chips, injectors and duty cycles

[brody]

running better means something to me maybe not to you.

no idea on afr as I dont dyno my girls car lol

so yo are saying at WOT w a stock chip and bigger injectors what will occur? the duty cycle will be the same as on stock injectors= a rich condition?

Many times being on the rich side of the fence smooths the car out, run better, maybe in your terms, but it's not "right."

[bastianshaw]

Many times being on the rich side of the fence smooths the car out, run better, maybe in your terms, but it's not "right."

if more driveability is wrong I dont wanna be right!
bump for more dicussion!

[brody]

if more driveability is wrong I dont wanna be right!
bump for more dicussion!

Less gas mileage is not good. Your old injectors were probably worn out. Anything feels better when you replace a broken/crap/worn part(s) with something that is in better condition.

[jlevie]

Motronic 1.3 is barely adaptive. Every time you come back to idle adaptation clears and starts again. If idle is not being triggered properly you run into problems with how the car runs. Motronic 1.3 is adaptive at in closed loop only when the ECU is getting O2 data. Moronic 3 and up can be considered "adaptive" more so than 1.3

When you say you can get a car to run 12.5 to 13.1 across all conditions what ate you doing to achieve this? If motronic was truly adaptive, it would pull back to 14.7:1 for idle and part throttle since that is what it is programmed to target at idle and PT which shows its barely adaptive.

Everything that I've seen says that learned adaptation is only reset when power is removed from the DME. That makes sense from an engineering standpoint and from the fact that the DME doesn't have an non-volatile memory.

I used a WAR chip to get the engine into that tune. I can't race the car that way, but we tried it on a dyno just to see how much difference it made. There was a difference over my normal Spec E30 tune, but it wasn't a lot. Most of the difference was in the area above 4500rpm, where the AFM is maxed out and the DME is only using ECT, IAT, and rpm for WOT maps. With a Motronic DME twiddling the AFM clock spring tension allows for optimal mixture below 4500, but the built in maps cause stoich above that.

Since I have to use an unmodified engine management system (adjusting clock spring tension in the AFM is allowed), my tuning possibilities are limited. What I have done is to use a well aged O2 sensor, selected an ECT and IAT from used parts that indicates colder than normal, and found an FPR that has slightly higher pressure. Since those are all stock parts, it is legal under the rules.

If I drive the car on the street, which I occasionally do, I see the learned adaptation richen the mixture. A power cycle of the DME clears that. Under race conditions the engine spends little time in closed loop, so adaptation isn't much of a problem. And since I have a relay in the DME power lead from the battery every time the ignition is switched off adaptation is reset. So at the start of a session there's no learned adaption.

FYI: the secondary contacts in the kill switch that one routes the DME power through on an E30 can't reliably handle the current flow. Those contacts will eventually burn and cause problems. By using the secondary contacts as a relay enable with the relay controlled by ignition one avoids that and gains a DME reset every time the ignition is switched off.

[nando]

The O2 sensor once in closed loop will trim fuel accordingly. It's not perfect but it can handle 19# injectors. It cant compensate for col start, cranking fuel or WOT. You know an octagon also can be used like a wheel.

yes it can.. fuel trim is applied everywhere! not just part throttle.. only real time EGO correction works at part throttle/idle, but long term stored trims are *always* active.

[ForcedFirebird]

The ECU has RAM that's read from the chip that is stored and modified. Question is, who are the ones getting that data back and using it for progressive tuning?

86 the o2 sensor on track cars that are allowed to have the sensor deleted, cold starts and drivablility will be sacrificed, but changing the proper maps, idle will be like a rock, even when a large vacuum leak is created. It's kinda odd watching the oil cap removed from an m20 and still have perfect idle with a Motronic ECU.

Original poster: Duty cycle is not hardware, that would be the physical injector. The software is manipulated to fire the larger injector less to equal the lesser flowing stockers as far as the amount of fuel delivered to the port. 19lb injectors are quite a bit larger, the small trimming of the RAM stored data and stock fuel maps will not compensate enough for them. Plugs will foul, excessive fuel consumption and in extreme cases, cylinder wall washing will occur.