LB7: Who's injectors, & how big?

DAVe3283

DAVe3283

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Sep 3, 2009
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Injector brand/size recommendations

Short version: 16.5:1, big cam, SoCal Stage 1 heads, S371. Twins planned in a year or two. I need injectors. What size and brand should I get?

Long version:
Long ago, I got Trent's S371 and Industrial Injection +60% injectors. It ran well enough for 60k miles or so. I then took the II injectors out and put them in my brother's truck (where they still run great), and built my motor. Mahle race cast 16.5:1 pistons, Carillo rods, COMP Cams' biggest cam, SoCal Stage 1 heads, RDL up-pipes, Exergy 12mm CP3. Stuck with the S371 turbo, planned on twins down the road. I got a set of used "Extrude Hone +100%" injectors, supposedly with only a few sled pulls on them. I had them sent to Exergy to check/balance, and they came back "good". Well, here I am not even 10,000 miles later, and the injectors are toast. Massive white smoke at idle, increasing black smoke on acceleration (and now just cruising on the highway), the works. I have bumped fuel pressure at idle to 60 MPa and it still smokes white a bit.

I had initially picked +100% injectors because I planned on twinning the truck around now, but that won't happen for at least another year or two thanks to these injectors taking a dump. :mad:

Should I step back down to +60% sticks, which seem to last 80k+ without issue? They won't support as much power once twinned, but they seem to last. Or did I just get a bad set of the +100% (don't buy used kids...)?

Ideally, I would like to buy a set of injectors that will last 5 years and at least 80k miles, and support ~1000 HP on twins. Truck is used to tow/haul, drag race (just for fun); mainly a street driven rig. What do you guys recommend for injector brand/size?
 
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Hot COCOAL

May the farce be with you
Jun 9, 2012
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I'd bite the bullet and get a new set from LSD, continue to save for your twin kit and send those new injectors out to exergy when you're ready:hug:

Or

Hope to find a deal on a set in the garage sale thread ;)
 
DAVe3283

DAVe3283

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I'd consider the LLY swap, but then I'd have to get the heads ported just to be back where I am at now. Plus all the wiring changes. I'd really rather not do that if I don't have to.

It seems lately large Exergy Injectors aren't holding up. Maybe I'll go back to Industrial Injection sticks. The set of 60 overs I bought 5 years ago are working great in my brother's truck still. Not what I expected, to say the least.

I think I could live with 75% overs, which will hopefully survive longer than these 100s did. Keep the info coming guys, this is helpful.

Sent from my FlashScan V2
 
DAVe3283

DAVe3283

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Brent@LDS said:
I would be more than glad to get you a quote on a set of injectors. Let me know if we can help.
Click to expand...
I see you offer oversized injectors now. Is that something you do in house, or is it another brand (Extrude Hone, Exergy, etc)? What kind of warranty do the oversized injectors have? You can reply by PM if you prefer.
 
DAVe3283

DAVe3283

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Sounds like 75% overs or so should make the power I want. Thanks guys for posting your real-world numbers!

Is there a certain size injector where the bodies get modified vs. just the tip? I have heard that above 75%, the bodies have to be modified which can reduce lifespan. Anything to that?

What's the lowdown on the SAC type vs VCO? Reading it seems the Cummins guys say the SAC type atomizes better and makes power with less smoke (this is good), but hazes more at idle than VCO. That doesn't make sense to me. How can it atomize better but haze more? Though if they make power cleaner or even just last better, I'll deal with some haze at idle.
 
THEFERMANATOR

THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
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Sac nozzles have the sealing area above the actual nozzle orifices in a cone shaped sealing area similiar to a valve in a cylinder head. A vco nozzle has the actual valve sealing the nozzle openings directly at the openings. Sac nozzles will hold some fuel between the sealing valve and the orifices(depending on design can vary how much fuel is in this pocket) whereas vco nozzles do not. So a vco nozzle in essence is supposed to have more precise control since theres no dead space for fuel to sit in, but the tiniest bit of debris or soot pushed back up the nozzle can hang them open since the sealing area is directly against the orifice openings. Ibelieve the lly+ use a sac nozzle with what is called a micro pocket where there is a tiny amount of fuel below the sealing area, but some sac nozzles have larger areas below the sealing area to orifice openings, and this can cause fuel drobbling out after the injector closes, and extra latency in operation.

So when researching sac type nozzles, you need to know which style you're researching to compare to. I know I'll be putting in a set when my stockers go out.
 
DAVe3283

DAVe3283

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Sep 3, 2009
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I ended up picking up a set of SAC (Motorsport) +75% injectors from Lincoln Diesel here on the form. Their reputation for customer service is well deserved, that was one pleasant transaction, and they even threw in a couple unrelated gaskets I needed for free!

I'll do a post on the injectors themselves in a few days once I finish the tune, but the initial impressions are VERY positive. Glad I went with the SAC-style tips.
 
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