How does one know when it's time for an injector upgrade?

[Flyin Ryan]

I have datamaster, I have a few things done but nothing major. I do however have a rpm turbo with stock injectors and my wideband shows me very lean conditions which I don't like.. I just replaced the seven year old walbro pump and 1 year old filter with new because of the wideband scaring me... but problem still exist.

I'm thinking either I need larger then stock injectors in which case i'll go with 60's but I am also thinking the bin that's in the truck currently is crap. It's a bin waller had burnt for me a while back but I throw it in at the same time I had the turbo upgraded so I don't know for sure. I might yank the 3bar and put the pitbull back in and see what happens.

\But anyways looking in datamaster how can I determine that I need larger injectors?

At 12lbs of boost my BPW is 10.19 and Inj DC is 48.4 which isn't english to me

Wideband shows afr of 14.5 to 15.1 at idle which it idles like crap I might add.. under moderate throttle though it's 13.0 and above to 16's and under little boost it's 13's to 11.

Thanks for the help

oh and quick run down of the truck's mods that might have a factor:

rpm stage 1 turbo
waller chip.. something along the lines of a t1-18 bin
air2air ic
alky injection
3bar map
afpr
open downpipe
walbro 255
taylor wires
accel coil
ngk ur5 plugs gapped @.029
stock stall, injectors, cam, heads, intake, etc the motor's never been opened up

 

[JSM]

Re: How does one know when it's time for an injector upgrade?

We can guess based on mods, how much horsepower your making, etc.

Actually you can calcule it.

IDC = (IPW * rpm) / 1200

You don't want to go over ~90% DC.

Pulse Width = amount of time injector is open per cycle.
Duty Cycle = percentage open -vs- closed. You stated 48.4% so your using about half your injector.

You can probably tune in enough fuel for what your doing currently though is my guess. You can also add some fuel pressure to make the injector "larger", stock aka small injectors will need a large fp change to see much difference though.

 

[Flyin Ryan]

Re: How does one know when it's time for an injector upgrade?

We can guess based on mods, how much horsepower your making, etc.

Actually you can calcule it.

IDC = (IPW * rpm) / 1200

You don't want to go over ~90% DC.

Pulse Width = amount of time injector is open per cycle.
Duty Cycle = percentage open -vs- closed. You stated 48.4% so your using about half your injector.

You can probably tune in enough fuel for what your doing currently though is my guess. You can also add some fuel pressure to make the injector "larger", stock aka small injectors will need a large fp change to see much difference though.

hmmm so your saying 48.4 is actually the percentage of injector being used... so that means at 2850 and 12psi of boost im using half my injectors capacity?

 

[JSM]

Re: How does one know when it's time for an injector upgrade?

kindof, i don't trust the DC on datamaster though.

 

[smeagol]

Re: How does one know when it's time for an injector upgrade?

Offhand, I would say you would be at the limits of the stock injectors if you ran higher boost. Many guys have gone high 11s on stock injectors. The question is if there is another problem in your situation.

What fuel pressure are you running? Have you verified if it's keeping up under boost? With those AFR numbers I wouldn't be pushing it too hard til you sorted everything out.

 

[Flyin Ryan]

Re: How does one know when it's time for an injector upgrade?

The question is if there is another problem in your situation.

Exactly what im thinking brian which leads me to not getting into boost with the thing. The afr readings on the lm1 are scary

What fuel pressure are you running? Have you verified if it's keeping up under boost? With those AFR numbers I wouldn't be pushing it too hard til you sorted everything out.

I've tried 38 to 58 (with vac line off and plugged) and it rarely made a difference in both the afr readings on the wb and the Sterm/Lterm counts in datamaster so im kind of not looking to get into boost with it anymore. I did see fuel pressuring rising with boost I believe but was mostly looking at the wb.

 

[smeagol]

Re: How does one know when it's time for an injector upgrade?

Exactly what im thinking brian which leads me to not getting into boost with the thing. The afr readings on the lm1 are scary



I've tried 38 to 58 (with vac line off and plugged) and it rarely made a difference in both the afr readings on the wb and the Sterm/Lterm counts in datamaster so im kind of not looking to get into boost with it anymore. I did see fuel pressuring rising with boost I believe but was mostly looking at the wb.

