Tuning SAFC Hi & LoThrottle

[redeclipse7782]

To start I have a forged internal and a 16g turbo running 15lbs of boost. I have an SAFC 2, Zeitronix wideband, and palm pilot data logger. The Zeitronix also has a datalogger that you run through a laptop. I am going to be tunning the car on the street. I think from reading past topics that I should make my pulls in 3rd gear and aim for around 11.8. My SAFC throttle settings are Lo: 35% Hi: 50%, how do i tune the low setting? Do I still pull in 3rd gear but not exceed 35% throttle?? or do i put the car in neutral and rev the car. I think I should pull in 3rd gear, but not exceed 35% because in neutral I am not going to be building boost, but im not sure. Any help & input would be greatly appreciated.
Thank You,

 

[wimploki]

To start I have a forged internal and a 16g turbo running 15lbs of boost. I have an SAFC 2, Zeitronix wideband, and palm pilot data logger. The Zeitronix also has a datalogger that you run through a laptop. I am going to be tunning the car on the street. I think from reading past topics that I should make my pulls in 3rd gear and aim for around 11.8. My SAFC throttle settings are Lo: 35% Hi: 50%, how do i tune the low setting? Do I still pull in 3rd gear but not exceed 35% throttle?? or do i put the car in neutral and rev the car. I think I should pull in 3rd gear, but not exceed 35% because in neutral I am not going to be building boost, but im not sure. Any help & input would be greatly appreciated.
Thank You,

Here's some SAFC tech tip settings

Normally, it's set at Lo - 30% and Hi - 80%

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

http://www.roadraceengineering.com/newafc.htm

 

[Randomrage]

There's stuff about Karman's in that link, I think that info is for 4g63's.

 

[clipsit]

I think they are...I checked it out and I am pretty sure its for the 4g, but hey they might be some what similar...I don't know...? Anyone with other knowledge know?

 

[selmerguy]

I would drive through the gears while logging and not go over 35%. At that tp you should not be building boost and you should tune more around the 14.7 range. Then after you get that where you want it do the hi setting in 3rd gear and tune for that 11.-- afr. Yhats how I would do it.

 

[Talon ESI-T]

The low setting can be in neutral in your driveway.

The high settings can be done in 3rd or 4th. The idea is you put a higher load on the car (allowing you to push the Throttle beyond you high setting) and the accelleration is not too rapid. This also will allow you to see where the AFR's are at for a given RPM and see how they react. If you bang through gears you are not seeing the whole picture of the AFR. The AFR may be rich due to a lower RPM carrying over into the next RPM bracket. You dont want to confuse this because you first reaction will be to lower the % of say 4000rpm (but 3000rpm is extremely rich making you think 4000 is rich because RPMS are increasing too rapidly). Now you are lean going into 5000rpm. You richen 5000rpm. The result is your AFR is not steady.

Does that make sense? Can be confusing if not explained clearly.

To high of a gear will result in a slower rate of RPM climb which is ok but it also means you will be at Higher speeds. This is why 3rd gear is used many times for boost controllers and fuel tuning.

Your high and low settings will depend on your driving characteristic. Try the above settings for starters.

Hope this helps

Terry

 

[redeclipse7782]

Ok for the high settings, do i want be in 3rd gear at about 3000rpms and slowly ease into full throttle? or can I just put the pedal to the floor in 3rd gear at 3000rpms? If I slowly ease into the throttle, at about what RPM in 3rd gear should I be at wide open throttle? Also is selmerguy correct, should the Lo settings be set at 14.7 for air to fuel ratio?
Thanks, much appreciated.

 

[Talon ESI-T]

Well it doesnt matter sort of.....let me explain.

The SAFC has two "maps" if you will. Low Throttle, you have Adjustments for each RPM point and High Throttle where you have the same RPM points and adjustablility.

