Stock injector size discussion...size matters

[SickLL7Crenshaw]

Are you serious?? Like I stated before do some research on me before opening your mouth. I've sent data logs and emailed rob multiple times, he told me i was maxed out and he couldn't do anything for me. My truck will run low 12's when I get my tire pressure and suspension set up. I've ran a 12.74 with a soft launch second time I tried my latest tune. I'm sure if I had more time at the track I would have already ran a low 12. Plus it's easier to get a Lbz or lmm closer to 12's because there rail pressure sees 26k and injectors are bigger than lly's. do some research and that might answer all your question before making yourself look dumb.

There injectors are bigger?? Hmm maybe you need to do a lil more research.. Plus dont get so offensive. I just called you out because like i said ive seen you post in multiple threads bragging about how much better your tunes are then robs and that you can build tunes for anyone. Oh btw if your asking what tables to change for your rail pressure then why you offering people that you'll build tunes for them??, because obvisously if you really knew how to tune you wouldnt be asking all this shit. Good luck breaking into the low 12s man

 

[Chevy1925]

There injectors are bigger?? Hmm maybe you need to do a lil more research.. Plus dont get so offensive. I just called you out because like i said ive seen you post in multiple threads bragging about how much better your tunes are then robs and that you can build tunes for anyone. Oh btw if your asking what tables to change for your rail pressure then why you offering people that you'll build tunes for them??, because obvisously if you really knew how to tune you wouldnt be asking all this shit. Good luck breaking into the low 12s man

Llys have the smallest nozzles of them all. Lb7 are the biggest and LBZ/lmm are between the two. So yes, LBZ/lmm injectors are bigger than lly.

Does that make it easier for one over the other to make into the 12s? That has yet to be fActually proven. Too many other variables to say the little differences in injectors makes the difference.

 

[quinton]

There injectors are bigger?? Hmm maybe you need to do a lil more research.. Plus dont get so offensive. I just called you out because like i said ive seen you post in multiple threads bragging about how much better your tunes are then robs and that you can build tunes for anyone. Oh btw if your asking what tables to change for your rail pressure then why you offering people that you'll build tunes for them??, because obvisously if you really knew how to tune you wouldnt be asking all this shit. Good luck breaking into the low 12s man

Wow. You are making yourself look dumber in every post by trying to prove me wrong when you don't even know anything. Like stated above, lly injectors are the smallest of them all. Also I never said my tunes are better than robs, jut said mine are a little stouter. You really need to learn how to read. And I know what table to adjust for rail pressure (which is not what we are talking about, it's rail valve flow) I was thinking they where adjusting a different table. Ill be sure to send you a pic of my slip next time I go to the track bud.

 

[JoshH]

How are you guys deciding that an LLY has the lowest flowing stock nozzles? From what I can see of the pulse width tables, it looks to me like the LMM has the smallest/lowest flowing nozzles. Here is where I get that. Let's look at the pulse width of each injector at the same pressure and fuel quantity of a stock tune (this table should be fairly accurate in stock form).

At 90 mm3 and 160 MPa
LB7: 1220 uS
LLY: 1304 uS
LBZ: 1446 uS
LMM: 1505 uS

 

[Chevy1925]

How are you guys deciding that an LLY has the lowest flowing stock nozzles? From what I can see of the pulse width tables, it looks to me like the LMM has the smallest/lowest flowing nozzles. Here is where I get that. Let's look at the pulse width of each injector at the same pressure and fuel quantity of a stock tune (this table should be fairly accurate in stock form).

At 90 mm3 and 160 MPa
LB7: 1220 uS
LLY: 1304 uS
LBZ: 1446 uS
LMM: 1505 uS

Pat posted some data a long while back about them. ill see if i can find them. How are you figuring injector size based off stock maps?

 

[coldLBZ]

Not to speak for Josh, but I think he is figuring injector size by looking at the pulse width to get a set amount of fuel at a set pressure. LMM has the largest pulse width, therefore it takes longer to inject 90 mm3 worth of fuel as opposed to LB7 injectors. Atleast that's how I'm understanding it, if I'm wrong please correct me.

 

[JoshH]

Not to speak for Josh, but I think he is figuring injector size by looking at the pulse width to get a set amount of fuel at a set pressure. LMM has the largest pulse width, therefore it takes longer to inject 90 mm3 worth of fuel as opposed to LB7 injectors. Atleast that's how I'm understanding it, if I'm wrong please correct me.

