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Tuning safc for n/a gas mileage

Old 04-10-08, 04:27 PM
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Tuning safc for n/a gas mileage

Ok i'm picking up my SAFC2 and wideband in a couple weeks to squeeze a little more power out of my N/A, but mainly to improve mileage. Relative mods are 2.5" exhaust w/ corksport catback, and the 6port is wired open.

I've been told/read that the best a/f ratio to tune for in an n/a is about 13.0-13.5:1 anyone confirm this?
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Old 04-11-08, 03:41 PM
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noooooooobody?
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Old 04-12-08, 06:20 PM
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I have heard that too for n/a.

For milage I leaned out the engine as much as I could while in cruise or in LO throttle map below 4000 rpm without the engine bucking around. This seems to get me around 14-16mpg. ...... I wonder what it was before....
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Old 04-12-08, 06:35 PM
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what throttle % were you using for hi and lo? and what were your ne points set to? I'm at about 17 mpg city/21 hwy right now, but i'm shooting for mid-hi 20s
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Old 04-20-08, 01:27 PM
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I too am trying to tune my NA FC for economical gas mileage. Im new the the AFC.... so i need some baby steps on basic stuff... the computer is installed per the wiring diagrams... the basic set up seems pretty straight forward... but then what? just drive the car and see what it reads... what are the functions that will be personally tuning, vs what should i leave to a professional? ( if any) vs what adjustments will the AFC automatically make....

Any SAFC gurus out there help?
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Old 04-21-08, 03:59 AM
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Originally Posted by endneu913 View Post
I too am trying to tune my NA FC for economical gas mileage. Im new the the AFC.... so i need some baby steps on basic stuff... the computer is installed per the wiring diagrams... the basic set up seems pretty straight forward... but then what? just drive the car and see what it reads... what are the functions that will be personally tuning, vs what should i leave to a professional? ( if any) vs what adjustments will the AFC automatically make....

Any SAFC gurus out there help?
If you have a wideband have someone watch it and start removing fuel till you have your desired afr across the board. If you do not have a wideband you can tune and n/a by feel and sound but I wouldnt recommend it if you are not too confident.

I personally kept removing fuel slowly over a few weeks until all backfiring stopped and I reached about 20mpg. I felt good power gains up to a point but beyond a certain point I was too lean and the car felt sluggish on the higher rpms so I turned fuel back up slightly.

My friend who used the same method was able to lean out his low range to the point that his O2 sensor triggered the check engine light. No damage to the engine but its safe to say that was too lean.
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Old 04-21-08, 11:04 PM
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BklynRX7... thanks for the info.. treat me like a child...

How do i remove fuel? seriously.. step by step.. all the numbers confuse the hell out of me! ... im learning!.... if you care to explain?

Also, after installation, i did a full re-initialize to "wipe " the previous info... but i don't know if i was successful.. since when you select "yes" and hit the center button, it makes no acknowledgment of your pressing "yes" anyway.. i continued to follow instructions and turned off ignition after pressing yes. Today i drove to work like normal, on a supposedly wiped SAFC, which should be making zero corrections? and i dumped a half a tank in 80 miles... HM? why... totally lost.. i swear i need a video tutorial... LOL

also.. no wideband... so lets go by "butt" dyno...
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Old 04-22-08, 09:53 PM
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bklyn... do you have any info on what you used for ne points/ throttle % for hi and low/ specific fuel % numbers for both ranges?
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Old 04-23-08, 12:33 AM
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Heres another few questions:

What are S4 owners to do with the tiny little band of TPS info available.. when i depress throttle.. i hit 100% real quick.. what does this mean for my info collection?

What "throttle points" are recommended for low and high? ( on the throttle point selection screen? example lo: 20% high: 80% ?

After setting up.. i zero'ed out all grid on my low and high throttle setting screens as well... so that should make the car run like stock right? no corrections?

Also.. i do now have a wide band in my possession ( borrowed and Lt-1 from a friend) i will hook it up tomorrow night
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Old 04-23-08, 05:30 PM
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best AFR for NA is 12.80. This is what I was told from Kyle at Mazdatrix less that 6 months ago. If you go leaner than 14.8 it will stumble LEAN. 6 ports wired open will KILL MPG. Set points for throttle on a s4 using TPS should be 98 low 99 high. This means you stay in the LOW map till your at 98% throttle position. If you get to 99% or higher ie 100% you go into the high map. If your going NA shoot for 12.8 AFR on a turbo shoot for 11.5AFR IN BOOST. The maps aere set in %. Zero is no correction, so go -4% for example, that would be 4% LESS fuel that a stock map.
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Old 04-23-08, 08:09 PM
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yeah i know how to use safc's, i did all of it on my friend's ka-t 240, just confirming a/f ratio numbers for an n/a rotary thanks a bunch.
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Old 04-23-08, 08:55 PM
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Originally Posted by chwkrx7 View Post
bklyn... do you have any info on what you used for ne points/ throttle % for hi and low/ specific fuel % numbers for both ranges?
I dont rmember mine but I can chck my friends tmorrow night.
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Old 04-23-08, 09:16 PM
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awesome, thanks dude. is his car s5?
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Old 04-23-08, 09:40 PM
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Originally Posted by socalrotor View Post
best AFR for NA is 12.80. This is what I was told from Kyle at Mazdatrix less that 6 months ago. If you go leaner than 14.8 it will stumble LEAN. 6 ports wired open will KILL MPG. Set points for throttle on a s4 using TPS should be 98 low 99 high. This means you stay in the LOW map till your at 98% throttle position. If you get to 99% or higher ie 100% you go into the high map. If your going NA shoot for 12.8 AFR on a turbo shoot for 11.5AFR IN BOOST. The maps aere set in %. Zero is no correction, so go -4% for example, that would be 4% LESS fuel that a stock map.
So cal.. thanks alot for answering my silly questions.. im learning a bit more every day... ON my acf2 i cant get the throttle change over % higher than i think 79%. is this just an safc2 vs safc thing?
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Old 04-24-08, 01:45 AM
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Some more info..
to confirm the above... the safc2 only lets me go as high as 69% on low and 70% on high ( on the throttle change over screen) So what this means is that when i hit 70% throttle.. )which is almost always when you pin the gas pedal o n an s4)... the fuel map switches over to the high map... and below 70% throttle is running your low map. this is correct yes?

