Stinger 4424 injector operation

[TheNewRed]

So I have owned the 4424 unit for a while now, and I'm about to install it on my street car. I have been reading up on the fuel injector operation with this unit, and it seems to be confirmed that ALL 6 injectors will be fired simeltaineously. I am having a hard time convincening myself that this method of injector control(or lack thereof), will provide reliable service, especially in the proximity of a daily driven car. I suppose it is the same method as a TBI setup, but it just seems very peculiar to me. Let's discuss!

My main concern is fuel puddling, which could result in detonation from the ununiform mixture.

 

[TheNewRed]

So, no thoughts on this subject from the community?

 

[TheNewRed]

Is there anybody out there?

Have I conceived the concept totally wrong, or is this to medeocre of a question to be answered?

 

[TheNewRed]

I have posted this question on multiple forums, and have received no more than a shrug, so I began my search for an answer. I found multiple articles, and even dug up some lecture material covering the subject from my college. Here is the low-down:

In multi-point injection, the injectors can all be triggered at the same time. This is called simultaneous injection, and the injectors operate twice per cycle. That’s once each crankshaft revolution, each time delivering half the fuel for the cycle.

In a 6-cylinder engine, the injectors are triggered on every third ignition pulse.

Source: http://www.cdxetextbook.com/fuelSys/gasoline/efiOp/simultaneousinject.html



Source: http://www.cdxetextbook.com/fuelSys/gasoline/efiOp/simultaneousinject.html

This method of fuel injection is said to be widely used, but simple search engine "searches" provide no OEM usage listings. The method has obviously been proven as an effective means of fuel distribution, and through my research I feel more comfortable with putting the system to use.

Another great article I found:
http://www.picoauto.com/tutorials/fuel-injection2.html

 

[Funkycheeze]

When you are at high power, even on a SEFI setup, the injectors are open up to 80% of the time anyways. The stock 7M TCCS uses batch fire (3 sets of 2 injectors). The major issue with batch fire (especially 1 batch of all 6) is getting the pulse width low enough for a stable idle on large injectors, as an injector will fire 6 discrete times each cycle. This means it will probably idle high, and pig rich.

 

[TheNewRed]

When you are at high power, even on a SEFI setup, the injectors are open up to 80% of the time anyways. The stock 7M TCCS uses batch fire (3 sets of 2 injectors). The major issue with batch fire (especially 1 batch of all 6) is getting the pulse width low enough for a stable idle on large injectors, as an injector will fire 6 discrete times each cycle. This means it will probably idle high, and pig rich.

You seem to have a decent grasp on this, thanks for posting. I hope the high idles are not going to cause engine bearing issues upon start-up. I may have to fabricate myself a oil accumulator.

 

[BoostMonger]

subbed, very interested on this as I plan on putting the stinger on my "daily" also :beer:

Sent From My HTC One S using Tapatalk 2

 

[Funkycheeze]

I wouldn't worry about issues with detonation, as at high load even in a sequential system the injector is open for much of the time that the intake valve is closed. The main worry is over rich idle, and an oil accumulator won't help. Perhaps use a set of smaller primary injectors with secondarys kicking in at higher load if the stinger can drive 2 sets?

 

[bigaaron]

I think there is a misunderstanding about "batched" injection vs. "semi-sequential". The stock 7M ecu, stock 1JZ ecu, and the Stinger would all be running semi-sequential injection. Batched injection, as in having all the injectors fire at the same time, is closer to a carburetor then anything. I think the Supra guys refer to the stock injection as batched, but they really mean three batches/pairs of injectors. For an engine with 550cc injectors and 450hp, like my own 1JZ, it idles perfectly and runs perfectly using semi-sequential injection. The only time this becomes a problem is when you go to huge injectors and try to have a normal idle, and perfect driveability at low speeds. Even 800cc injectors wouldn't have a problem with semi-sequential operation, just use a good quality injector in the newer style composite body with high impedance. With semi-sequential injection you get probably 90% of the performance of full sequential at low rpm, and the same performance at high rpm. I think the main reason for sequential injection is fuel economy, and a side effect is a little smoother idle. After all, look at how much power you can make with a carb! The old muscle cars made awesome high rpm power but idled poorly and had poor fuel economy.

The Stinger is a good reliable entry-level ecu, I don't think you will have any issues with it.

 

[TheNewRed]

Aaron, thank you for your response. I understand this uncovered, misconception. This is a perfect example of how a play on words, completely changes the perception of a simple operation. I will be posting regularly in this thread, as documentation of my experience with the 4424 unit.

 

[Funkycheeze]

If the 4424 runs semi sequential (3 sets of 2) then even better. That is what I run on the AEM, and it idles fine with 660s.