prana

Whats the best afr for the wrx my04 pre-boost (under 2400revs ?) I have it set to 12.71 but suspect perhaps slightly richer (12.2-12.5?) for boost ? Pulls along fine but turbo doesnt seem to spool quite as rapidly as I'd like for it ...

Scott.T

iTrader: (2)

Probably needs leaning out a bit to get the spool a bit quicker.
12.2-12.5 does sound a bit rich, but it all depends where on the load scale it's hitting. I wouldn't imagine it would be at the top end of the scale where the AFR's are close to what you mention.

Below is a screen shot from a stock 2004 STi map :

prana

Is your 14.25 in open loop or in closed - can you post your throttle position closed loop and calculated load tables ? I did think I was running to 12.71 a bit too rapidly. Nice map - very leaned.

Is there a reason why your transition is so gradual (same rpm - traversing load zone) ? Do you find it reaches boost quicker than the stock map ?

Scott.T

iTrader: (2)

These are stock base fuel maps.
Map above is STi.... SORRY, mis-read your post.
Map below is 2004 WRX, to give you an idea of the standard fuelling :

prana

No dramas.

Appears you are still running closed loop at 1200-1600 revs to 13.54? Do you find the engine labours harsh if you were coasting in that range? And when do you transition out of CL, what throttle and load ?
For example, pulling 4th gear at 40km/h ? What lambda you reaching at 1600revs ?

Interesting transition points throughout your maps.

Scott.T

iTrader: (2)

These are not my maps but stock maps lifted from OpenECU.

Transition points appear to be dependant on TPS and modified load, unless anything below 14.70 is considered 'Open-Loop' as per an apexi...

question : is this a threshold on the standard ECU if so can it be changed, as I've not spotted anything ?

Stock WRX has Closed Loop Exit set at :
Throttle position of 57.6%
Modified Load A : 156
Modified Load B : 88

Which must have input into the fuel load scale calulation.

Although I have not got my head round what's meant by modified load A & B in relation to the fuel load scale.

prana

14.7 in closed loop, my guess is stock tune transitions to open loop where map says 13.94, pretty common. This means most likely running around 12.2-11.9, very rich. I leave mine at 14.7 OL and still runs 12.20 at WOT (Actual lambda) not in load cells

I forget to answer your question - yes you can change these thresholds. You change value in table B, though I'm still perplexed by the scaling, I want to force all throttle positions and load scales below 2400rpms into closed loop for R&D purposes

Scott.T

iTrader: (2)

Yeh guessed you could change the TPS and modifed load figures and spotted your post on OpenECU where you were messing with the load figures.

But can you define the AFR where is switches from closed to open rather then using loads or TPS

prana

you can but not directly, you need to use the load and throttle position sensors, which is where the difficulty comes in.

For this Research purpose, I want to force all throttle positions and load below 2400revs into CL.

ZEN Performance

The closed loop control is much more complex than you give credit for. The decision to go into closed loop or not, is not really anything to do with the fuel map.

prana

Yup found that out the hard way - even affected the idle. I am trying to determine if there is a way but I'm seeing no's everywhere...

But do you know the answer to the original question ? The best AFR for torque under (as in no boost) boost range ? I don't have access to a dyno so can't measure the variations of torque vs actual AFR between the 12-12.9 range.

Scott.T

iTrader: (2)

True , there are about 5 different closed loop factors that are obvious and probably a few more that are not.