Thread: Troubles tuning setup with MAFT + SAFC

It's not going to run well at all with the SAFC zeroed because the MAFT isn't configured right.

What are you MAFT and AFC settings now?

MAFT AUX/BASE set for 650s? Idle +3 Mid 0 High 0?

And what are you SAFC settings?

Originally Posted by 98spydert

It's not going to run well at all with the SAFC zeroed because the MAFT isn't configured right.

What are you MAFT and AFC settings now?

MAFT AUX/BASE set for 650s? Idle +3 Mid 0 High 0?

And what are you SAFC settings?

MAFT:

aux/base set for 650's
Idle +3
Mid 0
WOT 0

SAFC:

1k 2 3 3.6 4 4.6 5 5.2 5.6 6 6.6 7
lo +45 19 18 23 29 29 29 29 29 29 29 29
hi +9 9 9 9 9 12 16 20 19 21 22 23

TH points at 15% 65%

With that the car run just ok. There are periods where it makes alot of power and others when it just bogs. Also I'm have major boost creep issues and whenever the rpms go over 5500 at wot the boost spikes to 25psi and and I hit fuel cut. On the logger I almost regularly see 100%+ idc's, especially when the boost spkies. It happens even during steady boost at mid to high rpm ranges. I figured 650's would more than handle my setup.

Start with AUX =0 BASE =3, Idle =0, mid =0, WOT =0 and zero out all of your SAFC settings.

If you can get your low trim close to 100% while cruising by adjusting the base knob, you should be in good shape for the rest of the tune. If this is waaaaay off, I'd just go back to your old settings that are working on for now and wait for someone who can help you in person. It's going to be too hard to trouble shoot and tune a car over the internet. Good luck, hope this gets you somewhere.

Originally Posted by 98spydert

Start with AUX =0 BASE =3, Idle =0, mid =0, WOT =0 and zero out all of your SAFC settings.

If you can get your low trim close to 100% while cruising by adjusting the base knob, you should be in good shape for the rest of the tune. If this is waaaaay off, I'd just go back to your old settings that are working on for now and wait for someone who can help you in person. It's going to be too hard to trouble shoot and tune a car over the internet. Good luck, hope this gets you somewhere.

Those settings put the injector correction for 460's, right? What's the theory behind these settings?

Sorry, make that AUX 0 BASE 9 to get your base curve about 20% richer. You're SAFC settings for 2K-4K are around 20% so by making this correction with the MAFT, you'll be able to zero out the SAFC and get the car to run well enough to continue tuning with the MAFT.

I'm not sure what's up with your idle corrections. With a 20% base increase, that'll leave you with 40% to go based on your old settings. So you're in the limits of the MAFT but it's still weird.

Let me know if that gets you anywhere.

I'm going to try this tonight. Let me get something straight; Is the goal here to be able to get the car running "well" with just using the MAFT, regardless of the actual settings that correspond to injector size? After then the SAFC can be used to fine tune the RPM band?

So, I'll try those settings and let you know how it works, thanks for your help thus far, I know its tough to help out with this kind of stuff on a forum like this.

EDIT* I reset the ecu, set the MAFT to 0/9, which puts the correction at +20% (520cc injectors) and zeroed out the SAFC. Upon starting the car the O2 trim immidiately went to 167% then defaulted to 100%, which I guess means the reading was higher than the sensor can pick up. In order to get the O2 trim around 100% at idle I had to adjust the idle knob on the MAFT 3 clicks cw and the trim held around 90-100%.

I drove the car for a few miles afterwards and immidiately the mid and high trims changed to mid: 103%, high 99%. I guess I should give it some more time to adjust and see how much more it changes. If the trims stay the same then that would tell me that the settings are good and it would be time to start making finer adjustments with the SAFC?

The goal should be to get the car running perfect with the MAFT alone. With the 2% adjustments in RPM mode, you should be able to tune WOT really well also. A lot of people who can't figure out the MAFT to begin with swear by the SAFC for tuning and only use the MAFT to translate the hot wire GM MAF. When I had the MAFT, an EPROM chip, and WB02, I was able to tune the car how I wanted without an SAFC or any other piggy back device. My air fuel ratio was consistant and I never hit a point where 1 additional percent of adjustment would have gained me anymore hp. The aditional 1% adjustment isn't worth the $200-300 IMO. That money is better saved and speant on DSMLink or a WB02.

If it's easier for you to tune with the SAFC or you want to use it because you already have it, get the car running perfect with the MAFT, then tune for WOT performance with the SAFC. It's better to tune with the MAFT because it's non WOT adjustments are based on airflow levels rather than rpm points. As the weather changes, you can throw any fine tuning done with the SAFC out the window. But for WOT, you can take advantage of the additional rpm points and 1% adjustments on the SAFC if you'd like. I'm glad those AUX/BASE numbers worked out for you, depending on where your trims settle you may need to adjust them a little more but it sounds like they're close.

I read too fast. Yes, the goal is to get your AUX/BASE where they NEED to be rather than where the book says they should be. Some of the MAFT units are just a little off so AUX 0 BASE 9 really is the calibration for 650s and the calibration for 650s according to the book is really 20% higher. So you can think of the so called 650 settings as 780cc settings.

yes, you want to get the fuel trims as close to 100% as you can, with just the maf-t.

103% should be able to be adjusted to around 100% once you enter rpm mode with 2% adjustments.

Drive your car like that for a while, so the fuel trims can settle down and get established, then enter rpm mode and adjust the mid and high to 100%, then bring out your AFC and fine tune with it, basically just add fuel where you see some knock.

glad to see that you fixed your pcv setup like i recommended.

Ok, here's a little update on how the tuning is going. The SAFC is still zeroed out nad the MAFT is till set for 520cc injectors. Basically aux=0, base=9, idle=2, mid=0, wot=0. I have yet to make any adjustments in RPM mode as I just wanted to wait and see what the trims would do on their own. The idle trim (FTRL) seems to vary from 100-130%, FTRM= 111% and FTRH 82%. So obviously the high trim is very rich and the mid trim is on the verge of overly lean.

My question is should I adjust the base settings to try and bring the mid trim closer to 100% realizing that the high trim will more likely become more rich and then brin the high trim back up with the rpm adjustments?

Also, I had a question regarding the RPM settings of the MAFT and how they relate to the airflow cutoff points that correspond with each trim level. Does it work similar to the SAFC with 4 adjustment points rather than 12? Is it correct to assume that any adjustments made to the 3k and 4k rpm points on the MAFT in RPM mode would only affect the mid trim?