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?

noooooooobody?

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....

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

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.

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...

bklyn... do you have any info on what you used for ne points/ throttle % for hi and low/ specific fuel % numbers for both ranges?

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

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.

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.

I dont rmember mine but I can chck my friends tmorrow night.

awesome, thanks dude. is his car s5?

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?

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?

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.

ok that last last post and concept confused me, how would u get better mileage with a lower afr of your adding fuel?

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 ^ .........

ok makes sense, i'm curious too, cause i want to get an safc and lean out my na

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?

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

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.

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)

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?

1)Depends if you have a heavy foot or a light foot.

2)Because you are going to suck in more air and tell the TPS if you are WOT or just a tad on the throttle.

3)The % is for the low map while if you go over 50% you go in high map.

4)Yes you should, because for MPG to go up you want to be lightly on the throttle vs WOT the whole time and waste gas. 2 different maps low and high. I think of it as cruising for mpg or fast driving. (But thats why they give you 2 files to choose for afc2)

5)If you want mpg you want to tune during cruising. But if you want to make a better map for spirited driving then tune for WOT. Its because its 2 different modes. Normal and WOT.

Anyone correct me if I am wrong.

I have an s5 n/a, The highest % I have for taking away fuel is -10% I am making more power just by feeling. But afr are the best way to actually tune the engine with the afc.

My car is an s4.. and because of that ( having only 1 wide band TPS) the AFC picks up 100% throttle.. about 99% of the time.. there is no cruising at 30% for example.. foot on the gas means 100% throttle. LOL... That said..

1) where should it change over? IMO at 1%.. then theres no reason to mess with the lo- map.. ( except for idle) One map to look at makes it even easier.

2) ... ^

3) ..........^

4) ...............^

5) Shouldn't, in reality, the 2 fuel maps be quite similar.. ( you always hear this: a leaner afr will make your car faster.. AND.... a leaner afr will give you less fuel consumption because its economizing the fuel )

Problem with tuning the afrs to cruising, is that if you ever watch the wideband, WOT AFR's are always lower then cruising afrs.. So if i tune to cruising, and then go WOT.. the wideband shows the AFRs a lot higher then what i want.. almost into dangerous levels.. This is why tuning to WOT makes sense to ME.. that way, i never go over a dangerous AFR #

Funny how dependent the way a person tunes is based on s4 vs s5.. seems to make a huge difference.. But this is all my own logic... so it could be way off.

Have you tried doing the 98% low and 99% high? It should NOT be touch throttle and it reads WOT or 100%

Im pretty sure thats just how the s4 tps works... if you've ever tried to adjust the tps on an s4.. you'd see that 1/4 turn of the cable linkage puts the tps at fully open. then you can keep turning a whole lot more. Weird, and gay.. but true.

ewwwwwwwwwww

:lol: zany huh? LOL..

I will provide a small success story for the SAFC users.

Have an 83 with an 89 n/a engine, full RB long primaries exhaust.
Installed the SAFC-II last fall, finally am driving it enough to get some results. I don't have a wideband so I'm just tuning by feel, and I wired the O2 sensor into the SAFC-II. Points of interest:

Cruising:
I set the low throttle to ~53% as that number is only exceeded on steep hills during cruising. Normal cruising for me is between 35-50%. Pulled out around 20-30% fuel throughout the cruising band (2-5k rpm). Fuel mileage has gone from 24-29 Imperial MPG.

WOT
High throttle maps starts around 65%. Harder to tune with only O2 sensor, really need a wideband. But couple things, can't take away fuel @ 3800 RPM and 5500 RPM.