Safc II boost settings? help

[Tictakman]

i just ordered a safc II for my 95 240 and want to know if anyone has knowledge in setting them. what would i need to set it for stock and then 5 lbs of boost?

is there a formula that i can use or just a set number that everyone goes by?

thanksZak

[:: orion ::]

You can set it for +50%, but the fact is the injectors will be static and have (most likely) a horrible spray pattern and not function well at over 4psi (maybe 5psi with a straight T3...?). You can't make injectors deliver more fuel unless you increase pressure.

You need bigger injectors, then tune the AFC.

Later - Brian

[Tictakman]

i see, ur saying that the stock ones cant flow much more than stock. right?

yes i am running a t3 and have a wastegate spring rate at 4lbs.

what injectors do you recommend? say i got 250 cc or 300.

300= what setting would i run?250= what setting would i run?

thanks orion

Zak

[Tictakman]

forgot to ask...if i do run w the stock injectors the way you said will it harm the engine or will it just idle rough?

Zak

[Nathan]

Stock injectors are 270...the minimum to upgrade to is 370's...the next step is probably 444's, then 480's, 550's, 660's, 720's etc.

[TurboKA37]

at 5 psi ur prolly looking for some 370cc injectors.

[fritts]

You shouldn't just use someone elses settings. Different cars, altitudes, temperatures all affect your settings. You need to go to a dyno and check your air fuel to tune them right. Your starting points should be way rich of what anyone gives you, for safety untill you go to the dyno.

[:: orion ::]

370cc injectors will get you to ~275rwhp, maybe a little less.

4psi from a T3 will be under 200 - Probably in the 190-195rwhp range. You *could* maybe get away with stock injecotrs, no AFC for this - BUT NO MORE. Get it on a dyno with a wideband to see...

But if the boost ever fluctuated or increased, it would blow the motor.

So, the safe bet is to get some 370cc injectors from an SR guy (they drop in, find 'em used for maybe $100-120) and tune the AFC to those. Now, it's my understanding that to tune an AFC, you start from the new injector size and back out the % to make it them same size as stock...so 370cc - 27% = (370 * .73) = 270. So a safe bet would be to set the high and low maps to -25% across the board, then get it on a dyno, or buy a wideband kit. Tune from there...

Later - Brian

[Nathan]

Hmmm, so in theory...you could back out both maps to -50% to account for 550cc injectors and be only 10cc's off...about 1.8% or something and it wouldnt matter Right?

[king_johnthegreat]

Where do you guys find the math to come with these numbers? I'm curious because I'm getting my 740's in the mail tomorrow, and compiling the remainder of my fuel system. I'm just trying to figure out a few numbers, but can't seem to find any formulas.John

[Nathan]

Well, my numbers are simple...the stock injectors are 270cc's...so twice that is 540cc's...and I'm looking at some 550 cc injectors...so if I have the 550's and I tune the s-afc down 50% across the board...then the 550's are working like 270cc injectors (basically).

[oi138]

yes but that won't work.540cc's=twice as big as stock.Which means you are gonna be running twice as much fuel. So the safc would have to back down 100% which can't be done.

[:: orion ::]

So the safc would have to back down 100% which can't be done.

No...

You base your % calculation on the new injector size...i.e. a 550 would have to be 'turned down' 50% to act like a 270...

A 370 wold have to be adjusted down 27% to act like a 270...

Think about it: -27% is the same as multiplying by .73...so 370*.73=270

Hope that clears things up...

But these are only baseline #s...tune it on a dyno!!!

Later - Brian

[Nathan]

Thanks for clearing that up Orion It's ALWAYS a good idea to tune on a dyno. The only way I would tune off a dyno is with a good wideband o2 sensor and my egt gauge. Even then, I'd rather have it up on the rollers.

[Tictakman]

well then, it looks like im in need of some sr injectors? does anyone have some they want to sell?

email me..

[email protected]

Zak

[Nathan]

Good luck...I've been looking for S15 injectors for days and cant find them...normal SR injectors arent showing up much either. Ebay is total crap for injectors right now too.

[Tictakman]

ahhhahahaha, that sucks. i wanted to put the turbo on this weekend.....

Zak

[:: orion ::]

Check the Freshalloy.com classified forums...

If you don't see it on the 1st page, search a little.

Later - Brian

[Tictakman]

ya i was a step ahead of ya man. im talking to someone right now about getting some.

for stock settings on my car with the safc, would it be 0.0 all across the board?

ill read the manual tonight(just got it today).

Zak

[Tictakman]

ok, ive been reading a little bit and have a few questions.

first of all, easy question. how do i take out the ecu? just the two brass hex bolts? thats what im guessing....

next, the manual says i have to enter in the type of sensor and sensor number. do i get that from the wiring diagram book? it only has the silvia listed but are they essentially the same?

any other helpful hints would be great. i think i only have to wire a few of the wires, not all of them.

ill keep reading.

Zak

[Tictakman]

one more question, do we use all three yellow, white, and blue?

i can understand the wiring for all three but if you dont use the blue like i heard in a post i just read then how would you wire the existing yellow and white?

i have also found info on the sensor number/names so i think i have the squared away.

here is the post ive been reading....

http://www.nissaninfiniticlub....iring

thanks peeps

Zak

[Nathan]

I havent even tried to wire mine up yet...but perhaps I should say about the injectors that I havent been able to find them for the price I want I'm a cheap guy!

[king_johnthegreat]

A little off topic, but I just payed $530 for my 740cc Tomei's. They should be here today... I bought them anticipating my rise in boost; and because I'm pretty certain that the 100% duty cycle I had my smaller injectors at didn't make 'em too happy. Luckly, they were my most expensive fuel system mod.John

[Nathan]

I'm getting pissed looking for injectors...I really want S15 480cc injectors, they are impossible to come by. I'm looking for 550's too but my absolute budget is 350 bucks...my money situation is NOT working out for this car and I'm running out of money quickly

[Nathan]

I also just got to thinking about it and realized that if I was running 550's off of my S-AFC II...then if I was making say 350whp at 15 lbs. of boost full throttle...then lets say I have the throttle depressed only 75%, the S-AFC II can only adjust things at two throttle points, part throttle, and full throttle...It might adjust for 50% throttle but then I'd be running lean at 75% throttle...quite lean. Does this sound right to you guys? The numbers are just an example not real life...I'm so out of money it's not even funny and I cant really afford a JWT retune

[Tictakman]

Hey, i got the safc in and working.. i need some help setting the throttle

step by step instructions would be great.

i dont know why but i cant seem figure it out.

thanks

Zak

[Tictakman]

alrighty. ive done everything there is to do. i ordered 370 cc injectors and ill be ready to run it.

1 question

i will be running 8 lbs of boost w 370cc injectors. what do i change the settings to on the safc now. and were do i change the settings at? what function?

Zak