Explain this to me

[cmann250]

12 valve injectors.

Why does everyone try to make them? If a $350 set is just as good as a $600+ set from Scheid, why is Scheid still in business? Why does Haisley run Scheid injectors in their trucks?

Those that understand, explain it in fairly simple terms please. Keep it factual and be prepared to cite sources.

Thank you.

[dazedandconfused]

Its all about quality. Scheid sticks are cleaner and make more power then the cheaper equivalent.

[bmoeller]

That would largely have to do with it, really. Poorly made tips smoke more, haze at idle (even in the summer), don't atomize the fuel as well. Poorer atomization equates to less power, more smoke, hazing, higher EGTs and potentially worse mileage.

I ran a set of cheap 370s and a set of DDP Stage 4s in my 97. Night and day difference. The DDP sticks made a bit more power, with the same or slightly lower EGTs, NO hazing in the summer (a bit in the winter), same mileage. Also got lucky, and got the 4s on sale (basically the same price as the 3s at regular price. IIRC, I sold the 370s to MMiller's brother, so it wasn't too bad to upgrade.

[skilletky]

my current injector is a 5x16, 17, or 18, not 100% sure, ddp goes by lpm, but they make quite a bit more power than my 7x15's. they smoke way less, run cooler, and get better milage. it depends on how smooth the nozzle holes are and making sure that they have the corect spray angle. ive been told that alot of places that make "cheap" injectors are using old medical equipment to edm the holes and it leaves them rough and alot of times the spray angle is off and they dont atomize the fuel very well. i asked ddp why they dont go by orfice size, and i was told that their nozzle orfices are cone shaped or kinda like an hour glass.

[RCCUMMINS89]

That's because DDP flow hones their nozzles.

But again, it's not worth the thousand dollars that they charge.

[cmann250]

BUMP! Round 2! RCCUMMINS, please explain flow honing injectors to me in simple terms. Is it like a port and polish on a head? I see this term thrown around and I'm not sure I understand it.

[ellis93]

Celeb,could we add to the discussion just what lpm is turned into as far as HP

Idid find this
ddp stg III (90 hp) = 50 LPM (liter per minute) 155° 5 hole extrude hone inj <5x12 270 bar

ddp stg IV (140 hp) = 66 lpm - 5 holes smaller than .0135 270 bar

ddp stg 4plus - no longer avail now considered comp waiver must be signed to obtain

ddp comp = 73-90 lpm depending on application same for pop

all four start out as 155° marine nozzles and are extrude honed

the flow numbers (lpm) i posted is what was printed on boxes that i received from ddp

there are posts on other forums that vary slightly with these numbers

measured the holes myself (.0135 gage would not go in a stg 4 ect)

have not used 50 or 75 hp ddp inj - have no idea what size the holes are

[RCCUMMINS89]

According to my dealer info.

stage 1 45lpm
stage 2 50lpm
stage 3 55lpm
comps 72+lpm


Flow honing is similar to wet sanding the internals of the nozzle. But it also radius' the beginning and the end of the nozzle therefore shortening the affective distance. It essentially makes the individual holes an hour glass shape. It also changes the spray pattern to the same way that shortening the barrel on a shotgun. This will make it burn better and cleaner if done a little, but can make it dirty if done a lot.

make sense or want me to explain it differently?

[ellis93]

I understand what it does,I don't understand how it equates in terms of HP tho. Really the whole HP rating of an injector is kinda BS to me anyhow,how can they even figure how much fuel is pushed to them.

[RCCUMMINS89]

HP is just a made up number..... completely made up.

[ellis93]

Rc.....how are yours flowed/checked....air or fluid?

[RCCUMMINS89]

Air.... currently I don't know anyone who does it with fluid....DAP is going to soon.... now the CR's are down with fluid. Now the flow honing media is a wet media where as others use a dry media.

Now we can find an average and constistency because he does the cr nozzles with both air and fluid..... so one can see the patterns of what fluid gains along with the air gains.

[ellis93]

I seen some treads on the "other sites",those that shall not be named where some exceptionally opinionated "guru" said that anything flowing over 5lpm was a joke

Guess he tests wet,seems fluid is harder to flow thru orifices than air?

[RCCUMMINS89]

Yes anything that flows 50 or whatever lpm is obviously air.... that would be a ton of fuel.

I agree with the fact that nozzles should be tested with fluid.... but it's not.

My builder flows the cr in lpm for air and cc's for fluid. He actually has a cp3 pump set up and the whole 9 for the common rail stuff.....

[cmann250]

It makes more sense to me know. My port and polish analogy was fairly close because (as I read it) flow honing aims to smooth things out and take some meat out of the right areas.

As far as hp for an injector, I agree that it is such a loaded number. Way too many variables. To my understanding the amount of appropriate flow honing would be linked to the quality of the EDM process, not a flat cut and dry number.

Now I know 5x18 is big and so is 72 lpm.