Ok so you need to set each of those. Your high and low settings are a reference to the TPS voltage the SAFC senses. If you set the Low to 30% - high to 80%, when you push the gas when you reach the point where you hit 30%, The SAFC will adjust the fuel percentage on the low "map". Now at the same time if you keep pressing the gas pedal, when you hit the 80% mark, the SAFC will begin trimming fuel based on the High "map".

So that brings us to your question. Does the SAFC understand WOT? Not really. I kows TPS voltage but has no idea where WOT is. So when adjusting the high "map" all you really need to do is press the gas enough to hit the 80% and adjust each fuel setting. Now you understand you dont just make the adjustment while driving. Datalog each drive and make sure you see the rpm ranges and TPS % so you can view the datalog and adjust them while you are idling.

IS there any advantage to just going WOT at a slow of RPM as you can? sure, i'll explain. When our ECU sees WOT the ECU goes into open loop. Meaning it no longer pays any attention to the O2 and it wont adjust the mixture. You are running off the "true" ve map of the ECU. If you tune the SAFC to the Ve table of the ECU, that means when the ECU is not in open Loop it will adjust the Fuel mixture to meet its target.

What happens if you tune to closed loop in high throttle?
Think about this for a minute.........ok minutes up. IF you tune the High "map" while the ECU is adjusting its mixture based on o2 and you reach the mixture you want, what happens when you go WOT? When you tuned the SAFC, what if the ECU was reducing the Fuel trim as far as it could, lets say -20% at 2000RPM. now your SAFC comes along and you reduce it 11%. You have a total of -31% When You go WOT, the ECU wont be reducing fuel trims fo what will your correction be now? Thats right -11% and rich as hell!

IF you tune WOT and your SAFC is -31% at 2000rpm. When you drop the throttle back and the ECU goes to closed loop it will look for its Target AFR. now Using the above math the Fuel Trim will be 0% and still allow the ECU to trim +/-20% to make up for driving conditions and weather air temp.

Make sense, pretty simple actually. Believe it or not the SAFC concept is over 13years old. They werent always digital though!

Terry

 

[redeclipse7782]

So if i set my lo to 35% and my hi to 50% what is happening from 0% throttle to 34% throttle? does lo mean from 0 through 35% and hi from 50%-100%? if so what happens between 35% and 50%? If you could paint me a picture on how you would tune the car.

 

[DSMcrazy3]

Just out of curiosity, with the built motor, running that much PSI, why not go with a standalone system, to get the real power out of the motor?

 

[XMasta19]

...because the safc is uber cool and the best way to go...unless of course you wanted to spend just a litttle more for megasquirt

 

[Talon ESI-T]

DEF not the best way to go! Many SAFC setups dont work on 2gnt's and the owners end up selling and lose their butt.

 

[redeclipse7782]

I really would like to get the megasquirt, I talked with another member from 2gnt about the ms awhile back here is a message he sent me about it that kind of detered me away from it:

"There are a few other issues too... Like where to put the coolant and intake sensors. The EGR hole near the throttle is an excellent spot to put the intake air sensor, but you will have to have it drilled and tapped. The coolant sensor fits in the stock location, but then you won't have a stock coolant sensor which means the factory idle valve won't work properly. You can get around this problem by getting some kind of nitrous solenoid or something to replace the factory idle valve, but I have not done this, only researched it a bit. By the way, your car will definitely not pass inspection after this, and you will probably have a check engine light on for the rest of the life of the car, and this shouldn't be your daily driver unless you don't have to be at places on time and have AAA Gold."

The car is driveable right now and it is running pretty good, I just want to fine tune it a bit more with the SAFC. This car is my 3 season car, its not a track car. If anyone lives in or around Massachusetts that has strong knowledge in the MS, and wants to help me install it and show me how to use it, I will gladly buy it. I just dont want the car breaking down on me all the time if I get the MS. Could someone list the pro's and con's of the MS???

 

[redeclipse7782]

Any ideas???