Edit/ Piggyback Tuning

[Pretzel]

Hey JB,

Sorry to have asked a question that seems to have stopped the discussion !

But it is something I believe we need to have an understanding of (Before any T's destroy engines due to sensors being asked to work outside their designed operating range !)

Can anyone answer the questions I posted above about the Edit working in Wideband with a Narrowband O2 sensor ? Street Tuner ? Anyone ?

Pretzel

[Lawsy]

Well even though its narrow band, it can still tell if its WAY to rich, or completely leaned out, guess for a while untill it manages to get the o2 within an accurate reading range, then then it can start getting fancy....

So what I'm just assuming is that the Ford PMC does a bit of spamming around with the AFR's untill it gets within its (oz sens) readable range.

I'm just guessing though. I have no knowledge of how it actually works, just adding some food for though untill someone who knows exactly what the answer is.

[Street Tuner]

Calculated VE% (Volumetric Efficiency) is the way it works

We know what the VE% of the engine is at 10psi (we tested and mapped it). We always ensure the injector delivers enough fuel for the VE% of the engine (plus headroom).

When the VE% of the engine starts to reach the limits of the stock fuel system (10psi map over 5000rpm) we reduce the system boost pressure to reduce the VE% and keep the fuel injectors in range.

Since we control the boost with the Edit, we also control the engines efficiency.

The narrowband voltage readout of the sensors ensures at all times that our calculations remain constant, and operationally correct. Dynowog would have seen that both our 8psi and 10psi tunes ran richer than stock.

that's a very simple explanation, but hope it helps

[Pretzel]

Lawsy,

The problem I see is that under power, the correct range is nowhere near what the sensor is capable of reading accurately (It is not calibrated or within spec to be taking readings that rich) Even the Ford ECU will only adjust using that sensor at cruise, under load it reverts to a pre-determined fuel load(I believe). Whereas we are being told the whole process is using this sensor to set mixtures, and keep them in check !

Thanks Street Tuner,

It's a pity I was not available to go to the Demo night at Herrod's, I could have asked in person ! Maybe next time ?

I still don't understand how this works(Maybe it's just me), the Narrowband O2 readings are only for cruise range (Lean mixtures), so how are you able to use it to set/confirm mixtures under power?

Also if you're using your calculated VE% to determine the fuel load required, does that not mean you are putting in a set amount of fuel(Set fuel map), which would not be adjusted by the ECU's learning process ? Does that mean it is operating the same as the factory ECU, and only self-adjusts under cruise ?

I have a heap more questions regarding how this works, but don't want to ask too many at once !

Pretzel

[Guest]

  Street Tuner said:

Calculated VE% (Volumetric Efficiency) is the way it works

We know what the VE% of the engine is at 10psi (we tested and mapped it). We always ensure the injector delivers enough fuel for the VE% of the engine (plus headroom).

When the VE% of the engine starts to reach the limits of the stock fuel system (10psi map over 5000rpm) we reduce the system boost pressure to reduce the VE% and keep the fuel injectors in range.

Since we control the boost with the Edit, we also control the engines efficiency.

The narrowband voltage readout of the sensors ensures at all times that our calculations remain constant, and operationally correct. Dynowog would have seen that both our 8psi and 10psi tunes ran richer than stock.

that's a very simple explanation, but hope it helps

<{POST_SNAPBACK}>

yes your tunes were ritcher than the std in that instance and much more acceptable than the ones that were in the car?

ve table adjusments are were its at and closed loop adjustments will work from there but as I said im still sceptical that the narrow band sensor is acurate enough to safely adjust full load mixtures? pls enlighten me even in a pm?

this is not to say there is a problem with the software just a problem with me getting my mind around it just as you have had a problem getting your mind around std injector size to rwkw potential?

you know in your heart that the narrow band works just as I know that that pretzel or I have never touched his injectors or anyone else to our knowledge!

look forward to a response dw

[Guest]

  Pretzel said:

Lawsy,

The problem I see is that under power, the correct range is nowhere near what the sensor is capable of reading accurately (It is not calibrated or within spec to be taking readings that rich) Even the Ford ECU will only adjust using that sensor at cruise, under load it reverts to a pre-determined fuel load(I believe).  Whereas we are being told the whole process is using this sensor to set mixtures, and keep them in check !

Thanks Street Tuner,

It's a pity I was not available to go to the Demo night at Herrod's, I could have asked in person ! Maybe next time ?

I still don't understand how this works(Maybe it's just me), the Narrowband O2 readings are only for cruise range (Lean mixtures), so how are you able to use it to set/confirm mixtures under power?

Also if you're using your calculated VE% to determine the fuel load required, does that not mean you are putting in a set amount of fuel(Set fuel map), which would not be adjusted by the ECU's learning process ? Does that mean it is operating the same as the factory ECU, and only self-adjusts under cruise ?

I have a heap more questions regarding how this works, but don't want to ask too many at once !

Pretzel

<{POST_SNAPBACK}>

what he said! :tosser:

seiously its just not cricket!!!

[Lawsy]

But.... hrmmm...

I always thought that if the tune is correct, or close to it (even if its a little rich), then the O2 reading is similar. Remember fuel in Doesn't = fuel out, its being burned. If the mixtures are near reasonable, then the fuel will be burned almost completely, I would assume... Well from a physics point of view that works, reality can be somewhat different.

[Guest]

  Lawsy said:

But.... hrmmm...

I always thought that if the tune is correct, or close to it (even if its a little rich), then the O2 reading is similar. Remember fuel in Doesn't = fuel out, its being burned. If the mixtures are near reasonable, then the fuel will be burned almost completely, I would assume... Well from a physics point of view that works, reality can be somewhat different.

<{POST_SNAPBACK}>

your missing the point there lawsy. Street tuner quoted that the factory o2 sensor can re adjust mixtures up to 25 percent either way from the VE table settings. Pretzel rightly quoted that the factory narrow band sensor is only capable of being accurate between 14:1 and 16:1 . anything below or above these figures is it grossly inaccurate, thus putting the engine into a situation where it either runs too rich or way too lean and causing the knock sensor to actuate and retard timing.

The selflearn process of boost can be understood as a target pressure is set and the psm will find the correct pwm to give the correct boost under all driving conditions. This is so because the sensor is capable of being accurate at this point.

But in the instance of air fuel ratio the narrow band sensor is not.

Hope this clears up my concerns as well as pretzels.

Hopefully street tuner can clarify these points.

Thanks

Dynowog.

[Lawsy]

I would have thought going up to 16:1 would be way to rich anyway and don't see this engine hitting that very often (most likely im wrong, but don't see a need for it to go this high, other than to flood the cat for some reason =/).

[speedzter]

  Lawsy said:

I would have thought going up to 16:1 would be way to rich anyway and don't see this engine hitting that very often

I think 16:1 is very lean ? , but I'm sure that's what you meant to say .

Wouldn't it be possible to replace the O^2 sensor with a wide band unit ?

Edited 26/12/04 09:45 AM by speedzter