Removing spray pattern caps on injectors to improve flow.

I've made my own flow tester just to show that this works. Basically, you take whatever injectors you have now, or whatever injectors you find at a junkyard, and remove the pintle caps, or the spray pattern caps, to give unrestricted flow. Most of the caps are welded or pressed on. They have small holes in them to determine spray pattern and flow. Removing them leave an exposed pintle.

In the video, I took LS truck injectors from a 4.8/5.3. These are EVERYWHERE in junkyards, and you will find them 8 at a time. You can buy the entire truck intakes for $25-40 complete with rails and injectors locally, since most people using these engines for swaps want a car intake. Since there were millions of truck intakes produced, nobody wants them.

I take the smallest of the bunch, the 22 lb/hr injectors, and cut off the pintle caps. I then reflow them. Flow went from 22 lbs/hr to 75 lbs/hr. A 240% increase!

https://www.youtube.com/watch?v=OfJ62HtSMPc

But, do they still atomize the fuel? or is it mostly liquid going into the chamber?

They atomize about the same as any other 60-120 lb injector that doesn't have a spray cap on the end of them, which is a large portion of aftermarket injectors in that range.

They run and idle fine. The Honda guys have started using them too. They're ~14 Ohms so they work with nearly all OEM PCMs without injector drivers.

In my experience, in performance applications, atomizing the fuel well before it gets into the combustion chamber is not really that critical.  Sure it's better if you get a nice homogeneous mixture but if you're not looking at emissions or OEM levels of idle stability then it's pretty far down on the list of things to worry about. 

Alfadriver introduced this subject many years ago.  I'm surprised he hasn't posted in this thread yet.

I can say that the injector flow tester has come in handy.

Here is a set of GM flex fuel injectors I had intended on running in my corvette. Flow testing them showed that 1 didn't work, and the other 7 had flow rates all over the place. Even after removing the caps, the flow differences were even greater. A friend of mine has the same injectors in a 5.3 powered truck of his making 700+ HP.

Waiting for the V8Kid...

He did a pretty thorough demo of this at the Challenge this year. 

I need to really learn more about this, as the challenge car has some oddly sized injectors that are too small for boost.