SAFC Neo - Toyota Nation Forum : Toyota Car and Truck Forums

SupraTuned · 02-10-2010, 09:24 PM

Ok, well, I know that this is going to be a loaded question.

So, a few months back, I asked about using a AFC for tuning the lex/550cc mod.

I have a zeitronix wideband system with a digital display, and an egt probe.
I have the AFC neo.
I have 550cc siemens injectors
I have the Aeromotive regulator

I don't think anything else really pertains to this question.

So, I drove the car with stock settings to the dyno, the car drove well and seemed content with the upgrades.

My question is one of tuning. The guys at the shop are supposed to be so knowledgable, but I asked them for some basic numbers in case my system got reset or something.

I asked them to jot down the ranges that they corrected on the neo for the engine for under acceleration, normal and hard, through all the adjustable RPM ranges.
Sooooo......basically, anything set to below 1000 is set to 14.5:1, which is basically idle. Ok, that seems fine
WOT is is set to 11.5:1, which in my opinion, is a safe way to go for a street car in case of boost spikes.
As I looked through the settings for 1500 on up to 6500, some of the increments were adjusted richer, and some were left with no correction.
I did notice under normal acceleration that it was running a little lean on the display, although egts stayed at about 1000F.
I called them, and asked them what their rationale was for not tuning in the 1500-6500 range very much. They really didn't give me a good answer, said that my egts and a/f ratio was fine. That really didn't answer my question.

So here is what I am really looking for; I understand what the two polar opposites for a/f ratio are basically: richer 11.5-11.7:1 for WOT and about 14.2-7:1 for idle and cruising, since this seems to keep the engine happy.

But now, since I would like to tune safely and not too much on the optimal performance side , what are the best ratios to look for in terms of light to medium accelarion throughout the range above (1500-6500)? I asked a few guys that tune around here, and they said they would show me sometime this summer, but I need to get it running top notch now.

When I look around on the internet for our cars, all I see are the nominal values that I listed above (11.7:1 WOT, 14.7: cruise/idle). I think that under light to medium acceleration, (normal driving) maybe 12.3 or so would be a good correction....But I don't want to guess, and the guys at the dyno do not seem very intelligent to me. Anybody want to share what good ratios would be for everyday light to medium acceleration through the power band?

funky_monkey58 · 02-11-2010, 08:06 AM

Quote:

Originally Posted by SupraTuned

.But I don't want to guess, and the guys at the dyno do not seem very intelligent to me.

If the car is running good now, leave it alone.

emiliorescigno · 02-12-2010, 03:03 AM

Quote:

Originally Posted by funky_monkey58

If the car is running good now, leave it alone.

+1000000

***bgrieger*** · 02-13-2010, 09:13 AM

The reason you dont tune mid throttle is because you can't on a piggyback. At idle and WOT, the ECU is running closed loop where Xairflow=Yfuel. Since no other meters are reviewed, if you tell it you have different air flowing it will automatically provide or remove a corresponding amount of fuel. Any throttle position in between and the ECU starts watching the throttle position, O2 and other sensors that all will give the ECU data that it will interpret to try to modify air and fuel dynamically to keep it inside the factory specs of the fuel maps.

So, if you took out some fuel or added some fuel, and the O2 sensor noticed the change and the ECU didn't like it, the ECU would simply add or subtract more fuel on it's own and override what you set up in your piggyback. This will keep happening up to the preset limit the ECU can compensate for. Beyond that it will not be able to tune, and might throw a CEL or store a code on you...or kill the motor from detonation.

This mid throttle tune is actually why Reg Reimer originally sold a screw set for the lexus AFM...The 25% +air and fuel from a lexus/550 mod isn't a perfect 25% every time, and so you could use the screw to tune the base ratio so the air and fuel got back in factory balance and the ECU Vf signal started showing that it was not compensating too much (Vf is the ECU's signal for whether it is adding or taking out fuel...there used to be a little meter a member made for a while that anyone could monitor it with). Then, your piggyback takes care of the WOT and idle tune to finish the job.

And that's why they didn't tune it...if they tried, call them idiots and never go back...

Jeeves · 02-15-2010, 05:15 PM

The common logic on the SAFC's is using the switching point. The AFC's have a hi and a lo maps, and there is a setting for where in the throttle range it fades or switches between those two 'maps'. (It's been a while since I used an AFC, you'll have to forgive me, I forget the proper names of all the settings).

If you set the throttle settings between the lo and hi maps to occur at 67%/68% throttle then you zero out the lo map (set 0% correction for all RPM ranges). What happens then is the lo map is in the throttle range where the ECU still relies and tunes itself with the O2 sensor. Above 68% throttle (give or take) the ECU will go into Open Loop where it ignores the O2 fuel trim calculations from the O2 sensor. So, the ECU no matter how rich (OR LEAN! So be careful!) the exhaust is above 68% throttle won't tune out the changes you make with an AFC.

At that point the car will naturally shoot for 14.7:1 while cruising around, then when you go WOT (which is of course > 68% throttle) you can tune for 11.#:1 with the AFC and it won't change your setting since it doesn't use the O2 sensor at that point.

That's been the common logic for all the old school tuning.

SupraTuned · 02-20-2010, 08:24 PM

Well, I am looking at getting rid of the neo because it is not very flexible. I sold my maft pro, and I am just going to go the maft gen 2 route. I have heard good things with this one, and I think that it allows full tuning across the board. Thanks for all the input guys.

Jeeves · 02-22-2010, 01:11 PM

You can't tune any of them across the board. They all have the same issues. You're mis-informed. They all have the issue of fighting the stock ECU. Welcome to the issues of piggyback controls.

Unless they remove or fake the stock O2 sensor out to the ECU you'll always be fighting ECU correcting for 14.7:1 in closed loop.

SupraTuned · 02-28-2010, 11:07 AM

Yeah, that seemed to be the collaborative issue with tuning it. I know that they aren't intended for mid tune, I just though they would be a little more flexible than that. The maft gen 2 sounds to be a little more my speed. I am going to probably sell of my safc, its really not that great.

Jeeves · 03-01-2010, 12:29 PM

It's not that they're not intended for mid-tuning, they flat out cannot do it. They state in the Gen2 manual that they cannot be used to tune closed loop.

http://www.fullthrottletech.com/forumdisplay.php?f=57

I've not used the Gen. 2, however looking at the manual all it seems to be is a downgraded Maft Pro (the Pro could've been set up identically) and it doesn't seem to have a laptop interface.

Control points:
Gen2: 14
Neo: 16

+/- Range:
Gen2: 60%
Neo: 50%

Display on the AFC wins IMO, easier to mount with the smaller cable too.

Perks really are that you can convert the MAF from an LS# to the Supra. Other than that, it'll still report a karman vortex signal to the ecu.

SupraTuned · 03-03-2010, 08:46 PM

I know the gen 2 is really just a version below the maft pro, but I just want something to cut my teeth with. I don't need to accidentally adjust the timing or something since the maft pro has so many more options and settings. I think I will give the maft gen2 a try and see where it goes.