safc 2 set up

[98and01eclipse]

what would be the best set up for a 98 gst 5speed with 500ing. big 16g turbo walbro 255 full pump.

and what is the fuel pressure spouse to be people say 43 for auto, and 38psi for manual.

 

[dsmcurse]

umm i think thats soppossed to read 500cc? thats your injector sizing? you have a AFC installed and want to know the best correction values? well you have to first figure out what your new injectors really are. you upgraded from 450 to 500's? hmm... any who, you gotta figure out how much bigger the new injectors are over the stock 450's.

back to basic math (sucks i know) figure out what percentage bigger the new injectors are. if your new injectors are, oh, for example say, 18 percent larger than you would pull 18% correction. that would get you started

from there you need to have a wide band to truly bring the afc to optimum conditions. and from my own personal experience, if your first map (the low throttle map) is set to switch to the high map at like, oh, say 75% throttle make the high map activate at 76% throttle.

what ever your throttle angle is to switch maps have those to numbers as close as possible. like 79% and 80% dont leve huge gaps in between those numbers. otherwise the afc tries to "connect the dots"of your two differant correction maps.

 

[bryanwheat]

umm i think thats soppossed to read 500cc? thats your injector sizing? you have a AFC installed and want to know the best correction values? well you have to first figure out what your new injectors really are. you upgraded from 450 to 500's? hmm... any who, you gotta figure out how much bigger the new injectors are over the stock 450's.

back to basic math (sucks i know) figure out what percentage bigger the new injectors are. if your new injectors are, oh, for example say, 18 percent larger than you would pull 18% correction. that would get you started

This is not a smart idea at all. Without being able to moniter a/f ratio's you are likely to blow the engine up doing this.

 

[dsmcurse]

i would have to disagree to a certain extent. like ten years ago befor widebands were affordable you tuned it off of a good condition STOCK O2sensor using a palm pilot or a apexi turbo timer that offered the narrow band O2sensor out-put. ten years ago dsmlink wasnt even thought of yet, and wide bands were only found at the dyno or the emmisions testing place. people ran AFC only and did the "blue-wire" mod which made the afc display O2sensor voltage. people did the math, figured they're correction using the formula thats provided IN THE APEXI INSTRUCTION MANUAL, and they ran fine.

fast forward to todays standards and that method just described to him is stone age. yes i know. but that did work back then. today we can get very reliable wide band gauges at a fraction of the cost. like $220 for a brand new wide band gauge. if you have a dsm and have ANY mods at all you should have one. theres no excusse.

the original poster claims to be rockin 500cc injectors. ive never even heard of this. but this guy is gonna pull minus like 10% correction. and your gonna tell me he's gonna just blow up his motor? i dont know? i think the OP should fill us all in on a little more details and really clairify his question

 

[98and01eclipse]

Hey im sorry I ment 550cc injectors. That's what wrote on them but them number imprinted 17113841 and they are fuel injector clincs. im getting a wideband im just trying to get everything I need to know ready for when I start the work. Sorry again

 

[spyderturbo007]

Do you have a logger?

Baseline mathematical correction for 550cc injectors is -18%, but I always start richer and work my way lean. Somewhere around -14% would be a good place to start for both the low and high maps. Make sure your arrow is pointed Northeast and the sensor type is set for Karmen. Set your TPS trigger points to 30% and 80%.

 

[talon2gbuyer]

Sorry to revive an old thread.. i have an SAFC on the way, and i switched from 450cc injectors to 650cc injectors, unfortunately my math happens to suck, hence why i'm a criminal justice major

What percentage difference are those injectors over the stock ones? i'm not sure I follow the logic for tuning the SAFC to run the car right. I know the low throttle should be set at somewhere around 25+ (usually like 40 on most tunes that ive seen) and High throttle set at like 60+ (55 ish being the average ive seen) but i'm not sure if those numbers pertain to me? My mods list is up to date as well.

Thanks for the help on this kinda confusing topic!