Re-Drilled Injectors

[straughsberry]

I think the important constant here is WOT and not TIME. We need to see a trend. If we see a trend, we can then say one item has "this" characteristic, and the other item has "that" characteristic.

Toady, how many of these graphs have you got/recorded? Do they show a trend?

[PHANTMXR6]

If it were that simple, it would be on a graph. I can make a graph do that by going from full throttle to no throttle and then back to full throttle....

Both graphs show nothing more than a line that goes up and down, as far as I'm concerned.

There's no load data, boost, rev range, gear info etc.?

It's a bit hard to be calling the differences without all the info.

No offence, IH8TOADS, but with the info you've supplied, apples aren't apples.

[XYZ]

Hey Guys,

Here is a better explanation of what I have been told:

"The FG has a split inlet port. When you fit injectors such as Siemens with a round spray pattern fuel hits the split in the cylinder under low air speed and pools causing a rough idle. The standard injectors are 4 hole duel pulse style so keeping with that style doesn’t affect idle quality".

He is not a Nizpro dealer either, so I am not sure if it is just sales talk.

Ben

[RAP1D]

I think he may be thinking of the older style Siemens injectors, which have a single orifice pintle.

These ones have a quad orifice, same as the stock injector... see pic.

The specs are listed on our website if there needed.

FG Siemens injectors

[XYZ]

Thanks mate.

[IH8TOADS]

Attached is a bunch of drilled injector data logs.....you're reading too far into it PHANTMXR6, I record AFR and OBDII data seperately so I can't be bothered putting it all together, but in the end of the day you can compare apples with apples with this data. I wouldn't post it if it wasn't relevant.

What does it all mean? Well my point is you can get a good WOT and idle AFR / behaviour with both injectors, HOWEVER there are times when they both behave differently. Nothing more to it, nothing less...and I'm not judging either injector here.

[IH8TOADS]

edit the screen shot is a deka log from a mates car.

[IH8TOADS]

edit the screen shot is a deka log from a mates car.

In regards to the split port and pooling....well I can't see how or where a pool would form, particuarly considering the low pulsewidths required at low rpm and the fact that air entering the engine would suck any fuel in fairly rapidly.

Have a look at this pic (sourced from APS website). The gap at the top of the shot is where the injector enters the ports. It faces down and obviously squirts fuel down. The factory injector, being a twin spray, is definately used for a reason but I can't see how a pool/puddle would form. Also we can't dispute the fact that the Seimens Deka injector DOES work in the XR6 turbo.

Lastly the rough idle....I'm not 100% sure what the cause is but I do know that if you do have a rough idle and you logged injector pulsewidth, RPM and spark advance you would find a strong relationship between the three. Take a look at the attached graph for example, this is just after start-up with spark un-controlled (didn't log PW in this one). I found that manually controlling spark with the deka's (factory PCM has 63 degrees advance for idle & drive nuetral rpm) produces a much more stable idle. There's a few other spark scalars that trim idle that can be re-calibrated also. With the drilled injector you don't get this problem.

So yeah in the end of the day, go with what your tuner recommends as you're most likely going to get a better outcome this way :-)

[IH8TOADS]

Full editor not happy and forgot to add graph!

[XYZ]

In regards to the split port and pooling....well I can't see how or where a pool would form, particuarly considering the low pulsewidths required at low rpm and the fact that air entering the engine would suck any fuel in fairly rapidly.

Have a look at this pic (sourced from APS website). The gap at the top of the shot is where the injector enters the ports. It faces down and obviously squirts fuel down. The factory injector, being a twin spray, is definately used for a reason but I can't see how a pool/puddle would form. Also we can't dispute the fact that the Seimens Deka injector DOES work in the XR6 turbo.

Lastly the rough idle....I'm not 100% sure what the cause is but I do know that if you do have a rough idle and you logged injector pulsewidth, RPM and spark advance you would find a strong relationship between the three. Take a look at the attached graph for example, this is just after start-up with spark un-controlled (didn't log PW in this one). I found that manually controlling spark with the deka's (factory PCM has 63 degrees advance for idle & drive nuetral rpm) produces a much more stable idle. There's a few other spark scalars that trim idle that can be re-calibrated also. With the drilled injector you don't get this problem.

So yeah in the end of the day, go with what your tuner recommends as you're most likely going to get a better outcome this way :-)

Thanks for your detailed replys mate. It has made things a lot more clearer. Still learning the "in's and out's" about these cars and I just like to be well informed before making decisions.

Ben