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Discussion Starter #1
Hello everyone. I am hoping to get a little clarification on injectors for the truck listed in my signature. When I began to build this truck my plans were quite simple, however things evolved into what it has become now and I feel as if I need more fuel to support the turbo set I ended up running. I have decided to sell my current 5x12 injectors and replace them with something larger. When I bought these injectors about 2 years or so ago the options were not what they are now. I do not believe I ever saw a 7 hole injector for a 12v Cummins. Well now that I'm back in the market I had plans to buy a set of SDX 5x14 or possibly 5x16 injectors and use the fuel plate to limit max fuel if needed. I know that SDX sells quality injectors and I'm sure I would be happy buying from them. Now to my questions. Who is making 7 hole injectors for a 12v? Would I really see a benefit in running a 7 hole vs a 5 hole injector? Are 7 hole injectors priced near the same as 5 hole injectors or are they some crazy priced custom jobs? I am looking for a little more fuel then I currently have but at the same time I don't want to buy too small like I did last time. Perhaps plans for the truck will change and I would have to go out and buy an entirely new set again. Lastly, hypothetically speaking, if I needed all the fuel a 5x14 injector could provide, would I be hurting performance by running a 5x16 injector while using the fuel plate to limit maximum fuel flow to that of the 5x14 injector? If I went that route I would always have a little fuel in reserve in case I decided in the future to get a little wilder with my setup (As has happened once already). Thanks for any input, I appreciate your assistance in making what hopefully turn out to be my last injector purchase.
 

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It depends on the nozzle of the 5 hole, but typically its a VCO style (though you can get them in SAC now), but the 7 hole's are SAC style, which will give you more power. After running a couple different 5 hole injectors, Id definitely go with the 7-hole, more power with the same driving characteristics.
 

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Funny you should ask this question-I'll be installing a set of 7 holes in my '98 12v today, replacing the incorrect spray pattern marine 370's that are in there now. I don't have any experience with most of the other vendors, but I bought mine at CPP. I think they were $500, which I felt is fair. Jamie (the owner) seems to be the only person who answers the phone, so you get the one person who can help you when you call. He's very nice to deal with and will take the time to talk with you about your truck and what you want it to do. I also asked him whether he pop tests his injectors. He told me that he not only pop tests each one and sets as needed, he also flow matches them. I don't know whether that means he tests different injectors and then groups them based on flow, or that he can actually adjust flow some way. I suspect the former. I should hopefully know how they run early this afternoon.
 
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Discussion Starter #4
Thanks for the help so far. And be sure to let us know how much of a differance the new injectors make in overall fueling but more importantly, idle quality and haze if any.
 

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It depends on the nozzle of the 5 hole, but typically its a VCO style (though you can get them in SAC now), but the 7 hole's are SAC style, which will give you more power. After running a couple different 5 hole injectors, Id definitely go with the 7-hole, more power with the same driving characteristics.
:agree2:

Here's some more details comparing them.
 
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Love my 7x.10

I spent 350 shipped on mine which was about 75 dollars cheaper then the 5x.12. While I have little experience with other size injectors, I am very happy with these.
 

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Hello everyone. I am hoping to get a little clarification on injectors for the truck listed in my signature. When I began to build this truck my plans were quite simple, however things evolved into what it has become now and I feel as if I need more fuel to support the turbo set I ended up running. I have decided to sell my current 5x12 injectors and replace them with something larger. When I bought these injectors about 2 years or so ago the options were not what they are now. I do not believe I ever saw a 7 hole injector for a 12v Cummins. Well now that I'm back in the market I had plans to buy a set of SDX 5x14 or possibly 5x16 injectors and use the fuel plate to limit max fuel if needed. I know that SDX sells quality injectors and I'm sure I would be happy buying from them. Now to my questions. Who is making 7 hole injectors for a 12v? Would I really see a benefit in running a 7 hole vs a 5 hole injector? Are 7 hole injectors priced near the same as 5 hole injectors or are they some crazy priced custom jobs? I am looking for a little more fuel then I currently have but at the same time I don't want to buy too small like I did last time. Perhaps plans for the truck will change and I would have to go out and buy an entirely new set again. Lastly, hypothetically speaking, if I needed all the fuel a 5x14 injector could provide, would I be hurting performance by running a 5x16 injector while using the fuel plate to limit maximum fuel flow to that of the 5x14 injector? If I went that route I would always have a little fuel in reserve in case I decided in the future to get a little wilder with my setup (As has happened once already). Thanks for any input, I appreciate your assistance in making what hopefully turn out to be my last injector purchase.
On a street driven truck, I wouldn't even consider anything but a 7 hole sac injector. They have more mid/lowend power for towing or daily driving, yet they hang right with 5 hole injectors up top.
 

