HELP! Car is running like complete crap! (SAFC settings)

[sonicnofadz]

I've recently just installed 650cc injectors. With my old fuel injectors (stock 450cc) the car ran pretty strong (for 10 psi off the EVO 16G) and everything was well. BUT NOW, since I've installed the 650's, all hell has broken loose. I don't even know where to begin with the SAFCII settings! I don't have a AFPR, my fuel system is completely stock except for the 650's. My mas is a stock 1G mas, with all the honey combs intact, the silencer removed, but the can has been cut to expose the K&N filter. I have not touched the adjusting screw. I first tried leaving it all zero'd out on the lo throttle settings and the car started smoking from all the unburnt fuel. Now I've left everything around -20 across the board (for low throttle) and this seems to be ok, until I try to accelerate. Then I get 43 counts of knock and my car is bucking from all the timing retardation. I know every car is different in respect to SAFC settings, but can anyone tell me some basic setting that I could try or explain to me if I am running way too rich or way too lean? What are the major differences between low throttle settings and the high throttle settings? I've been researching other people's settings and it seems that high throttle settings typical run a bit leaner than the low throttle. Why is this? Could it be that I absolutely need an AFPR because my injectors are too huge to run on the stock fuel pressure? PLEASE SOMEONE MAKE A SUGGESTION. THANKS

 

[falcone4g63]

get a fuel pump

 

[sonicnofadz]

okay, can explain why I might need a fuel pump? Maybe the increase in pressure will make the injectors easier to tune?

 

[CanadianTSi]

Try putting your high's in the -30 area.

A 190lph fuel pump would be a good idea since the stock pump can't move as much fuel as the injectors can flow.

 

[NeoStreamGSX]

start w/ upgrading fuel pump...w/ stock pump you're starving your injectors...you would also need a wideband o2 sensor to correctly tune your settings.

 

[FourG63 97GST]

I dont see how adding a fuel pump will help his situation. he needs low throttle tuning not dumpin more fuel. at -30ish the injectors should act like stock but it may be too lean.
its not something your can guess. you need tuning and numbers to tune by.

you had the AFC before your installed the injectors right? or you did it all at once?

 

[DSMJim]

First off -20 on low is way too low, you shouldn't be more than -14% at 1000rpm and go higher from there as RPM goes up.

On high you start at -14 and at 3000rpm be around -18, at 5000rpm -26 and -33 from 6K onwards type of thing.

The reason your knocking so much is because your drawing the injectors back way to far on the low. Remember at part throttle your at lower fuel pressure and you don't need a very large negative to compensate for the fuel pressure. That is why the negative gets larger as the rpm goes higher because on high throttle your turbo will bump up fuel pressure 1psi with every psi of boost so the effect of larger injectors becomes a lot more when fuel pressure is ramped up 50% over base. (40psi to 60psi or there abouts...)

 

[sonicnofadz]

OK! I REALLY appreciate everyone's input. Everyone here seems like an experienced tuner and I highly value your advice! I am pretty good at dsm repair, but as far as tuning goes, Im lost. This is the first time my DSM has been up and running long enough to really start to tune things since I've bought it =) THE RESULTS:

I noticed that anything in the -20 range or LOWER in my low throttle settings causes MASSIVE KNOCK COUNTS, as in the 0 to -20 range (using 30% low 80% high on safc II). I received the lowest knock count while having everything in the -30 to -40 range (for low throttle). I don't know why this makes, I guess by ADDING too much fuel is causing the unburnt fuel to combust after ignition (evidence of rich knock)? Anyways the car runs a lot better now that I've taken away ALOT of the fuel. NOTE:

650/450 = 1.444444... This means that the 650's are 44% larger than my stock 450s. This also means (I think) that they are flowing 44% more fuel than the stock injectors. So it MIGHT make sense to have my low throttle in the -30 to -44 range to correct out all the extra fuel the big injectors are spitting out. Please correct me if I am wrong to assume this. I haven't really tried messing much with the high throttle settings yet, I am just trying to get rid of some of the knock that is occuring during low thottle driving conditions (so the car is at least drivable somewhat). I did notice however that knock appeared sometimes when my boost kicked in accidently in the 2800-3400 range (10 psi on EVO 16G) and turning the high throttle to around -30 (for 3000 rpm) caused the knock to disappear for the most part (like what was recommended above by CanadianTSI). So I am making some progress! If these settings seem like they are completely wrong, please let me know! Everything seems like it is a little low, but I guess these are really huge injectors. After I install my new knock sensor I will begin to tune with high boost (14-20 psi). I will have just have to hope and pray nothing breaks

Thanks again for everyone's input, IT REALLY HELPED ME OUT ALOT!

