S-afc I

[rowland2004]

Well new to the forms here just picked up a 92 GSX
with a BIG 16g and the guy before me had the car tuned with a S-AFC I
putting 300WHP @ 22psi

But unless i was WOT if i was like half i was getting popping and Studdering.

But when i was lookin at the settings the S-AFC was set to a 2CYCl. and when i put it to a 4CYCL. the boost was soooooo smooth and strong no popping or anything and could do half throttle good too.

The only thing is that the S-AFC doesnt read the rpms correctly but when on 2cycl. mode reads them fine.

So didnt know if someone could Maybe tell me how to fix it . Thanks.

 

[RSTeclipse97]

Personally I would put it on 4cyl since thats what you have and my safc 2 only has 4 6 8 cyl so i dont know what to say about the 2 cyl thing since there is no such thing for a car. Aside from that my rpms read differant from my factory tach as well but no big deal. And if it runs great like you say set at 4cyl leave it there or take it somewhere and see what they have to say

 

[stefanOst]

People use s-afc I's to tune lawnmowers and chainsaws FYI...duh

 

[rowland2004]

Yea thanks guys, did a little more reading and for the GEN1 with the S-AFC I u have to pick the 2cycl. for the RPMS to read right.

The reason it is running better is cause that the highest the AFC reads the rpms is 2500
and fuel trim is at -5 where when it was reading it around 4000 rpm the fuel trim was -20 up to -30trim. And this was just a tune that the guy had before me.

But just to ask is it ok to put -5trim across the board for a normal driver. thanks again.

 

[rowland2004]

So i was out dailing everything in a little and looking at my LC-1 AFR and when on the gas it would be anywhere from 11.0-16

and when i let off the gas with it in gear slowing down the gauge would read 20+ but when on the gas would go back to 11.0-16 is that normal thanks.

 

[TurboStutr]

Yes that is normal...when you let off the gas the ECU stops supplying fuel to the engine, so it leans out. You should also notice when you're at cruising at highway speeds it will read more lean than if you were at WOT, so don't worry about that either. Also, the reason you have to set the S-AFC to 2-cyl is because the car has only 2 coil packs for all 4 cylinders instead of each cylinder having its own coil pack. So it's sort of tricking the S-AFC into thinking you have twice as many coil packs. It's nothing to worry about, I've had my S-AFC set like that for about 5 years now.

 

[rowland2004]

TurboStutr thanks,

But also my car is idling kinda ruff but when i change the 1,000rpm fuel trim to +5 or 6 from -4 it smooths out is this the right thing to do or is there something else to do.

Thanks kinda new to the Safc and dsm

cause the guy that i bought it from had it set
1,000-4,000
-4 to -8
then to 4,500-7,000
-15 up to -30

but i didnt like it because if i wasnt WOT i would get popping and backfiring.

And if u could would u post your Trims as a guide. And i have 550cc injecs. Thanks

 

[buddahboost]

Well you have a wideband so that very good. Do you have a logger though?

You need to see where your fuel trims are at otherwise its like shooting blindly

 

[rowland2004]

yea dont have a logger yet but the car was DYNO tunned with a logger and i wrote down all the settings, but it was pretty much tunned for WOT

Heres what they were at Making 300WHP @ 21psi

LO THR. HI THR.
1,000 -3 1,000 -3
2,000 -5 2,000 -4
3,000 -5 3,000 -5
4,000 -5 4,000 -15
4,500 -5 4,500 -21
5,000 -5 5,000 -21
6,000 -7 6,000 -30
7,000 -8 7,000 -30

But if anything ive just bump them up to a little richer and it runs much smoother.

does that sound ok as long as i dont go SUPPER lean.

 

[TurboStutr]

To be honest, every single car is different so it would be in your best interest to get a logger. I also have a big 16g with 550's and the S-AFC I so I can tell you it's well worth it. Then search the site here for a guide to help tune with the S-AFC and a logger, it's around here somewhere. You can learn a lot, and maybe add a little power and fuel efficiency just by getting a decent street tune.

 

[rowland2004]

k cool,

but lookin at the settings that where on there does it look close to yours.

And if u post yours not going to use them getting it tuned next week just seeing thanks again.