I was wondering if it was worth it to run an apexi afc on a basically stock car, the only mods are apexi intake and straight pipe to factory y pipe and factory mufflers. Car is a 90 vert n/a with all emissions still running , except cats.

I want it bc of the look and also a little tuneability, bc my car is running rich as hell.

 

I don't trust them.

 

i've used them on totally stock S5's with good results. i don't use it to make major changes, stock it hits about 12.5:1@4000 and then gets richer, to about 10:1 by fuel cut. i just flatten it out so that it runs about 12.5 all the way up to reline/fuel cut.

if you're watching AFR and the butt dyno, there is a big power gain from 11 to 12, but going from 12 to 13 wasn't that big of a difference, so i leave it on the rich side

 

Back in the days, I also had a 90 vert with intake, exhaust, underdrive pulley, and ps/ac delete. The SAFC was tuned at a shop and increase about 15hp from leaning out the mixture.

 

Thanks guys, I think im gonna go for it just so I can lean it up a little because its so rich that sitting at iddle you cant stand near my car without your eyes burning. Plus I would like to squeeze a little hp out of her. Im not gonna do anything else besides change my mufflers. And lightweight fly wheel nothing to crazy though, maybe like 14lbs.

 

just one more question. Do I need to get a wideband. O2 sensor or will stock be ok.

 

if you've never done it before a WB is really nice. on my last S5, i just made small changes and used my butt dyno. i think it was maybe -4% max? -6% wasn't noticeably faster, so i left it richer.

 

A wideband will help significantly...other than that, your just guessing.

 

Im quite interested in doing the same, I have a S4 with S5 rotors with a large street port and Im considering either the Safc to control Fuel or a full standalone and control timing and fuel how big is the difference is a Safc to a full standalone on an n/a build?

 

i put an SAFC on my S4 expecting the same gains as the S5's, but to my surprise the S4 didn't actually need it! the S4 runs in the mid 12's stock, so there isn't much power by leaning it out.

by contrast the S4 seemed to like a little timing advance (3-4 degrees) and the S5 doesn't.

with the stock ECU you actually do have to worry about detonation in the midrange, the stock map runs in the 14's there, and they will ping if you have too much timing

 

Thanks for the Information j9fd3s im currently in the process of squeezing out what ponies I can before I would actually need a aftermarket tune Ill play with timing just a little bit and see what it can do