Injector Duty Cycle in 2G

[asian312]

I've been doing much research into selecting the proper size injectors for my setup, but to this date I don't know how to tell if my injectors are maxing out on a 2G. I know the 1G pocketlogger can tell IPW but the 2G pocketlogger does not have that feature. Can anyone explain?

 

[chuckgeo]

Apex Super AFC will show inject. duty cycle

14b = 28 lbs/min (405 cfm at 15 psi)
small 16G = 34 lbs/min (505 cfm at 15 psi)
big 16G = 37 lbs/min (550 cfm at 15 psi)
18G = 41 lbs/min (600 cfm at 15 psi)
20G = 44 lbs/min (650 cfm at 15 psi)

i have all most all the upgrades expect for the turbo and inject. i run anywhere from 80 to 98% duty cycle with no shut off. my maf hacked per roadrace info-- screw out and just the center in. hope i answered you question.

 

[asian312]

Now that u mention that, how the hell to u read that? Mine seems to start high in the numbers ~90% and as I apply throttle in a run it decreases. Is this normal? And is this reading correct and usable?

 

[kpt4321]

Chuck....errr, what are you talking about?

The SAFC does not even recieve a signal having anything to do with the injector pulsewidth, from which the duty cycle is derived. Those numbers you are taling about are the flow abilities (or possible flow rates through the engine) of a turbo. While there is a link between airflow rate and IPW, they cannot be directly related.

Also: keep in mind that the SAFC shows Karman Hz, not lb/min or CFM. You 2g guys are lucky (gasp!) because you can look at lb/min, the rest of us have to just guess from the Hz reading.

You can derive duty cycle rather easily from IPW.... duty cycle is just the amount of time used over the amount of time avalible... the amount of time in one engine cycle is 120s/rpm, so the formula is just (IPW*120)/rpm. You can also take the amount of time required to open and close the injector into account, but I'm too lazy.

What is your intended setup? If you can give us some information, it will be easy to decide what size you need.

 

[DCJ98GST]

Yea but how do you get injector pulse width (IPW) from the pocketlogger? Mine does not show this value.

 

[asian312]

Thanx kpt4321 for the clear up. I didn't think those numbers meant anything. Just more digital read out to Oouuuu and AHhhhhh passengers :laugh:

Like DCJ98GST said, unfortunately on the 2G Pocketlogger it does not have the IPW parameter. I know what injectors I need (720) but dont want to deal with the idleing issues. The counter to that I've heard that ball/disk style injectors help out and make life tolerable. Any comments on this one? 660 will work, but it'll make the tuning window tighter than I like. I'm still learning thus I need the largest learning curve that I can get

 

[kpt4321]

What will the rest of your setup be, and what are you using to tune it with (just a SAFC?).

So, the 2g logger doesn't have Injector pulse width OR injector duty cycle? I could have sworn it did..... That sucks! In that case, I have no idea how you're going to know exactly when you're maxing out your injectors. You can look for common signs like a dropping O2.....

 

[asian312]

SAFC and wideband O2. I know a few very reputatble tuners that I seek their tuning techniques. By setup I'm guessing the rest of the parts list. Parts that I'm debating on are the injectors and FPR. Walbro 255 is on the way. This may seem a bit "ricy" but Im an Apex'i whore and it works. Also got a great deal when I started off and do all my own work. But anyways here goes.

Engine:
- Apex'i BOV
- Apex'i Intercooler setup
- Apex'i Dunk cat-back (sold)
- Injen intake (possibly switching for the LT1 MAF)
- 122 Performance O2 dump
- 2G manifold - ported
- 3" downpipe
- HKS Carbon TI exhaust

Turbo: Turbochargers.com
Eliminator variant:
- 7cm^2 turbine housing
- TD06H turbine wheel
- T03 compressor housing
- 46 trim comp wheel
- Monster thrust bearing
- ported

Electronics:
- Apex'i AVC-R
- Apex'i S-AFC
- Apex'i Turbo Timer
- Apex'i EGT and boost gauge
- Pocketlogger

 

[DCJ98GST]

Why not just go with the DSMlink. You can dial in 720's easily and it will give you injector pulse width and you can even adjust the dead time.

 

[asian312]

If I would have known about DSM link from the start I would swtich. But I did get an awesome deal that started me along my DSM path and would be more costly to turn around, sell stuff and go DSM link. Plus I like the challege that maybe a piggyback setup might rival a stand alone. I'm always up the challenge.