mooreboost

iTrader: (6)

I was reading this site on tuning the SAFCII on the Evo 8. It suggested using an OBD2 data logger and reading the stock o2 sensors readings and tuning off of that. I always thought that was a bad idea beacuse narrow band o2 sensors arent accurate at all. Are they accurate on the Evo, or is that site incorrect? It would be better to go with a wideband, right?

wprettyboy

iTrader: (17)

wideband!!

evilution310

there accurate because the ecu uses them to adjust from rich to lean in closed loop, but there not AS accurate as wideband I guess.

marksae

iTrader: (12)

Narrowbands are only accurate around the 14.7:1 air/fuel ratio range, which is the target AF ratio in cruise mode. They're not very accurate beyond that ratio. That's why they're called NARROWbands.

At WOT, the leanest you should tune to is around 12:1. So you'd need a wideband o2 sensor to read the AF ratio accurately.

It's probably a good idea to have both a wideband and pocketlogger. When doing your own tuning, you'll need to monitor knock, timing, and AF ratio.

turbolarry

iTrader: (1)

If you can only get one... get a logger. It tells you more information critical to tuning then just A/F. At WOT pulls, in 3rd gear, log; RPM's, timing advance, and O2's.
http://www.evotuners.net/forums/showthread.php?t=315
You can tune very well this way.

EVO8LTW

iTrader: (41)

I'd vote for the wideband over the pocketlogger, if you can only afford one. Assuming you are tuning an SAFC with a stock ECU flash, you can use the wideband to tune to a safe AFR like 11.0-11.5 and you don't need to worry much about the car pulling timing. If you are really going to get aggressive with the AFR or turn up the boost to 21+, then a timing logger becomes more important. A pocketlogger is only $175 or so. Is it really worth skimping?

RichJ
04 Evo RS Buschur Stage 4 w/Pocketlogger, wideband, SAFCII and mail-in Dynoflash

mooreboost

iTrader: (6)

Well even if I did have a pocketlogger with a wideband and a SAFC, and I realized my timing wasn't very good, then theres no way I could adjust it with the SAFC correct? Aside from adding fuel to reduce knock?

EVO8LTW

iTrader: (41)

If you have a stock ECU, the only timing issue that you are going to have is not enough (maybe it'd be different with 91 octane -- dunno). But, generally, when you pull fuel at high throttle timing is going to tend to be advanced. If you pull a lot (say you have larger injectors), it will advance a lot. If you add fuel, you'll tend to retard timing (which tends to work out nicely).

Not a perfect tuning solution, but with 660s and an SAFC you can make some good power on a stock ECU flash (see Buschur's results). Probably better to just get a reflash though from a $/! standpoint.

Blak94GSX

It is more important to know about the timing and the fuel trims than just knowing what the AFR is. Ideally you have both, but in my opinion, if you can only have one, get the data logger.

EVO8LTW

iTrader: (41)

Why would you care about fuel trims if you are tuning for wide open throttle? That really only matters if you were trying to dial in the low throttle tuning for bigger injectors, fuel pump, etc. Am I missing something?

Blak94GSX

Well the assumption here is that you have something to tune with, like an AFC. If you don't have anything to tune with then you don't need any gauges since there is nothing you can do about it and ignorance is bliss.

mooreboost

iTrader: (6)

Why would I worry about timing if its going to be retarded? I realize it wont make as much power but its a hell of alot better than knocking.

I would rather know my AFR and let the ECU retard timing as needed, for safetys sake.

marksae

iTrader: (12)

Your ECU retards the timing because of knock. You can have a nice safe AFR and still knock if your timing is too advanced.

marksae

iTrader: (12)

Also, if your boost is turned too high, timing retard from the ECU ain't going to be enough to save your motor.

mooreboost

iTrader: (6)

Does this mean an SAFCII is not a good tool for tuning on an EVO?