I have a Simtek on my 04 STi and keep getting the inclination to replace the narrowband with a wideband so it stays in closed loop(i believe this is what it does)

Is it worthwhile????
What exactly is the benefit of doing it?????
If it stays in closed loop does it mean better fueling????

Cheers

 

From my limited understanding of widebands:

1) It won't last more than ~500 hours if it's anything like mine. (The manual warned me)
2) The voltage output is wrong for your ECU. Mine can be fudged but only to behave as a narrowband (It's an LC-1)
3) It won't make the car stay in closed loop. Be interested in what data you have indicating otherwise.
4) I don't have a Simtek, ergo I'm going to 'guess' that it isn't using a MAF so by definition you don't have closed loop since for AFRs it needs to read the engine load for which it reads the MAF when in closed loop. Anyone jump in and correct me if I'm wrong..

 

Don't know anything about Simteks since we've got none of them here in Latvia.
If Simtek really does not support closed loop w/o wideband and does with, than your benefits will be:
higher mpg, especially on highways / cruising
more precise control for the fuelling, i.e. some corrections for a dirty air filter, etc

aXeL:
1) I don't run my wideband constantly, but I know people who do and they run 10 to 20 thousand miles on them if installed correctly
2) Wideband will need calibration for the ECU if it doesn't have a calibration already.
4) Don't know about Simteks again, but if ECU is running on MAP, than load is MAP-based. The principle is the same: ECU is calculating fueling based on load and map values and then makes corrections based on o2 sensor feedback

 

If you are on an new age STI with Simtek, then aren't you already running wideband?

 

1) Interesting - Which model widebands are these? I want one!
2) I wouldn't be surprised if the SIMTEK can read the lambda in full wideband mode. SIMTEK gurus?
4) True, again if it has CL mode.

Having never had a MAP based ECU I must confess I don't understand why I'd want one. My MAF based ECU is reliable, it measure's the real airflow rather than guessing, I can rescale it when I alter the induction and it enables load to be measured rather than guessed. Ergo my AFRs are calculated based on real values rather than guesses. And finally, when the car switches to OL it applies all the learnings from the properly measured values rather than making more guesses. I'm obviously missing something otherwise people wouldn't go MAP based. I can understand for Mk1s with the unreliable Subaru Lambdas but that's not an issue for an 04...

 

Simtek runs closed loop with OEM narrow band sensor to achieve AFR 14.7 within user selectable range.