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[philhoward]

In a perfect world, 12/12.5:1 would be about right but when in open loop mode, it has to revert to an uncontrolled map; shame it's "too" rich.  By the sounds of it, mine isn't too bad after all (hits 11.5:1 over 6000rpm).

Only way round this is an aftermarket ECU at a guess and probably with a wideband if you want to control it to 12.5:1 or so at WOT.

[AndyStobbs]

Why not mess about with injectors? This is how development works, you try something evaluate and move forward - or backward if it fails.
My reasoning with smaller injectors is a reduced flow rate. Yes this would mean the ECU adapting on the fuel trims to bring the CL fueling back into line - a missuse of fuel trims - granted - but as long as they don't get to the point where codes get set its a perfectly good way forward.
The cost of standalone management is prohibitive, I like my car but its just a 12 year old vectra worth £600 on a very good day - can't justify the £500 bill for standalone on it. Also I would lose my cruise control, lose my immobiliser, lose my mpg display on the MID etc. etc.
I've got a wideband sensor kit anyway, I use it to evaluate the AFR after playing with the fuel pressure.

Increased VE is why its still making more power, despite running rich. The more air I can get into it the better - as clearly the fuel is already there, in excess.
Same dyno, same operator, different days probably months apart, but I know the set-up was accurate on both days as I challenged the operator on it.

I want to see the fueling in the 12.8 - 13.2 range ultimately, or very near to.
Exhaust does get sooty and yes it does stink when the CATS are removed.

[Kevin Wood]

Why not mess about with injectors? This is how development works, you try something evaluate and move forward - or backward if it fails.

Sounds more like trial and error to me. The first thing you need to establish is control over the process you are trying to optimise. Controlling fuelling in a specific part of the map by swapping injectors is a bit haphazard, which is why you can't have it working properly at both idle and WOT.

I also wonder if the fuel trims discovered under closed-loop operation are applied at full throttle? After all, they are there to cope with variations in the engine, fuel and exhaust system after manufacture, so that would be reasonable. If that's the case, this mechanism can't be used to correct the fuelling at the top-end. Might be worth keeping an eye on the injector durations and see if they are following the fuel trim.

The cost of standalone management is prohibitive, I like my car but its just a 12 year old vectra worth £600 on a very good day - can't justify the £500 bill for standalone on it. Also I would lose my cruise control, lose my immobiliser, lose my mpg display on the MID etc. etc.

Fair enough. You just have to accept the compromises that route will require.

I've got a wideband sensor kit anyway, I use it to evaluate the AFR after playing with the fuel pressure.

Good. They are great pieces of kit and you really are in the dark without one!

Increased VE is why its still making more power, despite running rich. The more air I can get into it the better - as clearly the fuel is already there, in excess.

It must have been very rich when standard, then. Judging by the live data, the MAF tops out well before maximum power on these engines, so I'm guessing it probably goes into Alpha-n at the top end of the map, meaning it would be expected to go lean(er) with better breathing. Who's to say what really goes on inside the ECU, though?

Same dyno, same operator, different days probably months apart, but I know the set-up was accurate on both days as I challenged the operator on it.

I want to see the fueling in the 12.8 - 13.2 range ultimately, or very near to.
Exhaust does get sooty and yes it does stink when the CATS are removed.

Yep, agreed. that should be where the power is best.

[AndyStobbs]

Yes its been rich right from day one. It was going off the scale even on the first ever dyno run. I have the graphs for torque and power on my photobucket, but not the ones showings
 AFR. Will upload them if they're of interest.
It is my feeling that at WOT the injectors are just given a duty cycle and run with it so long as WOT is maintained. With respect to load and Rpm of course.
It may be that the ltft trim is used to adapt fuelling at WOT, but as you say unless you wrote the map you wouldn't know.