Looking for a good starting point on SAFC

[talon4show]

When I was going to go with a 16G I was going to use RREs settings with the same mods and then tweak from there but my new setup kind of has be thinking. Can anyone supply me with a good starting point for these mods:

AGP RS49T 50-trim turbo
AGP wastegate
Tubular exhaust manifold
Tubular O2 housing
Apex'i 3" downpipe
Apex'i N1 3" exhaust
Forced Performance 4" intake
GReddy 24 row front mount intercooler
GReddy upper and lower intercooler pipe kit
GReddy Type-S blow off valve
Aeromotive fuel pressure regulator
Walboro 255 high pressure fuel pump
Fuel Injector Clinic 650cc injectors

 

[Quasimondo]

I was going to link you to a Canadian DSM site that has a much better tuning guide, but since the site appears to be down, I'll cut and paste it here:

I think the current online guides for tuning your AFC are lacking so I'm gonna write up the process I use and stick it on my webpage. I'll write the draft up here and see if anyone wants to correct anything or give any inputs at all. (p.s. ignore the spelling for now please... and I'm not proof reading so I will have to edit it later on).

First off the following will assume you are using a datalogger to tune with (TMO or Pocketlogger). There are 4 basic steps to tuning your new style S-AFC properly on a 1G Talon:
1)Setting up the low settings in your driveway
2)Setting up the low settings while cruising
3)Setting up the high settings while wot (wide open throttle)
4)Setting up the part throttle response

Before doing any of this though you should have your base timing where you want it and your boost level where you wan to run it. Be realistic with your timing and boost settings... I will assume they are reasonable for your mods. Oh and make sure your fuel pressure is also reasonable.

1)Setting up the low settings in your driveway
Okay you've just install the S-AFC properly or want to start all over with your setup. Run your car until it is fully warmed up and hook up your datalogger. Log the following: o2 sensor, o2 trim, fuel trim low (ps if you don't know what these do please research first at www.tmo.com and/or www.hywell.org/plhelp/index.html).

(note I'll adjust thhe following to specify 90 trims as well)

First look at the fuel trim low:
-if it is peg full high at 140% then you are currently running too lean at idle. Richen up the 1000 rpm low setting in 5% increments until the fuel trim low value drops down some.
-if it is pegged full low at 60% then you are currently running too rich at idle. Lean out the 1000 spm low setting in 5% increments until the fuel trim low value raises above 60%.

So now you have a fuel trim that is below 140% and above 60% somewhere. Try to keep adjusting it as above but in small increments to get it to hover between 100% and 110% or so.

Notice that the o2 trim is actually a leading idicator for the low fuel trim. As you adjust leaner or richer you'll see the o2 trim immediately adjust up or down on average accordingly and then over time the low fuel trim will follow it's lead. As it does that the 02 trim will start to head back tot he center again.

It's very important to understand what is happening so I'll be specific with an example. Okay you've done the above steps and now at idle your fuel trim low is holding steady around 130%. You want to get that closer to 100%. So you richen the 1000 rpm low setting on the AFC by 5%. Immediately the 02 trim heads lower showing that the ECU is seeing that it's probably too rich and doesn't need to add as much fuel with the trim. Slowly the fuel trim low will drop down. As it does this the 02 trim sees a better leaner burn as starts coming back up to center from it's low rich reading. Once the o2 gets back to the middle the fuel trim low will no longer change as the ECU is satisfied again.

Okay so you have the 1000 low setting setup. After that you want to set the 2k, 3k, and 4k rpm low settings. Do this by using the gas pedal to hold the rpm at the given rpm you are trying to set and then make adjustements. Watch the 02 trim now. If the trim is averaging low then you are too rich and need to lean out the setting for the rpm you are at. If the trim is averaging high you need to richen up that setting. Keep adjusting until you get a nice o2 trim cycling somewhere in the middle. Do this for each of the above rpm points.

Now above 4k the ECU goes into open loop mode and runs mega rich so you can't set the 5k, 6k, 7k, 8k low settings in the method above. For now just set them to whatever the 4k ended up at.

2)Setting up the low settings while cruising

Basically you want to repeat what you did above for the 2k, 3k and 4k settings except now you do it while actually driving. The first step is really to get you in the right ballpark and to get a good low fuel trim to start out tuning with. You'll find that the settings will need to be adjusted as adding a load to the engine will affect things. So use the o2 trim in the method stated above.

