I was reading some articles in Diesel Power mag and had some questions about the injector nozzles on the 6.0 PSD. As I understand it the way a nozzle is listed is (number of holes)X(hole size in thousandths of an inch). So an injector nozzle that's listed as a 6X9 would have six holes of .009" each. What are the injector nozzles on a stock 6.0 PSD?

In one article about mechanical injectors they showed the nozzle being removed (actually the whole injector was disassembled) and cleaned with a tool that held a fine wire made for the task. Can the nozzles on a stock HEUI injector be removed like that? If so, can they be replaced with other nozzles with a different listing? Could you replace a 6X9 nozzle with something like 8X6.75 or 10X5.4? Both of those would have the same total surface area as a 6X9 nozzle, but would they have a better spray pattern and better atomization? Would going to 8X7(+3.7%) or 10X6(+11.1%) come close to a Spartan Stage 1 towing injector? When I see all the ads for higher flow injectors I wonder if it's just a different nozzle on the same injector body or if it's a completely different injector with different internals and everything.

Would raising the fuel pressure cause a similar effect as going to a slightly bigger injector? If you ran a FASS or Air Dog to feed the OE fuel pump (or maybe not if they can supply enough flow at that pressure) and a regulated return set to let's say 85 psi, would that do the trick? Kind of like a "poor man's version" of getting some added performance without the expense of new injectors. Would this cause better atomization of the fuel and give better mileage?

At this point it's just a theoretical exercise meant to engage folks in a discussion, but may bear on decisions down the road about what to do when upgrading my truck.... As always, any and all input is appreciated!!

 

The o-rings begin leaking above 75 psig.

 

No, you can't make a silk purse out of a sow's ear. FASS and AirDog make pumps that are direct replacements of the factory and are designed to handle higher flow situations. Also, the fuel pumps are self-regulating by a spring and the most pressure I've seen that those springs for the pumps can handle is 60 psi. You can go higher on the RR, but ITP recommends 60 anyway, I think the ATS version is 70.

However, you are limited to what the injector can do. There are a few components that are changed to a degree, but the biggest is in fact the injector nozzle and blow off valve being closed(that's about 15mm^3 right there). Even if you increase the pump flow on stock injectors, those stock injectors are still only allowed so much fuel through them due to both their size and their programming. You'll be helping the life of your injectors by doing this and there will be a little bit of gain, but not 90 hp worth it which is what those Tow Injectors give approximately.

 

Thanks for the quick response. So then the upgraded injectors are built with different internals? This is my first diesel and even though I've had it for three years I never reached the point of upgrading the fuel system. I have a ton of filtration and other reliability upgrades and was looking towards fueling as the next area to improve. I think the RR system will come first then a pump unless I can swing them both when the time comes.

Tex, it looks like you have about what I'm looking to end up with. How do you like the way your truck performs with those mods?

 

Hehe I know of a new design on the 6.0 injectors by my builder but im not gonna say anything lol. I'll be testing the new 3rd set.

 

Casserly has a new design that so far is doing pretty well. His Stage 1s have shown to be able to flow about 15% more then the ones that I first got. I can't really go any higher then those due to I still need to haul horses and other ag. goods.

Some, but not all. Some are just coated to be able to withstand the harsher environment of a hotter application(or even just be able to handle junk in the fuel better then stock).


Please don't tell me that one of those filtration mods is an a/m intake at this point? With bigger injectors you could make use of it, but not on a stock or just tuned truck.

I love it. It handles towing quite well, but the type of turbo I have on there helps that out as well. EGTs are alot better then what you would imagine to be the case.

I wish Matt was still tuning for SCT, because he had a really good Street Comp tune for these injectors that was really fun to drive. I still have a copy of it for SCT devices, but I just can't swear to what strategy it's for. I have my strategy changed a couple of times since then.

 

LOL crap. Yeah im gonna be doing the first set of 205's.

 

Oops, didn't realize that it was his you were talking about.

 

I believe Beans is testing his 175 currently and building a set of 190's next to test, then 205 for me. Lol Yeah I talk to Casserly weekly.

 

Elite has 8-hole injectors now, but I don't know about the hole size.

 

You dont want me to comment on that.

 

Yes, please explain.

 

I know who's idea that really was. But I aint gonna stir the pot Cart if you really wanna know pm me on the nation or the chat room

 

Oh come on. You should know that I of all people like a good pot stirring every now and again.

 

specifically to the fuel pressure issue. the heui injectors are similar to a syringe. they fill with fuel and push it into the cylinders. this can hapen several times during a combustion cycle. upping the fuel pressure will not change the amout of fuel the syringe will fit. most people that claim mpgs on injectors are both better and worse there is no consensus