Lets discuss Injectors, big fuel

[McRat]

Right...........


That must be why they are used in built motors

First cracked piston I ever saw in person was an LLY engine with 40hp Predator back in '04.

There are members of this board who have cracked LB7/LLY pistons.

 

[[email protected]]

How much rpms are people turning when they hurt pistons?

 

[skintback]

I cranked #8 piston while gassing it a little driving down the highway
I bought the truck brand new and had a tuner in it before i left the dealerships lot from there it was about more power and go faster

2005 CCSB 4x4 running EFI live
injectors stock
PW 3000
timing 32*
1 LBZ pump with modded reg
stock turbo
stock motor with head studs
Air dog 150

 

[fishsmith]

I cracked #6 running down the road at about 75mph. Although I had pulled my 5th wheel hard the day before. I was running Dmaxtuner tune. I think I got mine the day before and just finished it off the next morning. I had started playing with w/m, but I ran straight water in it while pulling. All stock injectors, turbo, cp3.

 

[calabria69]

so with more air flow, is there a more specific amount of timing and PW??? can you use a little less timing and more PW?? just in the learning stages, this is a great thread.....

 

[05smoker]

How much rpms are people turning when they hurt pistons?

I have heard of several cases where they were cruising along at lower RPMs (2k-ish) but it was shortly after they were running it hard or racing it.

I'm more of a fan of high timing than too low. I think a lot of PW and low timing (high smoke and high egts) are worse than most full on race tunes. Just my opinion, not any data or fact. I think Pat has mentioned somewhere before that he saw some break at 20 degrees timing before we had the ability to raise it higher.

 

[duratothemax]

Motor #1 (factory)

What happened- 2 pistons cracked all the way through, big cracks starting on 3 others

How many miles at this level- 85,000, abused daily

#1- Injectors- STOCK

#2- PW- 3200

#3- Timing- 27*

#4- Fueling-SINGLE UNMOLESTED CP3

#5- Turbo - couple different ones, BD, HTT, stock

#6- Motor built or not- NOT

#7- LIft Pumps - twin kennedy's



Motor #2

What happened- 2 broken rods, the rest of them were all bent Bearings, pistons, and everything else looked flawless.

How many miles at this level- 16,000 miles, abused daily, because you should be able to abuse a built motor without worries, duh.

#1- Injectors- STOCK

#2- PW- 3300

#3- Timing- 29*

#4- Fueling-SINGLE UNMOLESTED CP3

#5- Turbo - MPI twins

#6- Motor built or not- YES!!!

#7- LIft Pumps - twin kennedy's



Current engine:

Runs perfectly, has almost 18,000 miles on it.

#1- Injectors- Big Dipper

#2- PW- whatever stock LLY is, 1400? I forget

#3- Timing- stock LLY, 11*??

#4- Fueling- stock LBZ CP3; 26,000 PSI

#5- Turbo - MPI twins

#6- Motor built or not- stock LBZ short block, LLY heads, head studs, keyed cam

#7- LIft Pumps - twin kennedy's

.....

ben

 

[[email protected]]

I don't know a lot at all, but airmass (grams per cyl.) drops off a lot as rpms rise, but airflow increases. Since airmass decreases if you fuel the same you will have a lot more fuel than air.

In my tune I cut back fueling a lot to keep the air fuel ratio consistent. When I cut back fuel (pulsewidth) it also cuts back timing that is required for that pulsewidth. This is at higher rpms where it looks like problems with fuel spraying to early and too late are complicated with rpms.

I havent noticed any loss becuase of cutting back fuel at high rpms either.

 

[Huntinducks82]

What are some problems guys are havin after injectors. I have read this thread and others and have not seen any down side to runnin them. I plan on buildin my truck into a 2.8 pullin truck this winter and would like to hear about problems that come with injectors as i plan on gettin a set from BIG DIPPER.

 

[steakman]

Motor #1 (factory)

What happened- 2 pistons cracked all the way through, big cracks starting on 3 others
Nothings happened...YET.!

How many miles at this level- 85,000, abused daily
me - 143,000..treated nicley - it makes me $$$
#1- Injectors- STOCK
Same
#2- PW- 3200
Stock..??? How does one measure that.?
#3- Timing- 27*
Stock..?? Also - how to measure.?
#4- Fueling-SINGLE UNMOLESTED CP3
Same - Stock
#5- Turbo - couple different ones, BD, HTT, stock
Stock
#6- Motor built or not- NOT
Same - stock Engine
#7- LIft Pumps - twin kennedy's
None - About to order an Airdog100

So, basically I know nadda bout the engine itself..at least to the depth discussed here. (facinating to be sure). Question for you guys:

I run a Banks 6 Gun pda set up. It was suggested to me for mild tuning/no wild fuelling & combined it with a Transgo Jr in the Ally. I'm about longetivity not racing. Not in the abuse club..wihich is not to say it doesn't get worked...it does, from time to time by pullin my travel trailer.

Typically I run it (banks), at level 2 and the very odd time will go up to level 4/5..not often though. So, do I need to worry about internals (pistons/rods), at this time.??

Fluids - Filters et all, get done on a regular basis.


Thank you. Super thread..!

 

[ZeroGravity58]

How many miles at this level : 10,000

#1- Injectors: Big Dipper 25%

#2- PW: 2500

#3- Timing: 21* at 3000 RPM, 27* at 3800 RPM

#4- Fueling: stock LB7 with LBZ reg

#5- Turbo: 4094

#6- Motor built or not: Not

#7- LIft Pumps: Kennedy twin pumps

By going with injectors i cut 7* of timing off at 3800 RPM's and dropped my PW by 650. i also picked up 3 tenths and 3 MPH at the track....IM not a big fan of big PW. i only ran a few thousand miles with a 3000+ PW before putting in injectors.