Yep, you pretty much hit it on the head.

 

[Chevy1925]

but how is that taken into account for power increase for the years amung other factors? so far ive found the LLY injector tip size, still hunting for the rest. i know ive read it somewhere......

 

[Dirtymaxx03]

but how is that taken into account for power increase for the years amung other factors? so far ive found the LLY injector tip size, still hunting for the rest. i know ive read it somewhere......

That's what I was thinking. Each model increases in hp, and by what Josh posted, uS increases also. Who woulda thought lol

 

[Chevy1925]

Out of curiousity josh, what is the uS of a LLY and an 06 "LLY" based on the same constants as you have above?

 

[quinton]

but how is that taken into account for power increase for the years amung other factors? so far ive found the LLY injector tip size, still hunting for the rest. i know ive read it somewhere......

I know the lmm/Lbz has 7 holes if that's what are wondering.

 

[coldLBZ]

Again, correct me if I'm wrong. I don't think Josh is looking at max power between the models. He is just looking at a point where they deliver the same fuel, and in theory will make similar hp. Don't pick on me too bad, I'm trying to wrap my head around this as well.

 

[JoshH]

but how is that taken into account for power increase for the years amung other factors? so far ive found the LLY injector tip size, still hunting for the rest. i know ive read it somewhere......

They run more fuel quantity. If you look at a factory air box, there is a sticker with the HP rating and fuel consumption at that power. Mine is long gone, but from what I remember, it was 93 mm3 at 310 HP. You can see in this picture I found with a quick search, the LMM was rated at 365 HP with 108 mm3 of fuel.

Out of curiousity josh, what is the uS of a LLY and an 06 "LLY" based on the same constants as you have above?

The pulse width tables for the 06 LLY and LBZ are exactly the same because, surprise!, they use the same injectors. The power is limited by limiting fuel quantity.

 

[JoshH]

I know the lmm/Lbz has 7 holes if that's what are wondering.

LB7/LLY/LBZ all have 7 holes. LMMs have 6 holes.

 

[Chevy1925]

I know the lmm/Lbz has 7 holes if that's what are wondering.

no, LBZ and older are 7 hole, LMM are 6 hole

 

[JoshH]

no, LBZ and older are 7 hole, LMM are 6 hole

Tree'd... oke:

 

[Chevy1925]

They run more fuel quantity. If you look at a factory air box, there is a sticker with the HP rating and fuel consumption at that power. Mine is long gone, but from what I remember, it was 93 mm3 at 310 HP. You can see in this picture I found with a quick search, the LMM was rated at 365 HP with 108 mm3 of fuel.

The pulse width tables for the 06 LLY and LBZ are exactly the same because, surprise!, they use the same injectors. The power is limited by limiting fuel quantity.

i guess im not grasping it. if you have to limit the fuel on an 06lly to match that of a 05lly does that not mean there was an increase of injector size? or what else was increased to give the bump in power but needed fuel to be limited to equal that of an 05lly?

 

[Chevy1925]

Tree'd... oke:

bastard :rofl:

 

[quinton]

Ahh ok. I thought the lmm had the 7 holes. Misinformed

 

[JoshH]

i guess im not grasping it. if you have to limit the fuel on an 06lly to match that of a 05lly does that not mean there was an increase of injector size? or what else was increased to give the bump in power but needed fuel to be limited to equal that of an 05lly?

I'm not saying anything about power for a given amount of fuel. I'm talking about pulse width at a given pressure and fuel quantity. I don't know the exact formula for calculating flow through a fixed orifice (I'm sure someone like Fingers does, maybe he'll see this and post some info), but if you keep all the variables the same, then the largest orifice will flow the most fluid in the same amount of time. By that same logic, the largest orifice will flow the same amount of fluid in the least amount of time. So let's look at the information I posted earlier. With the fuel quantity being fixed at 90 cubic millimeters and pressure being fixed at 160 megapascals, the LB7 injector has the shortest pulse width of all the injectors. What this tells me is that the LB7 has the highest flow of any stock injectors because it takes the least amount of time to flow the same quantity of fuel. On the same hand, the LMM has the longest pulse width, so I believe it has the lowest flowing stock injector nozzle.

It is my understanding that GM did not just make up the pulse width tables with numbers they felt like putting in them, but they are actually calibrated to the flow rates of the stock injectors. Maybe I'm mistaken, but if that is correct, I'm posting what logically makes sense to me. I could be wrong here though.