Hello,

I was looking to get a S-AFC and wondering how difficult (or easy) it is to tune with the Evo. Can the S-AFC be tuned well with just a wideband 02 unit or is it needed to also have a OBII logger to check other engine information? What is a good and still safe A/F ratio for WOT with stock boost? Also what kind of horsepower and torque numbers have you guys seen from adding the S-AFC to a relatively stock Evo?

Thanks

 

I'm curious to see how the general evo owner will tune their car with an safc as well.

So far, I've seen the following occur (in order of expensiveness).

1. rely on other shops to tune. i.e. take it to a dyno and pay someone with 'supposedly' more knowledge to tune the car. Since I don't have an awd nearby, nor anyone I would even begin to trust with a turbo 4cyl, I can't see this as being a viable option for most.

2. buy an safc from buschur and pay extra for his recommendations. For most, this is probably a great idea since he obviously knows what he's doing and seems to have developed a solid program for tuning more power out of the average evo. I am _very_ curious as to what the recommended settings are to see just how rich the factory maps are. I've also heard it said by Tim Switzer that the evo tends to run dangerously lean at idle occasionally, so I'd like to see if they actually richen things up on the low map too.

3. tune it yourself through trial and error. datalogging, wideband 02, egt gauges will certainly help in this effort.

I've got an datalogging system, and since it's obdII I can't view the actual knock of course, but can see the timing. The way I would attempt this is to lean it out up top till the timing starts to become pulled, and then richen it up a couple clicks to find a happy medium. Obviously, this is going to be an iterative and continuous process. I used to use an EGT as well on my dsm, but found it to be less helpful than simply sticking to the datalogger.

 

This is difficult, inconvenient and expensive. There are not too many tuners that I know can be completely sure know what they are doing... I'm sure there are many competent folks out there, but I'm also sure (I know for a fact) that there are also lots of hacks out there... How to tell who's who?



While Buschur and others are very good and know their stuff, there is no way to be sure that the settings they send you will work with your car. I know for a fact that EVOs are all different. Mine for instance was knocking like crazy with the stock settings. The SAFC2 I had with AMS settings would have made matters a lot worse since it leaned out the A/Fs through much of the rpm range. You've got to know what your car is doing to tune it correctly.

I had the good fortune to have Al in Atlanta to custom tune a Dynoflash. What I saw was that in order to tune effectively and safely you need a wide band O2 sensor, a Knock sensor w/real time display and a datalogger. With this plus the ability to manipulate the timing maps too, you can tune around the knock sensor to get the most timing advance and the leanest A/Fs possible *without* inducing knocking and the subsequent timing pullback....

Just my $.02 (well, actually more like $600 ) worth of experience