tune explanation

[under pressure]

its been mentioned that a split is only a split shot by its tune, as it was stated there is no longer a split shot event beyond 1700 rpm.....but a single shot event happends from1700+
if this is truth, a split shot can be tuned to a single shot event. correct ?
i was under the impression there are operational/mechanicle differences between single and splits, however if everything stated in the first sentence is accurate, the mechanics of a split shot do not change mid stride, only the tune does.

is this correct.... or is the split shot event take place through out the rpm range.

thanks to whom clears this up for me.

 

[David N]

Wow this is about to get deep. Im in!

 

[Petro]

Subd

 

[sideactiondiesel]

Split shot is a mechanically controlled event that is done by the internals of the injector plunger and barrel assembly . To put it simply .

Now on a duramax or 6.4 powerstroke for instance there is a post injection aka main injection event And a pre-injection event is before the main injection event to start heat before the main injection.

 

[POWER-STRUCK]

an injector in a 7.3 has a mechanical difference but the tuning is different also, as far as 6.0 6.4 6.7 the "split" is called pilot injection and the events are controlled by the tuning

 

[under pressure]

ok, hasent answered if the split shot is a single shot event beyond 1700rpm.
or does it remain a split shot event.

im in this more for the theory and general info, as i had never heard this.

 

[Nobody Special]

A "split shot" injector ALWAYS has two injection events. As was stated earlier, IT'S MECHANICAL.

 

[CurtisF]

A split shot is always a split shot. It does not become a single shot by virtue of RPM's or tuning. It's a mechanical function of the injector itself that doesn't change.

 

[02BigD]

:whs: tunes simply need to be written for the type of injector one has.

 

[under pressure]

A split shot is always a split shot. It does not become a single shot by virtue of RPM's or tuning. It's a mechanical function of the injector itself that doesn't change.

here is the statement that started my confusion...

*** . After about 1700-1900 rpm there isn't a split shot commanded***

so does someone know for certain... does the written tune fire from the IDM twice in a split shot event ? or does the IDM fire once and the split shot fires twice by design.....

 

[neverkickn]

How many knowledgable people have to chime in here before you accept that the multiple injection that occurs in a split shot injector is mechanical and not a byproduct of tuning.

 

[Nobody Special]

here is the statement that started my confusion...

*** . After about 1700-1900 rpm there isn't a split shot commanded***

...written by someone WITH tuning software.....

I'm not sure where that idea came from.

so does someone know for certain... does the written tune fire from the IDM twice in a split shot event ? or does the IDM fire once and the split shot fires twice by design.....

I know for certain.

The PCM sends a fuel delivery command signal to the IDM that is non-specific to whether splits or singles are used. The duration of the signal and when the signal is sent to the IDM is ALL THAT MATTERS.

The IDM doesn't care ONE IOTA what injectors it is controlling. It sends out an electrical signal. What the injector does with that signal is controlled SPECIFICALLY BY THE INJECTOR DESIGN.

 

[under pressure]

got it, mechanical... i was digging for the tuning portion as thats where the comment came from, though, the orig. comment through me for a loop, thought i missed something along the way
that will be all, dismissed !

 

[CurtisF]

here is the statement that started my confusion...

*** . After about 1700-1900 rpm there isn't a split shot commanded***

so does someone know for certain... does the written tune fire from the IDM twice in a split shot event ? or does the IDM fire once and the split shot fires twice by design.....

got it, mechanical... i was digging for the tuning portion as thats where the comment came from, though, the orig. comment through me for a loop, thought i missed something along the way
that will be all, dismissed !

Just to help clarify for others as well.

The tuning does not ever call for any split-shot command. There is nothing in the tuning or the IDM that actually controls if an injector fires as a single or as a split, or commands a function of a split shot. It's purely mechanical on the injector side only.

The PCM itself assesses when and how long to fire based on what the tuning is commanding, and that signal is sent to the IDM, which then commands the injector to open and close at precise times. For singles or split shots, it's the same signal.

The difference in tuning between split shots and single shots is..... when and how long the event is commanded. Because of the mechanical differences between splits and singles, the tuning has to be adjusted in order for the engine to idle and run smoothly when switching from one to the other. The biggest changes to that tuning is the timing and the amount of fuel delivered (the latter being adjusted far more with larger nozzles).

Hopefully that's a short and simple explanation.

 

[85_305]

Split shot: has 2 'injections' per injection event, pilot injection main injection. The injectors are built differently with different guts.

The guy that said "theres not split shot about 1400rpms" or whatever he said was ill-informed. You cannot write out the internal workings of an injector to stop working @ a certain rpm.

If you put a single shot injector into a single shot truck, the ecu is programmed for 2 injection cycles per even, the pilot and main. This can cause the truck to run a little funny.

 

[Justin@DP-Tuner]

Split shot: has 2 'injections' per injection event, pilot injection main injection. The injectors are built differently with different guts.

The guy that said "theres not split shot about 1400rpms" or whatever he said was ill-informed. You cannot write out the internal workings of an injector to stop working @ a certain rpm.

If you put a single shot injector into a split shot truck, the ecu is programmed for 2 injection cycles per even, the pilot and main. This can cause the truck to run a little funny.

Fixed it for you.

 

[TyCorr]

We have ecu's? Never knew...

 

[lincolnlocker]

We have ecu's? Never knew...

google says we do

live life full throttle

 

[85_305]

Hmmmmm... apparently Tony Wildman is wrong too if its not called an ecu:
http://www.totaldieselperformance.com/v/vspfiles/assets/images/chipinstall94-97.pdf

 

[Duzitall]

Hmmmmm... apparently Tony Wildman is wrong too if its not called an ecu:
http://www.totaldieselperformance.com/v/vspfiles/assets/images/chipinstall94-97.pdf

ECM in those instructions. A rose by any other name.