3)Setting up the high settings while wot

Great so your cruising settings are setup now it's time for the fun part. Change the settings on the datalogger to log: throttle posision, IPW, knock sum, timing advance, o2 sensor and rpm. Set your high settings the same as your low setting but take off 5% across the board.

In second gear around 2000 rpm go wide open throttle at least to 6,500 then pull over. Have a look at the log. First make sure that the the throttle posistion is registering at 100% when you had your foot mashed. If it didn't find out why and fix it first.

Look at the knock sum:
-if it stays flat at 0 that's a good thing... it mean you have room to lean the a/f ratio out. It also means it's safe for you to do 2nd gear and 3rd gear wot runs from now on. So lean out the high setting -2% at each rpm point and go for another run. Do this until you start to see the knock sum jump up. When you see that look to see what rpm that knock occurred at and richen that rpm point back up the 2% you took off that run. You can run again like that until you knock another point and then richen that up. Kepp doing this until you think you are as lean as possible without causing knock.

-if however after your first 2nd gear run you see lots of knock it's a bit harder to tune. Again I'm going to assume you make inteligent base timing and boost setting choices. Lots of knock is most likely the result of running too lean, but it could be from running too rich or many other things like phantom knock. I'm can't write about them all so I'll assume you do not have any kind of phantom knock (false knock). Look at your o2 sensor voltage. As soon as your throttle position goes to 100% it whould peg to a certain value and stay there until you get off the gas. If you have a 91-94 Talon and the o2 voltage is showing less then 0.92V then you are likely running too lean and need to adjust the high setting richer by a bit and then do another wot run. If it helped keep doing this until you get it to go away. If after several tries it's not helping try going leaner... but if it gets at all worse stop and go richer again. Keep doing this until it's as lean as you can get it without knocking.

Done. Don't forget that if you tune like this on a really cold day you will likely be knocking on a really hot day. Also if you plan to do a lot of 4th gear highway wot runs you might want to do some now and check the knock... richening whereever you see it.

If you can't get the knock to go away try less boost for now and put your base timing to 5 degrees BTDC if it isn't and try again. It might also be phantom knock in which case you need to do some searching and reading of the DSM club boards.

4)Setting up the part throttle response

You'll do this with the TH points. For now set them to 30% and 70%. If you have a stock MAF then these settings will probably do you just fine. If you are running a hacked MAF we'll probably need to change this but for now leave it at 30% and 70%.

Basically it works like this... the S-AFC will use the low settings at any throttle position below the low TH point and will use the high settings when the throttle position is greater then the high TH point. When it is inbetween the two TH points it will average the 2 values dependant on how close it is between each. So at 50% throttle position in this case it would end up being the exaclt average of the high and low setting for that rpm.

Set your logger up to show o2 trim, knock sum and throttle position. Do some part throttle accelrations in each gear. Watch what happens when you get on the gas in each of those part throttle conditions.... watch the o2 trim.

-If it goes low then once the gas starts flowing (but still in closed loop mode) you are running too rich. Are your low settings higher then your high settings for each rpm point? If so then you need the AFC to start using the high settings sooner since they are leaner. Do this by dropping the low and high TH points. Keep doing this until the o2 trim does not fall right off full low. Keeping it exactly in the middle is likely not acheivable but it should not go full low or full high.

-if the o2 trim pegs full high it means you are going too lean under part throttle. If your low settings are richer then your high settings you are starting to go to the leaner high settings too soon. Start increasing the TH settings so that it keeps using the low AFC settings longer. Keep doing this until the 02 trim no longer goes full max and hovers somewhere near the middle. Doon't be too picky trying to get it exaclty in the middle but get it close.

This is the step that should get rid of any sluggishness noticed when driving. For people with fully hacked MAFs the low AFC settings are quite richer then the high settings. I find that the 02 trim drops off quick with 30% 70% TH settings. This causes bad responsiveness and sometimes knock and/or backfire. Each car will be different but for me 15% and 60% TH points seems to work well with my setup.

Done.

 

[talon4show]

Thank you very much! I will take some time to thoroughly read through this!

 

[spyderturbo007]

That will work, but he has a 2g so there is no way to look at knock on the logger.

I think this might work out a little better for you:

http://www.racingknowledge.org/ver3/viewtopic.php?t=1011