wideband tuning...quick q's

[LRS95TSI]

i have two q's...
1) when i reach full boost, should i still b at a good afr like mid 11's or should i be rich/lean?
2) i've noticed quite a few ppl that their afr goes rich in high rpm's around 10's with still good timing, is that correct?

i am curious about these two questions because i am experiencing both, and im heading to the track tonight...kinda need it to be ready! unfortunately my timing still is below 15 between 3600-5000 rpms.

 

[NewB2dsm]

It seems that on our cars the AFR makes little difference in power as long as you are not pig rich. The power comes with boost and timing. But a mid 11:1 afr is perfectly ok.

I was running 11.5:1 on pump gas (20psi) and 12.3:1 on 110 leaded at 26psi. The real power gain is from boost not the afr, unless like i said you are running sub sub 10:1 afr.

 

[LRS95TSI]

my buddy said to richen up my midrange. but what im confused at, is if my afr is good in midrange, where the hell is the timing?

 

[andymoraitis]

my buddy said to richen up my midrange. but what im confused at, is if my afr is good in midrange, where the hell is the timing?

Your air/fuel ratio may be good in the mid range, but is it correct for your setup? What we need to know more than anything else is if you're getting knock. Hook up a logger, look for dips in timing and that'll tell you whether you're too rich or too lean. It would also be helpful to us to know how much boost you're running. Finally, are you only using an AFC to correct for those 680's? If so, you could be jacking the timing enough to cause lean knock or leaving it so rich you're inducing rich knock.

Let us know and we'll try to help,

Andy

 

[LRS95TSI]

ok heres an indepth description....
at -38 on my afc, the car pulls really strong throughtout rpm range, i get good timing above 5500 rpms, however my midrange rpms still suck. heres a test i did...
i richened it up in midrange to like -26 on afc. my timing went lower then before but my airflow went up. when i lean it out to -35, my timing goes up by 2, but my airflow goes down. i am still seeing lower 10's on my wideband even at -37, and low 9's when i richen it up. i honestly have no idea, i thought as i approached the necessary afr on my wideband, my timing and airflow would go up??? is my dsm cursed? or am i just an idiot!?

 

[WhiteTsiAwd]

IMO, I think that your problem is because of the AFC. Your telling the ECU that there is so much less air flow then what there really is and its causing a lot of timing and knocking. 650's are about the max for a AFC. So maybe try getting some smaller injectors or going Standalone.

cody

 

[2gGSX]

don't forget a chip or dsmlink will fix your injector compensation problem too

 

[94Jettameowpsst]

My car was VERY hard to tune without a chip, with 650s i saw timing as high as 31deg advanced at 23psi on pump. As you can imagine, it had some knock to it

 

[LRS95TSI]

im honestly ignorant about chips, can some1 explain them or point me in the right direction? i mean should i have good timing throughout rpm's?

 

[94Jettameowpsst]

When you get a bigger injector the deadtime is higher (takes longer to open) so a chip compensates for that so instead of tricking the ecu into thinking its stock, it then performs like its stock and you wont have to use such a large correction factor. Im not sure why it raises timing but the more you lean it out without having a chip, the higher it goes. So you either run ## car pig rich and have normal timing, get an afpr and lower ## fuel pressure cause that sorta has the same effect as having a chip (it just lowers ## timing), or you get an eprom, or if you have one, splurge that 100 bucks and get a chip from keydriver or something. Hope that helps.

 

[spyderturbo007]

Wow, some of these responses are confusing.....

Anyway, I'd like to clear some things up.

i richened it up in midrange to like -26 on afc. my timing went lower then before but my airflow went up. when i lean it out to -35, my timing goes up by 2, but my airflow goes down.

This is normal. You have to think of the ECU as a large set of spread sheets. Essentially what the ECU does at WOT is use g/rev of airflow to calculate fuel delivery & timing. The higher the mass of air the ECU "sees", the lower you go on the timing map. This is done to protect the engine.

On the other hand, the SAFC-II lies to the ECU about air mass. So when you richen up the AFC, the ECU sees more air then before and drops you into a lower timing map. When you lean it out via the AFC, the ECU sees less air than before and places you on a more agressive timing map.

You have to remember that the airflow you see on your logger IS NOT CORRECT. The AFC modifies the signal before it reaches the ECU. After the ECU receives the molested signal from the AFC, it then sends that information to your logger via the OBD-II port.

So, like I said above, when you lean out the AFC the ECU "sees" less air and therefore YOU will see less air on the logger. So when you richened up from -35 to -26, the ECU received a higher airflow signal from the AFC and dropped you into a lower timing map. It then sent the higher airflow number to the OBD-II port.

im honestly ignorant about chips, can some1 explain them or point me in the right direction?

As you can see above, there is a trade off with the AFC. Remove air to compensate for larger injectors = higher timing. And high timing and high airflow, VE, etc = bad.

Chips are designed to remove this danger. The chip compensates for the injectors and DOESN'T jack your timing.

The ideal situation with the SAFC is to "feed" the ECU an air mass value above 2.1g/rev. This will place you on the lowest timing map and help protect the engine. On this map you will reach a max of 16 degrees at redline (Depending on factors such as knock, IAT, coolant temp, etc). The problem is that if you flow more air, you need more fuel......i.e. bigger injectors. To compensate for larger injectors you need to remove more air and so on....

So you can see, it's a vicious cycle.

Wow, that was fun. My brain hurts....

Hope something in my rambling helped.

 

[LRS95TSI]

that did clarify things, but my ultimate decision is...
right now i dont have the money for more parts...should i continously lean it out using my wideband and shoot for better timing? or is there something else i can do?

 

[spyderturbo007]

.should i continously lean it out using my wideband and shoot for better timing? or is there something else i can do?

You need to find a nice balance.

Most Eclipse's like an AFR around 11.3 : 1 (or at least in that neighborhood). Being you have a 2g, I would concentrate on timing. 12.0 : 1 might look good on the WB, but if your knocking like a SOB you're not going to go any faster.