 

[sonicnofadz]

First off -20 on low is way too low, you shouldn't be more than -14% at 1000rpm and go higher from there as RPM goes up.

On high you start at -14 and at 3000rpm be around -18, at 5000rpm -26 and -33 from 6K onwards type of thing.

The reason your knocking so much is because your drawing the injectors back way to far on the low. Remember at part throttle your at lower fuel pressure and you don't need a very large negative to compensate for the fuel pressure. That is why the negative gets larger as the rpm goes higher because on high throttle your turbo will bump up fuel pressure 1psi with every psi of boost so the effect of larger injectors becomes a lot more when fuel pressure is ramped up 50% over base. (40psi to 60psi or there abouts...)

What you have said above is really confusing me. I don't understand what you said about the turbo "bumping" up the fuel pressure by 1psi with every psi of boost? Does this imply that the fuel pressure changes during acceleration? If it does change, I had NO idea that it did this. I was under the assumption that the fuel pump always outputted the same pressure, and the fuel pressure regulator helped maintain a constant output pressure. Am I completely wrong ? I'm not trying to be sarcastic in anyway, I'm just trying to learn more about tuning, and how the DSM fuel system works, because I have very little experience tuning.

 

[mtwollet]

You might want to try -10 on all rpm bands (lo& hi) until you can have someone (else) who knows what there doing take a look at your setting all cars are diffrent so you need to have it properly checked out.

but for the nfo heres my setup
lo band -16 on 1000rpms and -15 on the rest of rpms

hi band -13 on 1000 rpms -10 on rest of rpms

(DO NOT ASSUME MY SETTING WILL WORK FOR YOUR CAR AND FIX IT ) HAVE IT CHECKED OUT OR DO AS I SAID AND SET ALL YOUR CORRECTIONS TO -10 ON EACH RPM BAND AND ON LO AND HI SETTING EMAIL me maybe i' can help you some

 

[loreak]

I definately think you need to be in the -30 to -35 at least. Im runnin -20 and i have 660's and also a 2g mas which with a stock 1g maf thats another 20% from my settings which would make it -40. Now granted the ecu is going to adjust for idle and part throttle quite a bit so it could deal with being off by a decent amount, but full throttle should get lots of knock.

 

[allturbo]

I don't understand what you said about the turbo "bumping" up the fuel pressure

the stock fpr (when it isn't being overrun) will increase fuel pressure 1 psi for every lb of boost. For example, lets say you're boosting 15psi and base fuel pressure is 40. Whenever you hit 15lbs of boost the fuel pressure will be 55.

sonicnofadz, is your fuel pump at least rewired. Your injectors will not act like 650s because the stock pump cannot support that kind of flow. That's why people were saying to get a fuel pump. I say get a 190lph pump so your injectors can do what they were meant to do, then tune. btw my 660s are set in the -30s for high settings on a 16g.

 

[DSMJim]

What you have said above is really confusing me. I don't understand what you said about the turbo "bumping" up the fuel pressure by 1psi with every psi of boost? Does this imply that the fuel pressure changes during acceleration? If it does change, I had NO idea that it did this. I was under the assumption that the fuel pump always outputted the same pressure, and the fuel pressure regulator helped maintain a constant output pressure. Am I completely wrong ? I'm not trying to be sarcastic in anyway, I'm just trying to learn more about tuning, and how the DSM fuel system works, because I have very little experience tuning.

Yep your completly wrong. Your fuel pressure regulator has a vaccum line attached to it right? When your car is idleing at -20 vac (two inces in one psi) what is your pressure? If your base without the line on is 45 and you put the line on and your at -20 vac you got to 35psi because your back negative 10psi or 20 inches of vac. When you boost its exactly the opposite. Your fuel pressure inceases because the pressure in the vaccum hose (now a boost hose sort of thing) hold the diaphram closed with more pressure just like your blow off valve. THat increases fuel pressure in a direct relation to your boost level. If your base is 45 without the vac line on and you run 20psi of boost your at 65psi at WOT with 20psi of boost. Yes this is how it works.

Runnging -20 is too much on the low. You will only need -14 to -15 tops. You will need -33+ on the high side. Also try changing your high low point to 30 and 60 that is a more common level.

 

[sonicnofadz]

Wow, I really have to thank all of you for such good info!! I have learned alot about setting up the proper safc settings. I pretty much need to upgrade my fuel pump to properly tune with my 650s so I'll start there (along with a new knock sensor just to be sure). I won't try boosting above 10 psi until I have upgraded my fuel pump. I had no idea the stock FPR actually increased the output pressure using the intake pressure as a reference. I always wondered what purpose that little vacuum line served (I thought it was apart of some weird emissions thing). Thanks again for clearing everything up!