S-AFC II Tuning w/ Wideband????

[speedfiend]

Alright first off I have searched for many hours and gained a lot of knowledge on using the afc unit. Second I completely understand that this unit does not adjust timing and can be dangerous to use do to this. First some background on the motor. This is a slightly modded blacktop s14 sr.
Mods:
Blitz FMIC
HKS SSQV Bov
N/A Throttle Body
Z32 MAF w/ correct AFC settings
Sard FPR
Stock 370cc injectors
Full 3" Exhaust
S15 T28 Turbo
Tubular Manifold
DNA Motorsports manual boost controller: stock 10psi
Defi Boost Gauge
SAFC II
Zeitronix Wideband datalogger
My question is exactly how do I set the low throttle rpm settings. What I mean is what is the easiest way to do this? I have my thr settings at 40%/60% lo/hi. First is that a good setting for those. This is based off of me longing my throttle position for a couple days to see how I drive and set in accordance. Now for the low thr settings I understand that this is setting the fuel for anything lower then 40% throttle. Should I just cruise in third gear making sure I stay below the 40% throttle and log my a/f curve across the rpm range in third gear? Or is there a better way to do this. Sorry for the long post but some help would be much appreciated. Once again I know the dangers of doing this on the street and hold no one at fault for anything that occurs to my motor. Thanx, Cameron

[johngriff]

The low/high throttle points in theory should be used as base for an interpolated map.

Meaning that if you set low throttle to 30% and high to 70% 31-69 will be delievered as the mean of 30 and 70 values per rpm point. It is basically a way to tune boost/throttle transition fuel.

Read the new AFC NEO guide as it has the best description of how to do this. If you are having trouble with this, you are getting bad af/r's on transition throttle, and your car is undrive able, then take it to a tuner.

I see that you are using stock injectors, you will probably not need to tune on this map all that much, though i would suspect portions of your tune will need this because of the response and flow of the s15bb compared to the stock turbine.

What are your AF/R's anyways. I fear you may not be able to get them to deliver the type of fueling you will be looking for with that turbo +10psi.

[speedfiend]

well i was going to go do some logging while cruising and show you exactly what the a/f looks like but my clutch line split tonight so i am gonna have to put that off for about a week. I havent really logged anything while just cruising at a certain throttle position so im not sure of the exact a/f #'s there. I have datalogged at WOT in 3rd gear all the way to redline and it runs super rich in the low rpms and slowly decreases till it crosses over to lean at about 4700rpm and then progressively get leaner till redline. I also dynoed my car a while ago and this was the same result on their a/f logger so I know it is correct. I will try to get you exact numbers for the a/f on the WOT run or post up the dyno sheet if I can find it so you can get an idea of what im dealing with. Thanx, Cameron

[speedfiend]

Ok well I found the dyno graph from awhile ago. This dyno was done when I didnt have the z32 maf and my vtc was not functioning properly but everything else was exactly the same and this is what my recent datalogs look like as well. Oh and the dyno was done in 4th gear and my datalogs were done in 3rd. Let me know what you think. Thanx, Cameron
http://img.villagephotos.com/p/2005-8/1060738/dynograph.jpg

[kuramaya]

You need to concentrate on full throttle/boost AFR's first and not worry about the cruising ones. Try and get it to 11.5:1 or as close. Set your Throttles to Low 25% and High 50%. Don't use up your NE points in the Low RPM Levelsm its a waste, the ECU Corrects anyway during closed looop. use them for the higer points. I used an SAFC with same mods and 256 Cams succesfully for almost 2 years. Set your points at 1,000 - 3,000 - 3,500 - 4,000 - 4,500 - 4,750 - 5,000 - 5,250 - 5,500 - 6,000 - 6,500 - 7,000.

[johngriff]

From the looks of that graph, you are actually pretty lean to really rich.

You could stand to be richer in your midrange (3-4.5k), then you need to lean it out up top, you can see that you are losing alot of torque from being so rich.

[steve shadows]

you can see that you are losing alot of torque from being so rich.

The real problem with you map is apparent in the torque and hp curve being so choppy and is more related to timing and modifications beyond the stock ecu's pre-tune.

also take into consideration your Fuel Pressure at the higher levels. Ive tuned several sr's 3 years back with AFC's and widebands and as long as the fuel pressure would rise with the increase boost the AFR would not be compensated with adjustments to the AFC. Ive even ran AFCs down to -50% all the way across and they were still at the 10.1:1 afr threshhold. Get something to turn down your fuel pressure, like an sard fpr if this is the case.

An ECU tune with a more appropriate timing map is in order, or a re-check of your base timing via cas is a good start.

hi-low throttle settings (as long as high throttle is set under 95% and TPS base voltage is correct ) will not affect hp or full throttle afr on dyno btw.

