Motronic 1.3 WOT maps, RPM only?

[Sagaris]

When the full throttle switch is engaged and the DME looks up the WOT maps, does it use RPM as the only input to detrmine injector pulse width, or does coolant temperature play a role as well?

[nando]

Coolant temp always plays a role, but above a certain threshold, coolant compensation will be 0%

[e30trooper]

if coolant is at 1/3 at all times will that effect WOT on 1.1 motronic ?

[nando]

the gauge is meaningless when it comes to the temperature the ECU reads. but generally, if you mean between the 1/4 and 1/2 marks, then no.

[e30trooper]

the gauge is meaningless when it comes to the temperature the ECU reads. but generally, if you mean between the 1/4 and 1/2 marks, then no.

ohh ok. im running a 71* thermostat if i get on it temp gauge goes right above blue and will stay there.

[nando]

that's probably too cold.

[e30trooper]

that's probably too cold.

yeah that what i thought. maybe running to rich also. I get alot of back fire between shifts. nie knowing the car will never over heat but it kill MPG , i avg with aggressive street and freeway about 22mph on the obc. I should go back to at least a 78* thermostat b4 i put in 17pounders. Thanks

[Sagaris]

Coolant temp always plays a role, but above a certain threshold, coolant compensation will be 0%

As usual, thanks for the info :up:

[jlevie]

What follows should not be construed as authoritative. It is what I've gleaned from on-line sources and observed when dyno testing/tuning.

When the WOT switch is closed the DME uses learned adaptation, IAT, ECT, AFM, and RPM data for timing and fuel up to 4500rpm. Above that it uses learned adaptation, IAT, ECT, and RPM data.

The choice of thermostat has little to do with engine temperature when the car is driven hard at speed for any period of time. The ambient temperature and radiator efficiency are bigger drivers. In low 90'ish ambients my Spec E30 will stabilize at about 190F a few laps into a 25 minute (or longer) race. It doesn't matter if I have a 75C or 80C (167F or 176F, respectively) thermostat installed. A lower temperature thermostat really only affects starting and low load temperatures. For best performance temps around 180-190 are best when using an OE (or chipped DME).