 

[JD4440]

How much can PW be reduced by using 100% injectors ? I've noticed these coming up where as I used to see only 40% / 60% .

 

[Drholliday]

How much can PW be reduced by using 100% injectors ? I've noticed these coming up where as I used to see only 40% / 60% .

I was talking to Dustin About this yesterday b/c he is running the 100% overs, and its what I'm planning on running. The topic came up about stock power levels with the 100 overs. He guestimated that it would be well under 1000 pw for a stock powered tune, possibly as low as 500. And if you think the stock tunes are around 1400 max pw IIRC. Thats a pretty big reduction.

 

[JD4440]

Guess I need to get with Brayden sometime and price me some options. Thanks Chris

 

[sweetdiesel]

So, basically I know nadda bout the engine itself..at least to the depth discussed here. (facinating to be sure). Question for you guys:

I run a Banks 6 Gun pda set up. It was suggested to me for mild tuning/no wild fuelling & combined it with a Transgo Jr in the Ally. I'm about longetivity not racing. Not in the abuse club..wihich is not to say it doesn't get worked...it does, from time to time by pullin my travel trailer.

Typically I run it (banks), at level 2 and the very odd time will go up to level 4/5..not often though. So, do I need to worry about internals (pistons/rods), at this time.??

Fluids - Filters et all, get done on a regular basis.


Thank you. Super thread..!

Steak

Im biased but i wont run a canned tune,Most of us on this site run custom tunes via EFI We have the ability to know how badly we are destoying are motors with the logging capabilities. It will tell us the timng and mm3 and duration of the fuel shot( for the most part).

Your Banks is a different story all together because it fools the factory sensors....Not many people blow motors with a Banks tuner.....They also dont realize the potential of these trucks though


IMO and i run tunes in cold weather......you need to adjust for the ECT and IAT....not many tunes do this This is one of the many things EFI live does.

Lot of people think EFI is for the power junkie,But its really for anyone that wants to CUSTOM tune ther trruck to it BEST potential

 

[steakman]

Thanx Sweet.

I understand timing being degrees before TDC and ATDC. mm cubed being actual amount of fuel going in...and at what point in the stroke. I would love a clear explanation of Pulse Width - at least in relation to these engines. is that infact (above), what it is.?

I see guys commenting on 3000, 2000 etc. ..am guessing that is in milliseconds and the total elapsed time of the fuel shot. My reading leans me to believe that this amount of time is reduced with larger injectors due to larger amounts of fuel going in over a shorter time period. 100% over - 60% etc. over are percentages of size increase over and above stock injectors.

So it seems there is far more room to play as far as the actual time one injects fuel: Using a said amount of fuel with larger injectors as opposed to adjusting fuel amounts with a stock injector..right.?

is gonna take some time to figure...hope Im on the right track of understanding.

Theo

 

[ZeroGravity58]

Thanx Sweet.

I understand timing being degrees before TDC and ATDC. mm cubed being actual amount of fuel going in...and at what point in the stroke. I would love a clear explanation of Pulse Width - at least in relation to these engines. is that infact (above), what it is.?

I see guys commenting on 3000, 2000 etc. ..am guessing that is in milliseconds and the total elapsed time of the fuel shot. My reading leans me to believe that this amount of time is reduced with larger injectors due to larger amounts of fuel going in over a shorter time period. 100% over - 60% etc. over are percentages of size increase over and above stock injectors.

So it seems there is far more room to play as far as the actual time one injects fuel: Using a said amount of fuel with larger injectors as opposed to adjusting fuel amounts with a stock injector..right.?

is gonna take some time to figure...hope Im on the right track of understanding.

Theo

You are right. When running a stock injector with a high pulsewidth you are chasing the piston back down the bore with fuel. By running a bigger injector you can inject the fuel faster with a smaller pulsewidth and at a more optimal time. Some people will say injectors are worth it, some will say they are not. Personally i think they are worth it and my time slips say they were

 

[Alligator]

I have heard of several cases where they were cruising along at lower RPMs (2k-ish) but it was shortly after they were running it hard or racing it.

I'm more of a fan of high timing than too low. I think a lot of PW and low timing (high smoke and high egts) are worse than most full on race tunes. Just my opinion, not any data or fact. I think Pat has mentioned somewhere before that he saw some break at 20 degrees timing before we had the ability to raise it higher.

Mine happened at idle right after start up. Brother was driving it pretty hard during the day I suppose, rolled into the parking lot, shut it right off w/o cool down. I get in 4 hours later, and chugging white smoke out of the tailpipe, and shaking the whole truck.

 

[steakman]

aahhhhh..! the fog clears somewhat...! so to find said optimal time, one must use EFI .. experiment too of course. very interesting. I can see how applying this knowledge would be extremely beneficial in making a tune that would provide optimum mpg's. If that is true, then I thinks I am gonna end up eating some of my previous comments (on DP) re: mpg's on lbz's. to a certain point anyway.

I am sure that there is a lot more to writing a tune than just pw/injector size and amount of fuel etc. But I disgress. I have no holed pistons that I know of, nor bent rods that I know of...so back to topic. The defence rests

Theo

 

[sweetdiesel]

Here is a picture of a cracked piston it only lasted 370 xxx miles with high timing And improper fueling via me.