Initial AFC Settings

[luv2eclipse]

2g
Evo 3 Big 16g (18 psi)
FIC 750c injectors
Supra Fuel pump (re-wired)
2.5" exhaust with o2 dump
FMIC


We got a logger I'm just trying to figure out initial settings and go from there.

80% high throttle and 35% low throttle

I started on high throttle settings at -25 cor all the way across

 

[drewvr4]

a dyno, wideband 02, or egt gauge are a must....period.

 

[luv2eclipse]

a dyno, wideband 02, or egt gauge are a must....period.

Of course they are, but this is not my car. I need these settings for a friends car. If it were my car I would run dsmlink and a wideband.But it is not my car.

 

[red_devil]

try
http://www.roadraceengineering.com/newafcsetting.htm

or
http://www.dsmtuners.com/forums/showthread.php?t=58403

You might have trouble getting it to run smoothly with those big 750s
-25 is a good starting point.

 

[luv2eclipse]

try
http://www.roadraceengineering.com/newafcsetting.htm

or
http://www.dsmtuners.com/forums/showthread.php?t=58403

You might have trouble getting it to run smoothly with those big 750s
-25 is a good starting point.

What about low throttle settings? I've never played with an afc with injectors that big. And I know how to tune and I'm pretty sure I'm going to have to retard the cas a little bit. I'm just looking to save some time and seeing what other people have theirs set at. Then I can take their settings, richen it up a little bit ### every car is different and then start from there.

 

[thekellbeast]

Hey man, haven't talked to ya since back in the DSMLife days. Hahaha... I second the DSMLink. That's what I'm running in my Talon.

 

[luv2eclipse]

It's not my car. My 1g has dsmlink, this tuning is not for my car.

Yea haven't talked to in awhile either, you should send me a pm with ## msn addy and we'll have to catch up sometime

 

[spyderturbo007]

Ouch, 750's and a SAFC.....That's going to be tough. Mathematical correction to hit the factory AFR of 9.5:1 is -40%. You might want to start around -35 or so to be safe. Keep a good eye on timing since it's going to be insane. TPS trigger points should be 30% and 80%.

Good luck, you're going to need it.

 

[i'm boosted]

Agreed....Timing would be insane to the point you are going to start knocking. Get a chip ASAP or switch to an injector that the AFC can handle. The limit for a AFC is about 680.

-Brian

 

[blcknspo0ln]

Agreed. Get those injectors out of the car ASAP or get a better tuning tool. Just for reference my Denso 660's were corrected on my SAFC2 at THpts 30/80 and -46% and I was still running 10.2:1 AFR @ 24* timing

 

[bling5tatus]

Ouch, 750's and a SAFC.....That's going to be tough. Mathematical correction to hit the factory AFR of 9.5:1 is -40%. You might want to start around -35 or so to be safe. Keep a good eye on timing since it's going to be insane. TPS trigger points should be 30% and 80%.

Good luck, you're going to need it.

How did you get 40%? I found 750's to be 66% bigger than 450's.... please elaborate.

 

[GVR4592]

The correction factor is -40% for 750's with stock fuel pressure.

If the car has an adjustable fuel pressure regulator I would drop the fuel pressure down to around 36 psi. That will make the injectors flow roughly the same as a 680cc injector and the correction factor would be around -33. Make sure the fuel trims are where they're supposed to be before you tune full throttle settings.

 

[spyderturbo007]

The calculation for injector size compensation is as follows:

[(S / N) - 1] * 100 = C

Where,

N = New Injector Size
S = Stock Injector Size
C = SAFC Correction Factor

So, in your case the calculation would be:

[(450 / 750) - 1] * 100 = -40%

Keep in mind, this is the mathematical correction factor used to hit the ECU's target AFR of 9.5:1. It will vary from car to car, so it's best to start a little on the rich side.