gs400 civi

iTrader: (4)

hey I was just talking w/ a friend/ coworker about A/F ratios and the SAFC etc. wht I'm wondering is, right now I know I'm running way rich, most likely because of the 550cc injectors whoever put in for whatever reason, and the SAFC doesn't have enough range to lean it out enough. I know I can go full stand alone and control everything including the vvti and timing etc. but is there something in between? something that will at least control the a/f stuff so I can have optimal ratios at WOT? maybe include some other functionality like timing control or even vvti? I'm probably just going to get some 370 cc injectors to fix this issue

JeffTsai

iTrader: (1)

As I told you last time. The only in-between a SAFC and a standalone is going to be a AEM FIC or a Greddy Emanage Ultimate. Thing is, those cost almost $600-700 or so after the boomslang harness. For about $500-700 more you can get a standalone.

gs400 civi

iTrader: (4)

with the AEM or emange ultimate, what will they control? would they use the same wires from the ecu? If I were to go stand alone now it would be overkill cause I don't have time to do internals, whatever else I would need for my pressure, so I'm thinking I should try smaller injectors or go this rout. Also with either of those, if I, (whenever I get back from overseas) do the internals these will still work/ could be sold?

RMMGS4

iTrader: (5)

I previously recommended you go smaller injectors if you are sticking with the SAFC

I used an E-manage without the boomslang. Just wired directly to the harness. Total wire length = 6"

ROPADOPA

What is your fuel pressure?

You should be able to lower your fuel pressure and if you have a good o2 sensor you should be able to get some control with your afc.

This also helps if your running a wideband and you can actually know weather your rich or lean at what events.

speedaddic

iTrader: (10)

I'm going with the AEM F/IC 8. It can control injectors 100% larger, but your injectors may still be too big since factory injector on the GS400 is 240cc. Like Jeff said, you might want to go with a full standalone but you'd still use your factory ECU to run AC and a few other controls.

gs400 civi

iTrader: (4)

how do I lower My fuel pressure?

speedaddic

iTrader: (10)

aftermarket fuel pressure regulator, but that may require a return fuel line.

gs400 civi

iTrader: (4)

ok update, I was told I have 550cc injectors and fuel is pulled back 50% by the SAFC at 6000 but its at like 9.6, I looked at the injectors and they say SL2-310, so they are 310 CC? if so why is it running so rich with that much fuel pulled back? I'm thinking that maybe that's just what's written on the connectors? is that possible.

speedaddic

iTrader: (10)

that sounds more like it. 550 cc would barely idle on our cars without standalone. They are 310cc. You figure 240cc is stock, you're not in boost until higher RPM so I'd pull back even more fuel at idle and start adding gas at 1500-2k rpm. I believe the GS likes to idle at 14.7-15

gs400 civi

iTrader: (4)

I've pulled back fuel as far as I can, my question is if those are 310 cc injectors I should be adding fuel not having to pull back

gs400 civi

iTrader: (4)

its been suggested that perhaps my stock regulator is malfunctioning, does anyone know how I can test/ fix this? unless the markings on my injectors are just on the connectors and they are acually 550CC's, all this extra fuel I'm getting makes no sense. Aso, yesterday i was messing around after work, it had just rained and was like 78 out, I did one pull from 2500 to 6000 in 2nd and my A/F was 11.6, everytime since, 9.6 to 10.2

JeffTsai

iTrader: (1)

The thing with the SAFC is that the tuning isn't very consistent nor accurate. All you're doing is skewing the MAF signal. The stock ecu has so many different maps, I'm talking like 20+ or more maps for different conditions. Cold temp, hot temp, safe mode, high octane, low octane, and too many other ones to list. If the ecu changes to a different map then the tune on the SAFC will be no longer correct. Another thing I've experienced with the Lexus ecu is that if you use a fuel controller that modifes the MAF signal only, you will get to a point where you pull back too much fuel and the ECU goes into one of its failsafe maps. For example if you're trying to run 550cc injectors which are nearly 2x the size of stock, and the stock MAF voltage is 1.0v(for example, not actualy number) at idle. Then you put in the 550cc and set the MAF voltage as 0.5v at idle, the ecu will see that that's not possible becuase there's a certain tolerance range set in. It has an internal "correct" range of 0.8v-1.2v at idle. When you go out of that range, the ECU generally goes into a failsafe mode and runs the engine rich even though you're pulling out as much fuel as possible with the SAFC.

So, in short the SAFC isn't great for controlling bigger bigger injectors. The AEM FIC and Emanage Ultimate skews the fuel injector pulse directly without altering the MAF signal at all. So in this case the idle MAF voltage still stays at 1.0v, but the fuel injector pulse at idle is 10ms for the 550cc instead of 20ms for stock injectors(again, not actual ms numbers, just an example of how the system works).

The markings on the injector indicates what CC they are. If it's an RC engineering injector it's usually engraved on the injector itself. If you saw the SL2-310 on the injector then I assume it's the RC injectors because that's how they code their injectors. Under WOT, the optimal AFR should be around 11-12AFR range. I usually target around 11.5AFR across the board under full load.

speedaddic

iTrader: (10)

great info Jeff, and on all my boosted cars are tuned at 11.5 across the board ( it goes a little lower when the meth kicks in ) and 13.0 all motor.

JeffTsai

iTrader: (1)

Oh yeah while we're on the subject of tuning tips I'd like to clear up a myth or big misconception. Leaner isn't meaner. On most engines, there's a pretty wide window where you will make power. Generally around 10.5-11AFR to 13-13.5AFR you will make the same amount of power. Some people think tuning on the lean side will give you more power which is actually false. The reason that running leaner on a factory ECU makes more power is because of the timing. When you bump it into the lower load cells(tricking stock ecu to flow less fuel or go "leaner") you are in the range of cells on the map where there is less fuel but also higher timing. Engine are usually tuned to have higher timing and lower fuel injector duration when cruising. The opposite is true when you go full throttle and the engine pulls back timing and adds more fuel. So when you tune it lean, you are essentially bumping down a few steps in the map where there is less fuel and more timing. The timing is what gives you power, not the fueling. If you run a standalone where you have complete control over the timing and fueling and sit on a load bearing dyno. If you hold the engine at the same RPM, you can see that the engine will make the same amount of power from that 10.5-13.5 AFR range when the timing stays the same. Some engines have a narrower window so maybe 11-13AFR for those engine, but my point is that fueling isn't a major contributor to how much power you make.

However, fueling is VERY important in terms of heat management. The reason all these turbo/superchaged cars run 11.5:1AFR under full boost is to cool down the combustion chamber. You can make the same amount of power at 13.5:1AFR on the turbo, but the engine would probably melt within one or two pulls on the dyno. You just need to be careful that when you lean out the stock ecu that your timing doesn't go too far out of hand or else you will have pieces of the engine shoot out of the block lol.