airflow hz vs timing (safc)

"Since a SAFC intercepts that signal from the MAS to the ECU and modifies it, it can change the amount of airflow that the ECU "sees." If you have to correct your SAFC into the positive range, than the ECU will see more airflow Hz than the MAF is outputting, and could change the timing map you are following. The problem with this is, higher airflow levels get less timing advance for safety, and lower airflow levels get more timing advance, because the ECU thinks you are pulling in less air.By leaning out the SAFC (big injectors, more fuel pressure, race gas) you decrease the amount of airflow that the ECU sees, and therefore you usually will get a bit more timing advance for power."

this doesn't sound to promising, is there anyway to battle this? (airflow vs timing with an SAFC)

 

[turbowop]

Use a chip with the correct compensation built in for injectors or different maf's. Use the SAFC for minor adjustments after that or for making adjustments for things like race fuel.

 

[Andy_S]

Quoting chicagoboostin:


this doesn't sound to promising, is there anyway to battle this? (airflow vs timing with an SAFC)



Ditch the safc and use:

Chip
Dsmlink
Full standalone

Safc is old school, there are much better options available.

 

+1 to the wopster.

 

[atc250r]

+2 for what wop said. If you are determined to not buy a chip then I would go with DSMap. As soon as I am ready to put my car back together (hopefully by spring), I'm going that route. It offers MAP support and you have full control of the fuel tables plus IIRC its less expensive than the Link.

John

 

Just FYI: the 2G 98/99 ECU is going to also offer speed density, plus the ability to tune all the maps, etc yourself, so its another option down the road.

 

[atc250r]

I'm looking forward to what comes of that, Jeff. If that set up is sorted out by the time I'm ready for it I may just give it a try. It all comes down to bang for the buck. Right now IMHO DSMap gives you the most for your money but if that 2G set up works out well then it may be the hot ticket.

 

I do have a keydriver chip, was just seeing what is around. I don't see dsmlink being an option for 519 at the moment.

 

If the chip is that far off that you need to use a lot of AFC compensation, its best to figure out why. If the fuel pressure is fine, and you have no boost leaks, a new chip can be burned to get you closer, instead of adding/removing a lot of fuel with the AFC.

 

Everything is right on, but I am getting really bad boost creep, and I don't have the motivation to pull the turbo off again to port the exhaust side. I have just have been reading about tuning and such. I am pretty sure everything will be fine, just have to tune for 25 psi in the high map once its all broken in. Thanks for the responses guys!

click

That is one of the more interesting documents I have been reading.