I'm new to the Suby scene and looking to do an engine management mod. I've looked into getting a UTEK but I don't even have a laptop computer so this option looks pretty pricy for me. I like the fact that the apexi unit is an onboard computer and can change fuel ratios from drivers seat. I know that the afc can't manage to the extreme of the UTEK, but how close can it get to the UTEK as far as horsepower? can it control timing?I 'd apprieciate some knowledge on this matter from someone who has been in the game longer than me. Thanks!

UTEC > SAFC.

search.

I know that the afc can't manage to the extreme of the UTEK, but how close can it get to the UTEK as far as horsepower? can it control timing?I 'd apprieciate some knowledge on this matter from someone who has been in the game longer than me. Thanks!

You''ll definitely find some answers doing a search but if you use an a/f controller combined with use of a wideband o2 sensor you can come very close in terms of extracted hp than if you are to use a Utec.
S-AFCs/SAFRs has been used in supras, rx7s, and those pesky dsms ;) for years with great results.
BUT...proper tuning is the key!, there are many experiences across these forums where folks go out and buy UTEC and other engine managment where they come back with worse drivablilty or even in extreme cases, blown engines!
sure the utec has more advantages due to more features(timing control), but choose what works for you, your tuning ability, and your budget

an a/f controller like the s-afc can be as analagous to a 9mm vs a utec is to a 357magnum in the wrong hands...still can make serious damage

the reason i would never recommend an safc is the mere fact that you cannot control timing. if you are changing MAF readings to change fuel, you are ultimately tricking the stock ecu into going to a different load site. when you go to a different load site, the stock ecu could easily adding more timing. so in essence, if you are adding boost and leaning out, you are then going to be adding more timing as well (not intentionally)...

...you can all guess as to where that would lead you.

if you are changing MAF readings to change fuel, you are ultimately tricking the stock ecu into going to a different load site. when you go to a different load site, the stock ecu could easily adding more timing. so in essence, if you are adding boost and leaning out, you are then going to be adding more timing as well (not intentionally)...

...you can all guess as to where that would lead you.

true that you will be intercepting the MAF signal and tricking the ecu to read off a differentl load site, but I'd have to speculate that the ecu isnt adding MORE timing as you suggest, because the load site is corollated with the existing factory timing map that is typically not as aggressive as it can be with controllable user intervention.

Btw, as an observation.. looking at multiple variations of tune, in the case that the factory ecu is not controlling boost, timing is typically pulled away as rpms get closer to redline.
Quite opposite the other scenario when factory is controlling boost, timing does get agressive but boost is typically decreased towards redline.

looking at my utec logs, the stock ecu wants to run 26* at 18psi.

lower load sites = more timing advance.

Not only will the ecu advance timing when ya remove maf voltage with a safc, but with certain mods using the safc will make the hard throttle fueling of a wrx go really wacky in different situations. Things like aftermarket intakes, larger injectors and many other mods will create serious problems while using something like a safc. One day you might think ya have the fueling tuned, and the next day the fueling at hard throttle will change a ton. Not just in one direction too. The fueling can end up going in different directions at different rpms dependent on how ya use the safc and the mods you have. If you're running a basically stock wrx a safc might work pretty well, but when ya switch to larger then stock injectors(or a list of other mods)......boom.

peace

What they said....

Using an AFC on a subaru, especially to an extreme is like asking for genital warts from a redlight leper with the clap...

You form the mental image..

Jorge (RiftsWRX)
www.ProjectWRX.com

:lol:

Man I know how to kill a thread...

:lol:

is like asking for genital warts from a redlight leper with the clap...

You form the mental image..

Jorge (RiftsWRX)
www.ProjectWRX.com

...unfortunetly i did, thank you.

Along the lines of what happy was saying also UTEC>UTEK

Piggyback's can be quite pricy if added up (ie. get AFC, then ITC, then AVCR, then bla bla bal, then etc)...and the UTEC is not your traditional 'piggyback'. Good luck with your EM choice.