question on tuning safc

[AN89HATCH]

Ive tried to search, this is going to be my first time tuning with safc, I am wondering when I tune will I only need to do 3rd gear pulls? or must i go from 1st - 5th? also how do you set the crusing in the high and low throttle? do i just drive the car normally (not buildting boost) as i adjust the safc

[Jookmasta]

the way i tune is first drive around normal and adjust the safc so that your a/f's are 14 or 15. then the hard part starts. You can tune to your liking but i have done two methods. The first method involves tuning each individual gears with varying throttle inputs. The throttle inputs are determined by what your throttle point is on your safc. It would prove useful to have someone watching the a/f's for ya while your driving. So when tuning each gear, get the a/f's under 12 while in boost and also make sure that the throttle input is sumwhat close to your throttle point. This is more important for the low throttle map than the high throttle map. Obviously with the high throttle map, go balls out on the gas pedal while having the other person watch the a/f's. Keep doing that till you achieve your desired a/f's. O ya, fifth gear is kinda weird to tune on the street as you may be nearing some crazy speeds. I suggest doing the fifth gear tune on a very very safe road with no cops. So the second method is the one i used after doing the first method of tuning. Its mainly third gear and fourth gear pulls. Same method as first gear pulls but without watching the throttle input. I did it due to my upping of the boost tho.

[Craving4Boost]

3rd gear would be good because it's easier to watch the rpm/wideband since it goes a little slower i guess. for lo throttle you should just subtract the fuel to get it to the stock 260cc of the KA and you should be fine across the board. but u may want to add a tiny bit of fuel at the hgiher rpm's..(but it's unlikley you'll reach 4-6krpm at lo throttlw) at high throttle just hit 3rd gear and keep adding/subtracting fuel to get about 11-12:1 afr at WOT...fix each increment until it's good across the board

sorry for the quick description...tell me if your confused

i think someone needs to write up a SAFC write up and sticky it

[Craving4Boost]

oopz i didnt know jookmasta posted already..haha his is better.. listen to him

[DRIFTEADOR]

you dont have to tune for each gear. the motor see's load and adds/subtracts fuel/timing as needed, it doesn't care what gear youre in. the advantage of doing high gear pulls is that you get more samples. If the wb and display could keep up with the fast changes i'd do all my tuning in 1st gear.

i wouldnt recommend taking it over 3rd on the street and if you have access to a dyno I'd just take it there. a loading dyno is that much better.

[nissanfanatic]

I do either third or fourth gear pulls. But I have open roads around here, so its pretty safe...

Just watch AF vs RPM and adjust changes in the high throttle map accordingly. Its way easy....

[240SicknessX]

you dont have to tune for each gear. the motor see's load and adds/subtracts fuel/timing as needed, it doesn't care what gear youre in. the advantage of doing high gear pulls is that you get more samples. If the wb and display could keep up with the fast changes i'd do all my tuning in 1st gear.

i wouldnt recommend taking it over 3rd on the street and if you have access to a dyno I'd just take it there. a loading dyno is that much better.

agreed w\ everything.

no need for tuning in different gears, nothing about the fuel management cares what gear you are in when you are in the throttle.

try to keep a static envrioment, the best way to achive this is on a dyno, but an hour on the street will work also in a safe area.

[AN89HATCH]

so im thinking of just going to get it dyno tuned, Im running 460cc injectors, and i know i will need to set them to -41% on the SAFC to get them to stock. my question now is what should i set the safc to so i can drive to the dyno. most likely i will need to go on the freeway, and i dont want to acidently go into bost and lean out my motor. is how ritch should i set the safc just to be safe to get to a dyno? after 2k rpm, should i set the safc across to -20 just to be safe?

[Florida240sx]

Bump...I'll be having 555cc..Shouldn't I be -50 across the board?Still trying to learn about safc tuning.Running rich won't hurt will it? Just foul out plugs...?

[virus77]

4th usually boosts the most and the quickest so this way you wont miss any spots throught the rpm band that have boost. And it allows you to get the most samples since the rpms are climbing slower, although you get up to 110-115 mph by redline so be carefull. Also I tune at nights, so during the day it naturally runs a little richer which will combat the hotter weather and you wont go lean on a cold night.

[Florida240sx]

What about putting your car on jackstands?

[virus77]

no load so it wont work, it like reving in neutral, also extremely dangerous having you car at 115 mph on jack stands.

[Florida240sx]

Yea that's what I though about the load.Yea but then you could be a lower gear and just acelrate slower couldn't yea.But no load....Just an idea thought it was a no, but just wanted to check.

