1G tuning on S-AFC

[tsi20gawd]

just to clear things up I dont think I told him to set the throttle point at 0low and 1high. I was just saying it is mutch simpler to tune the car that way 0 being idle and 1up being cruise and boost if your not running two seperate boost levels why over complicate things with two maps?
besides I dont even think this had anything to do whith his problem
well I hope you get it figured out good luck

oh yeah both of my maps are WAY diffrent
lates!!!

 

[kpt4321]

Originally posted by tsi20gawd two seperate boost levels why over complicate things with two maps?

Because the engine's need for fuel is based on load, and thus you want to be able to vary the amount of enrichment as that load changes.

If you didn't need load-based fuel enrichment, then the ECU would only have 16 points on the fuel map; one for each 500 rpm. If you didn't need load based enrichment, then it wouldn't have the additional 11 other levels for different load (g/rev).

oh yeah both of my maps are WAY diffrent

So basically what you're saying is that when you get to 88% throttle, your SAFC swtiches maps? That is going to cause the correction to make a big jump, and not very smoothly. Sounds like you're creating the problem you thought you were fixing.

 

[tsi20gawd]

what?
yes there is a big jump but im not tuning a 14b here the diffrence between 17psi and 22psi requires mutch more fuel on pump gas.
and im sure its not perfect by any means never said it was someone ALWAYS has a better idea bottom line is im not in high boost on a day by day basis when im in it it works very well. now there is about a 5% diffrence between my low map and high map(the map instruction i posted r from my fwd) for that reason no sudden changes to piss the ecu off a smoother transition between low and high maps my turbo is big so it takes quite a bit longer than a small turbo to jump from 17psi to 22 psi
besides this guy is not running crazy boost or a big turbo.
exactly why would there be a need to change the stock fuel tables so mutch on a smaller turbo?
I see absolutly no benifits from this mutch compensation from the stock tables at seperate tps based points considering the stock ecu has A LOT of the load/fuel/timing adjustments pretty well covered sounds 2 me like its just over complicating things a bit more than need be for that size tubo. the point of the piggy back is to "tweak" the stock setup not re map the damn thing. Were not trying 2 construct all new maps here just modify the ones we already have right?
you definatly got my attention so far.

 

[kpt4321]

Originally posted by tsi20gawd
yes there is a big jump but im not tuning a 14b here the diffrence between 17psi and 22psi requires mutch more fuel on pump gas.

Yes, it requires more fuel. However, the ECU does that for you automatically. What the SAFC does it apply a correction factor, and there is no reason this should be much different at 17 or 22 psi.

and im sure its not perfect by any means never said it was someone ALWAYS has a better idea bottom line is im not in high boost on a day by day basis when im in it it works very well. now there is about a 5% diffrence between my low map and high map(the map instruction i posted r from my fwd) for that reason no sudden changes to piss the ecu off a smoother transition between low and high maps my turbo is big so it takes quite a bit longer than a small turbo to jump from 17psi to 22 psi

For one thing, can you please use proper grammar and punctuation? It's really hard to read that.

Second of all: With your throttle points set 2% apart, when you hit that point you're just switching from one map to the other. That means a big jump in corrections, and a big swing in the signal the ECU sees as well as in A/F ratio. You do not want that, you always want a gradual smooth curve.

With the way you have it set up, you DO have a suggen change to "piss off" the ECU!

exactly why would there be a need to change the stock fuel tables so mutch on a smaller turbo?

Changes to the fuel tabe have very little to do with the turbo that you are running. They are dependant on the fuel system, which could require a lot of changes independant of turbo size.

I see absolutly no benifits from this mutch compensation from the stock tables at seperate tps based points considering the stock ecu has A LOT of the load/fuel/timing adjustments pretty well covered sounds 2 me like its just over complicating things a bit more than need be for that size tubo. the point of the piggy back is to "tweak" the stock setup not re map the damn thing. Were not trying 2 construct all new maps here just modify the ones we already have right?
you definatly got my attention so far.

I really don't think you fully understand how the SAFC works, or what we are doing with it.

This has nothing to do with over-complicating things, it is a simply matter of building a nice linear fuel curve that gives you the best possible correction at each load. Now, if you use the throttle points correctly (with a MAP sensor) then you will have close to the proper correction for each load, with a nice taper. If you set the throttle points close together like you have them, you will get two different corrections (rather than a nice smooth switch from one to another) with a quick swap from one to the other. This is not optimized at all.

That would be like the stock ECU giving you a pulsewidth of 10 ms at low throttle, and then 20 ms at high throttle, and just switching over from one to the other at 50%. That's NOT what you want it to do. Look at the stock fuel maps, you have a nice smooth taper. A SAFC with the proper load settings will achieve the same result.