Some Help With Injectors

[RSWORDS]

Hey guys, over on Diesel Bombers we are haveing an disscussion about 1st gen injectors and sizes.



This post was put up buy Smokem (Weston) he makes some really good injectors for 2nd gen truck and SWEARS that 6 holes are a waste of time on 1st gen trucks. here is his post

Look at it this way, Bosch quit using the 6-hole design in '94, even though the angle of the jet did not change. There are a few reasons, the technical term is known as low lift needle deviation. Basically, when the valve opens the needle is side-loaded which causes 3 holes to fire, and 3 holes do not. Also, the 5-hole design suits the offset incline pattern found on the 12v injector/combination. Hole size does not seem to be as important on the VE equipped engines, I believe soley due to lack of fuel quantity

Can some of you that are smarter about injector tech tell me if you agree or risagree with that statment...

[bgilbert]

How many 1st gen high horsepower customers has he built injectors for? You never know, he maybe right. Since I'm using a 6 hole nozzle with a piston that was designed for a 4 hole nozzle. The recipe for 500+hp is out there for a 1st gen though. All these guys trying to reinvent the wheel and haven't even broken 350rwhp . As kta used to say, try it and report back to us .

[Richie O]

I don't know spit about injectors and I admit it. One thing I did catch was he said the angle did not change in 94. I read all the time that the the spray angle is different in 94 and up compared to ours. Whats the deal??

[RSWORDS]

I'm not sure,

[ford69557ci]

Yes the spray angle is different between a p pump and ve engine. Lack of fuel quantity? I think there are some ve pumps out there movin a decent amount of fuel these days. I dont know if it was the size of the holes or the amount of holes, but my 6x18's sure made more power than my 435's. On a lower flow lower pop pressure pump a 6 hole stick will burn cleaner than a 5 hole stick of the same flow rate.

[Richie O]

As I say, I don't know. I wish I had more knowledge of this stuff. I love reading but when you read something that is wrong and repeat it it snowballs. I did put fuel in my truck today all by myself.

[ford69557ci]

I do believe my factory non IC sticks were 4 hole, I have never pulled the ones on an IC 1st gen, but I am pretty sure they are not 6 hole?? So where is he gettin that cummins stopped using 6 hole injectors in 94?

[Mark Nixon]

....I did put fuel in my truck today all by myself.

ROFLMFFAO!!!
Fortunately you live in a state where it's legal to handle a hose nozzle, you could have even been doing THAT wrong in Oregon!

Good job, Richie!

Mark.

[peobryant]

I though the spray angle on the I/C trucks and P-Pumped trucks were the same? Ours our 145* while the Non I/C trucks are 155*. That's what I've read anyways.

The Non I/C trucks ran 4X.012 injectors, the I/C trucks ran 6X.009 injectors and the 2nd Gens use a 5 hole injector.

[diesel freak01]

im not any kind of an injector man but i will say that i have read ppl taking nozzles from 2nd gens and putting on 1st gen bodies so that tells me that the angle is the same or relativly the same. i thought the ic injectors were a 5x9? i think you guys are right about the 4x12.

[ZSkibo]

Seem like he knows what he's doing. I will report what I see from my 5x18's he's building for me now. Should have them in before the end of DEC.

[KTA]

P-pumps run higher injection pressures and rates than a VE. Cummins went from a 4x.012 to a 6x.009 to reduce emissions while making the same power. It costs more to make a 6 hole than a 5, and thanks to higher pressure fewer holes is needed so they switched to a 5 hole for the p-pumps. There are many factors that go into optimum hole size, spray angle, and hole number. These factors are fuel quantitiy, injection time, injection rate, swirl, combustion chamber design, atomization, fuel viscosity, charge density, and a few others.

[Richie O]

P-pumps run higher injection pressures and rates than a VE. Cummins went from a 4x.012 to a 6x.009 to reduce emissions while making the same power. It costs more to make a 6 hole than a 5, and thanks to higher pressure fewer holes is needed so they switched to a 5 hole for the p-pumps. There are many factors that go into optimum hole size, spray angle, and hole number. These factors are fuel quantitiy, injection time, injection rate, swirl, combustion chamber design, atomization, fuel viscosity, charge density, and a few others.

So KTA, the question of the day is : Are the spray angles the same between a 91.5 through 93 truck and the 94 up p pump? Also is the non cooled trucks different than all of the above?

[KTA]

I have sets of each so I will have to take them apart and check to verify for sure. At one time I knew for sure off the top of my head, but I believe they are all 145deg on 1st gens despite the hole size and number diffrence. I will try to hunt them down tomorrow in the garage and look.

[Ace]

On a lower flow lower pop pressure pump a 6 hole stick will burn cleaner than a 5 hole stick of the same flow rate.

IOW, all other things being equal, more smaller holes will create better atomization than fewer larger holes.