100% it will always be averaging between the 2 points and so the map will be safer?

Does Grasshopper map AFC's dude? Might give him a ring and get my bad self booked in, im sure he'll know the deal!

Thanks!

Paz
 
i can see how your thinking there paz, but that not quite how it works. it maps between the two points so in effect your fuel graph will be smooth. the cross over mixture if upto you - you have two channels to map (high/low) so the cross over is effected by the difference between the maps.

easy enough to do yourself with a stethascope, just map it while on half throttle and then map with throttle nailed. then drive about a bit and see how it feels :nod: if you feel it bogging or struggling then map that area of the graph some more.
 
I guess its just trying to find a happy median with the map crossover really is it?? kinda like VTEC as if you have a VTEC controller and set it at 3000rpm it does no good as the cross over is too early and the engines torque and momentum cannot build up the required speed quick enough....

so with the SAFC II would it be best to have the car rolling roaded first and get the SAFC II set up on a RR?? You are meant to get an adjustable fuel pressure regulator so you can dial down the fuel supply and use the SAFC to supply the required fuel to suit your mapping......I have seen a few engines go pop from over ambitious tuning.... :smash:

Im getting one for my 86 too so let me know how you get on Paz if you are fitting yours soon? i will be getting mine in about a month as i still have the rest of my suspension to sort.... :thumbs:
 
Just to complicate things isn't it advisable to use a wideband lamba when our mappping to get a proper AFR??

I know it's not as important on a N/A car but you could do serious piston poppage on a turbo car :smash:
 
Old Skool Cars said:
I guess its just trying to find a happy median with the map crossover really is it?? kinda like VTEC as if you have a VTEC controller and set it at 3000rpm it does no good as the cross over is too early and the engines torque and momentum cannot build up the required speed quick enough...
Click to expand...

actually its beacuse the engine hasnt developed enough oil pressure to lift the cam into v-tec mode. normal pressure required is at about 4200rpm.

wide band lamda would be good, but paz is running pikey SPL mapping and needs it done quick. or at least enough of a map to get ti to the place to be mapped. you bringin the car at the weekend paz? wanna try to map it some then?
 
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