piggyback ECU, open/closed loop and WI?

[avendit]

Hi,

I have a latest generation toyota celica with an added turbo, running 12PSI of boost. I'm using a Greddy Emanage blue for tuning the extra fuel. The car runs great at WOT (244bhp) where it is in open loop and I have full control over the fueling, however because I'm using a piggy back I can be in the situation where I'm in closed loop, the car is aiming for 14.7:1 but I'm at 6-8 PSI :shock: . This results in timing being noticeably pulled by the ECU.

So I was thinking that some WI to make that part throttle closed loop situation safer (not too bothered about max power, pretty much there as far as conrods and stuff can take it - I just want to make it safe at part throttle). What effect would WI have on the closed loop function of the toyota ECU that constantly aims for 14.7:1?

And as a piggy back question - the emanage blue can control an additional injector, would this would be an acceptable way to control water input? I tune against MAP already so the water injection map should be easy to design :smile: .

Thanks in advance,
Avendit

[Richard L]

Originally Posted by avendit

Hi,

I have a latest generation toyota celica with an added turbo, running 12PSI of boost. I'm using a Greddy Emanage blue for tuning the extra fuel. The car runs great at WOT (244bhp) where it is in open loop and I have full control over the fueling, however because I'm using a piggy back I can be in the situation where I'm in closed loop, the car is aiming for 14.7:1 but I'm at 6-8 PSI :shock: . This results in timing being noticeably pulled by the ECU.

So I was thinking that some WI to make that part throttle closed loop situation safer (not too bothered about max power, pretty much there as far as conrods and stuff can take it - I just want to make it safe at part throttle). What effect would WI have on the closed loop function of the toyota ECU that constantly aims for 14.7:1?

And as a piggy back question - the emanage blue can control an additional injector, would this would be an acceptable way to control water input? I tune against MAP already so the water injection map should be easy to design :smile: .

Thanks in advance,
Avendit

If your fuel system targets 14.7:1 AFR, put in another injector will not help. The main ECU just trim the fuel IDC to retain the same AFR. This is a good opportunity to add water injection where it does not affect your target afr at cruising but offers a great deal of safety. IDC mirroring system is ideal system for this application where you need a wide dynamic range.

[avendit]

Sorry, I may have been unclear - I meant use the additional injector control to inject water/meth. My main concern is that adding water or meth into the burn cycle will throw the (ECU's narrowband) AFR measurements off resulting in the ECU fighting back while in closed loop?

Thanks for the reply,
Avendit

[keithmac]

Have a look on the Emanage boards, you can make a simple circuit that feeds a false 02 voltage to the cars ECU on boost so the car thinks it`s at 14.7:1 where in reality you can dial any mixture in you want.

I`ve pulled the 02`s completely on my 1st Gen GTO but you can`t get away with that on later cars without a CEL.

You can buy 02 simulators that will simulate stoich signal from an o2 sensor full time, this will give you total control over the whole fuel map without trimming from the cars ecu.

As Richard says, just adding more fuel be it petrol or methanol will just make matters worse if the car is actively seeking stoich from the o2 sensor.