Please read this log !

[chanley talon]

Rpm kn tim 02 Please help me decided what to tune to make this better . Thanks!
1875 0 23 63
2250 0 24 76
2750 0 24 78
3250 2 21 80
3781 1 17 80
4300 5 17 80
4800 10 14 78
5156 10 15 78
6000 9 18 78
6700 8 15 78

 

[donmagicjuan]

First of all, you will need to post a lot more data points if you want to get the best advice. There are too many gaps in that short list of data to be able to effectively understand what's going on with your engine.

Secondly, what boost are you running? Also, what are you using to adjust your fuel? I see no device in your profile, yet your O2 voltages would indicate you are running extremely lean. Keep in mind that tuning by O2 voltage is really just a crap shoot. The stock narrowband sensors were never designed to read accurately at the AFRs you need at WOT. It looks like you are seeing a lot of knock from the onset of full boost all the way to redline. I'd be willing to bet it's because your engine isn't getting enough fuel.

Lastly, your profile states that you have a 255 lph fuel pump with no AFPR. With the stock fuel pressure regulator, you will not be able to get a consistent tune due to erratic fuel pressures that do not rise 1:1 with respect to boost pressure.

My recommendations are

1) Get an AFPR for your larger than stock fuel pump,

2) Turn down the boost if you are running higher than stock levels, and

3) Post a log with more data points to better enable us to help you.

 

[chanley talon]

This car is not in my profile ! This is my brother in laws dsm . We were just looking to see how out of tune it is . But he does have the same mods as my car accept he is running the evo3 16g . He has a areomotive fpr and 550s will be here in a couple of days also hes running a 2 gmaf and he does have the super afc as well . He boost is set at 20 psi and it will hold it perfect. His car seems to have lower compression than mine.
So if the 02 volts dip low does this show a lean condition ? Thanks for your help.

 

[donmagicjuan]

Yes. Are you saying that he's running a 2G MAS with stock injectors until the 550s arrive? If that is the case, you will actually need to ADD fuel with the AFC, as the 2G MAS will report an airflow signal that the ECU interprets as roughly 20% lower than the 1G stock unit. The two units are calibrated differently. When you install the 550cc injectors, everything close to cancels out. This would explain why you're running lean. Again, I don't condone tuning like this, but I believe a target AFR of 11:1 corresponds to about 0.92-0.94 volts from the narrowband O2 sensor. By your voltages in the log I would guess you're in the neighborhood of 13:1.

Also, if you're still on stock injectors, 20 psi from a 16G is more than they can handle. This would also contribute to the lean condition. A good rule of thumb is roughly 15 psi on 450s, but you need to confirm this with a knock-free log.

 

[chanley talon]

Not understanding the 11.1 afr please explain. he has his fuel cranked up all the way in the hi settings .

 

[donmagicjuan]

The optimal AFR for a turbocharged engine is about 11:1 under WOT with pump gas. This is what you need to tune for with the AFC. This AFR corresponds to something around 0.92-0.94V from the front narrowband O2 sensor.

It doesn't surprise me in the least that you are having to add as much fuel as possible with the AFC. The stock injectors are being severely overtaxed, which is extremely unsafe. Not to mention it's still not enough fuel to prevent knock. You MUST lower the boost if the engine is going to survive much longer. Do not turn it up until you have larger injectors.

 

[chanley talon]

He dont drive it much the 550s should be here tommorrow . What 02 vaules should i look for to understand if im running rich or lean? Thanks for your help. So somewhere on the afc it tells me the a/f ratios. Boy i bet you think i sound pretty stupid.

 

[donmagicjuan]

Not stupid, just new to tuning. Don't worry about it, everyone has to learn sometime. A wideband O2 sensor would be the best device to assist you with correctly dialing in AFRs. Without one, you just have to guess based on the O2 sensor voltages. Basically, anything less than ~0.92 V is too lean, and anything closer to 1.0 V is on the rich side.

Here are some threads that cover the basics of the process, which you might find helpful:

http://www.dsmtuners.com/forums/showthread.php?t=105569

http://www.dsmtuners.com/forums/showthread.php?t=58403

For future reference, they can be found in the how-to section of the Tech Articles.