i was interested in buying a S-AFC for my 87 NA and i wanted to get some pointers on how to tune it myself. i plan on doing upgrades but they will be progressive. i wanted to start with the S-AFC cuz it will allow for tuning of each mod as it comes. i would rather not take my car to be dyno tuned cuz that will quickly add up.

 

well to tune it the "right" way you would need a wideband O2 sensor. Some guys can tune a car with a good EGT gauge as well. if you are serious about tuning it and don't think these ways are for you, i would install the majority of the parts that will make a difference (exhaust/intake) and then get it dyno-tuned after that. it's no use tuning it after each individual part. you can no-brain it and use someone elses SAFC settings who has similar mods, but most of the guys on here will flame you for that even though easily half of the guys with SAFC's on their NA's are not tuned "correctly."

 

wire it in and tak it to a dyno with a wideband $100-200 is a lot cheaper than buying a new motor

 

yeah the wiring and install is easy i've got mine mounted fluch in the ashtray area with the lid cut to fit it looks nice. but afte5r you do some mods have a pro tune in on a dyno for you it's safer and you'll get more out of it

 

on an na you can drop the numbers by about 8% at least safely. i drove around with -20% for awhile just to see if i could do it

 

now is that 8% through all rpms? and where can i get a wideband O2 sensor?

 

i'm considering selling my safc.
also, racetune in hayward has $40 dyno days sometimes. you get 3 pulls and torque, hp, and air/fuel printouts. you don't get to tune during the session, but knowing the air/fuel is very helpful for tuning safc of course.
you could even change your settings, and dyno again to see what changed, and then you're only out $80 total. not bad if you ask me.

 

On your S4 NA maybe set the throttle points to 50% for low and 95% for high.
That will generally keep you in the low map for crusing fuel economy.

For starters a cheap narrowband AFR gauge will do for leaning the low map.
Leave the high map near zero & the factory settings will keep you safe.

NOTE! The above is for NA's only. The above suggestions will detonate a turbo.

 

http://store.yahoo.com/sgpracing-store/aemuewiafmo.html $349
http://www.urdusa.com/Merchant2/merc...gory_Code=PERF $315.99
http://store.yahoo.com/machv/plxmwio2seki.html $349 (same as above)
http://www.techedge.com.au/vehicle/wbo2/default.htm (DIY; confused me)

or check ebay. always good cheap stuff on ebay.

 

thanks for the links. i didnt think they were expensive. so do i really need it to use the safc or is it better to use with it? i would like to install it as soon as i get it. btw it's the safcII....i heard that was better so i got it.

as much as i luv ebay, i really didnt see any wb for rx7's. so should i search normally without using the rx7 criteria?

 

oh, definately DO NOT include RX7 in the search. theyre just widebands. they use your O2 sensor bung (threaded hole). they use a 4 or 5 wire O2 sensor and many can completely replace your stock one so you dont have to drill another hole in your exhaust manifold or header. they have a seperate narrow-band wire than you can splice into your previous O2 wire which goes to the ecu (very important for gas mileage).

search the product names, not what car you intend to use it on. theyre universal.
search: AEM UEGO, PLX M, AEM wideband, PLX M-300, etc

its best to have one to tune your safc, otherwise its all guesses. i would never settle for an egt or narrowband sensor. a wideband is simply better and CAN be found for cheaper (than new) on ebay.

i didnt find any used ones, but keep an eye out. when i was looking at widebands, i found a cheap used one at the time.

 

95% for a high throttle? I think that's a bit excessive...maybe 80% would be a better high point.

You will want to bring the car to a qualified tuner if you aren't 100% about playing with this. I have never ever seen an SAFC "map" that was set clear across the board from one rpm point to another. Once on a dyno w/ a wideband, the tuner will be making lots of small changes from run to run.

You guys have to know that any changes at any rpm point (either high or low throttle) will effect the entire curve. Obviously small changes will not present any meaningful change, but if your high throttle settings are 0 and your low throttle settings are -20 you have effectively leaned the entire curve.

Also, remember that you can only change a set # of rpm points. The SAFC interpolates the rest of the points between the changes you make. So, if your high throttle 5K rpm setting is +4 and your high throttle 6K rpm setting is +1 the SAFC interpolates the setting @ 5500 rpm.

While it's normal for some cars high or low throttle curves to begin and end at very very very different #'s (like 20% difference) the curve overall should generally be a fairly smooth transition from beginning to end.

The SAFC is a wonderful tool but not without it's drawbacks. The false signal sent to the ECU does have an effect on timing.

 

95% for a high throttle? I think that's a bit excessive...maybe 80% would be a better high point.

You will want to bring the car to a qualified tuner if you aren't 100% about playing with this. I have never ever seen an SAFC "map" that was set clear across the board from one rpm point to another. Once on a dyno w/ a wideband, the tuner will be making lots of small changes from run to run.

You guys have to know that any changes at any rpm point (either high or low throttle) will effect the entire curve. Obviously small changes will not present any meaningful change, but if your high throttle settings are 0 and your low throttle settings are -20 you have effectively leaned the entire curve.

Also, remember that you can only change a set # of rpm points. The SAFC interpolates the rest of the points between the changes you make. So, if your high throttle 5K rpm setting is +4 and your high throttle 6K rpm setting is +1 the SAFC interpolates the setting @ 5500 rpm.

While it's normal for some cars high or low throttle curves to begin and end at very very very different #'s (like 20% difference) the curve overall should generally be a fairly smooth transition from beginning to end.

The SAFC is a wonderful tool but not without it's drawbacks. The false signal sent to the ECU does have an effect on timing.

 

what kind of effect on timing are we talking about?

 

yep get a 2 that way you get 12 points instead of 8. Thats always nice.

 

I have a safc2 but I dont know how much I can trust any local dyno shop to tune an rx7.

 

Hit the regional forums, see where people have had their cars tuned in your area!

 

You are saying that any after marke O2 sensor will work on my Rx-7