SAFC and the so called timing advance?

[uncle_louie83]

ok...i have heard about that the safc advances timing????

if so how much???

im also running 100 octane all day every day....well im going to start using it a week before i put the turbo on...so with 100 octane, 10 psi. Im shooting for right under 300...i meen right under...like 290...cause i have 450cc injectors as of right now. now i know that detonation will kill my engine. I havent used an safc before. Im used to turboedit with honda's (free edit program obd-0). But with the nissan im going to use the safc so thats why i could use some solid advice. Im trying to find an msd btm here locally for a decent price so i can retard under boost but my question is where should i set base timing at before i get the msd box? i know stock is 20...should i set it at like 16 or 15? im sure it would run like *** maybe? or maybe it will run ok...i need some advice here.

thanks

lewis

[fiznat]

ok...i have heard about that the safc advances timing????

Nope! You heard wrong. The S-AFC only allows you to mess with fuel, hence it's name: the Super- Air Fuel Controller.

Im trying to find an msd btm here locally for a decent price so i can retard under boost but my question is where should i set base timing at before i get the msd box? i know stock is 20...should i set it at like 16 or 15? im sure it would run like *** maybe? or maybe it will run ok...i need some advice here.

If you get a MSD BTM, you should leaving your base timing stock. Any retard that you will need in boost will be handled by the MSD. You should NEVER need to actually advance your timing.

[uncle_louie83]

lol...well ive heard it many times that why you move your fuel tables around so much with the safc that it actually moves the timing tables. i know i cant control them but its like your moving **** around so much that it causes the timing to advance some. Ive heard this over and over and thats why im asking about everyone here who has had expieriences with it. maybe what is your timing at WOT and such...

lewis

[Thee 240sx Owner]

Nope! You heard wrong. The S-AFC only allows you to mess with fuel, hence it's name: the Super- Air Fuel Controller.

If you get a MSD BTM, you should leaving your base timing stock. Any retard that you will need in boost will be handled by the MSD. You should NEVER need to actually advance your timing.

I don't mean to be an *** but its Super-Air Flow Converter

[Craving4Boost]

uhh does he really need to retard timing with 100 octane all day everyday? it should be good

[Import_Ant]

Nope! You heard wrong. The S-AFC only allows you to mess with fuel, hence it's name: the Super- Air Fuel Controller.

I was under the impression that, since the S-AFC tricks the computer through 'lying' about throttle position and other values, it doesnt adjust the timing but rather, indirectly modifies the point at which the ECU initiates timing advances because the ECU is working based off of false info about the throttle position and engine load. As a result, if the timing advance were to occur sooner than normal it would/could result in a greater advancement of timing throughout the powerband. Someone correct me if I'm wrong I just wanted to clarify my understanding since it seems to be conflicting with this.

If you get a MSD BTM, you should leaving your base timing stock. Any retard that you will need in boost will be handled by the MSD. You should NEVER need to actually advance your timing.

agreed but wasn't he talking about retarding the timing? causing the spark to occur later in the compression cycle would be retarding timing right? so 16 degrees BTDC would be more retarded than 20 degrees BTDC. unless im really tired and not thinking straight.

again, just trying to verify my conceptions (or misconceptions) about these subjects. This is something that I have been trying to clear up for a while as well.

-Aaron

[Craving4Boost]

I don't mean to be an *** but its Super-Air Flow Converter

yeah its super air flow converter because it adjusts the MAF signal not fuel directly

[:: orion ::]

Here's the quick version, as I understand it:

ECU uses LOAD vs. RPM to determine timing advance.

LOAD is determined by MAF voltage and TPS voltage. S-AFC ONLY modifies MAF voltage - So if you cut the MAF voltage in half (to run injectors twice as big as stock), the LOAD sensed by the ECU is too small, and you get timing advance as if you were cruising, and not at WOT.

SO it DOES NOT adjust the timting dirtectly...it just puts the ECU into the wrong spot on the LOAD map, which gives you timing values that are not correct.

- Brian

[nissanfanatic]

^Yup.

And if you ever watch on a Techtom, you can see that as you let off the gas more and more, timing goes up. Hence less airflow=more timing.

[uncle_louie83]

so your saying only at idle/cruising its not advancing?

so when im at WOT its not advancing at all right? if so then thats awesome.

lewis

p.s. cravin4boost...to answer your question. With 100 octane i wont need to retard timing until i get around 12psi, maybe more...not sure yet. But once i get to the point of needing to retard timing. Im going to use alcohol injection to compensate. i figure...stock timing...alcohol injection..100 octane gas....and 15psi, i should be making some good numbers.

[Craving4Boost]

hell yeah go for it..ultimate combination for ultimate power

[:: orion ::]

so your saying only at idle/cruising its not advancing?

so when im at WOT its not advancing at all right? if so then thats awesome.

NO.

Quite the contrary.

The stock ECU gives 8-10 degrees advance under WOT and under load. That's ON TOP OF the base timing, which the ECU assumes to be 20. You can set it at 18, or 22...and that will augment every timing value by the difference from 20.

Now, under cruising...light load, part throttle...the ECU gives up to 20-25 degrees advance. I've seen at least 48 degrees on the Techtom...

What the S-AFC does is reduce the LOAD the ECU sees, so it gives more timing.

So the ECU acts as it always does...giving appropriate timing for a NON-TURBO KA motor...but the AFC tricks it into giving a little more. And since the stock ECU is already to aggressive for real boost, more timing is BAD, BAD, BAD.

- Brian

[:: orion ::]

Oh...and for what it's worth...my motor blew at 6psi and 28 degrees total timing.

25 total probably would have been OK, but still on the high side.

23 total timing (3 degrees advance over base) is probably correct for low boost...5-6psi.

[WDRacing]

I ran at 10 psi with no retard and 91 octane using the SAFC. Alot of it has to do with how rich your running things also. If your in the 12.5 range then your alot hotter the the 11/1 range. So you'll need more timing retard with the hotter combustion temps. Although in general, retarding the timing will increase your EGT's, just not as much as running a leaner mix.

Whats best? .5 degree's of retard per lb of boost your running. If you use the MSD BTM, start with .5 and work smaller, since you'll be starting to retard timing at 1 psi when it's really not required until 8 psi or so.

So for 15 lbs of boost, you'd want 3.5 to 5 degree's of retard. Thats using the .5 to .7 degree's of retard per lb theory starting at any boost over 8 psi.

It's alot harder to explain then it actually is. I run 15 psi all day with my BTM set to .5 retard and using 91 octane gas. My AFR's are 11.5/1 on boost until peek torque which is about 4200 for me and then I lean it out to 12.6 or so all the way to 7200.

WD

[Checkered-Member]

12psi + 87 octane + stock timing + 14.7A/F with no intercooler ...................And PHAT water injection system…lol

I’m just messing…I don’t know if that’s even possible …is it?

[Jookmasta]

the safc does advance the timing just not directly. what happens is that if the safc maps are in the negative side, that is when you can expect timing to be advanced. as to how much timing is advanced, i really dont know as i dont have a scan tool. this has been discussed before and as pointed out, it is a fact. i personally run 15 degrees base timing. i use to run 13 but i decided to bump it up and i must say that the car idles ALOT better and gas mileage has somewhat increased as well as power. ur boost level will be ur determining factor but id say 15 is a safe bet for ten psi. also remember that all of my high throttle safc maps except the 1000rpm one are all on the positive side so the safc shouldnt really be messing with the timing.