[speedfiend]

Thanx for the reply's. I will check my base timing tomorrow and post that up and see where I should go from there. Thanx for the help. Cameron

[steve shadows]

Thanx for the reply's. I will check my base timing tomorrow and post that up and see where I should go from there. Thanx for the help. Cameron

In my experience eliminating the choppyness is almost impossible without some direct contorl of Timing or timing map manipulation and the AFC is not your man for the job.

[speedfiend]

Yeah I know Im not goin to be able to get the choppyness of the curve eliminated but I have all this equipment and the car is running to lean for it to be safe to run hard on the street so I would atleast like to try and richin it up in the low end so that im not risking detonation everytime Im WOT. Thanx, Cameron

[johngriff]

What are your highthrottle settings?

[speedfiend]

What are your highthrottle settings?

Honestly right now the safc is set to 50% hi thr. If that is what your asking. If you are asking what my correction values are for the hi thr. settings, i dont have any as of yet. I havent had a chance to run it and set any corrections yet cause the clutch line split yesterday. Thanx, Cameron

[johngriff]

So you are set to 0 accross the board then?

[speedfiend]

Yeah I am completely 9 all the way across the board right now.

[johngriff]

Its kind of hard for me to give you a heads up on settings since the dyno you did was done without the VTC, if it hooked now, your output is different (it would also explain why the torque is so low in the high end).

But, if you leaned out the map in the high end, it would advance the timing, which might give you more torque. That would have to be set up on a dyno to see real results, im sure its probably just the vtc.

[speedfiend]

Yeah I figured the torque drop off could be due to the VTC not being activated. But as for the fuel curve it is the exact same with the vtc activated. I did a WOT run in third about a week ago and datalogged it to compare that to my old dyno shit and it is almost identical on the afr's. My laptop crashed since so unfortunately i dont have the datalog anymore to show you that as well. I understand that you wont be able to give me any exact numbers but that is why I have a datalogger and I will do some runs and datalog that and go from there and adjust slightly at a time. Im just wondering with the whole timing issue, if I add or subtract enough fuel in order to correct the afr's across the board do you think it will have that detrimental effect on my timing since it wont be controlled except by the ecu. Thanx, Cameron

[johngriff]

Typically under load. When you remove AFM signal (so minus) you will advance the timing. When you add fuel, you will retard the timing. This isnt really a absolute truth since you have no way of knowing exactly where in the timing map your new value on the AFC is placing you.

So, adding in the mid throttle is a must, it will retard the timing(probably), and you will probably see less torque, though the AF/R's should be happy and you will be doing less damage.

On the top end, as you lean it out, you will be advancing the timing, and that is where I would be super careful. If you can get back to the dyno, that would be awesome, but in reality you need a better controller, or maybe just a ROM tune to get a better starting place.

[speedfiend]

Alright well my car is back up and running. I am going to go grab some new spark plugs today. Im getting the ngk iridium bkr7e plugs. I should be able to do a couple runs in the next day or two and I am gonna try and get my fuel curve a little better. Thanx a lot for the input everyone particularly johngriff. I am going to take your advice and richin it up in the low end and mid range since this wont be too detrimental to the timing. Then on the top end im just gonna lean it up very slightly just to pull a little fuel out of it. But im not gonna try to pull it back to 11.5 afrs since this will cause too much advancing of the timing and its not worth it. I wont be able to put it on a dyno for awhile so as of now all I will have is the datalogs. I will post up the dataloggs as I get them and show everyone the results. Thanx again for all the help. Cameron

[BigVinnie]

Oh and the dyno was done in 4th gear and my datalogs were done in 3rd. Let me know what you think. Thanx, Cameron


Why was the data log ran in 3rd gear and the dyno in 4th? In 3rd gear it would be a different LOAD, then if it was in 4th gear. This throws off your A/F ratio to the kind of power your showing on the dyno.

[speedfiend]

I datalog in third gear because im on a closed road and it is easier to run third to 90 then 4th to 120. As for the dyno Im no expert on which gear it should be run in so the guys at the dyno ran it in 4th. As for the a/f ratio I will be datalogging and tuning in 3rd gear. Once again this is being street tuned not tuned on a dyno. I just ran the dyno a year or so back just to see what kinda power I was putting down and that is when I discovered the horrible fuel curve. I got the ngk plugs so I just gotta wait for the car to cool for a bit so that I can install those and I might make it out this afternoon for some runs. Ill keep you guys posted. thanx, Cameron

[speedfiend]

Well got the plugs changed and figured I would post up a pick of what the old ones looked like.
http://img.villagephotos.com/p/2005-8/1060738/Picture204sm.JPG
As you can see from how white the tips are I am definately running lean. Hopefully I will be able to remedy that to a certain extent. By the way I replaced the plugs with the ngk bkr7e plugs. Cameron

[speedfiend]

I was wondering since I have the sard fpr should I raise the fuel pressure slightly before I do the tuning or should I just leave it at stock before and after tuning? If I should raise it what should it be raised to? Keep in mind this is stock injectors. Thanx, Cameron