[DRIFTEADOR]

i used to do 2nd gear pulls with either my other foot on the brake or the ebrake up. the first takes hard to get used to and is pretty dangerous and the second kills your rear brakes/pads

[uncle_louie83]

anhatch...your 460cc injectors will need to be set at -43%...not -41...

math conversion here

stock injector size divided by new injector size...and the subtract one

so for example260 / 460 = 0.56521739130434782608695652173913(always take the first 3 digits behind the decimal point as you number to minus the 1...so we will only be using the .565)now take the .565 and subtract 1 which = 0.435the only numbers you will be using is the first 2 digits behind the decimal point unless the third digit is a 6 thru 9..then you will round up and its always going to be negative since your new injectors are bigger than your stockers)

so your answer is -43%

another example of is like my injectors...there 440cc

260 / 440 = 0.590 -1 = 0.409here is fine example of when we will have to round up...so my injectors are 41% bigger...so ill set my afc at -41%

lewis

[sil80drifter]

Do NOT forget that the conversion from smaller to larger injectors is NOT linear. This is due to timing and actual injector/ECU design. When you have 460cc injectors, to idle correctly you cannot have the sAFC on -43 at 800 rpm (if that is a map point you are using).It will idle as it did on 270ccs around -15 to -20%. If you don't believe it, try it out.

sil80

p.s: When I was taught math, you rounded down on 0,1,2,3,4 and rounded up on 5,6,7,8,9.

Modified by sil80drifter at 9:26 AM 7/11/2005
Modified by sil80drifter at 9:27 AM 7/11/2005

[AN89HATCH]

Do NOT forget that the conversion from smaller to larger injectors is NOT linear. This is due to timing and actual injector/ECU design. When you have 460cc injectors, to idle correctly you cannot have the sAFC on -43 at 800 rpm (if that is a map point you are using).It will idle as it did on 270ccs around -15 to -20%. If you don't believe it, try it out.

sil80

p.s: When I was taught math, you rounded down on 0,1,2,3,4 and rounded up on 5,6,7,8,9.

Modified by sil80drifter at 9:26 AM 7/11/2005

Modified by sil80drifter at 9:27 AM 7/11/2005

so does this mean to idle correctly with 460 injectors at my ne point of 800rpm (for some reason i cant get my car to idle lower than 900rpm, will this matter?), I would have to set the safc to -15% to -21% ?
Modified by AN89HATCH at 7:20 PM 7/11/2005

[virus77]

For idle just do whatever works, Ive seen too many wierd things with corrrections at idle. For instance my 565cc injectors barely take a leaning to idle right, I just base it off of gettting a proper A/F so the car idles smooth.

[AN89HATCH]

thaks every one for the help. I decided to buy a wideband and tune it my self, hopfully it gets here in a week. now i have a cupple more questions rite now my low thr is 30% and hi thr 80% are these ok throttle points to use?and when you guys say 14.5 air/fuel ratio in vacume, do you guys mean in the whole vacume, or as I accl and the vacume goes up, should i start to have the air fuel ratio go down? example should it be like this vacume -18 (air fuel 14.5) vacume- 5 (air fuel 13.9) boost gauge 0 (13.0) etc? or should i stay 14.5 through the whle vacume, and low throttle? what is my air fuel ratio suppost to be in low throttle,14.5? or should it start to lower to 12's or 13's? or in low throttle will i still be in vacume? or be able to boost in low throttle? once i hit 1lb of boost should my air fuel ratio be 11.5 and keep it like that all the way up to my 7lbs? or is it suppost to gradually get to 11.5? example vacume 14.51k rpm 14.52krpm13.53krpm 12.54.rpm 12.5 or should this be 11.5?5krpm 11.55500rpm 11.56krpm 11.56500 rpm 11.5im still alittle confused

[DRIFTEADOR]

your low throttle setting will depend on what size turbo youre running. since the safc cant read load it decides how much fuel to add based on throttle. if you have a smaller turbo that makes boost at 20% throttle obviously it wouldnt be a good idea to have you low throttle setting set at 30% because 14.5 afr under boost is never good. btw, check this in 5th gear.

air/fuel will be like your first example. based more on load and not so much on rpm. heres a sample target air/fuel table. it's off a n/a motor and in kpa, but just to give you an idea:

14.5afr at full vacumm interpolated to 13.0 @ atmospheric pressure, from there to 12.5 at 5psi, and finally to 12 by 10psi and after works for me.