ok i have an 89 TII and im trying to tune it with my wideband.. well the afr keeps jumping around depending on gear and how i accelerate.. i was wondering if i could get a better safer tune by hooking up the afc to pressure instead of TPS. i heard it is not nessisary on a S% but i would like to get a better way.. would this help at all.. im stitting on stock injectors and like 10lbs of boost.??

 

Don't forget the stock map in the ECU is not a straight line.
It does some crazy things near closed throttle, especially when decelerating.
And of course when you're cruising, it goes closed loop & ignores the air flow all together.
How aggressive are you with the high & low maps?

 

well im at work so its just my best guess
mine is pretty smooth foing from about 2500 rpm at like +2 and i made it smooth untill about 6k where it is like +17 and than i dropped it off to +13. thats the high map and the low map idle is at -13 and i kinda just smoothed it out up to about 3500... ill get better numbers tonight when i get home

 

The maps sound very reasonable.
Throttle points? Maybe around 50 & 99?

As you may have seen from my other posts, I like using the pressure sensor for shifting from the low to the high map. (even on my prior S5)
That way, if you get any boost creep in cold morning air, the fuel can keep up.
And, if boost is a little low on a hot afternoon, the fuel dosen't get too rich.

 

i think my throttle point is 20 and 50 i think but i want to hook up my afc to pressure now.. it is an 89 S5 so any good write ups on it or recomendations from a expericened guy? help is alway appreciated

 

hello i recently bought a 92' type r twin turbo from japan , i live in the Bahamas , the car has an apexi super afc. can someone tell me how to adjust and set it .thanks

 

The short version:
Write down all your current settings in case something gets screwed up & you have to go back to them.
Initialize the unit.
Select the low map settings.
Hold the throttle at the 1K RPM point & lean the correction until you get a slight lean mis-fire.
Add back a few %.
Repeat the prior two steps for RPMs up to 3K & taper the remaining corrections back up to 0.
Set the high map corrections 10 - 30% above the low settings at RPMs 3K & up.
Taper the lower RPM corrections down to 0 at 1K.

About tuning the high map:
Much depends on your injector size & fuel pressure.
A wideband AFR is by far the best tool.
Without a wideband or EGT, you have to start rich and observe the exhaust smoke or read the plugs to lean it back.

I have not used an EGT, so check me on this:
Is I understand it, you can lean back fuel until EGT the falls, the starts to rise again at that load point.

 

nice writeup!!
what i do is pretty much the same.. with my wideband i tune it pretty darn rich above 2K in the HIGH maps (+30-35%) and turn the boost to the appropriate setting (of course with the proper added fuel and FCD and other parts needed) then i find a SAFE road and have a friend with me tune the SAFC back (-) as he or I watch the wideband and i usually tune for 11:5 VIA my wideband, its kind of a shot in the dark to keep 11:5 all the way through the RPM range but you get what im saying...

almost forgot!! if you need to wire it up click HERE!

 

On an S5, do I need to re-wire the s-afc to the pressure sensor wire? or just follow those setup steps for the s-afc? Is there a long version of this write up?

 

The S5's wide range TPS will work OK.
I just like having extra fuel headroom for the occasional boost creep on cold mornings.

 

anything for S4 turbo II?

 

Since the S4 TPS goes to 100% at 1/4 throttle, using the TPS to switch to the high map happens really too early.
The S4 works much better using the pressure signal into the S-AFC throttle wire.
Then, if you want to monitor the TPS, you can tap the blue (PRS) wire to the TPS signal, just to see if it's working OK.

 

if i hook it up to my pressure sensor wire do i need to change the setting from flap to pressure?

 

what about the automatic setting? when you do the intial start up and supposed to put the pedal to the floor then release...mightyvac?
this is if you switch to the boost sensor from the TPS...