I hooked up the wide band tonight.. went for a drive with friend to log some numbers.. Before starting, i fine tuned my tps as well ( closed throttle 1.00... WOT at 4.55) .....starting at zero correction the afrs were reading a pretty smooth curve from
13s in the 2k rpm range
15s in the 3-4k range
13 and 12s in the 6-7k rpm range

So sort of an up then down... Then i started removing fuel in both hi and low maps.. no more than 4% in low and 8% in hi...After this the AFRs were reading slightly higher.. which is the opposite of what i was aiming for.. Does this make sense..? by removing fuel... the AFR should have lowered correct? isnt that the game.. rotary engines run rich... so leaning them out ( removing fuel) gets better performance and mileage?
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Old 04-24-08, 02:25 AM
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i'm a n00b too so correct me if I'm wrong...AFR means Air to Fuel ratio, so if you remove fuel, AFR's go up. Higher AFR means lean, lower means rich.

That's always how I understood it.
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Old 04-24-08, 12:14 PM
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Originally Posted by red_dragon View Post
i'm a n00b too so correct me if I'm wrong...AFR means Air to Fuel ratio, so if you remove fuel, AFR's go up. Higher AFR means lean, lower means rich.

That's always how I understood it.
haha.. duh.. thanks you... .... but still that means that while i was deleting fuel, and the afr was rising, and i was starting at say 13s... then if i wanted to aim at a 12.8 AFR, then i would have to ADD fuel... to get to a 12.8... ( to lower the AFR... ) so that means i was already in a pretty good curve and im wasting my time with this SAFC.. LOL.. i hope not.
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Old 04-24-08, 11:41 PM
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ok that last last post and concept confused me, how would u get better mileage with a lower afr of your adding fuel?
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Old 04-25-08, 02:43 AM
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I guess what i was trying to say was... if my wideband is telling me for example 15:1 afr with no corrections made yet.. ( which is pretty lean) and i wanted to get to what everyone is recommending ( 13 ish AFR) then i would have to add fuel to achieve this... BUT.. it seems like people are always ranting about how rotary engines run too rich anyway, so why am i adding fuel to my already rich stock settings?

So im asking a question in this ^ .........
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Old 04-25-08, 03:37 AM
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ok makes sense, i'm curious too, cause i want to get an safc and lean out my na
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Old 04-25-08, 07:05 PM
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exhaust mods on NA's will richen them up( rb header to PS to a 2.5 straight pipe = VERY RICH see for your self http://videos.streetfire.net/video/8...lenc_18347.htm , so if your close to a stock setup, it should be close to 12.5 AFR. You hit a lean spot around 4k do to the secondairy injectors opening and leaning out the primarys for a split second. What WB are you using?
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Old 04-25-08, 09:15 PM
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Im using Innovate lt-1

I currently ( this week) have a rd header, stock cat, 2.5 inch y and 2 inch pipes after the y to the straight thru cans.. I swap out the stock cat for a straight pipe periodically
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Old 04-26-08, 12:57 AM
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Right on, bonney lake, hehehe I grew up in Edmonds, lynnwood area. Have you seen the mod where you remove the windshield washer talk for a CAI setup. If you dont mind hacking the filler neck hole bigger. I also removed the brake duct so now my filter can be ssen front the front with a straight shot of clean air. If you want, pm me your email and I will send you pics how I did it. After I did mine, I was able to pull 5th gear to around 145ish, gaining around 10mph on the top.
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Old 04-27-08, 12:03 AM
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ok i'm hoping not to thread jack cause this is kinda related,,
i hooked up an afm to my narrow band and checked what it was doing. turns out my car is very lean, so around 17 until u hit the gas, then it only goes up richer for a second and back to very lean,, unless it's high high rpm, now i'm wondering,,
why would i get better mileage by added fuel and makeing it richer,, would that use more fuel,,,
now i kinda figure that my injectors could use a cleaning but yeah, why is my na really lean when na's are suppose to run rich..?

(this is for when i get my safc)
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Old 04-28-08, 10:03 PM
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I second that! After tweaking the fuel correct for week or so... i ended up very close to the stock map... 1-3k rpm is like <1%> 3-4 is about <2%> and so on... the highest i ever remove is like <5%>.......... and i feel like my MPG are going down! but i suppose romping on the throttle is really killing my mpg while tweaking fuel corrections anyway..

New topic... I have an S4... ( single, low TPS) ......
1)Where should i have my throttle change over % ?

2)Why does it matter? AKA.. if i tune the low and high throttle maps exactly the same... then wont i get the same results?

3)What happens if i put the low at say 25% and the high at maybe.. 50% ?what is happening in that gap ive created

4) should i prefer being in high or low? any advantages? And if i WANT to be in high.. shouldn't i set the change over at like 1%?

5) should i be tuning my afrs to WOT or cruising revs? It seems that theres about a 2% dif between the 2... for example.. at WOT at 3k rpm i have 13.2 afr.. but at the same revs.. but not WOT ( just constanmt) im getting about 15% afrs. So if i tune to cruising, then when i go WOT.. it will drop to super rich 11 afr... bad yeah?
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