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Love my 7x.10

I spent 350 shipped on mine which was about 75 dollars cheaper then the 5x.12. While I have little experience with other size injectors, I am very happy with these.
who did you buy those from?
 

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On a street driven truck, I wouldn't even consider anything but a 7 hole sac injector. They have more mid/lowend power for towing or daily driving, yet they hang right with 5 hole injectors up top.
I agree, outside of a purpose built competition truck I always recommend 7 hole sac injectors of an appropriate size to anyone who asks.
 

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Discussion Starter #10
Thank you guys for the info. I think you have managed to make the decision easier for me. I'm going with a set of 7x12 injectors. I have been doing quite a bit of research lately and a fellow forum member put me in touch with the guy who built his injectors. I will be placing an order for them the day I get back onshore. Thanks again for all the help. I'll keep you guys informed as to how things work out.
 

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Thank you guys for the info. I think you have managed to make the decision easier for me. I'm going with a set of 7x12 injectors. I have been doing quite a bit of research lately and a fellow forum member put me in touch with the guy who built his injectors. I will be placing an order for them the day I get back onshore. Thanks again for all the help. I'll keep you guys informed as to how things work out.
:thumbsup:
 

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Discussion Starter #15
It'll be sometime in early to mid February But I'll be sure to post back to let everyone know how it works out.
 

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If you're looking for more fuel, then a set of DVs might help you out. I was running the 5x12s w/181s for a while and wasn't getting enough fuel. Then I switched out the 181s for a set of 024s, big difference!!!
 

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I'm trying a new nozzle through "the asian" that's supposed to be 7x11. Should have em in sometime late next week..... I also bought a set of 7x10 for a customers truck. Should have them in by Friday.

7 holes will have a smaller hole than a 5 hole of the same horsepower, so theoretically they'll atomize better and net better fuel economy and quicker spoolup too. That's going on what others have told me. Haven't tested for myself yet.
 

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Discussion Starter #18
If you're looking for more fuel, then a set of DVs might help you out. I was running the 5x12s w/181s for a while and wasn't getting enough fuel. Then I switched out the 181s for a set of 024s, big difference!!!
To be honest with you, the whole DV thing confuses me. I mean I understand that the shorter the shoulder on the DV the "Harder they fuel" but I also know that larger injectors also fuel harder then smaller ones (Barring injectors with lift work etc.). I'm not completely clear on the role the DVs play in driving characteristics. Would a 024 DV Fuel harder then a stock DV on a stock engine?.. Yes. But at what point do you upgrade DVs rather then injectors? Or vice versa? This has never been clear to me and searching for that info has been a struggle. I have decided to go with injectors simply because 1) I know my 181 DVs are better then the 131s I had and 2) I know that decent power has been made with 181 DVs and 3) I have a better understanding of the injectors role in fueling then I do the function of the DVs and the role they play in the overall scheme of things. Thanks for the suggestion though. DVs are not out of the question yet, but injectors are DEFINITELY my next modification. Perhaps someone knowledgeable will be able to explain IN LAYMENS TERMS the DVs role and how changes will effect operation rather then simply stating that "x DVs fuel harder then y DVs". Thanks again for the help.
 

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The DV is a valve that patially controls how much fuel is delivered to the injector. Think of your injector as a nozzle on a garden hose. The more you open the water valve(think DV) the more flow you get out the nozzle, even if the nozzle setting remains the same.

There's very little difference between a 131 and 181. And while it is true that you can make big power with 181s, it's easier to do with higher flow DVs. It depends on the pump too, 181s in a 215hp pump is good fueling, 181s in a 160hp pump, not so much.
 

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Do big injectors with stock delivery valves start to choke up? If so at what size injectors?
 
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