Monday, November 06, 2006 - 08:45 pm, by: Thads Cooke(Thadz)
Umm - yes, you are really Although I didn't make it quite clear in my other post
The point is that with closed loop, the ecu trims the mixtures so they ARE ideal and don't need adjusting. Straight after a reset they won't be spot on, which is why you take it for a drive so the ecu can do its learning to suit the fuel, altitude, ambient temp etc etc that is specific to your location. If you were to try and perfect the light load a/fs with a SAFC, it would only be pre empting what the ecu is about to do anyway!
The ECU will adjust to the optimum a/f for light load running automatically.
The value of a SAFC is in adjusting the open loop mixtures, which are a conservitive best guess by toyota to avoid damage in extreme conditions (ambient temp/poor fuel etc)- and therefore are disgustingly rich and retarded.
The reason that open loop doesn't use the o2 sensor to adjust itself is that it takes a few seconds for the a/fs to stabilise and the ecu to decide what the story is, by which time the engine would long since be toast if the settings wern't right!
Monday, November 06, 2006 - 09:34 pm, by: Joel Moore(Ttsoai2ei2)
What Kinda economy do you all get? i thought that 600km was great for a TT on a full tank. How many litres is my tank 72 or 78? My car is better than my dads v6 commo!
I love driving the car and the economy isnt bothering me but lets face it if i can get 100kms more thats $10 more in my pocket not the petrol companies right?
Does anyone know if the overdrive button will make the engine use more petrol if im doing 60kms? I thought it might due to the extra torque required to turn the gear.
Tuesday, November 07, 2006 - 12:05 am, by: Cihan Aday(Cihan)
Thads Cooke wrote on Monday, November 06, 2006 - 06:11 pm:
Im not sure exactly what the cutoff point between open/closed loop is on a 1jz-gte, but its likely to be open loop above say 4000rpm and 70% throttle, and potentially closed loop below that.
Anything above ~4psi and it switches straight to closed loop operation, RPM does'nt matter nor does TPS output.
I will film this happening on an air fuel ratio gauge for all ya'll.
Joel Moore wrote on Monday, November 06, 2006 - 09:34 pm:
Does anyone know if the overdrive button will make the engine use more petrol if im doing 60kms? I thought it might due to the extra torque required to turn the gear.
Joel, all that the overdrive button does is it activates the fourth gear, that's it. With overdrive off it won't shift higher than the third. Have it on all the time, the only reason you'd want to switch O/D off is when you want to do engine braking when you going down some steep hill (or at the drag strip if you don't want to shift it into fourth...). Having it off all the time or while say doing 100 kays on the freeway is downright stupid, as the car's engine is running at a higher rpm, using more petrol as a result, and wearing out more obviously for no good reason. Hope that clears it up for you
Tuesday, November 07, 2006 - 11:42 am, by: Mike Triggs(Mikeandimah)
Thads Cooke wrote on Monday, November 06, 2006 - 04:10 pm:
The biggest factor is going to be how its driven - cold starts and short runs will hammer economy, as will boosting it all around tow
I can vouch for this, at least in the Wizard, which is an auto turbo diesel 3.0l. Using the ScanGuageII, the worst fuel economy for the day is the first start of the day, with motor cold (and not helped by having a steep hill as first obstacle). All other runs in a day get better economy than that first one, and in fact get progressively better through the day ( I get a reading for each trip). Each run is around 6km.
Haven't tried it in the Soarer as the OBDII port or the ignition circuit which powers it is not working.
Our Soarer is not turbo, gets around 12.5 - 15.5l/100km probably not super high octane (it's not marked) all short runs. The average is around the 14 - 14.5 mark.
Tuesday, November 07, 2006 - 12:08 pm, by: Tim Appleton(Timbo)
Cihan Aday wrote on Tuesday, November 07, 2006 - 12:05 am:
Anything above ~4psi and it switches straight to closed loop operation
You mean open-loop, don't you?
My V8 has a funny habit of running lean in open-loop below about 3k rpm. It feels a lot like turbo lag. I've got a piggy-back but haven't been able to wire up the AFM mod properly yet.
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