Running turbo injectors with NA ECU and more...

[Jason84NA2T]

crowbar wrote: I have a 88T ecu that I want to run on a NA car. I plan to use your fuel injection mod where you 'over-size' fuel lines over injectors. I plan to use high resistance injectors 370cc from KA24 engines. These modded into a top feed rail from a 300zx car.

The NA car should run fine I assume? The ecu should run closed loop even though there would never be any boost in the 'load' calc? My car uses the smaller O2 sensor (like a 86 300zx NA does) and has a 3.90 rear.

You will need to adjust the k constant at the very least or it will never run right in open loop. Some people reduce the fuel pressure slightly if they don't have someone to burn them a chip, but that kind of defeats the purpose of upgrading the injectors.

Fortunately the 88-89 ECU's are very easy to install a socket/chip in.

[crowbar]

When running open loop, the turbo ecu should just see the MAF output voltage and figure the 'load' through the RPM/gear/etc. Since the MAF output would just reflect the non-boosted mass of air coming in, would it not calculate thefuel needed correctly?

[roastin300]

Yah i use to run turbo injectors with an N/A ecu. It ran ass rich, i got like 10-12MPG around town but on 8-9lbs of boost on a stock T3 i managed a 14.3 @ 102MPH at my 6K foot elevation. I was happy at that time even though it ran like butthole.

[300zxt]

Gee I wonder why using larger injectors than the computer is programmed for makes it run rich? :P

[G-E]

300zxt wrote: Gee I wonder why using larger injectors than the computer is programmed for makes it run rich? :P

maybe he has an overly restrictive intake and all the air has ended up in his head

[crowbar]

Jason claims that the ecu is non-adaptive. That means that it learns nothing from running closed loop. When running open loop, it relies predominately on the programming and MAF sensor readings.

So the ecu might struggle to adjust the PWM on the injectors (shortening the PWM in the case of big injectors, but even with O2 sensor feedback, there is probably a limit to the PWM correction. If its 10% or so, then big turbo injectors, (that are 50% larger) would be out of closed loop operational range, and also impossible in the open loop range. They would just dump fuel.

The car might be able to move from 180CC to about 200CC if what Jason says is true.

[G-E]

crowbar wrote: Jason claims that the ecu is non-adaptive. That means that it learns nothing from running closed loop. When running open loop, it relies predominately on the programming and MAF sensor readings.

not predominantly, entirely, that's the point, it doesn't adapt to fuel octane/knock and nothing to egt.... and it won't remember anything between sessions except codes

the best it can do is richen or lean the mixture a given percent of injector time, based on o2 sensor feedback

so when the car is running you will see the o2 readout alternating between rich and lean constantly as it can't adjust that finely without sequential injection

but I'm sure you think firing 6 injectors is still better so let's not go there

[crowbar]

I would question whether it forgets everything between runs (with the battery retaining memory).

As far as closed loop operation, there must be some stored learned variables.

You make a ridiculous remark again. If the car had fast enough feedback, it could keep the car well within a air-fuel range (perhaps 0.1 of 14.7:1). The problem is that it is slow feedback.

And yes, Nissan engineers thought that firing all six injectors, twice an engine cycle, was a good compromise. Do you have a point? Or even an argument?

Your odd argument about 'what you are sure of' just fortifies that you have comprehension issues. Good Luck.

[G-E]

the feedback is fine, the ecu is slow, and adjusting mixture "safely" with batch injection is slower still... I'm sure the ecu was designed to allow the batch injection to lean out a very slight increment so as not to ping, and if you don't understand why it is hard to adjust batch fire to o2 feedback, you shouldn't be giving any commentary

[crowbar]

You can't win arguments by changing the subject. Especially with run on sentances.

Again, Nissan used simultaneous injection for a reason. It allows distributed fuel delivery over the engine cycle. You claim some nonsense about doubling fuel. Its absurd. Please explain what you think you mean before going off another another diatribe.

I wonder if you can express yourself enough to explain that.

[crowbar]

For those of you that CAN read a timing diagram; please consider the following.

As the engine speed increases, the engine cycle time period is shortened. But the PWM on the injectors is increasing.

By breaking the injection into two distinct bursts within an engine cycle, the Nissan engineers achieved some 'psuedo-sequential' injection. That is, while the valve is open, some direct injection is taking place.

If one were to use a group (it isn't batch its called group) injection scheme, there would probably be some rpm where there would be cylinders that had disproportionate injection considering valve opening.

I suspect that at lower rpms and power levels, this is not as critical. At higher Rpms and power levels, it becomes more critical.

Most dyno graphs show the 300zx cars during simultaneous injection. By that I mean over 3000 rpms.

[Jason84NA2T]

Funny how a only somewhat related topic opens up the same old debate again. Both of you need to stop with the insults already.

I think anything useful to this topic was said on the first page.

Locked.