i've seen various post lately claiming that an edm injector will burn cleaner than and extrude hone. I would like to know why. especially considering that extrude honing makes a much smoother injector hole. I'm up in the air between ddp 4's, new era 435's, or a set of custom 5x16's. the ddp's seem to be the highest quality injector, and they flow match each injector by lpm instead of hole size. so anyone with personal experience what would make more power out of the three I listed? Also merits of edm over ex hone. fyi factory injectors use an edm'd tip and are extrude honed to finish them up.

 

Well, with the little knowledge I have about fluid dynamics and other principles od injection systems, here's my take on the subject!

There are many ways to EDM...as far as I know, some machines can make a "smoother" hole than others, and different methods of using the machine can achieve different results or finishes!!

To me, a "sharper" edge will tear through the liquid, making a finer mist...which makes a cleaner burn, and less smoke for a give fueling and power level!

Does it make sense...to me yes. To someone more educated in Fluid dynamics and such, I may be way off??

Chris

 

Good question, I too would love to hear input on this from some of the gurus
Don are you up for it?

 

I'm no Don (a fact I'm sure he's thankful for), but here's my take:

The rounder the hole, the better. The sharper the edges are, the better-- to a point. You don't want any stress risers or weak edges. That's why the factory sticks are honed to finish them.

There's nothing inherently superior about an EDM or honed injector. There are nice EDMs that will outperform cheap honed sticks, and there are nice honed ones that will outperform cheap EDMs.

Unless you are talking about a custom nozzle that's purpose built for EDMing (ala Don M), do not EDM! Only hone. There are more than a handful of cases where stock injectors with additional holed EDMed into them have failed-- causing engine failure of the catastrophic sort.

EDM give more flexibility to a nozzle designer to make a nozzle that reflects HIS priorities, not the OEMs priorities. I assure you that Bosch isn't optimizing CTD sticks for the flow rates we are trying to get out of them. RV275s aren't designed to flow what a Mach 6 will.

Changing the fuel flow rate also changes the optimum spray angle and hole count. Different timing also changes this, too. There is ONE optimum injector design for a given set of operating conditions-- everything else is a compromise.

For example, an injector designed for minimum smoke and power with 0-10psi boost might have a lot of holes and a shallower angle. But when boost comes up into the 30+ range, it will smoke like nuts and lose power.

Conversely, you can optimize a stick for big dyno power at high boost levels and it will smoke more off idle and at low boost.


With a honed injector, you can perform a great job of balancing them, but you can't change fundamental design parameters like spray angle and number of holes.

In the right hands, EDMs can be great. But the EDM will never be better than the person who's doing the design work.

What makes Don's sticks good is not the fact that they are EDM-- it's what EDM allows him to do with his fertile mind. Fertile, because of all the BS coming from it...

JUST KIDDING DON!

Balance matters a LOT in a set of sticks, but once that's achieved, a hone job has basically done all it can do.

JMO

 

I would think an EDM hole would be more "blueprint" perfect where an extruded hole's location and roundness could vary due to the density of the metal surrounding the hole.

 

If honda can have VTEC, variable valve timing and electronic lift control...

then why cant we have VINSPEC! Variable Injector Nozzle and Spray Pattern Electronic Control.

Sounds good to me. Who wants to make some tiny tiny electronic valves for the injectors?

 

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No chance in **LL my 12v will ever see any electronic BOOHO stuff in it

 

That come with a wing?

 

Then everyone would be putting VINSPEC stickers on Duraturds and Powerjokes...like they do with VTEC sticker on Mustangs and Camaros around here

 

[cough] avatar thief [/cough]

 

"Imitation is the sincerest form of flattery"
BTW, if you didn't create that smiley.......you copped it from somone else too.......

 

touche...

I did find it and had it for a while... then modified it to fit the 65x65 restraints.

as for the question, I agree with HOHN...

"With a honed injector, you can perform a great job of balancing them, but you can't change fundamental design parameters like spray angle and number of holes."

EDM is a much more 'controlled' way of machining a nozzle. Flow matching a set of honed injectors can make up for some of the variances in the process, but with an EDM injector (in the right hands) you can machine it to much closer tolerances.

 

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HAHA Ive actually been using it for quite a while but every time I shrunk it down it stopped doing the burn-out so after I seen you had done it I scooped it up right away Good work. At 100x100 there are many really cool ones that I have seen

 

so in the right hands edm could be better however no one is really intrested in 12v injectors due to the limited market? I know don has m4's but no one uses them. he also has honed 370's but how does honing a 370 due anything to help it's poor spray pattern? to me it seem ddp4's are the only viable option besides $1700 customs from buddah

 

Don't that is quite correct. In some circles the M4 is quite popular.

Jim