The Top DSM Community on the Web

For 1990-1999 Mitsubishi Eclipse, Eagle Talon, Plymouth Laser, and Galant VR-4 Owners. Log in to remove most ads.

Please Support ExtremePSI
Please Support ExtremePSI

Can someone explain SAFCs and widebands?

This site may earn a commission from merchant
affiliate links, including eBay, Amazon, and others.

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

brandonjperfect

Probationary Member
22
0
Oct 13, 2012
Bartlett, Illinois
I know its not really considered a dsm but i just bought a dodge stealth twin turbo, everything is stock besides an fmic, safc, boost controller, and full exhaust. he gave me a parts bin containing 850cc injectors and a 350lph fuel pump. Ive heard that if you get bigger injectors you need an safc (or dsmlink). Ive also been told you need to either buy a wideband, or have it tuned professionally. What exactly is wideband? is it just a computer software? if so what does it plug into? just want some clarification.

update: ive now just realized wideband is a gauge that i actually have installed on my car.. but the wire is cut.. so ill solder it back or have someone else do it. but what else do i need to buy to be able to tune my car at home.
 
Last edited:
I know its not really considered a dsm but i just bought a dodge stealth twin turbo, everything is stock besides an fmic, safc, boost controller, and full exhaust. he gave me a parts bin containing 850cc injectors and a 350lph fuel pump. Ive heard that if you get bigger injectors you need an safc (or dsmlink). Ive also been told you need to either buy a wideband, or have it tuned professionally. What exactly is wideband? is it just a computer software? if so what does it plug into? just want some clarification.

A wideband is used to tell you nearly the exact air fuel mixture. It is used for tuning and can be used to detect potential problems such as running rich or lean, leaning out in boost, exhaust/intake leaks, etc.

The SAFC is a stand alone fuel controller, it is used to trick the ECU into thinking it's seeing a normal amount of air however it's seeing a different amount. This allows you to keep stock AF ratios and the stock fuel trims while being able to run larger injectors. You will make more power but not as much with a real tuning solution.

Real tuning solutions will allow you to adjust things like fuel trims and timing just to give you a very basic idea. Different tuning solutions offer different options.
 
Okay thanks, and since i already have both the safc and the wideband, what else do i need to be able to tune at home? in case i plan on installing the new injectors soon

Well not knowing which SAFC you have I can't really help with that. But instructions for them are usually found online in PDF form.

However, like I said you aren't going to see a big difference between running those injectors or not. You make the most power off using the parts you have to their fullest and with out being able to fine tune everything you aren't going to do that. Timing will probably make the biggest difference for your car. As to what to tune with, you will need to ask on the stealth forums.
 
The one thing you need to understand is that the SAFC2 stops being useful somewhere around 650s with a 2g MAF. At that point injectors are basically larger than you can adjust with just an AFC.
 
Wideband good most important gauge for any turbo vehicle even stock and should be one of your first mods. Safc is garbage need i say more? Anyways here is how to tune with safc try shoot for 11.0:1 a/f ratio on the wideband by leaning out the fuel mixture in the safc. Just remember your just tricking the ecu so who knows what real danger and knock is happening while doing this. Try to save up for ecmlink even ecmlink lite for real safe tune. A tune is the most important mod on your car, you can have all the go fast parts you want but without a tune they are shit. Here is a good guide shoot just google how to use safc you will learn everything. Apexi Super AFC For The Eclipse/EVO good luck be safe dont blow it up.
 
I am tuning right now with a SAFCII and wideband, on my JEEP XJ :D, but the post still applies.

I suggest getting datalogging software if the wideband didnt come with it. I used the MTX-L by Innovate because its been proven to work, price is the same as a AEM EUGO MSRP but can be found for a lot less, and comes with software to log for your laptop or pc if its mobile

The reason I suggest logging, is because its hard to tune with SAFC II on the fly, its a lot easier to look back at the log, see you A/F ratios and then adjust accordingly, then test drive again. A dyno would be best to tune on, but not all of us have that luxury.
 
You asked for an explanation and we all kinda of glossed over that piece.

The wideband is simply used to monitor the oxygen left in the exhaust. Too much fuel (too little o2) you are rich and too little fuel (too much o2 for the amount of fuel) you are lean. You are trying to get your o2 to read at good stoic levels. See the the following and check out the table under Stoichiometry of combustion. These change depending on idle, cruising and WOT.

http://en.wikipedia.org/wiki/Stoichiometry

The AFC simply fools the car into thinking it is using stock injectors and stock intake etc... You have basically allowing the car to pump more air although it is not aware of it and you use the safc to increase fuel to match the new airflow.
 
The AFC simply fools the car into thinking it is using stock injectors and stock intake etc... You have basically allowing the car to pump more air although it is not aware of it and you use the safc to increase fuel to match the new airflow.

You have it backwards my friend. An safc, or most other piggybacks, intercept the maf signal before it reaches the ecu, and allows to you to control the signal input. By lowering the maf signal, you tell the ecu less air is being used for a specific load cell, thus, a shorter injector pulse is sent for that range, and vice versa. This allows you to use more fuel while keeping afrs in check, whether it be bigger injectors or more fuel pressure.
 
Everyone is talking about link. He has (essentially) a 3000gt with a TT V-6. Does LINK even work on a GT/Stealth? I don't think so. Their site doesn't mention anything about it.

As for the OP, you can always see about going with a GM-MAF and a MafT, set it for the injectors, and use the SAFCII for finer tuning.
 
It is all about the scale. What size injectors do those cars come stock with? Maybe a SAFC can control a large enough injector upgrade without getting all wacky like a set of anything above 660s can on a DSM. 850s sound rather large though. Sounds like an AEM is in your future.
 
I was not mistaken and that is exactly what I meant.

You are basically allowing the car to pump more air although it is not aware of it. See the intercept and manipulate above if you want to be technical. I did not bother to getting into the actual load cells since he asked what they did and why he needs them. Baby steps.

You cannot reliably tune anything over a 650ish with an SAFC2.

Here is the calculation if you care (650 - 0.308*650 = 450). That is 30.8 percent fuel and since you have about 25% max gain with the AFC. I did understand all this stuff and thanks Cdc, because now he should be able to use the above info we have all provided to make a good decision.

For my money I flip a few pins around in the ECU connectors, get a flashable black box (h8) ecu, some decent High Z Injectors, make own transistor plug and either learn to tune, like I am, or pay to have it tuned. You will have all the features of link.

The total on this would be $150 more than link and with some FIC 1100 HighZs.

Thom made the best point. Did a quick search for you. Someone make pigtails to convert you to a black box ECU and I knew Ceddy had the XML files for the ECU.

http://www.3sgto.org/parts-sale/11192-conversion-harnesses-flashable-ecu-sale-$55-$100.html
 
Last edited by a moderator:
Support Vendors who Support the DSM Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Innovation Products Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications MyMitsubishiStore.com RixRacing RockAuto RTM Racing STM Tuned

Latest posts

Build Thread Updates

Vendor Updates

Latest Classifieds

Back
Top