I'd go with a known good $59 calibration, see where you are at with your drivability and AFR numbers. Obviously don't go out and boost it on the first run after popping the chip in there... but see if it makes a big difference in idle/cruise conditions and gradually move into boost. If AFR's are still going lean, go back to square one and start looking for fuel system problems (or even question the wb02 readings?).

 

[Flyin Ryan]

Re: How does one know when it's time for an injector upgrade?

I'd go with a known good $59 calibration, see where you are at with your drivability and AFR numbers. Obviously don't go out and boost it on the first run after popping the chip in there... but see if it makes a big difference in idle/cruise conditions and gradually move into boost. If AFR's are still going lean, go back to square one and start looking for fuel system problems (or even question the wb02 readings?).

Well I have an ostrich and im bugging dig right now about it so i'll have to wait and see what he says after looking over the log files.

I don't have my wideband wired into the ecm and don't really like the idea of chopping up the factory wiring but wish I would do it already

 

[smeagol]

Re: How does one know when it's time for an injector upgrade?

Well I have an ostrich and im bugging dig right now about it so i'll have to wait and see what he says after looking over the log files.

I don't have my wideband wired into the ecm and don't really like the idea of chopping up the factory wiring but wish I would do it already

1) I don't think you need to chop up anything to wire the wb02 up
2) How much more do you like the idea of replacing the motor?

 

[Flyin Ryan]

Re: How does one know when it's time for an injector upgrade?

1) I don't think you need to chop up anything to wire the wb02 up
2) How much more do you like the idea of replacing the motor?

True and true.. I think at that point i'd have to legalize my mustang again, moth ball the truck or sell as a roller because im too damn poor to be rebuilding another time bomb

 

[Flyin Ryan]

Re: How does one know when it's time for an injector upgrade?

hmm I think im going to swap my 2bar map sensor back in to see if the fuel curve richens up more like it should be.. If it does then my problem is waller's chip and that he prob didn't configure it for 3bar for some unknown reason.

 

[turbodig]

Re: How does one know when it's time for an injector upgrade?

Better idea still - set your boost to stockish or below stock levels.
Put the original stock chip in + 2 bar sensor.

See how it runs. If it still has the same symptoms, 1 of 3 things is true:

1) You're moving a lot more air than stock
2) You're not providing as much fuel as stock
3) Something is outright broken.

It's been said here many times- you can't fix a broken truck with a chip.

 

[Flyin Ryan]

Re: How does one know when it's time for an injector upgrade?

Better idea still - set your boost to stockish or below stock levels.
Put the original stock chip in + 2 bar sensor.

See how it runs. If it still has the same symptoms, 1 of 3 things is true:

1) You're moving a lot more air than stock
2) You're not providing as much fuel as stock
3) Something is outright broken.

It's been said here many times- you can't fix a broken truck with a chip.

I agree with you Dig but what bothers me is that before I upgraded the turbo and installed the waller chip (both at the same time) the truck had an atr pitbull streeet chip and ran perfect. 3 degrees of kr at upshifts once in a while but ran perfect and hauled butt for a stocker with 18 psi. I never had lean conditions it was more rich then anything.

The moving too much air idea I thought about. Im lean in all spots whether or not im in boost so Im leaning towards the fuel curve or fueling being the problem.

Im going to try the map sensor first because it's a ten second swap then pop the g1 in with the pitbull on it and see how she reacts

 

[turbodig]

Re: How does one know when it's time for an injector upgrade?

I agree with you Dig but what bothers me is that before I upgraded the turbo and installed the waller chip (both at the same time) the truck had an atr pitbull streeet chip and ran perfect. 3 degrees of kr at upshifts once in a while but ran perfect and hauled butt for a stocker with 18 psi. I never had lean conditions it was more rich then anything.

The moving too much air idea I thought about. Im lean in all spots whether or not im in boost so Im leaning towards the fuel curve or fueling being the problem.

Im going to try the map sensor first because it's a ten second swap then pop the g1 in with the pitbull on it and see how she reacts

Sounds to me like you answered your question. Put the pitbull in with the 2 bar. See what it does.
Honestly, the fuel requirements of an RPM stage 1 are not going to be that much more than a stocker at low boost levels.

The idea is to isolate what you've changed.

 

[Flyin Ryan]

Re: How does one know when it's time for an injector upgrade?

okey, driven the truck five times so far with the 2bar map and pitbull chip swapped back in and here's a screen shot of how it's working out