ken6881

I know the Subaru guys decap there stock injectors with good success. Just curious if anyone has decapped a 5.3 injector to see what it would flow. Got bored tonight and decapped one just to see how hard it was. Pretty easy. If I can rig up a test stand I will try to get some results. FYI I don't plan to use the stock injectors in my build but just find this interesting.

JoeNova

A few guys have started experimenting with this. They flow ~60 lbs @ 58 PSI uncapped. The hardest part is flow matching. However far they were off with caps seems to get exaggerated once you remove them. The spray pattern also goes to crap. I'm not sure how that will effect idle quality.

I've build a test flow stand so I can flow 4 sets at a time and match them up.

ken6881

Wonder if base was bumped up if it would at atimise better. I have a set of 160lb injectors for methanol but I may run it on pump gas and a small nitrous kit if they flow 60lb

JoeNova

There is no atomization without the caps, that is there purpose. It just squirts a straight stream of fuel. No misting, no cone pattern. Just a stream.

CaliboyTA

iTrader: (2)

i think this guy is denmah on this forum, but he did the flow test for decapped injectors. also he address the issue about atomizations

Old Geezer

iTrader: (3)

to add to what Joe said: Depending on the location of the inj as related to the back of the intake valve, there could be some, maybe serious wall wetting. As in the fuel running down the intake walls, creating nasty idle/low rpm issues.

JoeNova

Aftermarket injectors like Deka 80s don't have caps either, and spray a straight stream pattern.

If you can save $320 by decapping your stock injectors and getting close on flow with the same pattern, it seems like a win/win.

aknovaman

iTrader: (7)

It's old news. Flow great at WOT but stink at idle.

Ntoxicaytd

They seem close enough considering those weren't even 28lb he checked and they came back over 60 lb for basically next to nothing

imma_stocker

iTrader: (19)

Little extra info as to why subarus take this mod so well. We already have individual runner intakes with injectors pointing down into the intake ports with short travel down a straight tube (this mod is usually done with a few other things and the combination is what shines).

As others said the cap is removed to increase flow and alter the pattern from spray to faucet. Fine atomization works great with nitrous and motor. Direct stream works better when cramming 60lbs/min of air through a turbo 4 banger.

A few of the big hp guys explained to me it has more to do with shoving as much fuel as possible down into the chamber in that short window (valve timing). With the direct stream each injection has a better chance of making it to the intake ports where the high velocity of air will carry, swirl, and mix when it enters the cylinder. Dunno how true that part is but a few unrelated high performance shops explained it very similar..... they also suggested various aftermarket injectors at the same time so there's the grain of salt.